Has anyone seen or heard of repairing an eroded valve seat with an insert? Is it common or feasible?
I don't know what caused the erosion on one exhaust valve seat on a 4239D engine. Likely related to the piston slapping the head because of shot rod bearing on that cyl. Piston pocked because of slapping and parts of outer edge of piston have broken off, exposing top of upper piston ring. No apparent damage to sleeve or head other than erosion to inside of port and bad erosion to back side of valve head.
Surprisingly, outer 1/16" of valve seat is still sound and shows no sign of burning or leakage, either to seat or valve. I could possibly get by with regrinding the seat and installing a new valve. JD's manual calls for exhaust valve seat width of 1/16" (+1/64" - 0").
FWIW, I have the machine shop equipment to mill an insert pocket and press in a repair but haven't tried it before. Any experience on the board?
Jim
repairing 450 head with a valve seat insert?
No offense, but if you don't do it for a living, have an engine shop machine the head and put in a new seat. It has nothing to do with equipment, it has all to do with experience. The $50 or so you save may cost you hundreds or more when it falls back out and takes the sleeve and piston with it, more if it takes the head or block.
As far as putting in new seats, no problem, I have had new seats put in virtually every head I have ever had done for well over 20 years, but would never remotely consider doing it myself.
Lavoy
As far as putting in new seats, no problem, I have had new seats put in virtually every head I have ever had done for well over 20 years, but would never remotely consider doing it myself.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com
Owner and moderator www.jdcrawlers.com
I agree with Lavoy on this. You may be a first rate machinist but if you have never done a head before, then I would spend a few bucks and have it done. Also like Lavoy, I too have had several seats replaced with no issues. I wouldn't try to just grind a new face into what is left of the old seat. I think it would just erode again.
Another thing to consider is the head itself. You say it is okay... but is it? Since the piston was hitting the head, I would be afraid of it having a crack that only magna-flux will show evidence of. I would send it out for the seat as Lavoy has said and while they have the head, have them check it for other damage.
I'm also curious what you did to repair the spun bearing? If you haven't done anything with the rod or the crank, then you will most likely have issues again. Just trying to save you some time and money down the road.
Another thing to consider is the head itself. You say it is okay... but is it? Since the piston was hitting the head, I would be afraid of it having a crack that only magna-flux will show evidence of. I would send it out for the seat as Lavoy has said and while they have the head, have them check it for other damage.
I'm also curious what you did to repair the spun bearing? If you haven't done anything with the rod or the crank, then you will most likely have issues again. Just trying to save you some time and money down the road.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.
Thanks for the replies. Very good info and sound advice. And, no, I won't attempt to install a valve insert if anyone can be found locally who knows what they are doing.
The valve problem may be moot, though. Since posting, I was able to remove the engine and check the crank. Two rods spun the bearing shell so both rods are toast and if I chose to repair it, the crank will have to have two rod journals built up. Haven't checked the mains yet so the problem may get bigger.
So I've got to figure out whether a new (rebuilt) engine or a short block is in order. Ugh.
Any ideas welcome.
Jim
The valve problem may be moot, though. Since posting, I was able to remove the engine and check the crank. Two rods spun the bearing shell so both rods are toast and if I chose to repair it, the crank will have to have two rod journals built up. Haven't checked the mains yet so the problem may get bigger.
So I've got to figure out whether a new (rebuilt) engine or a short block is in order. Ugh.
Any ideas welcome.
Jim
Jim,
If your mains are okay and if the rod journals are turnable, then I would have the crank turned to what ever it takes to get it back to a good surface. I think Deere will allow up to .30 thousandths on their cranks in your engine series. I may be wrong on that but my point is, you might be able to have it turned and then put oversized bearings in it.
If the engine is indeed toast, then there are a few alternatives to go with. Personally I would look for another used engine. It can even be an Ag engine or Industrial. That's the neat thing with these older Deere engines. They were used in several applications. All they did was change bell housings and the front components. You simply change what you already have over to the second engine. I know I have mentioned this before on here but I recently switched my JD 1520 Gas tractor to a Diesel. I used an engine that came out of a JD 350D crawler dozer. I have also over the years taken other Deere engines and made them into what ever application I needed them to be.
Short block is another alternative or a complete rebuilt engine. Look your engine over really good first. It may not be as bad as you fear. Good luck and keep us posted. >>> Leonard
If your mains are okay and if the rod journals are turnable, then I would have the crank turned to what ever it takes to get it back to a good surface. I think Deere will allow up to .30 thousandths on their cranks in your engine series. I may be wrong on that but my point is, you might be able to have it turned and then put oversized bearings in it.
If the engine is indeed toast, then there are a few alternatives to go with. Personally I would look for another used engine. It can even be an Ag engine or Industrial. That's the neat thing with these older Deere engines. They were used in several applications. All they did was change bell housings and the front components. You simply change what you already have over to the second engine. I know I have mentioned this before on here but I recently switched my JD 1520 Gas tractor to a Diesel. I used an engine that came out of a JD 350D crawler dozer. I have also over the years taken other Deere engines and made them into what ever application I needed them to be.
Short block is another alternative or a complete rebuilt engine. Look your engine over really good first. It may not be as bad as you fear. Good luck and keep us posted. >>> Leonard
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.
The two bad rod journals will require weld build-up before grinding. Both the rods and mains were already ground .020 under. I found a shop which specializes in cranks and he feels confident he can do the welding and then grind all journals. He provided a soft quote of $200 which sounds good to me. Any particular problems with welding JD cranks?
My next questions regard best sources for engine repair parts. I'll need a complete rebuild kit (sleeves, pistons, bearings, gaskets, etc) which I see advertised widely as well as a couple individual parts (rods, valve). Presumably, some of the aftermarket suppliers make good quality stuff.
Any particular sources to recommend or avoid? Normally I would source parts from JD but I expect them to be very pricey for these items.
I want to do this repair properly so I don't have to revisit the problem again, but in the end, this is a home machine and will see few hours of relatively light work. Mostly maintaining a dirt/sand drive and light grading and brush clearing.
Thanks for any comments.
Jim
My next questions regard best sources for engine repair parts. I'll need a complete rebuild kit (sleeves, pistons, bearings, gaskets, etc) which I see advertised widely as well as a couple individual parts (rods, valve). Presumably, some of the aftermarket suppliers make good quality stuff.
Any particular sources to recommend or avoid? Normally I would source parts from JD but I expect them to be very pricey for these items.
I want to do this repair properly so I don't have to revisit the problem again, but in the end, this is a home machine and will see few hours of relatively light work. Mostly maintaining a dirt/sand drive and light grading and brush clearing.
Thanks for any comments.
Jim
Jim,
Check here with Lavoy first for your parts. I'm not sure what all he carries but his main focus for this site is to help him in his business of parts sales and repair. He is also very good at keeping quality parts... so no junk and he is reasonable on cost.
If he doesn't have all you need, then don't discount Deere completely. Most of the Deere dealers I have worked with can get you after market parts that are of great quality and the cost is competitive. Otherwise remember the old saying that "You get what you pay for". If it is cheap then it is most likely exactly that... Cheap!
As for as you having the crank welded and then reground, I don't have a problem with it. As long as the shop doing the work has a good reputation and will back up their work. I have had cranks welded and reground and have not had any issues with them. I would also check around to see what is available. Deere has some Re-man parts that are reasonable in cost and may be the better value. >>> Leonard
Check here with Lavoy first for your parts. I'm not sure what all he carries but his main focus for this site is to help him in his business of parts sales and repair. He is also very good at keeping quality parts... so no junk and he is reasonable on cost.
If he doesn't have all you need, then don't discount Deere completely. Most of the Deere dealers I have worked with can get you after market parts that are of great quality and the cost is competitive. Otherwise remember the old saying that "You get what you pay for". If it is cheap then it is most likely exactly that... Cheap!
As for as you having the crank welded and then reground, I don't have a problem with it. As long as the shop doing the work has a good reputation and will back up their work. I have had cranks welded and reground and have not had any issues with them. I would also check around to see what is available. Deere has some Re-man parts that are reasonable in cost and may be the better value. >>> Leonard
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.
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