40/420 head

General help and support for your Lindeman through 2010 John Deere crawler
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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

40/420 head

Post by Bret4207 » Thu Feb 10, 2022 5:59 am

Pretty sure I've got a cracked head on the 420. Had the same thing on the 40. Is this a fairly common issue? Seems odd lightning would strike twice for me.
40C, 420C, 1010C-L-BH, Cat D4

fundytides
440 crawler
440 crawler
Posts: 223
Joined: Sun Oct 27, 2013 8:41 am
Location: Saint John, NB, Canada

Re: 40/420 head

Post by fundytides » Thu Feb 10, 2022 6:40 am

Common in my experience. Original? head on my 40 cracked, replacement head from an M cracked and the original head on my son-in-laws MT cracked. 2 were repairable by the local machine shop, the 3rd one suffered a catastrophic break. As you probably know new ones are usually available. Check with Lavoy, he can probably supply or source one for you if yours is not repairable.
have 40c 4 roller crawler, 1927 Ford T Touring car, 1931 Ford A Roadster, 1951 Standard Vanguard Saloon. Never a dull moment!

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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

Re: 40/420 head

Post by Bret4207 » Thu Feb 10, 2022 7:27 am

So it isn't lightning. Okay, thanks!
40C, 420C, 1010C-L-BH, Cat D4

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Bret4207
440 crawler
440 crawler
Posts: 169
Joined: Fri Apr 28, 2006 6:10 pm
Location: St Lawrence Valley NY

Re: 40/420 head

Post by Bret4207 » Fri Feb 11, 2022 5:42 pm

Well I was wrong. I can't find a crack in the head anywhere. Not that I can see with the nekked eyeball anyway. What I did find is that the seat for the exhaust valve on #2 is non-existent! There is nothing but a faint suggestion of a partial ring where the valve seat should have been, but that's it. I've never seen anything quite like it. I also found out I appear to have 2 .045 oversized pistons, or so they are marked, and one (#2) which has some evidence of metal being caught between piston top and head. I honestly don't know how it ran as good as it did. Got a rebuilt head enroute and I'll be ordering a few more parts too.

I'll eventually take this head to the shop and have it checked and rebuilt if possible.

Amazing!
40C, 420C, 1010C-L-BH, Cat D4

fundytides
440 crawler
440 crawler
Posts: 223
Joined: Sun Oct 27, 2013 8:41 am
Location: Saint John, NB, Canada

Re: 40/420 head

Post by fundytides » Fri Feb 11, 2022 5:49 pm

Disaster averted. Thanks for letting us know the outcome.
have 40c 4 roller crawler, 1927 Ford T Touring car, 1931 Ford A Roadster, 1951 Standard Vanguard Saloon. Never a dull moment!

Ray III
2010 crawler
2010 crawler
Posts: 609
Joined: Sat Aug 25, 2007 1:39 pm
Location: Troy, NY

Re: 40/420 head

Post by Ray III » Mon Feb 14, 2022 9:08 am

Same happened to me, just stopped being able to start it one day. Machine shop put new valve seat inserts in.

40 and older didn't have a water pump and were prone to overheating, but I didn't think cracked heads were common on a 420.

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