Suggestions while I have head removed?

lugbolt

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water circulates inside the block when running. There is a bypass hose usually at the front (or rear in the case of the bx's), that's where it bypasses, recirculates until the t-stat opens. Most engines have something like that. Some have it built into the water pump housing or front cover. I don't remember on the 782's and 902's which they have, and I'm not going out to the shop to look right now.
 

JeffL

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The only bypass systems I am familiar with use the bypass thermostat where as the t-stat open flow to the radiator it closes bypass flow thru the block. Is there other systems?
 

North Idaho Wolfman

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Yep I agree Pic head 3 (middle pic) looks suspicious.

Clean all three with acetone, and take pics even closer. ;)
 

200mph

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If the head is good, I'd check flatness or just bite the bullet and have it ground slightly. Starting with a clean flat surface with the appropriate surface finish profile goes a long way to ensure head gasket functions 100% over time.

Valve stem seals - These have to be some of the more expensive valve seals I've ever seen at $5.88 each. Too bad there isn't an equivalent part in the aftermarket. :eek:
 

North Idaho Wolfman

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Valve stem seals - These have to be some of the more expensive valve seals I've ever seen at $5.88 each. Too bad there isn't an equivalent part in the aftermarket. :eek:
There is, but you don't want them! ;)
 

LanceM

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Wow. Thanks for all the help guys. I see what you're talking about with the potential crack and potential hole. I think I would have noticed if that was a hole, so I'm suspecting debris there, but I'll double check. I'll clean it up better tonight and get more pics. Assuming it is a crack, is the better route to get a new head (around $700) or take it to a machine shop (unknown cost)?
 

pjoh784350

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Not that I would ever get this far into an engine, but this is why I love this forum. What great info and sharing to help others. Nice job guys and gals.
 

200mph

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There is, but you don't want them! ;)
It's too bad Kubota aftermarket parts have such a bad reputation. Valve seals have been around forever and it doesn't take any more effort to make a good one.

Personally, I'd measure the valve stem & boss and find an automotive equivalent... I hate paying the crazy markup OEM's think they are entitled to.
 

Jim L.

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Assuming it is a crack, is the better route to get a new head (around $700) or take it to a machine shop (unknown cost)?
Just as well off with a new head. It could be lock-n-stitched, but the labor would be around $700 with possibility of not fixing it.
 

Jpatrick

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When this is all over, I hope you get down to what the root cause of the problems are.

I'd be inclined to go with a working hypothesis of overheating due to or as a consequence of:

1. plugged radiator

2. failed water pump as you mentioned earlier

I will say that if the tractor was used for mowing, the radiator /prescreen are quite susceptible to becoming clogged with grass clippings. I have this kind of tractor and when I am mowing, I have to give the radiator an air bath about every hour in the summer to keep the temp closer to the middle of the normal range.

Other work doesn't run the temp up so much. I can use the loader all day and not have a heating or radiator clogging problem.
 

North Idaho Wolfman

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Assuming it is a crack, is the better route to get a new head (around $700) or take it to a machine shop (unknown cost)?
New head, they are not easily or economically repairable. ;)
 

200mph

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Out of curiosity where did the $700 come from mentioned in a few posts?

Looking at Messick's I found the following for the head assembly.

30 COMP. CYLINDER H 1E129-03040 S/N Break. Please Call
30.1 COMP. CYLINDER H - replaces #1E129-03040 1E129-03043 $806.44 equal #1E129-03040
30 COMP HEAD, CYLIN 1J002-03040 S/N Break. Please Call
30.1 COMP. HEAD, CYLI - replaces #1J002-03040 1J002-03042 $1,354.40 equal #1J002-03040

Although the description states Complete Head the illustration does not include the valves, seals, springs, retainers, etc...

Is there a different PN that would be a bolt on replacement head?
 

JeffL

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I would not attempt any type of repair. Casting cracks behind the valve seat will lead to a dropped seat as the press fit is gone. Try Coleman's near Kansas City, closer to you so shipping would be lower.
 

GeoHorn

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I would not attempt any type of repair. Casting cracks behind the valve seat will lead to a dropped seat as the press fit is gone. Try Coleman's near Kansas City, closer to you so shipping would be lower.
Ooooowwwww! So sorry! But so glad you found it before reinstalling.

A new head is the best answer., per JeffL and Wolfman.
 

SidecarFlip

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The old one will make a nice door stop or paper weight in as much as scrap prices are poor.
 

D2Cat

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If you send good pictures to someone who has a 50" monitor a crack like that looks like the grand canyon! The big bigger the monitor the easier it is to see.

I just noticed yesterday scrap prices around here went to $100 a ton, was $90. But a few months ago it was $50. Have to clean a lot of stuff to make it worth the trip!
 

LanceM

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I'm looking into the parts/costs now. Fortunately, the head I need is the cheaper one, part # 52360 (according to one supplier based on my serial). I have a few more questions.

It appears to me that the crack goes from the prechamber to the exhaust port. I've considered reinstalling the current head/gasket and replacing the water pump with a new one. This would allow me to solve the overheating issue before spending bigger money on the head. So, what are the potential effects of running the engine with that crack? I realize there is some risk of the valve seat breaking loose and then damaging the piston head, block, etc. However, it seems that there shouldn't be any oil/coolant contamination to worry about??? Is it a big no-no? Is it relatively harmless? What are your opinions there?

If I buy a new head, should I replace the valve train as well? Or swap mine over and likely need to do some lapping?

Head bolts- reuse or new?

Block- what's the best way to ensure I don't need to have it machined before installing a new head?