My rebuild quietly moves onward and I am at the point now where I need to bite the bullet and drop the cash on the internals and such. Heads are done.


Last thing I need to lock down is a decent set of 96x78 pistons and cylinders.

This is an econo build so not looking to break the bank here. Car will be cruised around town mostly, some AX and less than 2000 miles a year.



Looking for suggestions from you fellas and/or somebody who wants to sell me some. Would consider variations for a good deal.

thanks guys...
drew

Buy one of Jake's 78mm Ion-Nitrided cranks.

Keep in mind, with a 78mm crank you'll need a smaller diameter cam... I think, ½" circlet... Not sure exactly but you can find out for sure if you do buy from Jake.

You can get 96 cylinders by AA for about 150.00 and some Kieth Black pistons for
around 350.00 a pretty good match. Jake would be a good person to talk to about what will work for you I'm sure he will chime in here shortly.

I am planning on buying the crankshaft and rods from jake, not sure about the cam....I don't know if I can afford him.

well the thing is....i emailed AA and they want 630 bucks for a 96x78 which seems pretty steep for what your are getting and that's why I'm looking at other options.


i think there cheap 96mm P+C kits are for the 66 and 71 stroke cams....

drew

I thought you were going to bore some 94's for the 96's?

make sure the pistons you get match the pin diameter that come with the rods your looking at

Hey george...yeah I was considering that as well but the problem is the set of cylinders I have is for a 66mm stroke. If I could find a set to bore I would consider that as well.

I guess I'm just finding it tougher to locate econo 78mm P+C sets unless I spent a lot of cash or go for 103s

Don't go with anything over 100mm bore unless you get something that isn't prone to lots of warpage...

yeah great point....i do not want to go over 96mm. The way I have the heads setup they wouldn't be able to breathe enough and I would burn out the engine real quick.

I was hoping somebody in the club would have something lying around but no such luck yet it seems...

What are you talking about when you say 78mm piston sets? There aren't pistons that are necessarily specific for a 78 crank. There are 96 pistons for stock rod journals, and 96 pistons for VW/Rabbit/Chevy rod journals.

You need to make a choice about your rod journals, then that will dictate your piston needs. Don't put the cart before the horse, cuz you're on a slippery slope.

When someone said AA has pistons for $150, you do realize there is a company called AA (not Auto Atlanta) that sells inexpensive pistons?

Also, if you can only afford to buy one part from Jake, buy the cam from him. He has the best cams, with the good lifters.

I'm referring to cylinders that can handle a 78mm stroke crankshaft. To best of my knowledge, the common 96 sets for the 66 and 71mm stock cranks aren't going to cut it.

The crank has type 1 rod journals and the 22mm wrist pin. I have the rods to match. Its all off jake's site.

I locked it down tonight.

Then buy the rest of the parts from Jake....You need the reduced base circle camshaft, new lifters and the 96mm KB pistons for the 78mm stroke. If you want the right parts, save your money and get them from Jake.


Good Luck with your engine build!

[quote name='jasons' date='May 6 2007, 06:34 PM' post='897279']

When someone said AA has pistons for $150, you do realize there is a company called AA (not Auto Atlanta) that sells inexpensive pistons?


I said cylinders not pistons as there pistons are junk thats why I said Kieth Black pistons. I've got a 2270 kit from Jake and it came with AA cylinders and KB pistons.
Jake assured me that the cylinders are good and has even started using them for some of his complete engines.

good point...based on today's discussions I've concluded that I probably need to wait and buy the KB\AA P+C combo from jake for 78mm stroke.

600 bones is a good price for what your getting....

thanks for the input all I really appreciate it.

I knew thats what you meant by 78mm pistons. 96mm pistons with 22mm wrist pins aren't limited to or specifically made for 78mm cranks. Its just a good combo. You can use those pistons with other strokes too. Likewise you can use the 24mm wrist pin pistons with a 78mm stroke. Albeit, its probably not the best combo due to rod weight and ratio. But, thats the "econo" way.

It sounds like you're off to a good start. I don't know if its going to wind up as "econo" as you hope. But it sounds like you are buying the right parts. (spoken from someone who has bought the wrong parts). Get the cam from Jake too.

If you have some OEM Mahle 94mm cylinders, have them honed out and buy new 96mm pistons from Jake for a 78mm crank. The Mahles are just better quality than the AA cylinders. That is of course, if they are not destroyed to the point where they are not re-useable.

ok..important question.

Based on what I've read, my understanding was that stock cylinders (not the pistons) would not jive with a stroker crankshaft because the stock barrels for 66/71mm weren't long enough.


so what's the deal...is this correct or not?

that's when cylinder shims come into play

but 7mm worth potentially? seems like a lot

All cylinders are the same height wheather 1.7 1.8 or 2.0. The location of the piston pin is the difference between a 66 and 71 stroke. If you use a 2.0 piston with a 78 stroke you need to use shims to space out the cylinder.

But, one of the main reasons to use the 22mm wrist pin is to use a longer (and lighter) rod for a more friendly rod ratio. So, when you use the longer rods, even with the relocated wrist pin, you can end up with a wider (more shims) motor, correct? I think some early bug guys doing T4 conversions use the stock rods, to keep the motor narrow for better clearance.

Also when you are doing the math of 78mm-71mm=7mm, remember the 7mm is split between the bottom of the stroke and the top of the stroke so its actually 7mm/2 or 3.5 mm.

There are no special cylinders for the 78 stroke. Only pistons with a different wrist pin diameter, and location. These pistons allow a wider variety of rod selection.

Here is the combo that is proven to easily interchange and assemble easily.

RAT 2036 crank- 78.4mm
RAT 9500 cam (thats already a reduced B/C for strokers up to 80mm with our rods
RAT 3030 rods in 5.4 length
RAT 6330 P/C kit, these use the KB 96mm pistons and the AA cylinders and work well together.

That will drop right in, no clearancing needed at all.. expect to need .110-1.40 cylinder shim depending on the heads you use to attain a .040 deck height. This arrangement works best at 9:1 CR for most altitudes less than 5,000 feet..

BUT that cam requires compatible heads with correct port manipulation and valve sizes- skimp here and you may as well not een build the engine.

As you can see, we removed the guesswork.

Thanks for the response Jake.

As you might have seen from the order requests, I went for the 2037 crank and 3030 rods...and its now become apparent that I should go for 6330 P+C kit as well.

Not to mention some other stuff but I'm buying in chunks....

cool!
what are you planning for heads?

I have some rebuilt 1.8s with 42/36 valves and the exhaust ports have been tweaked a bit to help keep the temps down.

I know...they may run a bit hot and the engine might not be as efficient as possible, but based on cost and what I plan to use the car for it seemed like a good place to start.