I assembled an LY6 based 370 for a friend in July 2013. All fresh/new stuff, block was nice (had come out of truck because of 1 wiped out lifter, but all lifter bores looked fine). Lifters were soaked overnight like you're supposed to, and the engine was assembled with liberal amounts of Clevite bearing guard assembly lube. Engine sat for a year and a half, but was turned over a couple times during the wait.
Fast forward to yesterday. Used a pump to prime the engine through the valley cover port. With the valve covers off, we were only seeing oil come up through the pushrods on 4 driver side rockers and 2 passenger. Thought maybe we forgot DOD tower seals, but double checked and everything looks kosher there. If it matters, the rockers we're seeing oil on are #1 I/E, #5 I/E, #4 I and #6 I.
Now that all 6 quarts were in the engine, pulled the prime tool off and stuck a mechanical gauge in the port. Pulled all the spark plugs and cranked engine with the starter, makes 40-45psi no problem, however now not really seeing any oil to the top. So we unbolt all the rockers, and clean out all the pushrods (the assembly lube was more goopy than when new). Also look down through the heads, none of the oil holes in the lifter plungers looked plugged. Reassembled everything with oil, cranked with starter. Now seeing small amounts oil, but through only the exact same rockers as before.
After a phone call and some head scratching, convince myself that starter speed (150-200rpm) just isn't enough. Surely it'll all come alive at actual running speed. Hook everything up and fire it up for the very first time. At idle it makes 62psi and with a little bit of rev it goes to 73psi (which should basically be the bypass pressure). Let it run for 15-20 seconds, kill it. Pull both valve covers, only those same rockers are wet, the rest look bone dry. WTF?
Something stuck in the lifters? They're all "hard" if you push on the pushrod side of the rockers (i.e. I'm convinced they're either primed or just stuck).
Bearing clearances are fairly loose as this is an iron block build that was planned to be basic turbo thing. Mains were .0032-ish, rods were .0028-.0030. Oil pump is a GM 17801830 from Tooley that I did the simple porting on and 1 shim under bypass spring. Lifters are Delco LS7 lifters, LS2 lifter trays. LS9 cam (so OE cam, lifters, trays, etc, all the ports and passages should be lining up on problem). Pushrods are Tooley 3/8 7.400". The holes in the rockers are clean and clear. I had a theory that maybe since the bearing clearances are loose that the oil is head "down" through the path of least resistance instead of up through the pushrods??
I believe that since it's making pressure while cranking and running that all the fundamental things are correct like the gallery plug, the barbell, the crossover gasket on rear cover, etc. Half convinced that the lifters aren't transferring oil to the pushrods, just not excited to pull the heads to put a fresh set in.
Any thoughts or theories are warmly welcome. I'm in Denver helping out only until tomorrow, then will only be remote assistance again.
Thanks in advance,
TJ
Fast forward to yesterday. Used a pump to prime the engine through the valley cover port. With the valve covers off, we were only seeing oil come up through the pushrods on 4 driver side rockers and 2 passenger. Thought maybe we forgot DOD tower seals, but double checked and everything looks kosher there. If it matters, the rockers we're seeing oil on are #1 I/E, #5 I/E, #4 I and #6 I.
Now that all 6 quarts were in the engine, pulled the prime tool off and stuck a mechanical gauge in the port. Pulled all the spark plugs and cranked engine with the starter, makes 40-45psi no problem, however now not really seeing any oil to the top. So we unbolt all the rockers, and clean out all the pushrods (the assembly lube was more goopy than when new). Also look down through the heads, none of the oil holes in the lifter plungers looked plugged. Reassembled everything with oil, cranked with starter. Now seeing small amounts oil, but through only the exact same rockers as before.
After a phone call and some head scratching, convince myself that starter speed (150-200rpm) just isn't enough. Surely it'll all come alive at actual running speed. Hook everything up and fire it up for the very first time. At idle it makes 62psi and with a little bit of rev it goes to 73psi (which should basically be the bypass pressure). Let it run for 15-20 seconds, kill it. Pull both valve covers, only those same rockers are wet, the rest look bone dry. WTF?
Something stuck in the lifters? They're all "hard" if you push on the pushrod side of the rockers (i.e. I'm convinced they're either primed or just stuck).
Bearing clearances are fairly loose as this is an iron block build that was planned to be basic turbo thing. Mains were .0032-ish, rods were .0028-.0030. Oil pump is a GM 17801830 from Tooley that I did the simple porting on and 1 shim under bypass spring. Lifters are Delco LS7 lifters, LS2 lifter trays. LS9 cam (so OE cam, lifters, trays, etc, all the ports and passages should be lining up on problem). Pushrods are Tooley 3/8 7.400". The holes in the rockers are clean and clear. I had a theory that maybe since the bearing clearances are loose that the oil is head "down" through the path of least resistance instead of up through the pushrods??
I believe that since it's making pressure while cranking and running that all the fundamental things are correct like the gallery plug, the barbell, the crossover gasket on rear cover, etc. Half convinced that the lifters aren't transferring oil to the pushrods, just not excited to pull the heads to put a fresh set in.
Any thoughts or theories are warmly welcome. I'm in Denver helping out only until tomorrow, then will only be remote assistance again.
Thanks in advance,
TJ
