what should I gap the rings to on my blower shortblock i'm building

DarkoStoj

DarkoStoj

A mysterious figure named Darko
well I'm building a new shortblock for the blown 671 67 camaro and need to set the ring gaps either today or tommorow. I was planning on around 15-16lbs of boost, but i'd like it to be able to handle around 20lbs just for the added margin I guess.

its a TRW forged blower piston part # L2441
5/64 top 5/64 2nd 3/16 oil ring

I just want to have the 2nd ring opened up a couple thou more than the 1st ring. I bought the parts off milan, they are all new but I don't have the instructions for the rings, or know what kind they are.

also whats a good clearance to run on the rod bearings? I normally ran a .002 on the mains, is it the same for the rods?
 
I'm guessing based on some of your other posts that you probably don't have very high quality american made pieces in your car so .002" would be pretty bad on the mains I'm guessing. If this is an eagle crank I would push for .0028-.0035" on the mains and .0023-.0028" on the rods. Sometimes the foreign machining isn't exactly 100% eccentric and non-tapered and that + tight clearance = spun bearing. Generally it doesn't hurt to go on the loose side as long as your oil pump is up to the task.

As far as the rings go please contact the manufacturer because the expansion rate on the metal plays a big role.
 
LT1Pat said:
I'm guessing based on some of your other posts that you probably don't have very high quality american made pieces in your car so .002" would be pretty bad on the mains I'm guessing. If this is an eagle crank I would push for .0028-.0035" on the mains and .0023-.0028" on the rods. Sometimes the foreign machining isn't exactly 100% eccentric and non-tapered and that + tight clearance = spun bearing. Generally it doesn't hurt to go on the loose side as long as your oil pump is up to the task.

As far as the rings go please contact the manufacturer because the expansion rate on the metal plays a big role.
Click to expand...
its a forged GM steel crank with carrilo H beam rods
 
Ductile ring or Moly faced ? Take some picture of the ring. Figure 26-28 thousandths on the top and 30 on the bottom. Ring gap is not really going to affect power but to little of it and watch it butt them up.


DarkoStoj said:
well I'm building a new shortblock for the blown 671 67 camaro and need to set the ring gaps either today or tommorow. I was planning on around 15-16lbs of boost, but i'd like it to be able to handle around 20lbs just for the added margin I guess.

its a TRW forged blower piston part # L2441
5/64 top 5/64 2nd 3/16 oil ring

I just want to have the 2nd ring opened up a couple thou more than the 1st ring. I bought the parts off milan, they are all new but I don't have the instructions for the rings, or know what kind they are.

also whats a good clearance to run on the rod bearings? I normally ran a .002 on the mains, is it the same for the rods?
Click to expand...
 
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