371 Old's piston's, a technical question ?

G

Greg out west

Senior Member
Hi Guy's


I have a "B" engine that somebody built back in the late 50's..They set it up to used 371 Old's piston's (block bored out to 4") The guy I got it from said it was going to be use as a dirt track racer,,but it never got used & sat for 40+ year's.


I had the engine finished & assembled it myself..The Engine run's very good & I'am happy with it...Here's the question ?. Somebody was asking about installing small block chey piston in his A block .



One of the poster said to install the Chev piston backward's to reduce the offset the A block has in the Crank...I'am thinking maybe the Old's piston have a offset built into them & combined with what the block has, it might be too much thrust on the piston...Should I turn the piston around ?



Thank's for the help,

Greg out west
 
I have a model A block , with lightened and trimmed 1956 354 hemi pistons in it , and they are installed with the front marks facing the rear of the block..


JIMI
 
Greg out west said:
Hi Guy's


I have a "B" engine that somebody built back in the late 50's..They set it up to used 371 Old's piston's (block bored out to 4") The guy I got it from said it was going to be use as a dirt track racer,,but it never got used & sat for 40+ year's.


I had the engine finished & assembled it myself..The Engine run's very good & I'am happy with it...Here's the question ?. Somebody was asking about installing small block chey piston in his A block .



One of the poster said to install the Chev piston backward's to reduce the offset the A block has in the Crank...I'am thinking maybe the Old's piston have a offset built into them & combined with what the block has, it might be too much thrust on the piston...Should I turn the piston around ?



Thank's for the help,

Greg out west
Click to expand...

I think I'm the one that posted about putting the pistons in back wards. I'm not sure how much off set the olds piston have, and what kind of skirt the pistons have. But as a guess I would say yes turn them around.
 



Hi Paul George & Jimi



I think George said that with the double "offset" it was too much & would put too much pressure on the thrust side of the piston..I read in some book that the A has 1/8th off set in the block,Plus I'am thinking the Old's piston's have about .060 offset in them.. So when George posted about the Chev piston installed backward's, got me to thinking


Makes sense,,as these are V8 piston's, So I'am thinking the Old's crank is centered in the block & they get the offset via the piston's. Am I right ??? Look's like I'll be turning the piston around !!!



Thank's guy's
 
Greg out west said:
Hi Paul George & Jimi



I think George said that with the double "offset" it was too much & would put too much pressure on the thrust side of the piston..I read in some book that the A has 1/8th off set in the block,Plus I'am thinking the Old's piston's have about .060 offset in them.. So when George posted about the Chev piston installed backward's, got me to thinking


Makes sense,,as these are V8 piston's, So I'am thinking the Old's crank is centered in the block & they get the offset via the piston's. Am I right ??? Look's like I'll be turning the piston around !!!



Thank's guy's
Click to expand...

Yes you are, but if the piston has a slot in the skirt. That might not be good for the thrust side.
 
I also use the olds pistons I run them front to front but also worry about the offset
I have them out a few times and have wear on the thrust side that looks normal+
I Wonder what others are doing
Colin
 
I run 324 Olds pistons in a couple of my engines, front-to-front and have had good results. The 324 is 3.875" bore, like the Model A. Mine are +.060"
 
Other than original pistons not being available, which I think they are readily available these days, why would one run a 324/271 or Hemi piston?

Forged? Higher compression? Lighter? All the above?

Thanks
 


Hi Guy's


The 371 (CI) Old's piston, I'am using are much stronger built than the A piston,,I'ed think they'ed have to be,,was used in a 300 hp V8 !!


My engine came with them so decided to use them...Also a better ring setup...I'am thinking most of this part swapping came from the old Hot Rod day's,,,


I'am sure Jim & George will chime in on this... Jim, those 324 sound like a good deal..Also thank's for the club magazine you sent me year's ago..How you get a A & B engine to go 200 + is amazing !!!!!


Greg out West



 


Hi Chuck


This "B" engine is new,,Just test run so far. Hasn't been on the road yet, still working on the rest of the car...


Greg out West
 
Olds pistons, and other late-model pistons are stronger and have thinner rings which seal better and last longer. The ideal piston is one that does all the above plus is lighter,l such as Ross, which are forged pistons.
 
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