Compression down on one cylinder

[keycare]

Back again.
So I relapped all of the valves and used water and air to check the seal. No bubbles so they are now sealing well. I have the injectors serviced and re assembled. When I tested the compression, cyl 3 was still down compared to the other 2 but the diference was less than 10%.
The problem I am getting...
Running a topper for about an hour and the power drops such that I cannot get the revs above 1400rpm. I disengage the topper and the revs take about 10 seconds to get back up to 2000rpm. So I re-engage the topper and immediately the revs drop back down.
So I drive back to the barn, wait about an hour or so. Try again and the same thing happens, after about 30min to 1hr, the power drops again.
How do I establish what is going on?
Cracked cyl head?
I am pretty sure the fuel system is OK, but is there anything I might have missed.
I have had problems with the strainer in the tank getting blocked, so it's currently removed.
Should I test fuel pressure? What is the best way to do that?

Tbh I am very close to throwing in the towel, jobs are backing up.

Thanks for your time.

 

[Dieseltech]

Would have been a good idea to do a cylinder leak down test in the first place along with the compression test. I'd suspect piston rings/groove damage.

 

[560Dennis]

A lot going on in that photo. all the rusty evid around cooling ports. Probably the cause of failure. Need to flush the entire cooling system. This critical to repair. What I’m seeing.

 

[Fixingfarmer]

Did you repair the grove in the injector bore? A machinist should be able to ream that a bit with no ill effects.

If you still don’t have the cylinder head on you can test the fuel system fairly easily by hooking up the three injectors and cranking it over. Cheap easy make sure you have a good pattern same on all 3. Poor man’s pop off tester.

It will make a bit of a mess but then you know. And you can prepare with some pans and a cardboard backsplash

The diesel instructor at the local college used to run a pop off tester in the class room and it didn’t make a horrendous mess. He’d even let us light it with gloves and a lighter after he showed us the pattern we were looking for

 

[Fritz Maurer]

Back again.
So I relapped all of the valves and used water and air to check the seal. No bubbles so they are now sealing well. I have the injectors serviced and re assembled. When I tested the compression, cyl 3 was still down compared to the other 2 but the diference was less than 10%.
The problem I am getting...
Running a topper for about an hour and the power drops such that I cannot get the revs above 1400rpm. I disengage the topper and the revs take about 10 seconds to get back up to 2000rpm. So I re-engage the topper and immediately the revs drop back down.
So I drive back to the barn, wait about an hour or so. Try again and the same thing happens, after about 30min to 1hr, the power drops again.
How do I establish what is going on?
Cracked cyl head?
I am pretty sure the fuel system is OK, but is there anything I might have missed.
I have had problems with the strainer in the tank getting blocked, so it's currently removed.
Should I test fuel pressure? What is the best way to do that?

Tbh I am very close to throwing in the towel, jobs are backing up.

Thanks for your time.

This sounds like fuel filters.

 

[keycare]

OK, so the fuel tank is off again. Just re-checked compression and 1 & 2 are both 360psi, 3 is still a little down at 340psi. I can't imagine that would be the issue though.
The gouge in the injector hole is still there.
There was no blow-back from the dipstick and no oil coming from the rocker breather.
I have noticed that the oil pressure light comes on at roughly the same time as the power starts to reduce (the oil pump was changed when I re-built the engine).
I also noticed that there was a tiny bit of sludge at the end of the fuel line as it attaches to the lift pump (I removed the in-tank strainer but now have a replacement). That could be the culprit, but before a go any further I need some idea of what further tests to do.
I ordered a new cylinder head anyway (complete with valve gear), thinking it might get me more even compression across all 3 cylinders.
The liners looked good the last time I had the head off.
Going to try a squirt of oil in cyl 3 and re-check compression to try and eliminate the rings.

Any further pointers to test?

Cheers all.

 

[keycare]

I have spent the last few days stripping it down to check a few things out - replaced the fuel strainer in the tank, cleaned the strainer in the fuel pump, cleaned the injectors (had them tested and reset a few months ago), checked the valve clearances, did a compression test (380psi), removed and cleaned out the lift pump. The only thing I have not done yet is renew the fuel filters because they were done when I re-built the engine. I have had it running with the tank removed for a couple of hours today (using a couple of fuel cans), and every 5mins or so, the revs drop a bit, surge a bit, then return to normal (I have had it sitting at 1000rpm and 1500rpm). Is there anything else I should check?

 

[keycare]

So, to round off this thread.

I replaced the fuel filters and also cleaned out the lift pump.

It's all working now. The power is pretty good, no bogging down and consistent revs.

Thanks to all that made suggestions and helped. I think it was a collection of issues - compression and fuel delivery. Cleaning everything out (including the other hidden strainer in the fuel pump) and renewing seals and filters cured the fuel problems and replacing the cylinder head cured the compression problem.

I now have a cylinder head that could do with being tested, and possibly re-furbished if anyone knows of somewhere in Wales, please let me know.

On to the power-steering next.....

 

[Mcrafty1]

So, to round off this thread.

I replaced the fuel filters and also cleaned out the lift pump.

It's all working now. The power is pretty good, no bogging down and consistent revs.

Thanks to all that made suggestions and helped. I think it was a collection of issues - compression and fuel delivery. Cleaning everything out (including the other hidden strainer in the fuel pump) and renewing seals and filters cured the fuel problems and replacing the cylinder head cured the compression problem.

I now have a cylinder head that could do with being tested, and possibly re-furbished if anyone knows of somewhere in Wales, please let me know.

On to the power-steering next.....

Thanks for the update, Glad it's working out for you.

 

[560Dennis]

I read tales from wales in farm collector.
Should be no problems finding mechanic ,some very talented mechanics there , keep us posted ok !