Ultra-reliable "stock" engine?

[Dave_Darling]

I've been toying with this idea for a while. Months, actually... The note is partly thinking out loud, partly asking opinions of Jake, and partly asking opinions of anyone else who wants to chime in.


I have a 2.0L 914. My local PCA (Zone 7) rules have a particular class that I want to run in. In this class, the engine has to stay stock in most large respects. However, modifications that are specifically for the purpose of increasing the reliability of the engine are explicitly allowed. ("Methods of ensuring oil flow" and "external oil coolers" are listed as two examples.) So I am trying to come up with ideas for a motor that would be prepared to the limit of the rules.

The purpose of this motor would be to go as far as possible between overhauls--even just re-lapping the valves--while keeping stock or better power. (95 HP DIN.) The engine would see all manner of use, from daily-driving in the city, to 4-hour freeway trips (probably running 4000 RPM in top gear), to 20- to 30-minute lapping sessions which are almost constantly at WOT from 4200-5000 RPM. All of these in air temps ranging from about 30 degrees (very rarely) up to 110 degrees.

Restrictions:
Stock-grind cam
7.6:1 compression ratio
Max. 94.5mm bore (allowed 0.5mm over stock)
71mm stroke
Stock size valves
Must run D-jetronic fuel injection
Must use 914 heat exchangers and a muffler of some kind; SSI exchangers are OK
Stock distributor (points replacement and/or CDI is allowed)
No porting of the heads, though if that were somehow only done for reliability that might possibly be allowed
Stock cooling system
...And for my own personal convenience, it must also be able to pass current California smog tests. (It won't go exempt until 2004. :( And I'm not completely confident that the jokers in my legislature won't change that again soon!!)

From reading on the Shoptalk Forums, it seems that Jake believes that using the stock cam, stock compression, and D-jet FI are very good ways to heat the heads up until you run into problems. I have dropped three intake seats (mostly due to mixture problems I think) so far, so I am worried about overheating the heads. But those are the rules I run under...

I had been thinking to run LN Birals in the stock size initially. But the prices of the production Birals came out somewhat higher than I had been anticipating, and it seems the step up to Nickies might actually be something I could stomach. ;) It is my hope that using cylinders with superior cooling properties would help on the head temperature front. I was also considering some kind of coating on select parts of the heads...

Since 914s, particularly on "sticky" tires, can generate significant lateral G forces, I need to address the oiling issue. I have been using the Weltmeister Oil Trap, AKA "the tuna can", which is a small sump extension with an oil pickup extension. It has proven OK so far, and it does not seem to be in much danger of hitting anything. But Jake disapproves, and I can see that I might be very unhappy if I go over the rumble strips a little too enthusiastically and rip the thing off. So a less-vulnerable method may be in order, like an Accusump. I figure a 1-quart (or whatever the smallest size they make) would be more than adequate.

What other oil system modifications would be in order? An external oil cooler is often recommended for time-trial cars (20-30 minute run sessions at Wide Open Throttle, 4000-5000 RPM the whole time). Would it still be necessary with the other mods mentioned? Would it be a better idea to block off the stock cooler location and only run the external cooler? If an external cooler is recommended/required, would a large fan-equipped cooler in an area with mediocre air flow that is heated by the exhaust being below it be good enough, or would a cooler with lots of cold air flow be required?

Would other coatings be recommended? Cryogenics or heat treatment? I am still, quite frankly, rather skeptical of most of the claims made for cryo treatment (my research has turned up quite a few people on each side of the debate) but I am willing to give it a try if it really will help.

Stock valves or aftermarket? They must be the stock sizes, of course, but whose?

Will having a lightweight valve train help the engine be more reliable? I can see how it could help if I miss a shift and over-rev the motor (to a limited extent, at least) but is there any point with the stock mild-mild-mild cam?

Would tightening up the deck, while still maintaining the 7.6:1 CR, be worthwhile from either a reliability or a power standpoint?

Pretty obviously I would want to use the 911 swivel-foot valve adjusters, have all of the moving bits balanced, and so on.

And finally, of course, is the question of money. Nickies will cost--yes indeed they will!! And all of the other detail work (balancing, CC'ing, 911 valve adjusters, match-porting the oil pump, etc., etc., etc.) all takes time which means money. I wonder what kind of ballpark all the above would land me in?

Thanks for any thoughts on the above!!

--DD

[Yilon]

Dave:
I myself ALWAYS ran strictly within the rules. HOWEVER, there were a lot of no-good cheaters I ran against.

Stock-grind cam: Do they mean STOCK cam or stock lift and duration? (The faster you get to max lift, the more power. If they do not do visual checks, chat up a cam grinder!)
7.6:1 compression ratio: If they mean stock combustion chamber CCs, a clever man can play with deck heights to great advantage.
Max. 94.5mm bore (allowed 0.5mm over stock)
Stock size valves: normally means stock valve head size. Some clever guys do machine work to lighten the stems. The rest of the valve train needs to be as light as practical. A good man with a grinder can do quite a bit of good here.
Must run D-jetronic fuel injection: Do they restrict throttle body size?
Must use 914 heat exchangers and a muffler of some kind: Think sttraight through here.
Stock distributor (points replacement and/or CDI is allowed): CDI is the only way to go with (of course) the matching coil sold by the CDI manufacturor.
No porting of the heads, though if that were somehow only done for reliability that might possibly be allowed. In a place long ago and far away certain people found that a clever man could port a head and then acid etch the head to make it look as if no porting had ever been done. (I mention this only so that you can detect cheaters, of course.)
Stock cooling system: If they allow 'power pulleys,' some advantage might be gained here. My own 'power pulleys' always were degree etched to aid tune ups. (No one ever seens to check the diameter of a degree etched pully.)
...And for my own personal convenience, it must also be able to pass current California smog tests. (It won't go exempt until 2004. And I'm not completely confident that the jokers in my legislature won't change that again soon!!): The nice thing about FI is that the metering sizes can be easily chaged to lean the engine down to 'pass' as long as the engine is never driven hard with the lean settings. The valve lash can be set to about TRIPLE the recommended, again as long as the engine is never driven hard.
The heads can be modified to prevent dropped seats; this is a reliability issue.
If I had the bucks, I would try to go dry sum, for reliability of course.
And the final step, for reliability of course, is blueprinting and balancing.

Is this all the tricks? This is not even the whole first chapter. However it is the first few faltering steps for a fellow GermanLook guy.

[Powerman]

Dave, I would go with an Accusump for the oil starvation problem.

[Wally]

Dave,
As a tech geek, you will probably have thought of this, but lightening the flywheel (to about 5.2 kg's) will help spinning the revs up quicker. So will ligthening and polishing the standard rods with about 120 grams each. This is done overhere by BAS and would not decrease strength, so I was told.
Good luck,
Walter

[Dave_Darling]

First, let me say that I had a nice long reply written earlier but my browser ate it. :(

Second, my intent isn't to "get around" the rules (i.e., sandblasted port work looks like no port work) but to stretch them just a little.

But the main goal really is reliability. I would like to see rather over 100,000 miles of abuse on this motor before I have to pull the heads off. Hopefully 200K or even more!

When I say "stock", I do mean stock. I can't monkey with the lift/duration of the cam, or even how rapidly it gets to full lift (I think that could compromise reliability anyway), and so on.

Sadly, the flywheel falls into what I cannot do. I can't even really lighten the reciprocating/rotating bits at all, except in the interest of reliability and balancing. (But no, taking 50g off each of the rods for "balancing" is very definitely a no-no.)

So the question remains--what can I do to ensure the maximum of reliability out of a basically stock engine that sees a lot of hard use? ... I do hope Jake chimes in on this one, even though it has been moved outside of his vendor-specific forum...

--DD

[ShApE]

i would lighten the flywheel it quickens ur revs but but lowers ur top speed

[BergRace]

Originally posted by ShApE
i would lighten the flywheel it quickens ur revs but but lowers ur top speed

"lowers your top speed" Think not!!

[kdanie]

Dave, You hit all the things I could think of.....Jake says cryo helps aluminum disipate heat, Cryo the heads, heck, cryo the whole engine. Coat the piston tops, valves and combustion chambers (I think I would do the exhaust port also) with ceramic metalic coating to keep the heat in the combustion process and out of the heads/oil. Coat the iron cylinders and exterior of the heads with a heat sheading coating to blow off more heat. Use stock size Manley valves with undercut 8mm stems, especially on the exhaust (they will build custom sizes at reasonable prices if they don't stock what you need). Stock sodium filled valves are heavy, tend to fail (according to Jake) and have huge stems. Full flow the case (search the STF for pictures or talk to Jake), use remote oil cooler with fan, remote oil filter (the stock filter mount has several sharp corners in the oil passages) and an Acusump. Run a tight deck like .035", better quench=more complete burn=more power (you are not reving real high so .035" should be ok). Coat the piston skirt, cam, cam gears, rocker shafts, oil pump with dry film lubricant (less wear and friction). Use some ARP rod bolts. I would also run forged pistons too but that's just me. Light weight valve train always helps reliability, it is better to run light weight parts rather than more spring pressue (lighter springs also free up power). For the coatings I would go to MicrCoat in Santa Rosa CA (north bay) and talk to Bruce Corneto, phone #(707) 578-4010, he's a one man shop so you may need to leave a message if he is busy.
ken

[cnavarro]

Our Nickies would most definately make it "ultra-reliable"-- no doubt there. We have some smaller bore type 4 Nickies left over from our last run that i'd be happy to wheel and deal on :-) We could set you up with some 96's and you could save some money by using Keith Black 96's...just a thought.

I'm in the process of building up my 2320 and i've gone all out and had the heads coated with a thermal dispersant and I have had the exhaust ports ceramic coated as well, as was suggested in another post. The dry film lubricant idea is an excellent one as well for the gears and even the bearings. You could go so far as coat the rods and crank with oil shedding coatings. I've looked into Calico Coatings myself; their site can be found at http://www.calicocoatings.com/ . You could most definately opt for the cryo'ing. Coating the piston tops is a mixed bag-- you'll increase the thermal efficiency but decrease the volumetric efficiency, sacrificing about 1 horsepower for a little better fuel economy. I'd personally spend the money on coating the piston skirts to reduce friction, but that might be overkill with nikasil.

One thing to ask the rulebook- do you have to use the stock intake runners and plenum, or can you swap in a different one. Our estimates show our intake should be a bolt-on 11HP with the stock d-jet on a 2.0L. Worth a try :-)

Take care,

Charles Navarro
LN Engineering
http://www.LNengineering.com

[Dave_Darling]

Jeesus! 11 HP more out of D-jet? Or your plenum will support flow up to another 11 HP? There's a difference between the motor and intake being able to flow that much air, and the complete engine (the whole system, FI and exhaust too) being able to provide it.

11 HP is a whole lot!

Sadly, I am restricted to stock manifolds and throttle body size.

I am also restricted to 94.5mm bore, so the 96es won't do me much good.

Hmm, piston squirters? Might not be worthwhile, but then again...

--DD

[BergRace]

"Coating the piston tops is a mixed bag-- you'll increase the thermal efficiency but decrease the volumetric efficiency, sacrificing about 1 horsepower for a little better fuel economy"

Could you elaborate on this please?

Thanx.

[cnavarro]

I am also restricted to 94.5mm bore, so the 96es won't do me much good.

We can make as small as a 91mm bore, fyi, out of the same blank, so 94.5 is no problem at all :-)

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

[Massive Type IV]

The engine you desire is VERY tough to make happen. For it to encompass all the things you desire, including passing California smog,being trackable,being reliable.

The class rules limit you to many things that create inefficiency, and unreliability (in my opinion)

with an engine like this, al the power and reliability must be "fluffed and buffed" into the engine. The Blueprint process means alot,as does the enhancement of the "squish",which is limited as well because you must keep the engine to 7.6:1


This is very unstable ground to base an engine from, and honestly it scares me away due to having to pass the emissions testing and etc. The 100% stock engine is inefficient.

[Mueller]

Jake, why do you say the stock motor scares you?

It's been proven to work for almost 30 years? Sure it's not the most effiecient package, but it works without a doubt, there are or were I'd say thousands of 914's going strong as built by the factory for years and years.

Had the owners taken proper care of these powerplants, I'm sure many more would be alive today (the motors and cars that is)

Dave is not asking for a specific HP level, he just wants something to run for a long time and not scatter a few years down the road. His layout for parts and ideas seems just about ideal and he should be able to obtain at a mininum stock HP leves if not a few more percent.

I am building my motor just about the same way as DD wants except I'm going for one class higher that allows me to run the Euro P/C's, so I am. [would that make me have more class than DD?, LOL]

Did you mention balancing the rotating assembly Dave?

Hey Dave, I have all new stock sized SST valves, retainers, springs, lash caps that I am not going to use since I picked up a set of freshly rebuilt heads from Jon Watts, I'll make you a good deal if you want them. Besides, after the 911 crash, I might have a 3.6 motor at my disposal :)

I do wish I had done the piston squirters, [this is something Capt Crusty did not disaprove of believe it or not] but you'll need an external cooler to get rid of the extra heat that is now in the oil.

Hope no offense Jake, this is your forum after all :)

[Tom Perso]

I think there is one hangup with this whole deal.

The STOCK cam.

From what I've heard, the stock cam retains heat in the combustion chamber for faster heatup and better emissions.

Good for passing the sniffer test but not much else.

Dave, what about rockers? Still stock?

Later,
Tom

[Massive Type IV]

yes, more or less it is the stock cam......We have a great stock engine, but why spend the same amount of time making it stock when you can build it to a more efficient 2056,have more power and etc for the same price???The temps run the same and the engine lasts just the same no matter what.

[Oliver Knuf]

Trying to build up the 100% all-purpose engine is hard. If you wish to run 200kmiles, you want something, that even Porsche never did (ok, maybe 80year old grandpa drove only 55mph straight for 30 years, but even then...)! My tips for such an engine would be....

Some words to the cam. The profile, that a German GB 2,0l 100HP 914 engine has, is a 272° cam (or US ~252°) with 106° spread, 10,9mm Valve lift (8,3mm cam lift), 2,8mm lift at TDC and a wide powerband for an original engine, that lets you rev up to 6000rpm with a good overhauled valve train. It's a good cam, that can run very well with the d-jetronic.
I would blueprint all the internals, resurface the flywheel, balance flaywheel together with pressure plate crank and gears and keys. Trick item here for me would be a very reliable and powerful Fichtel & Sachs pressure plate with an aluminum race ring, as it is nearly 2kg lighter and is totally stock in optics. You don't have to machine your flywheel. Another trick item would be a set of 57gram Witzemann lifters, as they are in stock size, look like a Type 4, but are pretty light. Together with slightly tapered pushrods, equal weight intake and exhaust rockers on straight mounted shafts (without wobby shims), together with lightened original valves ot 7mm stem valves from Schrick, a good and reliable conversion. Machining the c/chamber to a better form is hard, but possible. More sense would make 100% exact volumes. Most important for me is a totally straight case, where the main bore sits super straight and the deck heights are totally the same. Only a good machine shop can do that in real high quality. Then you can be absolutely sure to have the same c/r no all 4 cylinders and having correctly angled rods in your engine.
At least I would prefer the combination with Type 1 pistons in 94mm bore (B-type for 82mm lift) as they are approx. 120g lighter than the 914 units, are "press"-forged and dissipate the heat pretty fast.
Are there restrictions on the seat machining? First, start with new seats, bigger outside diameter. The originals tend to fall out, as they were pressed in with not enough oversize by factory!
There's a lot of power in machining the seats more "racey", e.g. radius the angles to the port and to the chamber, seat width only as large as needed etc.! Exhaust port matching to the exchangers, machining the exchangers to a straight and oval surface, maybe fitting an old 911 muffler to your 914, as the mufflers are interchangeable from the old models.
Running a small (Schadek) drysump pump is a must, as the hp and reliablility gain is worth the lost power of getting the larger gears turned. Even the cooling with the original, stock cooler is better then (having 8-12 Liter in your sump system helps :-) and maybe some harder or underlayed pressure-springs are the way to receive a more constant oil pressure under all conditions.
At least, measuring, measuring, measuring... is the most important thing you can do to obtain a 100% engine.

If I would give a quote... a German GB engine, that has original 100bhp at 4600rpm would produce with these goodies a minimum of 15ponies more with extended reliability!

[Pillow]

Mueller writ:
>Hope no offense Jake, this is your forum after all<

Actually this is everyones forum. In the R.A.T. area that could be said, but not in the general engine questions area.

So say whatever you want this should be a place for debate. Please post freely.

... Granted of course everyone should be nice to each other. But disagreement on issues is a good way to learn and undestand different outlooks on engines and their building.

[Pillow]

Very interesting post Oliver.

>At least I would prefer the combination with Type 1 pistons in 94mm bore (B-type for 82mm lift) as they are approx. 120g lighter than the 914 units, are "press"-forged and dissipate the heat pretty fast.<

I am sure the LN Nickies could be bored for it.

DD, would this pass "tech inspection"?

[Dave_Darling]

One or two things seem to have gotten lost from this thread...

First, the primary purpose of this engine would be to last and last and last through driving conditions that are the next-best thing to intentional abuse that I can think of. Power is of secondary or even lesser importance.

Second, I am not really interested in "things you can't tell are cheating". It doesn't matter if nobody else can tell, I would know and I wouldn't like it.


OK, and now a few responses to specific notes:

Charles, I know that it's not a problem to get pistons and cylinders of just about any size from you guys--my reply was to the idea of buying the spare set of 96es you had lying around. (Wish I could, but...)


Mueller, you may be able to take advantage of the manifold that Charles N. described. It might be very interesting to have a discussion with him and Shad about it... Also note that you can actually raise compression up to 8.1:1, since you're allowed a half-point over stock. It's just a tenth, but hey...

If I wind up with this kind of motor, I will probably just have someone (most likely Jake) just plain build it. I can supply core heads, and if he asks I can get a lot of the new parts (nice to have connections, yeah?) but I'll let the builder choose the exact parts. And have whatever profit there is from them--that is often part of making enough money to put food on the table... I've found that bringing in your own parts is a decent way to sour the relationship between you and your mechanic. Thanks for the offer, though!!


Tom, the rockers are not specified. However, I am certain that rockers with ratios that are significantly different from 1.3:1 (the nominal stock figure) are disallowed. I can see lighter rockers as a reliability improvement as long as I use the stock cam--because an engine with the stock cam is worthless above about 5200 RPM--but ones with a bigger ratio are a performance improvement and are a no-no.

Perhaps roller rockers might be worthwhile to cut down on wear? Or maybe not...


Jake, I agree that what I'm asking is non-trivial. That's why I'm not just slapping a motor together at home as we speak. And, at least from what I've read from you, the stock cam and stock low compression ratio are two of the larger problems with reliability. (And quite possibly the D-jet FI, too.)

But it's in Da Rules. A 2056 with carbs and a nice cam would instantly put me into a class where a lot of not-so-nice things will happen. First, I will have to have a full cage put in. Second, all of the other cars on the track with me will have huge fat tires (possibly real slicks?), suspensions with a lot of development in them, fully-braced structures, large 911 brakes, and so on. The ones that don't serve as "rolling chicanes" will have motors up to (I think) 3.0 liters of displacement. I think I would be in with the modified Sixes, also--not quite sure on that. A the very least, I'd be in with "#22", Newlin's 1400-lb semi-tube-frame car.

Uhhh, no thanks. I want a car I can drive to work, take off early, drive up to Thunder Hill, then spend the weekend flogging mercilessly. And I want my driving to be the limiting factor, not the car--I want a car that, on its own merits, has a chance. (I'm sure I won't for a good while, but part of the reason to do this is to get better.) And having a car that gives away 100+ HP and 200+ lbs, not to mention suspension and tires and brakes, in order to remain a street car, is not going to work for me. Not to mention having to pick up a trailer and tow vehicle because I can't legally drive on the streets. (Smog-O-Rama.) So that's the "why".


Oliver, I do know of at least one 2.0 914 motor that ran for 250,000 miles before it was rebuilt. I don't know how it was driven, but the owner did claim that he took it to the red-line from time to time. He certainly is the exception, though.

My 1980-vintage Porsche parts manual only lists one cam for all of the 914 motors, including the GB code ones. There used to be a web page (I wish I had saved the info from it!!) by Hugo from the Netherlands that had valve opening and closing points for three or four different "stock" cams that had been originally used over the years, and noted that they had all been superceded by one cam grind. (I don't think he counted the cams that were used in the later Vanagons with hydraulic lifters.) So your GB-spec cam is news to me.

The GB-spec motor also uses pistons that give it 8.0:1 compression. I must keep 7.6:1 compression.

(BTW, the Porsche manuals show the GB making 100 DIN HP at 5000 RPM, not 4500.)

Balancing all of the rotating parts, both statically and dynamically, is assumed. The balance might be to a tighter tolerance than under ordinary circumstances... (1 gram? Less?) Ditto the deck heights, chamber volumes, and compression ratios for all of the cylinders. I would think they would be set up on any reasonable rebuild, but that perhaps this sort of build would be to tighter tolerances.

I am still not sure about using lifters and pistons that are significantly lighter than stock. In particular, having lightweight pistons would make for an engine that revs more freely, the same way a light flywheel does. The lightened flywheel is only allowed in the next class up (the one Mueller is shooting for) and I believe that the lighter pistons would fall into the same category. Which is a shame because they would definitely reduce the stresses on the rods and crank... :(

Seat machining, at least in terms of making sure the suckers stay put in the head, should be free. But a five-angle or venturi grind on the seats is going to be a no-no.

The 911 mufflers that I've seen do not mate to the 914 heat exchangers, unless I swap to the really awful 75-76 ones. (The ones that make a tight 180-degree bend near the heads.) The 911 mufflers have two inlets for single pipes; the 914 mufflers have twin pipes going into each of two flanges. I figure a Bursch muffler setup or perhaps Triad (from Washington state) would be the way to go on that.

I had not considered a dry-sump setup. That is worth considering, as an alternative to the Accusump. I could run into problems with that if it does free up extra power. (I have heard that it takes more power to run than you gain from not having a wet sump.) Thanks to you and to Yilon for suggesting it.


Thanks for the replies!! I'm still trying to wrap my brain around this all...

--DD

[Tom Perso]

Perhaps roller rockers might be worthwhile to cut down on wear? Or maybe not...

Dave, I can't see why not. Also, are 911 adjusters allowed? I would run those just to make sure your valve adjustments are spot on.

Also, maybe adding some oiling to the heads. Shad, Jake, and I talked about this, I don't think it went anywhere (too much on everyone's plate???).

Adding some kind of oiling system to the heads could help keep temps down. Think of plumping off the end of the main bearing oil feed (it's on the driver's side of the motor, near the fan housing (now, thats for you 914 folks). Tap off of that, run a "T" and then install some squirters into the valve covers. You could be running cool oil right on the top of the head and maybe get some cooling out of it. It would return to the sump via the pushrod tubes.

Not much of a HP added, but longevity (which is what you want!)

Later,
Tom

[cnavarro]

We plumbed Shad's engine with lines going to the valve covers and we actually made all the tooling and programming for the billet valve covers, complete with the rifle bore to plumb oil to squirters aimed at the valves.

We held off on the project because they would be pricy, not to mention the aluminum will draw up some extra heat compared to stock valve covers. Our new heads will have an oiling provision to improve cooling and oiling of the valves, springs, guides, etc.

If there really is enough interest, I guess we could make a few sets for those interested, considering we have a huge stock of extruded aluminum billets to make the valve covers out of.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

[Bleyseng]

Ok Dave, I went and read the Zone 7 rulebook just to see what you could do. Not much really, except to use higher quality parts.
So, go with the nickies that alone should really help when you run autox to keep things cooler.
Blueprint this baby like a race motor where everything is as close to perfect as possible.
As for the Djet, the go to a dyno shop and tune the MPS to run at the right A/F mixtures at partload and WOT under load.
Before I did this my oil temps would skyrocket to 240 degrees during runs. I share my car with my son so we go eight times! After tuning the MPS I stay under 210 degrees on a 80' day.
A 200,000 mile engine, well I don't think the heads/valve guides were ever designed to last that long (heads 100k maybe). But the rest can especially with the nickies. There are several cars I have seen that were into the 160k range that ran really nice, of course they had been maintained. Sadly, most 914 haven't as you well know.
Cost, probably into the $5000 range with the nickies.....
Using Megasquirt might be the answer the the FI problems and squeeze some extra hp out of a motor at high rpm.
Geoff

[Oliver Knuf]

Can we find the race rules anywhere in the net?

[cnavarro]

Oliver,

The PCA rulebook can be found online at http://www.pca.org/pca/clubrace/docs/forms.htm

Charles Navarro
LN Engineering

[Dave_Darling]

The roller rockers sound like an interesting possibility. 911 adjusters are a definite "yes". Spraybars in the rocker box sound interesting, but a really serious PITA. Worth consideration, though!

One problem with the Porsche club(s) is that there is no one set of rules for anything. The Club Race people use one set of rules for their wheel-to-wheel stuff. If I were ambitious, I could make three or possibly four Club Races per year by driving for up to 8 or 12 hours each way. Zone 7 (N. Cal. and a bit of Nev.) uses another set of rules for its time trial and autoX series. Zone 8 (S. Cal.) uses a third set. The Parade autocross (Parade is the national PCA convention) uses a fourth set of rules. The Porsche Owner's Club, who do a lot of big-track stuff, use a fifth set.

Any similarities between any of these sets of rules is purely coincidental.

The rules I am trying to follow are here: http://www.pca-ggr.org/ggrrulebook.html
The classification rules are here: http://www.pca-ggr.org/ggrrulebook.html#_Toc532905425

The class is B-Improved.

--DD

[Massive Type IV]

As long as those rockers are self oilers they are good for reliability...Pauters are NOT self oilers and will NOT work with 80% of cams on the market,including some of the ones that Pauter even makes to go with them!

[Oliver Knuf]

Some interesting points in the rule book for stock category are:

Cam Timing: Any cam timing may be used

Cooling: Any oil-, water-, or air-cooling change, which allows the engine to run cooler, is permitted, unless otherwise prohibited. The 914 plastic engine cover water tray may be removed. Such changes tend to extend engine life and should be encouraged

Fuel Pump: Any fuel pump may be used. Fuel pumps should not be a problem. If, in a specific case, the fuel pump is a limiting factor, the driver should be allowed to correct the problem

Balancing: The motor may be balanced. Note that this is not necessarily a recommended procedure. Most Porsche engines are built so precisely that they will not achieve any noticeable performance increase through balancing

Motor Re-builds: To allow for normal rebuilds, the motor may be over bored to a maximum of .5mm. Note: to remain in the Stock or Improved Category, any motor, which is rebuilt, must retain the stock compression ratio. If any procedures (such as truing the heads) change the compression ratio, cylinder spacers or other parts and/or techniques must be used to bring the motor back to stock compression ratio

Adjustments: Except as noted, any modifications for the sole purpose of facilitating adjustment of the car or the motor (such as modified valve adjusters) are permitted

Non-Performance Modifications: Any modification that is clearly not related to performance is permitted

Ok, I would use a 911 cooling system, maybe horizontal mounted with an external oil cooler and modified intake runners, but stock intake diameters. Just an idea. I would use a modern cam, that produces more hp, as most modern cams can produce more hp than the stock unit. Use the lightest stock parts, like the 8mm rockers with swivel foot on straight mounted shafts, use 94,5mm bore original Kolbenschmidt (as this is the rule), use a fuel regulator instead of the original non-regulating fule pressure holder. Redisigning of the C/C is helpful, as you can design it to modern aspects. If you would have a European engine sheet, why not updating the engine to a European config engine? If you can run a European engine, it would be very helpful!

[Dave_Darling]

Originally posted by Oliver Knuf
Ok, I would use a 911 cooling system, maybe horizontal mounted with an external oil cooler and modified intake runners, but stock intake diameters. Just an idea. I would use a modern cam, that produces more hp, as most modern cams can produce more hp than the stock unit. Use the lightest stock parts, like the 8mm rockers with swivel foot on straight mounted shafts, use 94,5mm bore original Kolbenschmidt (as this is the rule), use a fuel regulator instead of the original non-regulating fule pressure holder. Redisigning of the C/C is helpful, as you can design it to modern aspects. If you would have a European engine sheet, why not updating the engine to a European config engine? If you can run a European engine, it would be very helpful!

Changing the cam grind is not allowed. I'm not sure how else a "modern cam" could produce more HP than stock, other than by having a different grind. The cam, due in large part to the experience of the folks over on the Shoptalk BBS, would be Web-Cam's stock grind.

When you say "fuel regulator", do you mean a fuel pressure regulator that is referenced to manifold vacuum? (The stock one maintains a constant pressure.) This would require tweaking the FI parts to correct the mixture, but that can be done.

I cannot redesign the combustion chamber--porting the heads is not allowed. Polishing them to eliminate "hot spots" is arguable, and would be done if it were worthwhile for that.

I'm also not sure what you mean by "European engine sheet". The rules, as written, apply to stock US-spec 914s (that's what you can start modifying from). The GB-code engines had an 8.0:1 compression ratio, which is not allowed in the class I wish to run, so I cannot use a European-spec motor.

--DD

[Massive Type IV]

I'm sorry, but this race class makes zero sense to me......None.

They are forcing you to race with an inefficient engine, and won't even allow a cam change???

I'll almost GUARANTEE you that 90% of the participants are cheating if you were to tear them down....

You know what they say, if you are cheating and "They" are not you are wrong, but if they are cheating and you are not you are just dumb........

Just my outlook..

[Dave_Darling]

I would agree, if we were talking about purpose-built race cars. But we're not. We're talking regular everyday street cars, with minimal modifications. The rules structure makes perfect sense to me--it is a place for people who don't want to spend big bucks on a hi-po motor and still want to have fun on the track.

Hey, if you let them swap cams--then why not head work? Cause you can surely get a whole heap of power out of the heads if you work them enough. Of course, your buddy over there who didn't spend $10,000 on developing his cylinder heads (for his $4,000 car) won't be able to keep up...


Actually, the rules don't really have to make sense--as long as someone signs up to play by a set of rules, they need to follow them. If everyone else is cheating, then I'm an idiot. If you knew me in person you'd know there's nothing new about me being one. But I doubt most people in the class are--and I'm pretty sure you'd get a big flame-war out of some of them by suggesting it. (Yeah, some of them are a bit touchy--and so are other folks... ;) )

Oh well. Sounds to me like you really don't want to have anything to do with this kind of motor. That's too bad for me, I s'pose.

--DD