Anything else to do when changing a head gasket?

[Lobanz]

OK. I have both heads back from the machine shop. Had then shop do valves on both. Kubota had some pitting and was quite warped. Stress cracks were on the pre-combustion chambers and they said they didn't leak and that this is not uncommon and wouldn't be a problem. The Yanmar head didn't have any cracks. Great deal at this shop -- they did both heads for $140. :shocked:

I have everything I need for the Yanmar except the radiator. About to start reassembling. New belt, hoses, gaskets, radiator cap. Got some high temp (2400 deg) nickel anti-seize. Of course this does not go on some things, like head bolts, but I do like to put it some as much as I can -- especially on exhaust manifold bolts/nuts. Maybe the Yanmar injectors that are notoriously hard to get out -- they slide in and are held by a bolt on plate; they rust in there where they slide in. Will lean of rust and apply a light coat of anti-seize.

The machine shop mention that I might want to get my injectors tested, but they also said that if I haven't had any trouble with it running rough or having lack of power, then it probably isn't necessary. The injectors are already out. I will call and check the price, but I probably won't get them checked. Haven't had any trouble with them that I know of. What do you guys think about having the injectors tested?

Also, I know that I don't put any gasket sealer goo on the head gasket. What about other gaskets like water pump and/or thermostat housings, etc? In the past, I've used it and not used it and didn't have trouble either way. Will see what the Service Manual says. On both engines, there we are couple of places where there was ONLY gasket sealer goo and no actual gasket (water pumps). I ordered proper gaskets for everything.

 

[Coyote machine]

Injectors are one of the most crucial and most often overlooked parts of many diesel engines. The ply a huge part in making the engine run evenly, and keep it from doing things like overheating.
Pop testing and verifying spray pattern will tell if they are delivering the correct atomized fuel/air mixture. I strongly urge you to get them checked. The loose fuel line distribution caps/nuts could have adversely affected the fuel/air mix or otherwise, but since you now know it was happening you can now prevent it going forward.
Personally, I wouldn't touch the timing until everything is back up and running. Then if you're still having issues and everything else is normal, then address it, possibly. Methodical troubleshooting is the best way to find the cause/effect of an unknown problem.

Injectors are so crucial the major manufacturers/rebuilders reassemble them after exhaustive testing in a clean room to prevent microscopic DUST from adversely effecting their proper operation. Videos of same are on the net; it's quite amazing what lengths they go to to make sure they work correctly. Yours will be deemed OK or not by the pop and spray pattern compliances mentioned above.

As to gaskets/sealers or not. I'd go with what I found on disassembly. Or if there is a question about the waterpump/block interface make sure both surfaces are smooth with no pitting and use grease/Vaseline to assembly the mating surfaces, or a gasket and grease to mate them. Torque to spec and recheck after ten hours.

 

[Lobanz]

Dang. Rocker arm tower stud stripped on the Yanmar. Two of them. Have know idea why. Didn't even get close to torque spec (40 ft-lb). Was not cross threaded. Looks just like THIS GUY's. Hope Hoye has replacements.

Got the head on though, but couldn't proceed past the rocker arm assembly due to the stripped studs. So, we put on the water pump and new fan belt and one of three new hoses with new hose clamps.

My 13 year old daughter wanted to help, so I pretty much just walked her through it. She wanted to learn more about how to use tools. She set the torque wrench, torqued the bolts and everything (we practiced on something else first and I double checked her settings and explained the technique). Worked out well. The two boys (16 and 9) did all the disassembly on the Yanmar and the 9 year old and I did the Kubota. They did a good job labeling everything like I told them.

Anyway, looks like more waiting on parts...

 

[Mace Canute]

Dang. Rocker arm tower stud stripped on the Yanmar. Two of them. Have know idea why. Didn't even get close to torque spec (40 ft-lb). Was not cross threaded. Looks just like THIS GUY's. Hope Hoye has replacements..........

Coincidently I just made two similar rocker hold down bolts for a friend's John Deere A. The threads weren't quite that bad but the thread form was badly deformed. They were a tad larger though, 5/8 inch on the larger diameter and a 1/2 inch on the smaller.

 

[Lobanz]

Coincidently I just made two similar rocker hold down bolts for a friend's John Deere A. The threads weren't quite that bad but the thread form was badly deformed. They were a tad larger though, 5/8 inch on the larger diameter and a 1/2 inch on the smaller.

Hast thou a lathe or other majick?


Here are the part numbers with links to Hoye site in case anyone else has the same problem (tractor is Yanmar 1610D, 3T75U engine):

• STUD: 105225-11350
• ROCKER ARM LOCK NUT M8: 26756-080002

Parts on the way!

But I wonder why they were so weak. They went with the head to the machine shop. Don't know if anything would have happened to them there. Torque spec is 40 ft-lb. Seems a little high. Dunno.

 

[brain55]

If they are 8mm studs, then the torque spec should only be 20 ft lbs.

Brian

 

[Lobanz]

If they are 8mm studs, then the torque spec should only be 20 ft lbs.

Service Manual said 40 ft-lbs, and parts supplier (Hoye) confirmed (probably looking at same service manual). I suppose service manuals can be wrong too. There is another Yanmar service manual that covers several engines, will cross check with that one.

 

[Lobanz]

Injectors are one of the most crucial and most often overlooked parts of many diesel engines. The ply a huge part in making the engine run evenly, and keep it from doing things like overheating.

Well, you definitely were right here. The Yanmars were all fine. But the 2 of the Kubota's injectors were stuck open and 1 was stuck closed. The guy say that it would probably have ran but that it should have been making a lots of smoke. Wasn't making lots of smoke and didn't seem to run bad at all -- just overheating. The diesel mechanic DID say that the delivery valve holders being loose WOULD ****** the timing. He also said that he would have expected them to leak horribly. They didn't leak to my knowledge.

$65 each to rebuild -- replace all the guts so will be like new. $84 ea + shipping for new ones.

So, there is enough evil happening here to explain the overheating. Hopefully, the cylinders were not washed down to the extent that the rings are eroded. Hopefully THAT's not the real cause of overheating. We'll see.

I video'd the injectors on the test machine and stuck the clips together:

 

[Coyote machine]

Well, you definitely were right here. The Yanmars were all fine. But the 2 of the Kubota's injectors were stuck open and 1 was stuck closed. The guy say that it would probably have ran but that it should have been making a lots of smoke. Wasn't making lots of smoke and didn't seem to run bad at all -- just overheating. The diesel mechanic DID say that the delivery valve holders being loose WOULD ****** the timing. He also said that he would have expected them to leak horribly. They didn't leak to my knowledge.

$65 each to rebuild -- replace all the guts so will be like new. $84 ea + shipping for new ones.

So, there is enough evil happening here to explain the overheating. Hopefully, the cylinders were not washed down to the extent that the rings are eroded. Hopefully THAT's not the real cause of overheating. We'll see.

I video'd the injectors on the test machine and stuck the clips together:

You're welcome! That's some of the best money you could spend. Not possible for the tractor to run right with the injectors behaving like that. And the delivery valve holders on top of the injectors, not a good situation. The 2 pissing injectors would have delivered the wrong amount of fuel, and the dead one would cause a lean cylinder. Did you note which cylinder each one was in? So you had a retarded, lean on one, over fueled on two condition.
You're lucky it ran at all. I'd suggest you get the best fully synthetic oil and run it exclusively from now on. Wide open injectors could have caused premature cylinder wall and lower end bearing wear, in addition to overheating from the dead one. By running synthetic oil you have a chance of preventing further damage of those and all crucial engine parts.:thumbsup:

 

[Lobanz]

[...] I'd suggest you get the best fully synthetic oil and run it exclusively from now on. Wide open injectors could have caused premature cylinder wall and lower end bearing wear, in addition to overheating from the dead one. By running synthetic oil you have a chance of preventing further damage of those and all crucial engine parts.:thumbsup:

Hmmmm.... Well, should I be running synthetic in all the engines? You mean like Mobil-1? Been running Rotella-T Triple Protection (15w40 I think). I buy it in 5 gal buckets.

Wish I had a compression tester. After a valve job and a new head gasket, that should tell me about the rings. Might be a good $30 to spend.