ShopTalk Forums | Aircooled VW Tech & Restoration Help

Hi All!

I'm building a 82x103 T4 engine ~2700cc's and now I'd like to know your recommendations on the valve sizes. Should I go for the biggest that can be fit into T4 heads (48x40?) or should I select a tad milder approach?

Of course the intended use of the engine dictates this. So, I'm planning to use the car almost every day and it sees some occasional 1/4 mile racing.

Can you also recommend a cam which would suit my intentions the best. As you guys do have the knowledge I'd rather not learn this the hard way...

The carburation will be carried out with 48 Dellortos, Weber IDF's or possibly a mechanical injection such as K-jetronic, recommendations on this one?

And finally, does anyone of you have any experience of Riechert Tuning horizontal fan? It's based on Porsche 911 fan as the upright conversions. The image can be seen at:
http://www.ismi.net/riecherttuning/coolingt4.htm

The reason why I'm going for this is that the engine is to be fitted in a '67 T3 Variant and as it does not have enough room for upright conversion I thought this would be the only way to cope with the problem. Also if you've got any ideas how to take care of the cooling chores, please do share your ideas with me.

Happy New Year to each and everyone!

Best Regards,

Jarno Lahti

Huh? No-one?!

.Huh? No-one?![/QUOTE]

I'm guessing it's because most of the informed ones on valve sizes (not intended to be derogatory) are from the east and are unable to log onto tunacan due to a routing problem. I've been disappointed myself as I found this forum to be lots of fun and always educational to a complete novice

Yeh, not many posts lately. If I were building my engine to the 2700CC level, I would definitely go with the largest valves that would go into 1800-type heads with the chambers slightly unshrouded and polished for eight-to-one compression. I'd also go with one stage wilder WebCam (I'm going with an 86a for my 2056CC and dual 40 Dells). I personally would think about dual throttle body injection and not even try to experiment with any Jetronic set-up. Also, the choices of exhaust systems, aren't that great and, I think, a really critical item to making big horsepower. Let us know what you finally decide on.

Jarno i'll take a shot at valve sizes. We built a 75X103 (2499cc) for desert racing in the earli 80s. At that time FAT was the only visable type 4 motor builder. When we contacted then about valve sizes for that size motor built from a 1700 core, they said that stock valves flow enough that the motor should be capable of 200 HP. They also said nearly all of their racers wanted big valves even though they weren't needed. Our car owner made the same decision, I think we ran 48X40 and I must say it was an impressive motor.

Thanks for the replies guys!

I guess I'll go for 48x40, even though the engine is not meant to be the most extreme engine one can build. At least the heads are up to the task if I'll decide to pump out the last HP's out from the engine.

Any experiences about the riechert-style shroud set-up?

I guess I'm going to make an Ahnendorp-style exhaust system for the engine...

Also other ideas are welcome!