October 21, 200718 yr i just got back to NZ....and on firing my brumby(EA81) up found that it had a distinctly tractor'ish sound to the motor....and was as gutless as a lada. it was running on only two cylinders after a little messing with what i thought was an ignition problem...... i found the following compressions #1....0 psi #3....25 psi #2....130 psi #4....130 psi i've just yanked the motor thinking i'd burnt valves or done a major on a headgasket.....got the head off and the valves look good and the headgasket hasn't been leaking. when i was cranking the motor to get the compression readings there was no 'whoosh' of air into or out of #1 sparkplug hole.....and there wasn't anywhere near the amount of air going into or out of #3 compared to #'s 2 & 4.....which got me thinking....can the hydraulic lifters stick so that a valve stays open?
October 21, 200718 yr Author How do the pistons and rings look? all look good....getting new rings just in case but the bores, pistons & rings look ok. even with totaly shagged rings it should still have little bit of compression shouldn't it?
October 21, 200718 yr Sounds like a stuck valve. Could have stuck open or something for a short time. How long was it not run? GD
October 21, 200718 yr Author Sounds like a stuck valve. Could have stuck open or something for a short time. How long was it not run? GD its been run at least a month by my father
October 21, 200718 yr Its been a while since i have seen one of these, but what I would look at is things that are common to both cylinders. That can be a HG, the cylinder head, or something with the cam. nipper
October 21, 200718 yr Author Its been a while since i have seen one of these, but what I would look at is things that are common to both cylinders. That can be a HG, the cylinder head, or something with the cam. nipper i thought about a cam problem...but the one set of lobes run both banks of cylinders an the L/H side was doing its thing without a problem so i ruled out the cam its self as the problem
October 21, 200718 yr i thought about a cam problem...but the one set of lobes run both banks of cylinders an the L/H side was doing its thing without a problem so i ruled out the cam its self as the problem like i said its been a while Can you do a leak down test on the cylinders. Get the valves closed , note where the piston ends up, and pressurize the cylinder. Have you done a wet/dry test? Are there any bubbles in the coolant? nipper
October 21, 200718 yr Author like i said its been a while Can you do a leak down test on the cylinders. Get the valves closed , note where the piston ends up, and pressurize the cylinder. Have you done a wet/dry test? Are there any bubbles in the coolant? nipper can't do a leakdown test as the head is on the bench. there was no bubbles in the coolant and it wasn't loseing any
October 21, 200718 yr can't do a leakdown test as the head is on the bench. there was no bubbles in the coolant and it wasn't loseing any Take the head to a machine shop. They can pressure test it and check for cracks etc. Is the cross hatch pattern still on the cylinder walls? nipper
October 21, 200718 yr Author Take the head to a machine shop. They can pressure test it and check for cracks etc. Is the cross hatch pattern still on the cylinder walls? nipper LOL...yeah that was the first thing i looked for after looking at the valve/seats etc
October 22, 200718 yr Author after scratching my head for awhile i rang a very good mechanic that i used to work with to pick his brain on what the problem could be.....and got told that a cam worn on the back side (opposit the lobe) would cause the lifters to stick and hold valves open....he had exactly the same thing happen on a toyota diesel. so i need a new cam or to get my'n built up then reground....and don't have enough time to pull the motor apart to get the cam out sorted and back together before i need to travel 500 miles to a new job.....so i'm off to the local subaru wreckers to try find a replacement motor to get me going till i can rebuild my one....with a few select mods along the way....like 60thou off the heads:grin:
October 22, 200718 yr after scratching my head for awhile i rang a very good mechanic that i used to work with to pick his brain on what the problem could be.....and got told that a cam worn on the back side (opposit the lobe) would cause the lifters to stick and hold valves open....he had exactly the same thing happen on a toyota diesel. so i need a new cam or to get my'n built up then reground....and don't have enough time to pull the motor apart to get the cam out sorted and back together before i need to travel 500 miles to a new job.....so i'm off to the local subaru wreckers to try find a replacement motor to get me going till i can rebuild my one....with a few select mods along the way....like 60thou off the heads:grin: Seems unlikely that a worn cam would be the cluprit, since I gather this problem has occurred suddenly? Cams don't wear out overnight..... I think your theory of stuck hydraulic lifters deserves more investigation before you go out and buy a new motor...... I'd certainly say to neglect anything bottom end related (short of a broken conrod!) since I doubt you would ever get a 0psi reading even without any rings at all!
October 22, 200718 yr Author for me its suddenly....cos i only got back from a year in aussie last wednesday....the ute hasn't been driven for the last 6 months but has been started and run for an hour every weekend.
October 22, 200718 yr I'm leaning towards the stuck valve(s) theory myself. When #1 is on it's intake stroke #3 is doing it's exaust stroke. Possible the engine sat in that particular spot of valve timing and a slight amount of rust formed on valve stem, just enough to cause valves to hang a bit. An intake valve stuck at full open position can give you no compression. Exhaust valve may have been just slightly open, hence the low reading on #3. My .02
October 23, 200718 yr for me its suddenly....cos i only got back from a year in aussie last wednesday....the ute hasn't been driven for the last 6 months but has been started and run for an hour every weekend. Unless it had no oil in it at all, a cam will not wear out to such a huge extent in only 24 hours of running..... and as you mention earlier, a bad cam would cause problems on an opposing pair (1 and 2 or 3 and 4), not one bank....
October 23, 200718 yr Author Unless it had no oil in it at all, a cam will not wear out to such a huge extent in only 24 hours of running..... and as you mention earlier, a bad cam would cause problems on an opposing pair (1 and 2 or 3 and 4), not one bank.... yeah thats kinda what i thought but i don't have time to get gaskets, strip it down,findout what problem is and sort it out and reassemble. found a solid lifter motor that should(!) keep me going untill i can get this one fixed
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