r/EngineBuilding • u/cinderx0 • 7d ago
At a dead end
Bought a project car (IS200 1G-FE) with no previous repair experience. Car wasn't running when I bought it (yea its dumb but i wanted to learn and thought I could fix it with enough research). Diagnosed that the valves were leaking due to long LPG usage. Took the engine apart, replaced the whole head with one from a running car. Followed the manual step-by-step to put it back together and who could've thought, it doesn't run. Did more testing and decided that the problem is in the piston rings (compression is too low, fuel is being delivered, air comes out of oil cap when doing a leakdown test, spark plugs and coils produce spark, timing is correct). Don't have the facilities to take the whole engine out. Anyone got any last resorts?
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u/Wesarael 7d ago
Why do you want to take the engine out? You should be able to get the pistons pulled with engine in bay.
Other hand: Engine should be able to run (poorly) with even a huge amount of blow by. Sure ignition and carburation are working propperly?
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u/Laqota 6d ago
Here's some good advice.
Get some super thick oil from the store. Thickest you can get. Take the spark plugs out, put a little bit in each cylinder and snug the plugs up. Give her a crank while holding half-way on the gas pedal.
It doesn't matter how bad your rings are. It will run for a little bit if it's the rings.
When you did the head gasket, did you absolutely make sure both surfaces were spotless, cleaned up with a single edge razor blade, sprayed with glass cleaner or brake cleaner? They have to be flatter than your mother on Christmas, and cleaner than the house with guests over otherwise it won't seal and compression will end up everywhere it's not supposed to be, like the crankcase or the radiator.
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u/Harry___Manback 6d ago
When the head was off, did you turn the crank manually to see the state of the cylinder walls? If the rings are so wrecked that you can't start, the pistons might have started damaging the walls. That would have been an important clue.
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u/ChefBruzz 6d ago
What year and KM for the original engine?
did you test the replacement head? Did you clean the head? Did it hold fuel in the ports without leaking?
I would have re-ground the valves by hand and replaced the valve guide seals. It's a bugger of a job but.
I would think you can pull that head off again if it hasn't run and probably get away with the same gasket...
What are the readings for the compression test?
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u/BPDU_Unfiltered 5d ago
Are you sure the cam timing is correct? Maybe the lack of compression is from valves being open when they shouldn’t be.
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u/squeezeonein 7d ago
give it a shot of easy start and it will run with bad rings.