360 Crate Short Block

[George G. Leverette]

Remember the saga with the 360 crate short block that grenaded with about 500 miles on the engine? Well the replacement block is blowing white smoke out of both pipes. The car was running good, went on a 120 mile trip and the engine light came on indicating low oil pressure, the oil was checked immediately prior to the trip. It took two quarts to fill the engine. dirving along I noticed the smoke when leaving a light. The compression reads:

#1-160 #2-180
#3-160 #4-170
#5-165 #6-155
#7-160 #8-170

The spark plugs were black from excess fuel
Coolant level normal
Slightly rough idle

What other trouble shooting steps are needed to determine oil consumption, there are no leaks evident?

[peg leg]

The stories about crates seem to be true ones. Much maligned on this site.
It really sounds like your oil consumption problem is valve seal related. Your compression is excellent. Black plugs indicates oil burning, not fuel burning rich. You either did not get valve seals at all (doubtful) or the wrong seals were installed. Possible that the valve stems were not lubed before install, and the seals burned up. Hell, they could be installed wrong, not pushed all the way down the stem to the casting.
Ron

[George G. Leverette]

Thanks, will check that tomorrow. Any other siggestions?

[peg leg]

Can you pull a valve spring and check to see if the valves are the right stem diameter for the guides in the head? Could remotely be the cause if they are too small.
Ron

[72Challenger]

I notice this is a short block, not a complete crate engine. Where did the heads come from? Possibly worn guides? Stem to guide clearance should be checked, as peg leg suggests. Not expecting the wrong valves to be installed, because you certainly would have noticed that on the last engine. But perhaps excessive wear could exist.

[peg leg]

I had a Suburban which, like most chubbies, split it's heads nearly in two. I ordered world products heads with 2.02 valves. They came with 2.02 seats and 1.88 valves!
Anywho, I talkd with the guy who's machining my 360, and he suggests that the rings could be bad, in spite of the compression readings you are getting. Look at the hole with the lowest reading, and you might see scoring there.
Ron

[72Challenger]

Leakdown tests are very revealing for these sort of problems.

[pcrmike]

Had something similar happen on my 360 in the crew cab, it was due to the fiber intake gaskets I used, and the intake. THe intake had a crack in the heat crossover, so I replaced the gaskets with fiber (racing) gaskets without the hole for the crossover, to "block" it off. After about 400 miles, some oil had accrued up there, and as I am driving, it blew a WAD of white smoke out and smiked for the next 20 miles home. It didn't miss or anything, but used oil like crazy. After removing the intake, found the holes in teh gaskets, burned thru, and released a bunch of oil into the exhaust. I would check the intake gasket first, and if all the plugs are showing black, I am inclined to suggest perhaps PCV sucking oil into the intake. Check under the carb. You never know... :-) Good luck PCRMike