100mm 964 cylinders on a 3.0 block

[Aircooled4evr]

is it in any way, shape or form possible to use 100mm 964 cylinders on a 3.0 SC block (and heads)?

Cheers, Mads

[Henry Schmidt]

Originally Posted by Aircooled4evr

is it in any way, shape or form possible to use 100mm 964 cylinders on a 3.0 SC block (and heads)?

Cheers, Mads

Yes, we've done it.
You mist use early 964 heads.cylinders.
Reduce the cylinder spigot diameter. Increase the case spigot bore. Slot the holes for the head studs (different stud spacing) and run a .280" base shim.
It works but it is ugly on many levels.

[Aircooled4evr]

wow .. that was a quick answer! thanks.
sigh, that was what I feared. i'm ok with a little machine work, but moving the holes for the head studs ... i'm not sure i will do this on a super good 3.0 block.
But have you seen the prices for a set of 98mm mahle cylinders? used or otherwise.
Wow .. and there are many 964 sets for sale out there, at a quarter of the price!
so I just thought.......

[Aircooled4evr]

p.s. and a 95mm set for that matter.

[Henry Schmidt]

Originally Posted by Aircooled4evr

wow .. that was a quick answer! thanks.
sigh, that was what I feared. i'm ok with a little machine work, but moving the holes for the head studs ... i'm not sure i will do this on a super good 3.0 block.
But have you seen the prices for a set of 98mm mahle cylinders? used or otherwise.
Wow .. and there are many 964 sets for sale out there, at a quarter of the price!
so I just thought.......

My description may have been misleading. You don't relocate the head studs in the case, you slot the cylinders to accommodate the narrower stud spacing.

We have moved the studs in the case before, widening the stud spacing but that was on a real RSR case where the customer wasn't willing to step up for real RSR heads. The process was easy and actually made for a better end product.

That slide valve RSR engine ended up gracing the cover of Waynes first addition engine rebuild book.

[Aircooled4evr]

Cool!
yes, I misunderstood you. Now I have something to think about .....

[Henry Schmidt]

Originally Posted by Aircooled4evr

Cool!
yes, I misunderstood you. Now I have something to think about .....

I haven't looked in years but I may even have a set of slotted cylinders and base shims on the shelf ready to go.
If I can remember, I'll check tomorrow.

Send me an email.

[Pesch]

Asked the same question over the 930 area some time ago:
964 cylinder on 930

Get some pictures about what it looks like :



Still thinking about it

[Aircooled4evr]

I've considered it overnight.. I'm in!
If any of you have anything good lying around, I'm interested.
And or- do any of you know this dealer?



He has several sets for sale for $ 600 ....

[rosenbergendo]

Why do this? We are going to start a fresh 3.0 build with 98mm cylinders and 4.0 RS crank. Curious why this route would be better?

[Aircooled4evr]

Primarily because of the price!....
I can make the modifications myself, to use the 100mm.
And if the heads need to be modified, to achieve a better squeeze in collaboration with the 964 pistons, I can probably do this as well. (even though I just finished polishing them)
In addition, I'm curious what characteristics 70.4 X 100mm will give!

[rosenbergendo]

Originally Posted by Aircooled4evr

Primarily because of the price!....
I can make the modifications myself, to use the 100mm.
And if the heads need to be modified, to achieve a better squeeze in collaboration with the 964 pistons, I can probably do this as well. (even though I just finished polishing them)
In addition, I'm curious what characteristics 70.4 X 100mm will give!

Ask William Knight!

[Henry Schmidt]

Originally Posted by Aircooled4evr

I've considered it overnight.. I'm in!
If any of you have anything good lying around, I'm interested.
And or- do any of you know this dealer?
He has several sets for sale for $ 600 ....

Autobahn Dismantling
444 Vernon Way
El Cajon, CA 92020
Phone: (619)444-2290
Fax: (619)444-0394
These are the guys who get all the Singer take offs. Great guys to deal with.

BTW
If you're looking for early 964 cylinders sets, we have a few sets.
$ 600 plus shipping works for me.

[Henry Schmidt]

Originally Posted by Aircooled4evr

Primarily because of the price!....
I can make the modifications myself, to use the 100mm.
And if the heads need to be modified, to achieve a better squeeze in collaboration with the 964 pistons, I can probably do this as well. (even though I just finished polishing them)
In addition, I'm curious what characteristics 70.4 X 100mm will give!

You can modify them if you have a mill and a lathe.
I would seek a custom piston to maximize this modification.

70.4x100 is a cool high revving oversquare engine. They are commonly found in the likes of Formula 1 cars, two-stroke racing engines and anything else where you want to rev the engine up to produce power. They keep piston speed down which helps reliability by putting less force into things like your crankshaft and connecting rods. In general, these engines will produce more horsepower than torque and require gearing to take advantage of their top end pull.

We built a 66x100 engine a few years back that saw rpm close to 9000.

[Aircooled4evr]

Originally Posted by Henry Schmidt

BTW
If you're looking for early 964 cylinders sets, we have a few sets.
$ 600 plus shipping works for me.

You're a cool guy to know!
yes, I am interested in a set of 100mm up to 600 bananas.
Or maybe a good discount if I buy two sets?
Maybe I can make the later style recess, in the contact surface on the cylinder top end... The only thing I'm really interested in, is if they have a good "roundness" and that they have a nice surface (do not know the technical words on English)?
And if I can't use the original pistons, I will have to see who makes light "race" pistons. (for human money) to my specifications.
And I have to learn how 964 combustion chambers are designed. I will "work hard" to achieve the optimal squeeze!!

[Aircooled4evr]

Originally Posted by Henry Schmidt

70.4x100 is a cool high revving oversquare engine. They are commonly found in the likes of Formula 1 cars, two-stroke racing engines and anything else where you want to rev the engine up to produce power. They keep piston speed down which helps reliability by putting less force into things like your crankshaft and connecting rods. In general, these engines will produce more horsepower than torque and require gearing to take advantage of their top end pull.

We built a 66x100 engine a few years back that saw rpm close to 9000.

I wili NOT make a 66X100 raceengine!
But yes, I love an engine that revs free and fast! And, even though it sounds weird, I like that it does't have too much torque (TOO much)
This is simply because I like to use the engine fully, without it going at ridiculous speed.... And although I would like to use it on a trackday once in a while, I am NOT a race driver! And it's going to run mostly on the street! Does that make sense?

Something completely different, I have set myself a goal with this engine, which goes directly against what I am in the process of building. For this time I will fight hard to get the engine to go as far on the liter as possible!
This might sound weird, but I simply can't help it! and tune over the top ... It's my core hobby, and my cars always get too wild for the street. (my hair is starting to turn gray) and in my eyes, tuning for better fuel economy is also a kind of tuning ...
I have already bought a WebCam 21/21 for my project, but now my engine is getting too big and rev-depending for it, I think ... Sigh
But am I to use a cam with bigger overlap, then I will have serious problems reaching my goal...

[Aircooled4evr]

Originally Posted by Henry Schmidt

70.4x100 is a cool high revving oversquare engine. They are commonly found in the likes of Formula 1 cars, two-stroke racing engines and anything else where you want to rev the engine up to produce power. They keep piston speed down which helps reliability by putting less force into things like your crankshaft and connecting rods. In general, these engines will produce more horsepower than torque and require gearing to take advantage of their top end pull.

Me and a couple of friends are designing a new gear set for the 915 gearbox. (1st and 2nd, high gearshaft included) So we can get it exactly the way our engine wants it!
And again, simply because we can, and it's way too expensive to go out and buy!

[Henry Schmidt]

Originally Posted by Aircooled4evr

You're a cool guy to know!
yes, I am interested in a set of 100mm up to 600 bananas.
Or maybe a good discount if I buy two sets?
Maybe I can make the later style recess, in the contact surface on the cylinder top end... The only thing I'm really interested in, is if they have a good "roundness" and that they have a nice surface (do not know the technical words on English)?
And if I can't use the original pistons, I will have to see who makes light "race" pistons. (for human money) to my specifications.
And I have to learn how 964 combustion chambers are designed. I will "work hard" to achieve the optimal squeeze!!

We can have the custom pistons made for you at a reasonable price.
Send me an email with contact info and we'll try to work something out.
Discount for quantity? of course, we've got piles of the stuff.

[Dpmulvan]

I’ve been trying to decide what to do with my 3.0, This option sounds interesting, something different. Henry you said it was ugly what did you mean?

[Henry Schmidt]

Originally Posted by Dpmulvan

I’ve been trying to decide what to do with my 3.0, This option sounds interesting, something different. Henry you said it was ugly what did you mean?

Slotting the cylinders to adjust head stud spacing, reducing the spigot diameter (thinner cylinder wall), boring the case (irreversible change), .120" base shim.(unstable cylinder platform). If you try to use late 964/993 cylinders you have to machine the heads flat. More irreversible changes.
All of it is ugly.

Back in the day when the 964 recall happened, the dealers had boxes of the early cylinders they were throwing away. One batch we got was 11 sets. That makes playing with these cylinders intriguing.
Now, not so much.