911 heads

Yaninnya · Post by **Yaninnya** » Thu Nov 13, 2003 2:25 am

Frallan, you mentioned the company which is converting 911 engine to 4 cylinder. Have you more informations about the company and this mod?

Wesayso · Post by **Wesayso** » Thu Nov 13, 2003 4:18 am

I believe that would be the PartsObsolete engine?

http://www.356shop.com/4_cylinder_911_motor.htm

Yaninnya · Post by **Yaninnya** » Thu Nov 13, 2003 4:50 am

Did anyone has any expieriences with this engine?

Cam · Post by **Cam** » Thu Nov 13, 2003 6:14 am

Piledriver: The Scooby motor is very, VERY closely related to the VW motor. Infact it's almost scary. Not sure about head stud spacings and the like, since I have'nt played with Subarus. If you're going to get performance subaru heads, you may as well just swap over the whole motor with one from a WRX. Put in a rally style dry sump or a Kennedy sump conversion and you'll be away. There was a type1 powered autocross L-bug in the UK, built and run by the late great Peter Harrold

which used subaru heads. Not sure what model they were from, the conversion was done before WRX's were around. The advantage of using the type one would be all the aftermarket hi-po parts that are available. Something us TypeIV owners don't have access to... Yet!
It is interesting to note tho, that AMG got rid of the 4 valves in the Mercedes Benz E55 V8 in order to accomodate a second spark plug. Something which the Porsches have and the Subaru's don't. Yet in saying that, the E55 does have two intake valves and only one exhaust.

Fredrik: Thanks for calling yesterday, mate. Was great to talk about this stuff in person. You're a true genius! Also cleared up many things I had'nt noticed before in regard to camshafts, boxes, etc...

Sharing info and ideas is what it's all about guys!
Cheers,
Cam

roo · Post by **roo** » Thu Nov 13, 2003 8:33 am

i'm not sure how i'd feel about myself if i had H2O heads especially if they weren't VW.

Hey Frallan, whats the reasoning for not offseting the heads. i can see where the valves may interfere but a little relieving wouldn't be a problem. Great info.

Frallan · Post by **Frallan** » Thu Nov 13, 2003 12:33 pm

Hi again,

Imgine sitting holding the domed Porsche piston in your hand looking at the dome with the wrist pin in horsontal position.
You now have the valve relief for intake at 12:00 position and exhaust at 6:00. Up and down. Right?
Consider that the reliefs are very close down to the outer perimeter of the piston.
They are also very close and deep in to the piston, close to the inside of the rings.
Move the valve relief 2 mm to either side.
If you where close to the rings inside, now you are closer.

I had a cast rocker fail on me due to valvefloat at too high revs. The exhaust hit the bottom of the valve relief and nothing else, I thought. Until I inspected closely. A crack from the bottom of the relief and in to the ring glands had developed.
I changed piston and cut the old one apart. Now I could see how little material there was at one point.
When converting to turbo I had the pistons coated with a ceramic heat resistant special fantastic magic whatever.......never had a problem but still, I know of the weak link that it could be better.
Rather design so I have a better solution.

roo · Post by **roo** » Thu Nov 13, 2003 1:02 pm

i know it wouldn't be the ideal solution but could you run a shade more deck hieght to compensate so you don't have to relieve quite as much? asuming you don't have to drop the CR too much.

Wally · Post by **Wally** » Thu Nov 13, 2003 1:34 pm

Cam wrote: It is interesting to note tho, that AMG got rid of the 4 valves in the Mercedes Benz E55 V8 in order to accomodate a second spark plug. Something which the Porsches have and the Subaru's don't. Yet in saying that, the E55 does have two intake valves and only one exhaust.

Cam

Cam,
Also interesting is that the original Apfelbeck heads have also two intake valves and one exhaust valve...AND two spark plugs!
These heads were specially developed for the aircooled VW engine and have OHC as well.
I know this well, since I have hold one in my hand recently; my friend Roberto is building an type 4 engine with them. It will take some time tho, but he has all the right equipment (at his work) and is very able to use it

Greetings,
Walter

Paul Illick · Post by **Paul Illick** » Thu Nov 13, 2003 6:45 pm

You guys are totally dangerous. The limit to the T4 motor is the exhaust ports? Well you've sure found a nice solution to THAT one! Keep up the good work.

Cam · Post by **Cam** » Thu Nov 13, 2003 6:53 pm

Cam,
Also interesting is that the original Apfelbeck heads have also two intake valves and one exhaust valve...AND two spark plugs!
These heads were specially developed for the aircooled VW engine and have OHC as well.
I know this well, since I have hold one in my hand recently; my friend Roberto is building an type 4 engine with them. It will take some time tho, but he has all the right equipment (at his work) and is very able to use it

Greetings,
Walter

ooooooooh

Reproduce, dude. REPRODUCE!!!!
I have never heard of these heads before tho. Could you give me some background?

Paul: I think Fredrik did his T1 conversion in the 70's. So it's hardly a new thing. The other option would be to just go with SCAT split ports. Rework them to your liking. These would have serious power offerings if worked over correctly. *ponders* hmm.... sodium, titanium, stainless and still having pushrods

.... oldskool

I know these heads have been used heaps in aircraft and for many years with much success. So with some machine work they should be able to handle hi-po car use no probs.

Bobtail · Post by **Bobtail** » Thu Nov 13, 2003 7:03 pm

I spoke with Roberto some time ago about these heads and he posted some pics , which Ive since lost

He mentioned the cambox was in 2 pieces ???

What you know Wally?

Cam · Post by **Cam** » Thu Nov 13, 2003 9:48 pm

I remember having a VW Trends magazine, when I was growing up. It had a yellow beetle, with graphics over the rear 1/4 and down the lower part of the sides. The graphics were all done in darker colours and looked PHENOMINAL. The car was on EMPI 8's, had no bumpers, etc....

It had some MONSTER of a TypeIV in it and the dude had had his own heads made. It made crazy power figures.

I wish I could find this mag, I've been hunting for it. Last I remember, I'd taken the mag apart and put it up on my garage wall, when I was about 12 or 13. I'm sure I kept it, but can't find it anywhere.

If anyone has it could you PLEEEEEASE scan it for me and e-mail to [email protected]
It would be an issue around 1984.

Frallan · Post by **Frallan** » Thu Nov 13, 2003 11:01 pm

yes custom made pistons is the way to go and is ofcourse the best way to solve it if you resist the work to center the heads.
If you want more than 10:1 compression which was maximum we could reach with 90 mm 2,7 pistons, customs are a must anyway.

The red car on previous page is Swedish and the owner is Mika Janson Stockholm.
He won everything in VW dragracing for many years with this engine located in different shapes and forms of cars.
It ran both single and twin turbo succesfully. (Whipple S/C last year) I talked to Mika a month ago and he finally admitted that the main problem through all the years was too much horsepower, the car had traction and directional problems most often but still it was enough to win. ´Last year or two I did not see it run but I know it was handling much better.
Apart from all else that is mentioned on these 911 hybrids, his engines just like most autocross VW's in Scandinavia, used Kugelfischer 3 dimensional fuel injection.
Basically a piston calibrated fuelinjection unit with boost sensitive curve adjustment. Absolutely one of the best units until electronics took over. Again for those that know Porsche, the unit is commonly used with 911 racing turbo back from the high hp turbo era.

Both car and engine are for sale. If I am not wrongly informed, in it's latest development stage, the engine has two Whipple superchargers instead of turbo and Haltech or was it maybe Autronics FI.

Post by **Piledriver** » Thu Nov 13, 2003 11:40 pm

The suby heads on the late Mr Harrolds car wre pre WRX, but that motor has been around for years, it just wasn't called a WRX then...

The main PITA about the Suby heads is they use 6 studs, and I can't find one for cheap to play with, even cracked.

The main thing going for a head swap vs a motor swap is that the wasser bottom end is probably stronger (with CrMo rods etc, top end VW aftermarket guts (I.e. Pauter rods) are still a small fraction of what the Suby guys pay)

..AND no ~$1000+ conversion kit would be required to make it fit. A wasser and 228mm clutch will bolt right in.
(Given the input shaft bearing in the flywheel mod)

Wally · Post by **Wally** » Fri Nov 14, 2003 12:31 am

Cam wrote:
Reproduce, dude. REPRODUCE!!!!
I have never heard of these heads before tho. Could you give me some background?

Funny you should say that since he does also bought the molds for those heads.
It would not be 'economical' at all though to make some for others, since it is so very labor intensive to also make all the other stuff that one would need because of the OHC lay-out.

Bobtail,
The Apfelbeck heads are very historical, because they were described in a '70's tuning book from his hand in Germany. Ludwig Apfelbeck is/was a very highly respected tuner that wrote several books on tuning in general also.
The history is that a few semi-ready heads and the molds and all were purchased by a competitive auto-crosser that knew that who-ever finished the heads and drove races with those heads would win all races. To avoid that, he bought the lot and stored it for many years, not in the oppertunity to make them ready in the meantime.
(Mind you, auto cross in Europe is run with beetle derived steel-framed buggies on dirt tracks. No tarmac.)
Probably plans were changed, rules maybe also and the heads 'forgotten'.
Untill now.

We haven't been able to find any car/engine yet that has a set of these heads on them, so Roberto has to work from scratch as far as the cam drive is concerned.

I took a picture of one of his heads early this year of a raw head and send it to Alex. He has posted it on GermanLook.com in the engine gallery. When I see him again I will take some more of a more ready head.

Greetings,
Walter