Spec advice for new motor build

[dub_crazee]

So im finally coming to the end of my 3 year long project on my bug

http://i591.photobucket.com/albums/ss352/PanelKraft/Our%20Vehicles/Project%20German%20Look/DSCN2508.jpg~original

and now need to consider the engine.

i have two donor motors - a 1700 type iv and 2 litre type iv - both died with valve issues.

I am thinking about building a 2056cc motor based around the 71mm crank. Eventually going EFI and turbo but on carbs to begin with. so heres my plan

CU Case acid cleaned and machined for porsche fan
Crank, pulley and 915 conversion flywheel dynamically balanced
Stock 2litre rods balanced and ARP bolts (however for a little more £ i probably could get a nice set of rods - thoughts on this?)
96mm Keith Black Pistons
considering using OG barrels bored out as i have read the OG barrels are made of better material?
Straight cut cam and crank gear
Cam choice im unsure on at the moment - opinions?
Stock lifters and push rods (although i have been recommended to sleeve the case and use uprated lifter. again opinions?)
Rockers?
Dry sump kit
CSP python exhaust

Heads. now i have a set of 1700, 1800 and 2000 (square port) heads. 1800 have the biggest valves but i was considering getting the square port heads reworked. what do you guys rekon?

Once turbo'd im looking for around the 170bhp mark so quite low on boost. i want the motor to be driveable/reliable rather than an all out race motor.

any opinons/help great appreciated

Deano

[NO_H2O]

I love the 2056 combo. But your end plans may require some changes to your current plan.
KB 96 pistons are normaly not forged. You will need a forged piston if you are going to go to a turbo setup.
Also you might want to stay with a 94mm slug and jug set with forged oistons to run it boosted. The added cylinder wall thickness will help to keep the power sealed inside.
The square port heads will limmit your exhaust options. Most performance exhaust for type 4's are built for oval ports.
You need to match your cam lifter combo and cut pushrods to proper length after checking the valve geometry.
You have already answered you own rod question.
Think everything thru and try not to buy too many things twice while going from a nice N/A setup to a bosted/EFI set up.

[NO_H2O]

BTW, That is a nice looking ride.

[dub_crazee]

Thanks for your reply :)

What brand pistons would you recommend? i take you point about the barrell thickness
the reason i was thinking about going sqaure port heads was ive had trouble with the oval ports sealing before....but then again the exhaust was poorly made. CSP do a suitable exhaust as their stubs are interchangable. Is that the only downside to the square port heads?

Thanks again

Deano

ps any reccomended suppliers? Ive been in contact with Stateside tuning in the UK but was also thinking about jake in the US.

[NO_H2O]

Lots of piston choices out there. I would make sure it is forged. Jump over the the type4rum on shoptalk and do some searching I have read were people use Chevy 305 pistons, Ford, JE 94's, etc. Wally might chime in with some info here.

[judgie]

if your thinking of going the turbo route in the future go for the square port heads, much better chance of keeping the exhaust gas in the header and not blowing out the side of the crapy copper sealing ring.
forged pistons are a must if your going to go turbo.
you dont really need to go tpye 1 lifters if your going turbo as you wont be using high rpm so the stock size will be fine.
cam wise you want somthing quite mild with little overlap, turbo motors do not like overlap.
rods as you say a few more £ and you can have some h beams and apart from anything else there much lighter than stock. the stock rods with arp bolts will work well just there heavy. not so much of a problem with a low reving turbo motor.
wouldn't bother with the stright cut cam gear as again your not going to be running big rpm with super h/d valve springs. you will need to run slightly stronger inlet springs then you would with a n/a engine, you need to overcome the boost presure as well as the cam lift.
rocker wise you dont have much choice as theres stock and pauter, i run lightend stock 1700 rockers in my race motor that have worked well up to 8000rpm so far. Wally has had a few problems with stock rockers and his turbo motor but i dont think your going to be running the same sort of bosst as he is so shouldn't be a problem.
i get all of my engine parts from stateside tuning and he nows his stuff and will sell you what you need not what he has.

[dub_crazee]

Thanks again for your input no h20 - i will check out the type4rum i htink i read somewhere mahle type 1 94mms are a good choice il check it out.

judgie thanks for the comprehensive response.
you have confirmed my thoughts about the lifters and exhaust. tbh i dont expect the motor to ever see more than 5500 rpm
rocker wide i think ive got some 1700 ones knocking around so il check them out - i saw wally's issues but this motor wont be straining anywhere near as hard as his.
judgie do you recon type iv heads or get james to do it? your only uo the road from me (now in north hertforshire)

[Xellex]

hey Judjie, do you have any pics of the lightened 1.7 rockers? I was curious about how it's done :)

[judgie]

i send all my machine work to stateside tuning along with most of the the other engine builders.
I'll try and dig some pic's out of when i did my rockers, its a long boring job and trying to get them all the same wieght was a reall pita!

[dub_crazee]

anyone used those super squish pistons on aircooled.net? supposed to be detonation resistent....which i gues can only be a good thing in a turbo motor!

[NO_H2O]

I think the "Super Squish" pistons have a special dome top to them. I don't think that would be good for a turbo combo.

[Wally]

Yeah, I agree with the former posters: if your really planning on turbo in the future, try keeping the barrels as thick as possible. Most important therefore is to go look and measure up the old barrels if they are still round enough and if they will support a set of new 94mm pistons.
The cool thing about forged pistons is, that they will usually be made too big in diameter, so you can have your barrels be honed out a bit more till your on the right spec for wall-piston clearence :)
Then again, I believe there are also 95mm forged AA pistons now and that +1.0mm will cover all rust and scratches you may have encountered with old barrels.
New 'B' Mahle pistons are not readily available at the moment iirc, so make a plan. Maybe the true forged 94mm AA's are worth a look?
Boring and honing is usually just as costly as all new barrels and pistons, though the original barrels are _usually_ indeed better then new these days.

In short: your choice in pistons and cylinders is very important in a build like this.

[dub_crazee]

thanks for the info noh20 - i figured there must be a reason that i hadn't seen them in turbo spec motors.

Thanks also wally, ive been on the aa website but they dont seem to list those pistons anymore? maybe a temporary thing. i have 8 2.0ltr barrells to chose from so im sure i must have some half decent ones i could have re-honed. I also read about people struggling to get the mahle 94mm pistons and theyre going up in price.
building a motor seems to be bit of minefield tbh and costs can easliy spiral out of control. especially once you look at issues others have had and how they over come them (treating springs and lifters fo example)

After a bit more research i think this is a more likely spec

CU Case acid cleaned and machined for porsche fan
Crank, pulley and kennedy 915 conversion flywheel dynamically balanced
H Beam rods
94mm forged pistons and OG barrels (JE pistons look sweet but mega cash)
stock cam and crank gear
webcam 119
stock lifters
1700 rockers
44 x 38 square port heads with 1 piece stainless steel valves, hd single valve springs, cromoly retainers, hardened valve collets,
8:1 cr
Dry sump kit
CSP python exhaust w/custom muffler

[dub_crazee]

forged 94mm mahle pistons £280 then id have to get rods to suit the wrist pin :)

[Wally]

I would try to use type 1 lifters and definitively double springs. 119 has 0.500" lift and your not using Ti retainers!

[dub_crazee]

Do you think i should go that route or a cam with less lift? i supose at the end of the day im not aiming for mega BHP but more reliability.

[Wally]

Turbo = dual springs, heck, most n/a application should have dual springs. Only the mildest of cams can run safely single. Quoted for truth: "Your valves are floating, you just don't know it" .
You asked for advise what would we do...but I can't look inside your head ;-)

[dub_crazee]

Thats a fair enough comment. i just read about the issue with your single hd springs weakening on your 2.0ltr motor....how did the cryo springs work out for you in the end out of interest?

[Wally]

The cryo'd ones were actually down on spring pressure because of that treatment and I needed more spring, not less, so I didn't use them.
Both Scat singles and the Berg duals were very down in spring pressure after some use, hence I now use the CB650.
They are such a nice spring, I would almost recommend them for everything, also because the 650 seems more progressive in rating, so lower lift cams don't get the higher pressure, but the spring lives much longer, which is good if your going turbo later. After all, you don't want to start the turbo motor with an already weakened spring.

[dub_crazee]

interesting. i suppose a lot of people dont think about the other side affects certain processes have. thanks for sharing your experiences with them. the cb650 sounds like a good allround spring to use.