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Discussion Starter · #1 ·
i have a 2 cyclinder tractor 31hp and a intake bolt fell into the enigne and when i tried to crank it one day it spun half way around and stopped .. i stopped and pulled the head off to find the bolt laying in the cyclinder it did mush the piston up alittle but only under cranking power and i stopped after two tries i am wondering how do i tell if i need to change the piston as well as the head maybe somebody can help or send me to a site that can helpo me with this ethier way i would be thankfull for any help
 

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Lost in the 60's
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Well... do you have a picture of the head and piston...that would really help. But if the valves are not broken, the head not cracked, and no hole in the top of the piston.....and the mushed that your talking about is not bad.. and you can clean out any metal particles........then it should run. Thats all that I can tell you without seeing it.
 

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Discussion Starter · #3 ·
Henry Highrise said:
Well... do you have a picture of the head and piston...that would really help. But if the valves are not broken, the head not cracked, and no hole in the top of the piston.....and the mushed that your talking about is not bad.. and you can clean out any metal particles........then it should run. Thats all that I can tell you without seeing it.
i just rememberd that it did bend the valve but did not bend the alluminum push rod and it cracked the valve guide when the bent valve tried to close but i have checked the head with a steel ruler and a feelier gauge and it is holding the same in any direction(the head it flat it is a diesel) hope this helps you
 

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Troll Hunter
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I know it is diesel, but you might drop the piston down and inspect the cylinder. In the early 70s I had the shaker support nut('69 428 CJ MachI) on the side of my air cleaner come loose. I didn't notice any unusual movement of the shaker, so was unaware of any problem. I drove it into town and when I went to slow down, the idle was high and I thought that the fast idle was stuck because of the 20* temps, so I kicked it and it dropped down to normal idle. Within 15 minutes it was beginning to overheat, so I headed to the garage to inspect it. Not good. The loose side support had caused the shaker to stress the air filter stuf and it failed and fell into the carb (high idle) and when I kicked it down it injested it into a cylinder( I still can't figure out how that thing got through the intake and by the valve, but it did) it swedged the top of the piston enough that it cracked the cylinder. A lot of work, but at the time 428 CJ blocks were easy to come by. Just a word of caution.
 

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Discussion Starter · #8 ·
pistons

thanks woodz i will check that this type of tractor has removable cyclinder so i can pull off the jugs one at a time or all of them and inspect it all ...but i did not think about doing that cause i can turn the engine over by hand and i can see the cylinder and it is is great shape but you guys have me wondering if i should take the piston and have it check or atleast pull it ou and check it alot closer :thumbup: :thumbup:
 

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Hates: Liver. Loves: Diesel
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I'd leave the piston alone and fix the valve to make sure it seals. Its a tractor, not a road car :)

I only say that as an owner of about a dozen tractors; the demands placed on those low-rpm diesels is minimal. Heavy loads are usually intermittent. As long as you're not beasting on it in a manner that causes black smoke more than 25% of the time you should be fine. The higher temps associated with black smoke can make hot spots on those gouges in the flame decks, but I've run pistons that looked worse. I left a screwdriver in a VTA28 V-12 28-liter marine engine once and it ran for three days before we took it out. The plastic handle was gone and the metal had kinda fused to the piston.

Avoid grinding or smoothing those gouges. Adding 1/2 cc to that chamber will alter the compression pretty drastically. As it is now you've displaced metal but not removed any. They are dents, but they haven't added a lot of combustion space. In a gasoline engine it would be critical to remove potential hot spots and in doing so you might take the compression on that cylinder from 9.5:1 down to 9.48:1. In a small diesel like that, you might take it from 20:1 to 17:1 in a hurry.

Fix the valve, replace the head, run it.
 

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Discussion Starter · #10 ·
pistons

curtis73 thanks that is what i thought i do pull a plow with it but it in is sl1 super low first and about 3/4 throttle i can get a head for about 100 dollars and a used piston for about 50.00 do you think it would be best although it will probaly be fine like it but go ahead and change it cause it is cheap??what are your thought on just getting used parts that are not bent ?
 

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woodz428 said:
at the time 428 CJ blocks were easy to come by. Just a word of caution.

Should have bought a dozen if money provided! What an investment! :thumbup:

Wondering if I should buy LT1s and other (fairly) common modern hi-po engines... buy and store for later sale... :confused:
 

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If you can get the piston and rings for $50, and the jugs come off individually, I'd go ahead and replace it. If the piston is cracked where you can't see it and fails later, it will most likely gouge the bore, meaning the jug would need replacing too. Even if it didn't, you'd have to pull it all apart again. I'm assuming the jug has a taper at the bottom so you can slide it on the piston without a compressor, like a motorcycle with removable jugs. I'd replace it now to be safe since it's so cheap. Will cost that much more money and time to change it later.
 
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