d8h issue

[john stewart]

Are you sure that the decompression system is not interfering with the valves seating correctly?

Edit: I re-read your initial post.

I am wondering about the possibility of a valve having been bent when the glow plug went through which is now not sealing, causing the blowby and low power.

It’s an original electric start heads, so no decompression valves.
I’m now thinking valve damage as well

 

[john stewart]

Did run turbo drain into drum, I was still getting blow by out of breather, so at least I can now eliminate the turbo
I think I will pull the heads tomorrow. Hopefully I find something definite

 

[Old Magnet]

Back to glow plugs, what I have for reference material states to use a 1P7324 glow plug.
Overall length is 117.5 mm, the element part is 23mm long and the tip diameter is 6mm.

 

[Clayton Dort]

Do you hear this noise more so on the left side of the motor if your sitting in the seat?

 

[8k bill]

John check to see if you haven't mixed a fuel pipe between two cylinders, they will run but with less power and plenty of blow by. Bill

 

[nicky 68a]

John,your thread is a heartbreaking read mate.
I feel your pain.
I'm no fitter,but I've owned 12 x D8 dozers in 30 years without going bankrupt and my gut is telling me,that engine is going to be needing the heads off sharpish,and the sump.

 

[john stewart]

Just an update and closure on the matter.
Tried a lot of different things to no avail, i eventually pulled both heads to reveal, two cracked heads on No1 and 6. These were brand new loaded heads, so my frustration was now even higher. It had also just started to melt the tops of those pistons
I had been speaking too a lot of old school well qualified mechanics, with a mixed bag of responses. I got one more opinion from another respected (old cat) mechanic, with which i was asked, if i simply hadn't crossed over no.1 and 6 injector lines over on the pump? I had a abrupt response as i knew then and there, that this was my mistake. i hadn't been looking at the forum lately, but if i had (8k Bill) would probably have done the same, cheers! The plungers are next to each other on the pump, i think the lines got bent in the workshop while off, then with little trouble they were reassembled in the wrong order.
As explained earlier, it ran alright but was down on power, had a funny noise and had increased blow by.

I learnt the hard way but hopefully this will help others

Thanks for all the help

 

[d9gdon]

Well, there you go.

 

[kshansen]

john stewart,

Sorry to hear of the damage but at least knowing the problem has been figured out has to be some comfort!

Now if I could just figure out why this 20 year old brush cutter won't start.......good spark and compression and I had the carb apart once!

Maybe if you could get the D8 running you could run it over so I'd try fixing something else!

 

[nicky 68a]

Hell fire.
I've got the buggers crossed in the past,but been lucky enough to get them quickly.
This is a hard pill to swallow John.
As to what you'll do next,the passage of time will help you make the desision

 

[8k bill]

Yep been there and done all that, I too managed to catch it before it left the workshop. We all live and learn the hard and expensive way sometimes. cheers bill

 

[56wrench]

just as a comment, whenever I pull off injection lines, I always leave the clamps on if at all possible and pull the whole clump off all as one or on some engines in two clumps. then there is less chance of mixing up lines. if the clamps are left tight, the lines should not move enough to get them mixed up. I've seen some god-awful messes when guys took all the lines off individually and then bent them all to hell to get them back on. then the clamps wouldn't fit so they left them off causing lines to rub and wear through