Cadillac 331 pistons

[Flo]

A buddy of mine (his name on here is "germaninline4" afaik) recently bought pistons from Egge for the `59 390 Caddy rebuild of his wife. He said, they seemed really decent quality for a solid stock rebuild and used them.

He was crew chief at Mercedes formula 1 at one point, so I trust his judgement.

Obviously no telling, if the 331 piston is the same quality, but the stuff made by Egge themselves, which I have seen looked decent stock replacement.

Greets
Flo

[NormS]

The engine I'm working on will have some mildly ported heads,Stromberg tri-power carburetion,and a newer design cam with considerably quicker ramps than the original factory cam, or the cams made by most of the cam grinders that have the cam cores for these vintage engines. So it will be making a little more power than stock. The intention is to not take it over 5000 rpm.

[NormS]

Thanks, guys, for your input. We've decided to go with some Autotec pistons from RaceTec. The guy, at RaceTec, that I talked to assured me that they have forgings tall enough for these pistons, and the price was considerably lower than I expected. He had been monitoring this thread , and had already consulted their design engineer when I called.

[GerryP]

...He had been monitoring this thread , and had already consulted their design engineer when I called.

That's customer service.

[pdq67]

Racetec can make you a custom set in their AutoTec line

Their AutoTec customs are quite economical compared to everyone else's customs.

If you need any help with it I'm a dealer

Go to this page below and click the 3rd link for custom order form

http://racetecpistons.com/pages/forms.php

OK, then please post up what they want for these.

"by pdq67 » Tue Aug 21, 2018 5:01 pm

I will say that way back in say the early '70's when I put my old junk301 together, I bought W/JCW steel-strutted cast 1/8" over 283 pistons that had 1/8" tall 1/2 round domes like the 290 and 315hp engines had.

Cost all of $39.95 per set of 8 or so back then. I ran the dog-shit out of them! Many a 7,500 rpm blast!

I think they were either Badgers or Simplex/Triplex(??). I went to buy another set for another 301 and couldn't find them anywhere.."

pdq67"

[resurrectionjoe]

Racetec can make you a custom set in their AutoTec line

Their AutoTec customs are quite economical compared to everyone else's customs.

If you need any help with it I'm a dealer

Go to this page below and click the 3rd link for custom order form

http://racetecpistons.com/pages/forms.php

OK, then please post up what they want for these.

"by pdq67 » Tue Aug 21, 2018 5:01 pm

I will say that way back in say the early '70's when I put my old junk301 together, I bought W/JCW steel-strutted cast 1/8" over 283 pistons that had 1/8" tall 1/2 round domes like the 290 and 315hp engines had.

Cost all of $39.95 per set of 8 or so back then. I ran the dog-shit out of them! Many a 7,500 rpm blast!

I think they were either Badgers or Simplex/Triplex(??). I went to buy another set for another 301 and couldn't find them anywhere.."

pdq67"

I'd have to know specifics to give an accurate quote as there are options available on a custom piston that can vary the price.

If you'd like to PM me with specifics I could give you a quote but I suggest you sit down before you read it because the pistons are going to cost a bit more then $39.95

[Pro-SeriesFab]

Any reason why you can't bore the cylinders out .006-.007" and run some 97mm stuff? There's a couple of interesting choices there.

[PackardV8]

Any reason why you can't bore the cylinders out .006-.007" and run some 97mm stuff? There's a couple of interesting choices there.

The obsolete stuff generally has a much higher piston compression height than newer engines. FWIW, the Cad 331" has a 2.010" compression height.

What are the heights on the 97mm you were suggesting?

[pdq67]

Jack,

Good point!!

pdq67

[DCal]

Any reason why you can't bore the cylinders out .006-.007" and run some 97mm stuff? There's a couple of interesting choices there.

The obsolete stuff generally has a much higher piston compression height than newer engines. FWIW, the Cad 331" has a 2.010" compression height.

What are the heights on the 97mm you were suggesting?

I thought he meant that there is good ring selection at 97mm bore and he's right.

[piston guy]

Well under $800 from Autotec at "retail" MUCH less than the cost of EGGE's.

[NormS]

Actually, the compression height for the 331 Cadillac is 2.093". I found very few other engines were even close to that. From my initial measurements, it looks like I'll need a compr height of over 2.105" to get closer to zero deck. I'm trying to close up the quench clearance to around .035", so that this engine has better detonation resistance on the crappy pump gas that it will be running on. I was assurred that the taller AutoTec piston forging could handle this increase in compr height.

[NormS]

Actually, the compression height for the 331 Cadillac is 2.093". I found very few other engines were even close to that. From my initial measurements, it looks like I'll need a compr height of over 2.105" to get closer to zero deck. I'm trying to close up the quench clearance to around .035", so that this engine has better detonation resistance on the crappy pump gas that it will be running on. I was assurred that the taller AutoTec piston forging could handle this increase in compr height.

[PackardV8]

Actually, the compression height for the 331 Cadillac is 2.093". I found very few other engines were even close to that.

Close, but not quite; the '55 Packard 320" V8 has the same bore diameter as the 331" Cad and a 2.072" compression height.

From my initial measurements, it looks like I'll need a compr height of over 2.105" to get closer to zero deck. I'm trying to close up the quench clearance to around .035", so that this engine has better detonation resistance on the crappy pump gas that it will be running on. I was assurred that the taller AutoTec piston forging could handle this increase in compr height.

Have you calculated the compression ratio? Kind of a Catch 22, as that additiona compression height may add .3 compression, so the gain in quench has to work with the higher compression. Since they'll be custom pistons, maybe investigate having them dished.

[Truckedup]

Actually, the compression height for the 331 Cadillac is 2.093". I found very few other engines were even close to that. From my initial measurements, it looks like I'll need a compr height of over 2.105" to get closer to zero deck. I'm trying to close up the quench clearance to around .035", so that this engine has better detonation resistance on the crappy pump gas that it will be running on. I was assurred that the taller AutoTec piston forging could handle this increase in compr height.

Tight quench is always good but keep in mind when the Caddy engine came out in 1949, low octane fuel was very common.I believe that was the "Kettering" engine head design, reasonable compression on crappy fuel?