D1462-D1 engine head questions

[ozyclint]

Hi, I have a tractor with a D1462-D1 engine. Been having trouble with head gaskets.
A while ago the gasket failed between cylinders. Got that fixed, or so I thought. 16 hrs later it starts blowing compression into the water jacket. Pulled the head a 2nd time. Looked like evidence of compression bypassing the gasket.
Got the head checked. Machine shop said it wasn't flat and they machined it.

Notably when undid the head bolts some if them where a lot easier to undo than they should have been. Not sure if they have stretched or if it's because the head was warped after the first head gasket replacement.

Worth getting new head bolts??? They are super expensive. AU$500 for the head bolts and gasket.

I'm pressure testing the block and it seems OK.

When I install the head bolts how many torque stages should I use? Should they be retorqued after some engine run time?

 

[200mph]

Torque is a poor indicator of clamp load, but easy to measure. To ensure proper clamp load make certain the threads are clean; The underhead of bolt/washer (if used) and head surface are smooth; Use the correct lubricant at these points if called for.

Probably best to source the gasket directly from Kubota if not already done so.

How well do you trust the accuracy of your torque wrench? They are not always accurate, especially over time.

Don't have the torque specifications/procedures for your engine, so will not comment.

 

[85Hokie]

Torque specs:

Foot pounds

 

[Russell King]

Since you had the head machined, you may have to use a shim or thicker gasket to compensate for how much material was removed.

And it is best to follow the prescribed pattern to torque the head to the block. (I don’t have that but in general it will start at the middle of the head and crisscross outward.). The torque should be done in three or four steps.

The bolts may have been stretched and yielded so since you’re having trouble with the head gasket I suggest that you get new ones.

 

[ozyclint]

Thanks for the info guys!

 

[ozyclint]

They machined 10thou off the head.

 

[ozyclint]

Any tips for removing the two head studs so I can replace them?
I tried 2 lock nuts but I can't get them tight enough to not slip o the thread instead of turning the stud out.

I can heat the stud locally with oxy if needed without heating the block. Just in case there is threadlocker on them? Speaking which, should threadlocker be used on the new studs?

Also, there is a part that supplies oil to the rocker assembly that sits proud of the block face. Is there a way to remove it? I'd like to ink the head and place it on the block and slide it around a bit to check the block for flatness. I can't seem to get any feeler gauges under a straight edge but then I couldn't under the head either and the machine shop deemed it not straight. They didn't charge enough for machining it too justify doing it for no reason so I do believe it must have been warped.

I just want to be sure the block is flat too.

 

[Russell King]

I am not sure if you can get that tube out but look at illustrated parts list and see if you can buy it. It may have an odd name, I recall some discussion on this website about it.

There is also an o-ring that goes over that pipe but I think there are other locating pins that would limit moving the head much.
No idea on the studs question.

 

[ozyclint]

back again.
It is leaked compression into coolant again after the last head gasket change. not much, a few small bubbles in the coolant overflow bottle. I retorqued the heads bolts and got another 1/8th of the turn. (new head bolts and studs) This seemed to work to stop the bubbles, however it is doing it again. Apart from retorquing the heads bolts for a 3rd time I'm a bit lost as to solving this persistent problem.

The block was flat as far as I cold tell via straight edge and feeler gauges.
engine oil is clean. pressure tested block while head was off and it held pressure no problem.
Only things I can think of is block is not flat enough or crack in cylinder liner that only manifests itself at operating temperature.

Any suggestions?

 

[ozyclint]

It blew the head gasket between cylinders 2 and 3 again yesterday.
It's been leaking compression into the coolant since the last head gasket change as mentioned above.
I'm certain it's leaking the compression into the water jacket via holes that are ridiculously close to the bore. It looks like compression has been bypassing the gasket into 2 of these hole at the rear of number 3 cylinder.

here you can see the 8 water jacket ports that are very close to the bores. So close that almost half the hole is covered by the metal sealing ring on the gasket. These ports are blind and are blanked off by the gasket and do not run through into the block.

This shows the evidence of compression getting into these water jacket ports.

Here you can see how close they are to the bore where I suspect it was leaking.

Any reason I can't tap these holes, put a bolt in it, cut the bolt of close to the head face and have the head resurfaced? This should allow me to prevent compression getting in there again.
Any reason this thing has blown the gasket between 2 and 3 for a second time? I can't get feelers under a straight edge anywhere on the block. Would the compression leakage into the water jacket on the cylinder somehow cause it?

If I can blank of those ports what would be the best material to use and what thread sealant would be best? just heat proof loctite?

This is the 3rd time I've had the head off now and something has to be done about these ports because it seems impossible to get the gasket to seal there.

 

[lugbolt]

check the deck of the block for flatness. It needs to be perfect as does the head and the surfaces need to be very clean, and close to mirror finish if possible. In other words, you don't want machine marks. If it was blown between cylinders there is a good chance that it, too, may have some low areas that should be addressed.

Injection timing may be suspect, it would be wise to check the spill timing. Possible injector issue as well. It'd probably be worth having them checked out as well. Additionally, you may want to verify that your coolant temperature indication system is functioning properly as that is generally one of the leading causes of cylinder head gasket failure.

yes-always replace the head bolts. Or at least I always do.

 

[007kubotaguy]

Are you using Kubota gaskets ?

 

[ozyclint]

It is a grey market tractor and I get the gaskets from a grey market parts stockist which is the best I can do.


Apart from using feeler gauges under a straight edge, which I've done, how else to check block flatness?

 

[ozyclint]

Had a mechanic check the block for flatness. he said .002" feeler gauge went under where the gasket blew. He said it's not a huge amount and worth assembly with new gasket and this time retorque head bolts 3 times after running for several hours.

Interestingly he said he has had a different kubota engine have the same problem with leaking compression into the water jacket through those ports on the head that are so close to the bore. He had them welded up and the head machined and says it worked fine. Will get that done this time to eliminate that problem.

 

[lugbolt]

Had a mechanic check the block for flatness. he said .002" feeler gauge went under where the gasket blew. He said it's not a huge amount and worth assembly with new gasket and this time retorque head bolts 3 times after running for several hours.

Interestingly he said he has had a different kubota engine have the same problem with leaking compression into the water jacket through those ports on the head that are so close to the bore. He had them welded up and the head machined and says it worked fine. Will get that done this time to eliminate that problem.

.002 is a big deal on a diesel.

 

[Russell King]

For the head gasket you may be able to get it from Kubota as OEM by identifying a tractor model that is not grey market that has the same engine. You may want to see if they will just use the engine type to sell you the head gasket.

The more experienced mechanics that post here always recommend OEM head gasket