Did I fuck up by not lapping the valves?
#1
Honda-Tech Member
Thread Starter
Did I **** up by not lapping the valves?
So I have this K24A4 in my 2003 accord and it had a no compression issue when I bought it. The guy I bought it from said the mechanics believed it jumped timing due to a bad tensioner and probably bent some valves.
So I pull the engine, it does look like the intake cam was clocked wrong at TDC so I do believe that it jumped timing.
I pull all 16 valves and the exhaust valves look fine, but there were 4 bent intake valves, 1 per cylinder. Bent just slightly.
So I replace all 8 exhaust valves and lap them because the valve seats looked crusty and covered in crud. But I just replaced the intake valves with no lapping.
I put everything back together, I time everything correctly (so I think) and I try to crank it and it sounds like 0 compression.
I do a compression test and it's practically 0 across the board, maybe 10-15 psi in 2 or 3 cylinders.
What the hell? Did I **** up by not lapping the intake valves? The seats looked OK, not perfect but no crud on them really.
Brand New valves. Brand new Felpro head gasket. Brand new timing chain, tensioner, and guides.
So I pull the engine, it does look like the intake cam was clocked wrong at TDC so I do believe that it jumped timing.
I pull all 16 valves and the exhaust valves look fine, but there were 4 bent intake valves, 1 per cylinder. Bent just slightly.
So I replace all 8 exhaust valves and lap them because the valve seats looked crusty and covered in crud. But I just replaced the intake valves with no lapping.
I put everything back together, I time everything correctly (so I think) and I try to crank it and it sounds like 0 compression.
I do a compression test and it's practically 0 across the board, maybe 10-15 psi in 2 or 3 cylinders.
What the hell? Did I **** up by not lapping the intake valves? The seats looked OK, not perfect but no crud on them really.
Brand New valves. Brand new Felpro head gasket. Brand new timing chain, tensioner, and guides.
#4
Honda-Tech Member
Thread Starter
Re: Did I **** up by not lapping the valves?
Final entry on this thread. I fixed the issue.
The issue wasn't the valve seats, I pulled the engine, pulled the head, and used valve grinding compound on all the valves only to put it all back together and still have 0 compression across the board.
Turns out the new valves were a hair longer than normal and that put the valve lash so tight that it actually never fully closed the valves. I re-adjusted the valves and now it runs well.
The issue wasn't the valve seats, I pulled the engine, pulled the head, and used valve grinding compound on all the valves only to put it all back together and still have 0 compression across the board.
Turns out the new valves were a hair longer than normal and that put the valve lash so tight that it actually never fully closed the valves. I re-adjusted the valves and now it runs well.
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