even with a blown headgasket shouldnt I still get some compression reading? What are typical symptoms of a severely blown headgasket?
Compression through carb and intake
- Thread starter baktasht
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StarTech
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It is possible to have zero compression with a blown head gasket if blown severely enough. I know for sure as I just repaired one a few weeks ago that was that bad. It had nearly an inch of the gasket missing where the metal core melted away. The head also melted away the two plastic push rods guides. With only a half of oil left in the engine I was thinking more along the lines of a broken rod but it was the head gasket instead.
But normally it is the heavy oil assumption that kills the engine where the head gasket blows between the cylinder and push rod galley; unless, caught before severe damage occurs.
But normally it is the heavy oil assumption that kills the engine where the head gasket blows between the cylinder and push rod galley; unless, caught before severe damage occurs.
Got the valve cover off and it looks like the Intake valve is moving a very small amount and the exhuast valve not at all. Pulled the cylinder head and it looks like the previous owner tried a DIY repair and made a few mistakes:
* He put the intake pushrod on exhaust and the exhaust pushrod on the intake
* Bend the aluminum pushrod which was placed incorrectly on the exhaust side
* He lost one of valve caps. only the intake had a cap
Both valve seats look okay. TONS of carbon build up everywhere which I will clean up. The valves both seem to move freely. There was also a broken piece of the plastic pushrod guide in there which I took out. Was also missing the intake tube o-ring. Was also missing one valve cover bolt and a few other bolts on shrouds. So I don't know what on earth happened to this thing before I got it. So many things put back together incorrectly.
I straightened the aluminum pushrod with a metal working hammer and put things back together, seems everything moves correctly now. At least visually.
I have the following on order. Let me know if you see anything else I'm missing:
* head gasket
* valve cover gasket
* exhaust and intake gaskets
* Intake oring
* Intake pushrod
* Exhaust valve cap
* Carburetor, gaskets, and fuel shut off valve
I bought this thinking it was just a carb replacement it needed. But if I can get it running after all this clean-up and some new parts hopefully it will run well for a while.
Thanks again for all the help so far!!
* He put the intake pushrod on exhaust and the exhaust pushrod on the intake
* Bend the aluminum pushrod which was placed incorrectly on the exhaust side
* He lost one of valve caps. only the intake had a cap
Both valve seats look okay. TONS of carbon build up everywhere which I will clean up. The valves both seem to move freely. There was also a broken piece of the plastic pushrod guide in there which I took out. Was also missing the intake tube o-ring. Was also missing one valve cover bolt and a few other bolts on shrouds. So I don't know what on earth happened to this thing before I got it. So many things put back together incorrectly.
I straightened the aluminum pushrod with a metal working hammer and put things back together, seems everything moves correctly now. At least visually.
I have the following on order. Let me know if you see anything else I'm missing:
* head gasket
* valve cover gasket
* exhaust and intake gaskets
* Intake oring
* Intake pushrod
* Exhaust valve cap
* Carburetor, gaskets, and fuel shut off valve
I bought this thinking it was just a carb replacement it needed. But if I can get it running after all this clean-up and some new parts hopefully it will run well for a while.
Thanks again for all the help so far!!
You were right, the exhaust valve was not opening at all. See my post right above this one.
bertsmobile1
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Measure the height of the valves from the floor of the head. It should be identical
Pushrods bend because the valve can not move
Only 3 reasons for this
Valve is hitting the piston
valve is stuck
valve guide has moved & the valve spring is coil bound.
Pushrods bend because the valve can not move
Only 3 reasons for this
Valve is hitting the piston
valve is stuck
valve guide has moved & the valve spring is coil bound.
Good points. Where should I be measuring from and to? Are you revering to the valve stem end of things? Or the valve face?
bertsmobile1
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Valve stem
When you do it regularly you can see it without measuring
The valves are the same length and so are the valve guides
Both are set to the same depth in the head
so the stem ends should sit even when the rockers are removed.
When you do it regularly you can see it without measuring
The valves are the same length and so are the valve guides
Both are set to the same depth in the head
so the stem ends should sit even when the rockers are removed.
Gotcha, makes sense. Will check that tomorrow to confirm how they line up.
Okay, got things cleaned up a little bit. TONS of dirt and old oil/exhaust residue clumped up everywhere, so I would guess it probably did overheat at some point.
Got most of the carbon buildup on surfaces that I could reach cleaned up. Thoughts? Anything obvious I'm missing before I start re-assembly this weekend?
Got most of the carbon buildup on surfaces that I could reach cleaned up. Thoughts? Anything obvious I'm missing before I start re-assembly this weekend?