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L28 with possible sticky valve

Old 05-22-2005, 08:17 PM
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Smile L28 with possible sticky valve

Peoples,

I have an L28 with a possible sticky valve. It has an irregular knocking type noise from the top of the motor around the 4 or 5 cyclinder. It does affect the idle. It sometimes stalls the engine. This is just sitting in the garage.

When I bought the vehicle it had been sitting for 8-10 months and wasn't runnig smoothly. After a upper motor cleaner (nitrous and water and other magic stuff) and a huff and puff through the carby, it wasn't making noise. But since I have been fixing the the carby and adding a set of extracting and loosing the keys (had to get new ones made up), it has started again. Will flushing the oil be enough to unstick the valve?

Any suggestions or questions welcome.

Joe
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Old 05-23-2005, 06:03 PM
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First I would do a compression check. Then I would pull the cam cover and see what is going on in there. Some mixes through the carb can burn the valves so be conservitive with that stuff because you may have an injector not working and a hot mix of nitrous with no gas can do in an exhaust valve real fast. There are additives you can put in the oil, one is made by Lucas and is very affective, pour it over the valve train and button her back up. If that helps then you can change your oil regularly. Avoid the motor flush if you can, it can cause those old seals to start leaking.
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Old 05-28-2005, 07:35 AM
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Thanks...will be pulling the cam cover off in the morning. But it doesn't look good atm because I did a compresion test today and found he no. 6 sparky was [email protected]#ked up. It had been hit by something. The valve maybe be hiting it. The only other thing is it might be something in the actual cyclinder from when i was doing the exhaust and inlet manifolds.

So in general..."I'm Not HAPPY JAN"!!!!

-----UPDATE--------

No 1 has now been hit!!!

I have removed the rocker cover.

I have not found too much wrong with the whole valve and cam assembly. The pistons turn straight away (no looseness that I can see) throught the spark plug holes. Going to redo the valve clearences and see if that makes a difference.

Last edited by bigjoe; 05-29-2005 at 07:33 AM. Reason: Update
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Old 05-31-2005, 05:34 PM
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I had my mechanic mate come around last night finally. He believes the head has been arggressively shaved. The spark plugs that are stanard size are too long and hiting the pistons or could be the rear baearings on the crank shaft.

The old man (father) made up some spacers for the current plugs and the engine is running smooth. idle is a bit rough but that is the timing I think. Timing was done with the spark plug problem.

Hopefully the new dizzy is going to correct the problem with the spark. In the end I'm really hoping I don't need to rebuild the bottom end of the motor.
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