Oil return tubes with long stroke engines

[Wally]

Oliver,
BTW: I saw your bug in VW Speed magazine. Its looks even better in there than at the digital converted pics, I saw in your thread!
I plan on using a 80 mm crank with 5,7 inch rods and Mahle 24 mm pin pistons. This gives a very big increase in engine with (breite). What do you use for longer oil return pipes? As far as I know, they don't sell longer oil return pipes for Type 4 engines or do they/you ? How do you solve this problem usually?

Thanks in advance,

Walter

[Oliver Knuf]

Hi Walter!

At first, thanks for the compliments. A question: Which type of piston do you want to use? Mahle 94mm? I think, that the combination with the 5.7" rods is not the best choice. Tell me more!

[Wally]

It must really become a very strong, racy engine of about 2,7 ltr: the long rods will move the powerband up in the revs, as I wanted. This requires quality heads and piston/cylinder combination: I have found an unused set of Mahle Nikasil set with 102,9 mm bore. Pistons are dark grey of color and the cylinders are designed for the long 80mm stroke, as I understood. For heads I haven't decided yet, but I very much like the Remmele new heads with type 1 design exhaust ports. Saving up has started....
Not sure about the cam yet. Doubting between 324 and 332 degrees and/or a split cam design. Maybe with 324 I can stay with single springs and have some more drivebility to boot. It will be in a 1303, modelyear '75 beetle (already GL of course) street car.
For induction I plan on a DTA Fuel injection (www.dtafast.co.uk) and combined (direct) ignition, crank triggered.
Just collecting parts/advise so far.
Since the long block is the basis for everything, I value your opinion and I was very pleased with the announment of your new Titanium push rods. I reckon that with a set of those, I don't really need the extra ligth cam followers of 54/57 grams at € 500,--/set, because with your titanium push rod set, I have the same total weigth with the standard type 1 cam followers (bushings will be done anyway)and your push rods as with the ultra light cam followers and a Chr.Moly push rod set... or am I mistaken?
Wil they come in extra length also?
Hope to have given you enough info so far.
Mit freundlichem Gruss,
Walter

[Oliver Knuf]

So you plan on having, what a Type 4 mostly doesn't like, revs! I would recommend a set of rods not over 5.5 inches for a Type 4 and with a stroke of 80mm it wouldn't make sense to go over 5.4" rod length. Sorry, but you will not only move the powerband up, you will make it pretty small with it! Even torque will only be there, if you are in higher revs than normally!

Your plan is good, the Mahle Nika sets are rare, so keep them, but don't use it with a too high c/r, they don't like it! The sealing area in the heads are as thin as on all 103mm German cylinders, that wasn't enough under modern aspects for an aluminum cylinder. They started to break in this area.
I recommend the light lifters together with the light pushrods, lighter rockers and a nice pair of heads. What do you think about Type 4 heads with real Type 1 ports, where you can attach a Bugpack or GB header? Use them with original valve covers and a common fan shroud? Maybe without cutting away much of the rear sheet metal to get them in? Stay tuned, there will be a new head coming up! Not as expensive and you can use them with more common parts.

[Wally]

Oliver,
Thanks, your expertise comes from experience also, I notice from your answers: this is the best. One question though: The reason I chose the 5,7 '' rod is that even with this length, the original rod length/stroke ratio is higher ! It seems strange that approaching the original rod ratio would give such a different engine characteristic. Furthermore, I hoped to reduce side stress in the cylinder walls by the longer rod and so also reduce heat build-up.
What are your feelings on that matter?

I'am very axious to hear from the latest head developments. keep me/us posted! Looks very promising.

Could you also please comment on my question for the longer pushrod tubes?

Walter

[Oliver Knuf]

Different ways to get longer pushrod tubes. I keep always a set in stock that is about 10mm longer. At first you can underlay the tube with another tube seal to get more distance, then, if you need pretty long tubes, take 16 and make 8 of them, by cutting and soft welding. Other possible way is to get them in aluminum as a longer version. There's a shop producing them in aluminum, never used them, but they are existing here!
A rod of 5,5 inches makes a ratio of 1,74:1 that is still pretty high! Between 1,65-1,7 is optimal. With the 5.7 inchers you'll end up with 1,81:1 and that is way too much! If you would have an 88mm crank or more, then the decision would be ok!

I'll give more informations to the heads when more info is there! :)