thmotorsports.com is having a sale on all Supertech pistons. $120 shipped for all four, but with no rings. Rings are still $20 per piston.

Since I have this great opportunity to order pistons, what bore size should I get? 83.5mm would give me room to bore more if anything went wrong with the motor, but at the same time I'm not too concerned about it as I'm not planning on this being my lifelong power making motor. I really want to get a set of 9:1 or higher compression pistons made, but I'm settling for these just to get the car on the road again because of price. That being said, I'm leaning more towards the 84mm set if there are no objections.

Also, has anyone determined the max safe bore we can go with? Float, you went with an 84.5mm bore and think there's still room for more, right? I'm not worried about max bore for off the self pistons, but more like how far can one go in case another set of pistons and a fresh overbore is more viable than a new block.

Never bore a block more than you need to. Especially the CA. SOME CA's (not all, and I think they MIGHT have been just the European ones, but I'm not sure on that either) had an issue with what's called core shift. Basically when the cast the blocks, there was an issue with the cooling ports in between the cylinders. Those passages weren't centered properly and when you bore the engine out, you punch into the coolant passage. It doesn't usually show up until you bore past 83.5mm. Also, NEVER assume you won't have to rebuild again. The rebuild I'm on now shouldn't have happened. If it weren't for an improper engine assembly, it wouldn't be happening. The reason I had to bore out to 84.5mm was because the #4 cylinder had been so badly scored from a piston ring that didn't get deburred that boring out the 84mm didn't remove the scoring. Althought I think beyond 84.5mm is possible, the cylinder walls are getting very thin.

It's not that I don't think it'll need to be rebuilt again, it's that if it does need the cylinders freshened up I don't mind sourcing another block. Although I probably shouldn't think like that. With the other issue with the water jackets possible I think I'll stick with the smaller bore. Thanks for the advice.

http://thmotorsports.com/supertech-perf ... 52780.aspx

Right?

That is a really good deal. I may have to order a set though I wasn't ready to rebuild, yet. The website is kind of vague, though. Are you sure it's 4 pistons with wrist pins?

Just a thought, but is it possible to shave the head down to bump up the compression from 8.5 to 9.0?

Thanks

Milling the block or head to increase compression is never a good idea. It changes the shape of the combustion chamber and the clearance between the piston and the quench pads. It also changes the cam timing, so now you have to buy adjustable cam gears to reset the cam timing.

Got it. Thanks.

I don't think you can get pistons cheaper than that so I might have to do it.

That's definitely for a set of four. The MSRP is the usual for a set of four and the usual price is around $450, but that's with rings. $120 without rings is a great deal. I'm thinking of getting two sets to build a couple motors, but I really want a higher compression motor for when I do a high(ish) horsepower build.

mdb4879 wrote:That's definitely for a set of four. The MSRP is the usual for a set of four and the usual price is around $450, but that's with rings. $120 without rings is a great deal. I'm thinking of getting two sets to build a couple motors, but I really want a higher compression motor for when I do a high(ish) horsepower build.

Same here. I'm running 10 PSI on a DE engine (9.5) and it's nice to have the higher compression, but at this price, I might live with it.

After learning about dynamic compression and why our motors have relatively low compression than newer turbo motors I feel pretty safe with more compression. Better response and more power with less boost sound great to me.

Just be aware that if you're on pump gas, the higher compression ratio can limit the amount of boost you can run before you run into issues with detonation.

Understood. There's plenty of E85 in my area. What compression I go with depends on whether I want to run pump gas or E85 and my cam choice.

Ahh, E85 opens up your options considerably.

Sweet lordy that is cheap.

Do... do I order a set? For the hoard?

My CA18 pile-o-parts is getting very dragon hoard-like, you see.

There's no such thing as too many CA parts!

You're telling me! I'm beginning to feel like TMS over here. Got a whole shed full of CA18 bell housings and engine blocks.

So NOW there's a sale on Supertech pistons......

I ordered an 83.5mm set Wednesday, got an email yesterday saying they didn't have any in their warehouses and they would ship directly from the manufacturer, and got an email today saying they had to cancel the order and give me a refund. So the sale may be a false alarm. I'm going to give them a call Monday and see what the problem was.

Don't deal with that vendor.

Oh, I see you already did and got the same treatment I did on my RB26 piston and rods which made me rush to tell you don't deal with them. The only thing they do fast is charge your credit card. They are bad. http://www.yelp.com/biz/thmotorsports-inc-morton-grove

DO NOT DEAL WITH THAT VENDOR

That's strange. I haven't had any problems out of them with anything else I've ordered, and I've ordered plenty in the past.

My pistons had to get ordered from Supertech warehouse as well. I ordered from FRSport.