IH 674

[Insbroker2]

Recently bought IH674. The tractor had been sitting for several years. It did run but very poorly and very black exhaust. 3 cylinders have 120 compression #2 has 30 compression. Removed valve cover, all are moving as they should. Tried oil in the cylinder, did not increase compression. Any suggestions on next procedure. C-200 gas. I also read that distributor rotation should be clockwise, but mine is counterclockwise?

 

[ss55]

Recently bought IH674. The tractor had been sitting for several years. It did run but very poorly and very black exhaust. 3 cylinders have 120 compression #2 has 30 compression. Removed valve cover, all are moving as they should. Tried oil in the cylinder, did not increase compression. Any suggestions on next procedure. C-200 gas. I also read that distributor rotation should be clockwise, but mine is counterclockwise?

A leakdown test to determine where compression is leaking from cylinder #3.

 

[leroy in ne]

was Valve adjustment checked? When you had the cover off.

 

[Insbroker2]

was Valve adjustment checked? When you had the cover off.

I did not. I only verified that they were all moving.

 

[JOCCO]

If the valves are moving it is most likely a bad valve or seat. Next piston failure of some kind Stuck rings, broken piston.

 

[leroy in ne]

I did not. I only verified that they were all moving.

An inadequate valve clearance will keep a valve from fully closing, usually results in a burned valve, sometimes you get lucky and catch it in time.

 

[Jimmydog]

I agree with Jocco, sounds like something seriously wrong with piston. A cheap endoscope if you can borrow or buy one would be a quick way to verify or eliminate piston failure. I just picked one up for just such occasions for a hundred bucks, you can get ones that hook up to a smart phone for 20-25$.

 

[JOCCO]

Another way to leak down is make a fitting (or buy one) take out spark plug, put that in its place. Put engine on compression stroke, add compressed air. If its going in the base its piston and liner. Out the exhaust, exh valve so on for intake. You may also get bubbles in radiator indicating a crack or bad head gasket. Honestly I see a teardown in your near future.

 

[Jimmydog]

Leroy makes a good point too.

 

[JOCCO]

Yes to what Jimmy said a borescope or inspection camera in the plug hole will some times find the issue.