Lil Mule

Went and looked at a 6BT in a large 30K Taylor forklift.

The last tech that looked at this thing says the motor is shot, it has a blown head gasket and needs to be replaced.

I say he's full of it.

1) This thing runs good - a little low on power but not too bad

2) no coolant in the oil - Not always present with a bad headgasket, but sometimes.......

3) No pronounced miss - If I crack each injector, I get about equal RPM drop out of each.

The tech supposedly ran a compression test but I saw no numbers on his report showing what each cylinder read.

What is the spec for compression readings?
I'm going out tomorrow and spend some time looking this engine over good.

If the headgasket is bad, it may just need a head job.

At $4000 it would be considerably cheaper than the $14,000 they were quoted to replace the engine.

Lil Mule

Noone knows? Lotsa looks, no answers,

DZLPWR

Check out this post https://www.dieseltruckresource.com/...mpression+test

bob4x4

Compression pressure is not given by Cummins nor is it usually recommended.A second Gen engine should show in the 400+ range,I wouldnt expect an industrial motor to be the same as a higher reving pick-up engine.Most 5.9 headgasket failures are not compression leaks but oil or coolant.

Bob

Dr. Evil

Why?? The engine make compression...seems to me a compression test is a good indication of engine health...at least thats what an old Cummins mechanic told me.

infidel

More often engine condition is determined by a blowby pressure test.
You can make your own blowby measurement tool for under $10. A blowby orifice tool is just a tee with one .221" (15/64-in) outlet (pipe plug with a hole drilled in it). Connect one end of the tee to the end of the blowby tube. Put a manometer on last tee outlet. That is your blowby tool. A simple manometer can be made by looping 6' of clear tubing with water in it half way. Measure how high the water level rises with a tape measure, multiply it by 2, convert it to LPMs

Rough conversion is:1"= 27 lpm, add 3 lpm for each one inch (1/2'' of rise in the tube) of water

New engines numbers are;
63 liters per minute(2.5" water rise = 5" of water) @ 2200rpm,
76 L/Min (3.5" rise) @ 2500rpm
85 L/Min (4.5" rise) @ 2800rpm.

Worn engine that needs rebuilding are roughly double i.e.
126 L/Min(10.5"rise) @ 2200rpm
152 L/Min(14.5"rise) @ 2500rpm
170 L/Min(17"rise) @ 2800 rpm

Valves out of adjustment or a head gasket blown will also cause high numbers.

The way I do it, same idea, is to block the blowby tube with a 1/2'' pipe nipple with a cap that has a 15/64 hole drilled in it. Use 3/8'' id looped clear tubing with water in it slipped over the oil dipstick tube. Use sharp tipped felt marker to mark the water level with the engine off, have someone start an already warmed up engine and run the rpms up to 2.2, 2.5 & 2.8k rpms. Mark each water level with the pen, measure then multiply each by 2.

This is all very simple to do, just hard to explain with words.

John Faughn

A simple compression is if it starts and runs on all cylnders it has to have compression ,I like Infilels info for looking life left.


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94 2500 4x4 cummins A.t.,bought from this site a couple weeks ago.