Low Compression? Ford 4500

[Grimspyder]

Hello,
I had a question. I recently was able to get my tractor running again. (thanks for all the help)
But I am still having a very hard time starting it. I thought the compression was good but. I did another compression test, and the readings are low from what I can tell. I bought the service manual for the tractor (Ford 4500) and it says the compression ratio should be 16.5:1.
Which according to Copilot this engines compression should be at 242.55.
Given:
Compression ratio: 16.5:1
Bore: 4.4 inches
Stroke: 4.4 inches
For diesel engines, the compression pressure typically ranges between 275 and 400 psi12. Using the compression ratio, we can estimate the pressure:
[ \text{Compression Pressure} = \text{Compression Ratio} \times \text{Atmospheric Pressure} ]
Assuming atmospheric pressure is approximately 14.7 psi at sea level:
[ \text{Compression Pressure} = 16.5 \times 14.7 \approx 242.55 \text{ psi} ]
However, due to the efficiency and specific characteristics of diesel engines, the actual pressure is often higher. Therefore, for your engine, you should expect a compression reading in the range of approximately 300 to 400 psi.

And after doing some googling it it should be in the 300 range.
My readings are :
1:160
2:240
3:220

So they are low, and one very.
But; I would like know if it is a it should not start start condition, or if its low but starting it shouldn't be that difficult.
If that makes sense.
Also, besides doing an overhaul is there anything that can be done to make starting easier?

Thanks

 

[dodge man]

I’d say just one cylinder is low. Does it have glow plugs and are they working? The trick is to figure out why you have a low cylinder. A bore scope might tell you why. It might take a tear down.

 

[Grimspyder]

No it doesn't have a glow plugs. I will test it again to make sure.
I do have a bore scope, so Ill take a look.
Thanks

 

[mike0000]

How about checking the valves/setting the clearance? Making sure the low cylinders valves are fully closing?

 

[Grimspyder]

Everything looks good as much as i can tell with bore scope. And the valves might have been a little tight. I set them again.
But nothing changed with the compression.
So I am not sure.

 

[thepumpguysc]

300 psi + is your target number..
U could try some ring free down the injector holes.
Or a gear reduction starter, if they make’m for your engine.