Rebuild Forged Questions

[TORONTOTALON]

Hello Fellow Tuners,

Just so you guys and gals have a little back round about my car I got the bottom end rebuilt all stock De Glazed cylinder walls new rings/pistons new bearings and balanced . I didn't do any sort of break in period like an idiot just started it let it idle bla bla bla. Long story short the rings now hold NO PRESSURE at all the air flows right by them when I do a leak down test.

So my questions are i'm going to be doing new rings and am wondering if I were to decide to do forged internals.

what needs to be done to the motor to take the forged internals before i put them in rebalance or special hone etc.?

Can i just hone the cylinder walls and through in forged piston/rods in?

And why is it when I do a leakdown test I get crazy blow by but I do a Compression test its perfect 145psi across the board?

It is a 6 Bolt and my profile is up to date.

 

[300dollarGSX]

Were the rings gapped correctly? Did you space the gaps apart? Even without breaking the engine in properly, you shouldn't have huge amounts of blowby. You're certain the air is escaping into the crankcase and not through the valves? Odd. Maybe the bore was out of round enough to not make a good seal.

I'm using forged pistons and rods. I had the cylinders bored and had the machinist use a torque plate. The pistons are usually balanced to each other very well, just like the rods. It doesn't hurt to have the entire rotating assembly balanced, though. They removed a bit of material from my crank as the new rod/piston assembly was lighter than stock.

 

[costas14]

after your rebuild dont you just let it idle for a couple minutes then change the oil and drive it at certain rpms?

 

[300dollarGSX]

Normally, it should only idle for a short time to verify timing and check for leaks. You quickly want to put a load on the engine (accelerate rather quickly to ~45 mph or so), then remove the load (let the throttle shut) and let the engine build high vacuum. The load forces the piston rings down in their bore and out against the cylinder walls allowing them to seat properly. Removing load forces them up in their bore also helping them to seat properly. Repeat those steps 2 to 3 times (some say up to 5). Then for the next 500 to 1000 miles or so, vary engine speed.

 

[TORONTOTALON]

Postive its comeing from the crank case i have had the valve cover off when do the test....