old and tired

[jatibb]

would low compression (very low) keep a 22r from starting. my sons truck slowly lost power last night and now wont start. we checked timing, adjusted valves, checked plugs, for spark and fuel delivery. cannot get to fire. plugs showing spark when grounded to fender, wont fire with starting fluid and seems to sound like gas when openeing throttle by hand. compression is, 50/90/90/50. VERY low i know, we know we need a rebuild or replace, but would this keep it from firing and at least running rough. he has been driving it running rough anyway. he needs to get to work while searching for replacement motor or truck.

 

[ToyFamily]

Check this forum: Older Toy specific, alot of 22r(e) info, also check the FAQ there (at the top)
http://pirate4x4.com/forum/forumdisplay.php?f=12
also found this there, might be a dead end, might not.
http://pirate4x4.com/forum/showthread.php?t=724112

Nick

 

[madizell]

Internal combustion engines need three things to work:

1) compression

2) ignition

3) fuel

If you have those three things it will work. If you have them in the correct proportions and at the right time, it will work just fine.

Lack of proper compression can and will stop a motor from working, but when it does, your spark plugs will generally come out wet because with really low compression, the fuel delivered to the cylinder tends to puddle after only a few revolutions, and the engine floods, which leads to cylinder wash down, which tends to increase the low compression problem.

Without casting stones, verify your valve setting procedure to be certain you are establishing gap at TDC on the power stroke, not TDC on the exhaust stroke. Also verify your timing procedure. If you are comfortable that you are doing these parts right, then try this:

Pull all the plugs, pull the coil wire, then crank and test for compression on all cylinders. Then squirt a bit of heavy oil (whatever you have but Lucas Oil Stabilizer works great for this) into each cylinder and test again. If compression jumps up, you have dead rings or too much ring gap, and no amount of over the counter additives will bring it back from the grave. If heavy oil in the cylinder does not change compression, it is more likely the valves warped or mis-adjusted, worn cam lobes, a displaced valve seat, cracked head, or some other issue that is causing the valves or heads not to hold compression.

You can also do a leak test if you have compressed air. I make up a screw in fitting for the spark plug, either from the compression test kit or an old spark plug, then run each cylinder to exactly TDC on the power stroke, then add air to the cylinder. You will be able to hear the leak from either intake or exhaust or engine breather, and you will have a good part of your answer.