Compression

[Judge]

I have a Hesse Hornet air compressor --it is essentially a Jeep L4 engine that runs on cy's 1 and 4 and compresses air on cy's 2 and 3. � I find it hard to start and have gone thru the carb. �Today I did a compression check and found �70 and 68 lbs on cy 1 and 4. � What is a good reading for a vintage Jeep flat head?? � I don't think that engine has much over a 5.5 cr, does it, so maybe 70 lbs is ok. � I need to check the timing, but with 6 inches or more of snow predicted for tonight, I had to chain up my tractor and stop playing with the toy! �Thanks

[F Bill]

70 is about 30 pounds low for a decent running motor. On a HH I don't know.

When you were testing it, was it still pumping air in the compressor half or does it have a way to disable the Compressor cylinders??

[Gunslinger]

My motor had a compressor head on it when I picked it up, seller decide to keep the head and sell the block.  I got home rebuilt the motor and put the head from my previous motor on it, so to answer your question, the compression and motor specs on that motor should be the same as for any of the L134s.  It should just be the head that varies.  As far as releases on cylinders 2-3 I did not get a good enough look at the compressor head to tell.
Todd

[Judge]

Thought 70 lbs was low.  As for air pressure  release, the HH has a warning  on it stating not to start the engine with the air drain valve closed.   I want to check timing when I get a chance.   I assume the "cut" in the flywheel pully is TDC to be alighned with the pointer on the block.  Since the HH does not have a battery ( or gen/alt, for that matter), I have to get it close to another vehicle to " jump start' it  --not difficult to do, but requires moving some vehicle aroound in my barn.

[Carls_jeep]

70 psi compression is marginal for the engine to start. I think your going to have to overhaul your engine, all four cylinders and valves.