Yanmar 1610 Head Gasket Replacement Thread

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agirlandhertractor
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby agirlandhertractor » Mon Jun 01, 2020 12:39 pm

Agree with leakage between water jacket and fire ring.

Strongly encourage you to take head to a qualified shop and have them check and plane the head for absolute surface flatness. Once these things overheat they can warp ever so slightly.

With my own head gasket repair from a few years ago, I made the critical error of not checking head, which led to a second failure and more time/money spent on fixing it a second time.

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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Mon Jun 08, 2020 1:21 pm

Hello again, I finally managed to have my head checked for flatness, at my own place of work on an extremely accurate co-ordinate measuring machine. Across the whole cyl head there is a value of 0.055mm for flatness which is just over 2 thou. I believe there is a 3 thou tolerance on the flatness? Having run the tractor I can confirm that it never got 'into the red' on the temp gauge during the gasket issues so maybe this is another pointer to the head being as flat as it is. You can see from the graphical analysis that the majority of the 'high' points measured are on the two ends of the head, the middle section is concave shall we say. Unless anyone can convince me otherwise i think I'm going to go for it...

flatness.jpg
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winston
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby winston » Mon Jun 08, 2020 2:40 pm

I'll not try. :mrgreen:

jonokimber
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Wed Jun 10, 2020 9:24 am

Hello. I started getting everything back together today and hit an issue with the cylinder head nuts that go on the two end studs. One of the M12 x 1.5 flanged nuts has definitely stripped its thread. At the final torque it stopped getting tighter and continued to spin. I undid everything and sure enough a few slivers of thread came off the nut when i took it off. The stud looks in good shape.

Q1 - Will the act of torquing up the cyl head and then undoing it again have damaged the gasket?
Q2 - Will these nuts be ok as replacements?

FLANGE NUTS METRIC FINE PITCH
DIN 6923,
HIGH TENSILE STEEL CLASS 10, ZINC FLAKE (GEOMET)

Example designation prevailing torque type hexagon flange nut, all metal nut, thread M12 x 1.5 property class 10 with non-electroliticall applied zinc flake coating

Hexagon nut DIN 6923 – M12 x 1.5 – 10 – flZn – 720 h

These are the preferred coatings for fasteners and other parts in the automotive industry, as they offer various advantages:

Good appearance (colouring)
Very good protection against corrosion (720 hours with a required duration of salt spray in the case of our products)
Resistant to extreme temperatures
Good chemical resistance
Environmentally friendly
Good friction characteristics
No warm-loosening torque
No risk for high-strength fasteners of any hydrogen embrittlement

This is the stud for the nut that stripped. I will replace both nuts on both studs though.
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Here's the shiny new gasket prior to torquing up.

IMG_1516.jpg
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winston
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby winston » Wed Jun 10, 2020 9:43 am

Take what I say as old man's opinion, not fact. I would not worry with the loosening and retightening of the nuts since it has not run.

No fastener guru but sure looks like those nuts should work fine.

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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jimjumper » Thu Jun 11, 2020 6:48 pm

I was considering rebuilding the top end on mine when agirlandhertractor started her rebuild. I pretty much did it the same way, being extremely careful, and for what its worth, i am just about to do the first oil change after 10 hours of break in. I cleaned and checked the head for flatness and then took it to a machine shop for his opinion. I just kept measuring and checking things as I put it back together and it fired up on about the second stroke and has run like a watch since. Replaced rings, rod bearings, head gasket, water pump, radiator and any gaskets that were removed. Cleaned pistons, injectors, valves and seats, and honed cylinders. I would have liked to have had the head planed but there wasn't enough thickness to clear the injectors. I'd say the head came out looking pretty good though. Just go through it all step-by-step and it wasn't that difficult. I re-torqued the head nuts after1 hour of running, and then again at both the 5 and 10 hour marks. Probably over-kill but I didn't want to do it again. Before and after pics of the head before I re-installed.
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jonokimber
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Fri Jun 12, 2020 6:08 am

Thanks JimJumper I appreciate your reply. Your head preparation looks amazing. The new nuts have arrived today so I’ll hopefully get some more done. I’m particularly worried about the fuel system and bleeding that but let’s see.

One question I’m still not sure of. When checking for torque after a few runs do you all check under the rocker cover and even under the rocker arm?

jimjumper
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jimjumper » Fri Jun 12, 2020 7:03 am

I did. I found that 2 nuts moved, barely, after an hour of running and I got one to tighten maybe a few degrees after 5 hours. By the 10 hour they were set. But the 2 cylinder heads are torqued to 130 ft. lbs. I would think that with the 3 cylinder getting less initial torque that it would be more important to recheck the torque later. But that is just my thoughts since I have only done my own.

jonokimber
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Fri Jun 12, 2020 10:26 am

Right all, bit of a disaster...

I assumed ALL the M12 threads on the cylinder head were 1.5 pitch, including the two studs. It turns out the studs are 1.25 pitch. During my preparation period I tapped out the stud nuts to 1.5 pitch. It was hard work and now I realise why as I was changing the pitch! The reason I wanted to tap them out was because they were quite hard to get off the studs, mainly due to corrosion at the top of the studs. When I tried to put these 1.5 pitch nuts back onto the 1.25 studs one stripped completely and the other seemed to hold ok, but probably wasn't.

Today, armed with some new M12 x 1.5 nuts (the wrong pitch) I went to try putting the cyl head back on. Still no luck (obviously), so I thought i'd try and run a die over the studs, again, choosing the wring pitch. The situation is that I now have the top few threads of one stud at the wrong pitch. I will try and file these threads off as fortunately there is quite a bit of spare thread once the cyl head and nuts are on (see picture below).

Question - Is there a specification for the M12 x 1.25 flanged cyl head nuts that go on the two studs?

The reason I ask is that when I'm looking to buy some there are options like grade 10 and coneloc that suggest a locking torque with slight deformity of the threads. I'm not sure if this is a good thing or not as locking torque may detract from head compression as i'm tightening it up.

stud file.jpg
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winston
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby winston » Fri Jun 12, 2020 10:47 am

Not for sure, check with Hoye, but I would get 2 of these 121450-01210 and 121450-01220. https://www.hoyetractor.com/PROD/121450-01210.htm
https://www.hoyetractor.com/PROD/121450-01220.htm

jonokimber
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Fri Jun 26, 2020 9:06 am

Right then, after my little thread pitch disaster I've got the head back on. Sourced two new high tensile flange nuts, ground off the damaged thread and got it all torqued up.

Thought I'd have a go at the rocker arm and valve clearances today but that has ended in more threads stripped and damaged nuts. Following the advice on 'agirlandhertractor' thread I was tightening them up to 40 ft.lbs which is 54 N.m (Head bolts 29, 58, 72-79 ft lbs, cylinder head assist bolts to 22 ft lbs, rocker arm nuts 40 ft lbs. Intake manifold 18 ft lbs, rocker arm cover bolts goodntight.)

CBA6465C-02DC-441C-BE1D-1E69C26BCE3F.jpg
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I did them at 40 N.m to start with and the torque wrench clicked fine. I then changed it to 54 N.m (it's still set to that in my toolbox) and the threads on the nuts have stripped. To make matters worse they are now stuck on the studs. I managed to get the studs back out of the cylinder head by using two M8 nuts locked together on the smaller diameter thread on the top of the studs. I am left with this...

IMG_1620.JPG
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QUESTION - How can I get these nuts off as the thread is damaged and they just spin on the spot.
QUESTION - Anyone know the 'spec' of these nuts in terms of hardness / strength?
QUESTION - Can anyone confirm the torque that they should be tightened to please?

winston
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby winston » Fri Jun 26, 2020 3:38 pm

I would cut in from two sides with an angle grinder with a cut off disc being carful to not quite touch the bolt threads. then split with a screwdriver.

I know the 220/226 is 27 ft lbs. Yours likely the same.

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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby jonokimber » Mon Aug 03, 2020 11:35 am

So, it's been a while, but i'm back with what I think is good news. I had to order new studs and nuts in the end, hence a bit of a delay. I got it all back together including some new coolant pipes and seals and gaskets etc a few days ago and yesterday was the big day! It took ages to bleed the fuel through but all the cranking on full throttle with the compression lever pulled and the injector fuel lines cracked open at least gave the chance for the oil to circulate and get pressure. In the end there was no choice but to crank her over with compression and fuel at the injectors, she started first time with a little puff of white smoke and I ran her for 10 mins on 1500 rpm checking every available spot for leaks etc. Everything was absolutely fine. No fuel leaks anywhere, no coolant leaks anywhere and smooth running with no visible exhaust smoke whatsoever. I took the radiator cap off and the coolant is running really well, no bubbles (YES!!!) I didn't want to push my luck so turned off and left for 24 hours to cool. I went back today to check torque on the cyl head bolts that are accessible and they required no tightening. I ran again and went for a pootle round my field at about 1500rpm. Pushed it to 2000rpm on way back up field, temp gauge moving each side of the bottom white line, so in effect barely getting warm at all. That said, when i got back i felt the pipes and they were almost too hot to touch but not quite. I have uploaded a video to YouTube that I will ask people to check, just to see what they think of how she sounds? Please also comment here on what you think I should do next in terms of a run in?

Finally, what level do i fill up the radiator and overflow tank please? At the moment i've filled it up to just above the fins inside the actual radiator looking down through the spout.

Here's the vid, please listen with sound...
https://www.youtube.com/watch?v=c7EKcYUB-Ls

She's deffo got the Yanmar hammer sound but always has and always will!!

many thanks

Jono

winston
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Re: Yanmar 1610 Head Gasket Replacement Thread

Postby winston » Mon Aug 03, 2020 5:31 pm

I would fill radiator full and maybe half way on bottle and see how it turns out. Sounds good to me.


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