long rod 200

peugeot bill

Well-known member
having inherited another 200, this to play with. im looking at building a long rod motor.a 302rod length is 5.09 vs. our short 4.71 rod, this would mean finding a stroker style piston with a 1.21 pin to deck height. it would improve top end, especially above 4000 rpms. there might be a clearance problem,to be seen. but the availibility of good rods are endless. the bottom end can take the rpms if prepped and it's time to develop a practical roller cam system. i think this motor will be dry sumped, too


bill
 
I checked out the ACL link awhile back for the short compressoin height pistons. I think it said "not for Highway use", or something similar. I don't know it that means it is strictly a race type part and won't last much more than a few thousand miles or it might be they haven't done enough testing to give a guarantee for it.

But if you do buy and install them let us know!!! I'm real interested in how the a long rod motor comes out.
 
I think you will find that the 5.09" rod big end width is to narrow. Another option may be 2.0 pinto rods. These measure 4.98" and if I remember right, a .990" big end width.
 
The best option is to use the aftermarket 5" Pinto 2.0 rods which came with the 0.9112" wrist pin, or the stock 2.0 Pinto items which were used with the 0.945" wrist pin. Bore the main bearings to suit the 2.047" crank pin they use.

The smaller Pinto rod pins can be ground out to 0.927" size, or the larger pins bushed to suit the smaller Chevy piston pin.

Only bad thing is that you have to bore 56 thou over. On an old engine, there is a small risk in doing that.

The other options is to long run weld the crank to create a correct rod spacing. If you machine the sides adjacent the rod journal, you will use the added metal as a side support. Then you can run the 302 rod on the thicker six cylinder rod journal. Make sure you don't muck with the fillet radius, or the crank will fatigue crack.

The ACL pistons ride in at 3.68 to 3.74" diameter at an 1.163" tall compression height. They are very strong for non forged items, and have been used on Turbo 250 Falcons in Australia with excellent sucess, as they duplicates of the 2003 XR6 Turbo piston, but are 48 thou bigger and of much better construction. With the right mods, a set of 302 pistons give

7.808"
x______
x|>>>>..|
x|__O__|1.163"
x>>|.|
x>>|.|
x>>|.|
x>>|.|
x>.|O|5.09"
x>..|.|
x>..|.|
x>.|O|1.563"

Crank throw in a 7.808 block is 3.126/2, and this gives enough room for a perfect 0.008" (8 thou) postive deck. With a big 38 to 79 thou thick gasket, it would be okay.
 
first. side clearance on the rod is not a problem,many engines like volvo the rods are narrower than the journal.
second. the 302 uses the same bearing as the six, making installation a snap
third. pistons are lighter too, combined with the rods it should make for a stronger bottom end. less angle on the large ends
and fourth. this is going to be a race engine only, so if it launches we just load up the trailer,go home and start over
 
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