bluebalt07

iTrader: (8)

Swapped the head out on my car because the one on it was leaking oil. Got the timing set but when we tried to start it we only have compression on 1 & 3. We turned the motor over by hand before trying to start it to make sure it was in time so we didn't bend any valves so we know it's not that but we are at a loss. The head is a remanufactured one that came fully assembled. Obviously at least one valve on each cylinder isn't sealing but does anyone have any idea why or has anyone else had this happen?

BLAZIN07SS

iTrader: (7)

dumb question but on the compression test you made sure that each piston was at top dead center when being tested?

Bika

iTrader: (3)

even if the engine were out of time slightly it would still have compression. I believe we can be up to 3* out before we get valve contact.

Have you rotated the engine with the valve cover off to see whats opening and what isnt?

Bika

iTrader: (3)

I think you are confusing compression test with leakdown.

HyperMuffin

It makes no difference when doing a dry or wet compression test.

bluebalt07

iTrader: (8)

Yes when we turned it over by hand we had the valve cover off the whole time. When it was out of time and we tried to turn it over by hand we could feel it hitting the valves and it was only 1 or 2 links off on the chain

LS6Rally

iTrader: (14)

where was the old head leaking oil?

BLAZIN07SS

iTrader: (7)

ugh brainfart i fail

a leakdown test really should be the next step though

Coblasts

Remember,
Intake,compression,power and exhaust
Being at tdc isn't enough ,you have to be on the right stroke!

bluebalt07

iTrader: (8)

It was leaking around the timing chain tensioner. The shop that put the head together said that when they assemble the head they turn the cams so that the lobes are fully pushing down the lifters to bleed the air out of them but sometimes they don't let it sit quite long enough and that keeps the valves from fully sealing til the air bleeds out. Could it be something simple like that?

bluebalt07

iTrader: (8)

That wouldn't explain having compression on 1 & 3 and no compression on 2 & 4.

Bika

iTrader: (3)

Yes. Leakdown time.

Are you saying you had Zero compression on 1 and 3?
What was the gauge actually reading?

bluebalt07

iTrader: (8)

No 1 & 3 had compression. 2 & 4 had none and this was with the trusty finger test because we didn't have a tester with us today.

Bika

iTrader: (3)

sorry i had it backwards. but if there is zero compression that head has to be fuct.

Where in Ohio are you?

bluebalt07

iTrader: (8)

Seems to be zero but there may be the slightest bit. Could it be what I said about the lifters not having all the air bled outta them and not letting the valve seal?

I live in a little town called Bloomingdale, about an hour west of pittsburgh, PA.

Bika

iTrader: (3)

Ah. yer way down south. I'm up above Youngstown.

Im not sure, but I dont think its a lifter problem. if a lifter is collapsed the valve will be closed, not stuck open.

bluebalt07

iTrader: (8)

Yeah I'm about an hour and a half from Youngstown.

Idk what the deal is because the cams turn over fine and the valves move fine but apparently they just aren't closing fully

Bika

iTrader: (3)

you need to find a shop to do a leakdown. it will reveal which valves arent sealing.

bluebalt07

iTrader: (8)

I'm also gonna call the company that built the head to see what they have to say because it came with a warranty but I'll get a leakdown test done on it. I'm really hoping this head is useable though

bluebalt07

iTrader: (8)

Just called the company and the only thing they said was that it could be 180 degrees outta time but some of the valves aren't closing so that can't be the problem.

bluebalt07

iTrader: (8)

Pulled the head off again and rotated the cams while shining a light through the intake and exhaust ports to see which valves weren't sealing. There only seems to be 2, an intake valve on #4 and an exhaust valve on #2. Is there anything I can do besides send it back to the company and have them redo the lifters and valves on those cylinders?

Bika

iTrader: (3)

Yup. They duffed the valves. You can take the cams out and disassemble the springs, valves, and lifters to see if they were installed wrong. Just be careful not to drop a valve into the cyl.
They may have just reused valves that were bad/bent.