911 heads

[Bobtail]

Has anyone considered the 964 cylinders. they're 100mm nickies and wally is working on adapting them to type 4/type 5 use. i have spoke with him about it and its still in the works but maybe a possibility. don't know if it'd be easier to use eccentric bolts and change the pattern on the case like the type 5 guys are doing or weld an redrill the stud pattern on the head itself. with those jugs could make the head swap easier. something to consider anyways.

We looked at that because the pistons match the head also, but the stud spacing is too far out, requiring the block to have the registers removed and new registers welded in.
Not impossible, indeed we have seen it done, but a lot of work never the less.

[roo]

does someone have a pic of the cambox or could clue me in as to how it works. do you just hack off the extra material and weld it up for four cylinder use. how does the oiling work and how many cam bearings are used. and how do they attatch to the heads. i understand the pinning and shortenign of the cam itself but how does the rest of the swap work. never worked on porsche stuff. thanks

[Bobtail]

does someone have a pic of the cambox or could clue me in as to how it works. do you just hack off the extra material and weld it up for four cylinder use. how does the oiling work and how many cam bearings are used. and how do they attatch to the heads. i understand the pinning and shortenign of the cam itself but how does the rest of the swap work. never worked on porsche stuff. thanks

The camboxes stay as 911 you use 1 and 2 from one side and 5 and 6 on the other. The 2 empty spaces need sealing.

Pic from the left hand side before we setup the twin spark


Notice the gaps at the front of the heads

[roo]

thanks. i was more interested in the internals probably should have stated that. i was thinking the cam box was a single unit per side not three separate units. the cam box doesn't attatch to the heads at the studs do they? and the cam runs through three separate cam boxes on the 911 correct? or am i missing something? thanks for all the help its definetly appreciated.

[Bobtail]

thanks. i was more interested in the internals probably should have stated that. i was thinking the cam box was a single unit per side not three separate units. the cam box doesn't attatch to the heads at the studs do they? and the cam runs through three separate cam boxes on the 911 correct? or am i missing something? thanks for all the help its definetly appreciated.

I thought that ,I just dont have any pics of the engine in bits at the moment.


Swedish I believe

[roo]

found a site with some pics of the cam box: http://www.instant-g.com/Projects/911Rebuild/index.html Got another question what is the bore spacing on a type 4? I tried to find it but no luck. i'm guessing its 118mm same as the 911. What are you guys doing for oiling system on the 911 headed engine? And do you have to run a "dummy" cam in the case? thanks

[Shad Laws]

Hello-

Got another question what is the bore spacing on a type 4? I tried to find it but no luck. i'm guessing its 118mm same as the 911.

It's 124mm. So, you have to add 6mm of material between stuff.

Stud pattern on late 911 is 86mm x 86mm, and on T4 is 96mm x 78mm (with one stud offset an extra 4mm).

Take care,

[Shad Laws]

Hello-

i was thinking the cam box was a single unit per side not three separate units. the cam box doesn't attatch to the heads at the studs do they? and the cam runs through three separate cam boxes on the 911 correct? or am i missing something? thanks for all the help its definetly appreciated.

Here's the way it works:

Each of the six cylinders and each of the six heads are seperate. The heads are held down by four studs that pass through the "floating" cylinders... very analogous to VW.

There are only two camboxes - one per bank. This is because the cam needs to have well-aligned things around it so the bearings don't bind up .

Each head has two dowel pins on it for alignment and six 8mm studs (three around each valve) to the cambox. The installation procedure is that the cylinders and heads are put on as normal, but not torqued down. Then, you put the cambox atop the heads and move everything around a little so the dowel pins all line up. Then, you tighten (but not torque) down the little 8mm studs for the cambox to maintain the alignment. Then, you torque down the head studs like normal. Then, you torque down the cambox.

Often times, for disassembly, you only undo the head studs and leave the heads attached to the cambox. That way, you don't have to repeat the alignment dance - it's already done for you .

Although it's functional, you have to admit: it is NOT the optimal solution to the problem .

Take care,

[roo]

Thanks Shad for clearing that up. But how in the world do you add the material (or remove it for a type one case) and get the cam covers to bolt up and not leak.

[roo]

From what i can think of, the easiest way would be to open up the chambers on the heads at an offset so the head spacing is 911 but the cylinders would be type4/type1 spacing depending on what you would use. Cam boxes would bolt up as normal but have to be sealed off for the two cylinders not used. The cam wouldn't go with the firing order and the oiling system would have to be taken care of. Anybody know of companies that grind 911 cams from blanks? if the cam(s) could be made cheap enough you wouldn't have to cut, pin, and weld up a stock 911 cam and have more options when it came to cam selection. After that the swap doesn't seem all that bad as long as you can figure out the oiling and pulley system.

[Frallan]

Hello Roo,

why do you say "if you can figure it out"?
Ther are many conversions and many people willing to share pictures and experiences to use your own way of doing it.
Piper cams is mentioned as one source and as far as I know Web cam does prototypes to nay engine, if you wish and can tell them what yoy want.
My cams were ground from two differnt sources. First set from an old retired man working out of his basement and the other from a fairly expeienced autocross cam grinder in Sweden.
I heard about this solution to cut and pin together a Porsche cam first time yesterday. Also seems to be an economic solution and maybe good if the joint is relieble.
Just in the VW scene in Sweden, I know of 4 different 911/VW hybrid engines. 1 in UK and probably many more around.
There is ofcourse the company that cuts 911 engines apart to make 4 cylinders but that is another and quite an sophisticated variant.

[roo]

I guess i should have said something like if i can figure out how you guys are doing it. the conversion isn't so popular back in the states. A few quick questions if you don't mind. How do you have the oiling system set up on your motor? Did you open up the heads at an offset? Are all the pullies on your motor from the diesel or did you have to fab something up?

[Cam]

You better have a Mill, a Lathe and alot of time.....Those are 911 heads.

Don't know if you'd need that much, dude. The machinist's I've asked have all said it will be no probs and the head work they can do on 911 heads compared to TypeIV items is scary

The way I see it is... I've already paid a fair bit for a typeIV motor. The heads on it are set for the tip. Infact, I shelled out so much, just for a mint case and nothing else beyond that I will really be using.
2.0 or any other 914 items are worth between $500 (if I'm lucky...) and over 1K. And thats probably in $US since we never had the cars here. On top of that I'll need to pay GST, shipping, taxes, etc... To get them into the country.
Then I've got to get them fully worked, by the right shop, with the right gear (flow benching, etc...) and at the end of it all, they still won't flow properly for forced induction use.
So I would have forked out a couple of grand for a set of heads which will look nice, granted, but there won't be any guarantee of them not dumping valve seats on me, let alone all the other probs these heads have. Then I'll go for a stainless exhaust... Another 1.5K and again, same probs.... Won't flow properly. Infact, they won't even be upto standard 911 head flow, combustion, heat resistance, etc...
Now I can get a set of top quality, used 911 heads for about 1.5K landed here. Probably another $500-1K machining and they're on my car. They flow right, make sensational combustion. And even though I'm still going to have to get an exhaust made, the builder will have alot more give when doing the design.
All in all, it won't be much difference in price. However, initial plans tell me the 911 heads will come out cheaper. But I already have factory air cooled high performance heads. The pinning of the cam's won't be overly expensive, but will still cost. Yet then again so will a TypeIV hi-po cam, lifters, rockers, pushrods, pushrod tubes, etc, etc, etc....
Each to their own, I always say. I'm a purist in the fact that I love aircooled VW engines. But I also LOVE Porsches, so won't loose any sleep over it Plus I would have been going Porsche had I of chosen 914 heads, anyway. So, meh...

[Frallan]

Hi roo,

The oil system is kept as close as possible original.
Modifications:
oil squirters but has no connection to 911 heads or not. Rather the turbo.
one oil line to each head for bearing opressurized oil to cams.
Same line feeds oil squirter holes over each rocker pair.
The pump is a schadek 30 mm and the cover is GB with integral oilrelief.

The heads on this engine are offset approximately 2 mm each over the piston cylinder. Cam boxes are not modified with this offset.
BUT, it is not the type of engine I would copy, if I build it again and I know of nobody else that has this version.
It is better to center the heads and modify the cam housing/rocker boxes to center on top of heads.

You ask if the pulleys and everything else is stock. The pulleys, belts and idlers are stock. The extensions for the cams are not stock. "home made".
This seems to be easier when building for TIV were, what I can see the extensions are not needed.
The intakes in my case are "homebuilt billet". They mate directly to the 48 IDA bore spacing. Really nice. When I swapped to 55 mm TWM all I did was some minor porting and then they bolted right on.

Now, Cam has a good point.
This modification is cost effective compared to TIV heads but only if many "if's" are fulfilled.

If, you really need top flow and performance
If, you can do machine work or have it done by friends at low cost.
If, you can get good used 911 parts and use second hand. If you are to purchase new valves, guides, rockers etc. No way it is cheap. If you go for advanced cam profiles (911 racing) the Porsche racing rockers are needed. Now we are in to high dollar parts.
New 911 cylinders and pistons. Almost as expensive as LN...sorry just slightly joking. I have no idea about Porsche prices on cylinders but probably same region as LN.
If, you do not mind building your own fan housing.

Probably some more "if's".
BUT, it is rewarding. Incredibly nice running engines and very reliable. Russ Fellows is a hero in my eyes when he races and drives to track with reliability. Good job!

[Piledriver]

Frallan---
Could you adopt me?;-)

KILLER job.

Now, any info in Subaru heads? 16v, correct bore spacing.
(same as T1) 2.2 90mm bore, 2.5 99 mm bore. (not certain of 2.5 bore spacing)

It's been done once... Probably even easier than 911 heads if you don't mind a little water.