Head gasket replacement - how to?

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jonokimber
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Re: Head gasket replacement - how to?

Postby jonokimber » Sun May 24, 2020 6:09 am

Hello everyone, great forum. I'm in the UK and about to embark on a head gasket change on my Yanmar 1610D. I bought all the parts and some extras from Hoye. I've had to buy some tools too and I think I'm about ready. I have a few questions and clarifications, I hope someone can answer them and this post can help others in the future...

1. What engine oil should I use (I read about zinc as a requirement for old diesels?)

2. Can someone confirm, maybe from the maintenance manual, the cylinder head torques and order? (I have seen conflicting info on this, specifically in this thread stating that inner cyl head bolts needed to be retorqued to 78ft-lb after a heat cycle. I also have seen "The head bolts are re usable on the YM2000. They are torqued in stages from 44, 88, 118, 133 ft lbs. Rocker arm bolts 58-72 ft lbs." in another thread.

3. Can someone tell me the torque values of the valve / rocker cover? Torquing them is mentioned in the Hoye HG replacement guide.

4. Are there torque vales for the muffler and anything else I may need to remove?

5. Can I re-use the oil line copper washers?

6. In order to check the valve clearances i will need to rotate the engine. How do I do this and does it matter which direction I turn?

7. What is anyone's advice on changing engine oil and oil filter before or after the head gasket procedure?

Many thanks in advance for any answers.

Jono

jonokimber
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Re: Head gasket replacement - how to?

Postby jonokimber » Sun May 24, 2020 6:39 am

agirlandhertractor wrote:Be sure to clean your head bolts and threads thoroughly before installing the new head gasket. Apply a little CLEAN motor oil to the bolt threads before installing into the head.

UPDATE 2018: Also, be sure to chase the threads in your block. The threads on my 1601D engine (model 3T75U) are M12-1.50, NAPA or similar should have a tap in stock locally. If you have a different engine model take one of your cylinder bolts to NAPA so they can make sure you get the correct tap.

If you've never chased these threads, the threads may be caked with gunk/rust. Don't skip this step or your torque measurement will be inaccurate, and you may have to use this guide a second time later on. Ask me how I know. :oops: :oops: :oops:


Image

For the head gasket itself, I used the copper spray-a-gasket from Permetex to help seal any minor imperfections. The local autozone had it for a dollar less than Amazon Prime, plus i could get it right away.

Make careful when installing the head gasket that you put it the right way. It may LOOK right if sleepy or tired, but be sure the oil holes line up:

Image

right way:
Image

(photoshop kept crashing when trying to add actual text, so I had to draw my writing :D)

Here are the torque specs and tightening sequence:
Image



It looks to me as if the 4 cyl head bolts inside the rocker area are covered up by the rocker arms? If this is the case how on earth do you check them for torque after a heat cycle? Also, how do you remove the rocker arms? Is there an easy way to get the whole assembly off or does it all have to come apart individually? It looks very complicated?!

winston
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Re: Head gasket replacement - how to?

Postby winston » Sun May 24, 2020 7:56 am

1, https://www.hoyetractor.com/support/kno ... ?article=1

2. Pretty confident torque for head bolts shown in agirlandhertractor thread is correct for your 1610.

3. Goodntight for rocker arm cover. :mrgreen:

5. You can reuse the copper washers but they are inexpensive. The old ones can also be annealed.

6. Socket on crankshaft pulley nut or bump starter. Doesn't really matter which way you turn it.

Rocker arms can be removed as an assembly. Just loosen off bolts equally to release tension on pushrods. I believe you are right about rocker arms covering some head bolts on your model. Probably a better answer but if you determine to retorque you might consider checking the bolts that are accessible and depending on what you find just tighten the hidden bolts the same distance as the exposed ones.

If you have much experience with mechanics you should have a bit of a feel for how tight you can go on different size bolts.

Best of luck to you.

jonokimber
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Re: Head gasket replacement - how to?

Postby jonokimber » Sun May 24, 2020 11:42 am

winston wrote:1, https://www.hoyetractor.com/support/kno ... ?article=1

2. Pretty confident torque for head bolts shown in agirlandhertractor thread is correct for your 1610.

3. Goodntight for rocker arm cover. :mrgreen:

5. You can reuse the copper washers but they are inexpensive. The old ones can also be annealed.

6. Socket on crankshaft pulley nut or bump starter. Doesn't really matter which way you turn it.

Rocker arms can be removed as an assembly. Just loosen off bolts equally to release tension on pushrods. I believe you are right about rocker arms covering some head bolts on your model. Probably a better answer but if you determine to retorque you might consider checking the bolts that are accessible and depending on what you find just tighten the hidden bolts the same distance as the exposed ones.

If you have much experience with mechanics you should have a bit of a feel for how tight you can go on different size bolts.

Best of luck to you.



Thanks Winston, I really appreciate your reply. I feel a bit silly for asking one or two questions as I have now found some more info.
I agree the torque values in the agirlandhertractor thread is correct for your 1610. I think the other values came from a different engine model.

I'll get it to the point of strip down and I'm hoping to get the head measured for flatness very accurately as I work for a metrology company. I really don't want to have to do this job twice. I'll probably have some more questions at that stage, maybe some sooner! I have bought a tap and die set for tapping the block threads. I have a decent scraper, new socket set last year, two torque wrenches of a mate, gloves, all the gaskets, some new hoses, new fan belt, water pump is only a month old and the old one is probably the cause of the head gasket going.

I'll take plenty of pics and maybe start a new thread too. It probably won't be as good as this one but who knows!

winston
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Re: Head gasket replacement - how to?

Postby winston » Sun May 24, 2020 3:35 pm

Be looking forward to your progress.


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