Flathaed cracks
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Cargo Master
Joined: Nov 2004
Posts: 2,858
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From: Friendswood, Texas
Flathaed cracks
Pulled the heads from my F1 motor. Thre are a number of the head bolt hole to water jacket cracks that I understand can be ignored (True or False?). By visual inspection, I can only find one of the cracks from the cylinder wall to the exhaust valve opening. Can these be reliably repaired. Crack does not appear to be too ssevere but as luck would have it, that particluar pistion at the top of the stroke so I cannot see the cylinder wall (engine is frozen). I am going to wet mag it this evening or tomorrow night to get a more definitive handle on what is cracked and what isn't.
I trying to determine what approach I should take in dismantling this engine. If it's still salvageable, I will be careful. If it's toast with these cracks, I will take a more aggressive approach. This is the first flathead I've ever torn apart (i.e. - I'm learning on this one). Any help would be appreciated.
I trying to determine what approach I should take in dismantling this engine. If it's still salvageable, I will be careful. If it's toast with these cracks, I will take a more aggressive approach. This is the first flathead I've ever torn apart (i.e. - I'm learning on this one). Any help would be appreciated.
Fleet Owner
Joined: Jul 2004
Posts: 27,299
Likes: 1,059
From: NM
Head bolt to water jacket cracks: yep, they are common as dirt and can be ignored if the bolt can be torqued to spec. Use sealer.
The cost of fixing a valve seat to cylinder crack varies a lot, and you place your block's fate in the machinist's hands. It isn't always successful (you still pay!) It will generally also include the cost of sleeving that cylinder. You're talking big bucks overall on an engine that isn't even rebuilt yet. Usually fixing this kind of crack is to salvage a block that has had porting work or has otherwise no problems. You'll have to decide if you want to spend the bucks. There are still plenty of crack-free blocks to be had, and IMHO you are better off to start with one of them even if the up-front cost appears to be higher.
The cost of fixing a valve seat to cylinder crack varies a lot, and you place your block's fate in the machinist's hands. It isn't always successful (you still pay!) It will generally also include the cost of sleeving that cylinder. You're talking big bucks overall on an engine that isn't even rebuilt yet. Usually fixing this kind of crack is to salvage a block that has had porting work or has otherwise no problems. You'll have to decide if you want to spend the bucks. There are still plenty of crack-free blocks to be had, and IMHO you are better off to start with one of them even if the up-front cost appears to be higher.
Elder User
Joined: Sep 2003
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From: Augusta, ME
Cost wise I had two cracks like that, and my machinist quoted $500 to fix both, that included pinning the cracks, sleeving 2 cylinders, and replacing two valve seats. He was confident he could fix it and make it reliable, but he also knew someone that had a good block for half the cost which is what I went with. However, he said don't scrap the old block yet, it may not be perfect but one day it will be in better shape than what's left out there. So I've tucked it away in the garage for some day when I have money to burn and nothing left to fix on the truck. 
Scott
Scott
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Cargo Master
Joined: Nov 2004
Posts: 2,858
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From: Friendswood, Texas
Originally Posted by Scott123
However, he said don't scrap the old block yet, it may not be perfect but one day it will be in better shape than what's left out there. So I've tucked it away in the garage for some day when I have money to burn and nothing left to fix on the truck.
Scott
Scott
Unfortunately, space it a premium here so hanging on to it just won't be practical if I can't use it. No rush to get rid of it right now though but I do need to at least get the exterior of the engine cleaned up some. I'l pull the water pumps, generator, intake manifold, exhaust manifolds distributor, etc. Some may be rbuildable, some may make good cores, others may be servicable as is. Guaranteed that if I throw something from this engine away, I will need it for whatever I end up putting in there and whatever I keep, I will end up with five others just like it.
Roast em' if you got 'em
Joined: Mar 2005
Posts: 22,017
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From: Rio Rancho, NM
Originally Posted by texan2004
Guaranteed that if I throw something from this engine away, I will need it for whatever I end up putting in there and whatever I keep, I will end up with five others just like it.
