Butchered block

oldwoodsman

oldwoodsman

Senior Member
I received a Model a block to use as a replacement while I do some work on my engine. I had no history of this engine, after tearing it down I found good babbitt and cylinders, but someone had butchered the head bolt hole for the drivers side water outlet. I would like to put it back together, but don't see a fix for the hole and threads. I put it on my Bridgeport and indexed the hole to see if I could put some kind of an insert in there, but it would take a 3/4 inch insert and that would put the insert close to the cylinder. Any other ideas to save this block for a temporary replacement? :confused:
 

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I had one that way on the center or #1 stud. I drilled it and got a bolt with fine threads and tapped it to that thread. I locktighted the bolt in and sawed it off as close to the deck as possible and filed it as close as I could. I put a head on it and marked the center with a drill and put it on the bridgeport and drilled it and tapped it to 7/16-14 and decked the block. It is somewhere still running with no problems. I actually built this motor for my own use and had no intention of selling it but, it ran so good and the repair was never an issue, when I was pressed to sell it, I told the customer of the repair and it didn't matter as long as I would warrantee it for a reasonable time so he was happy. Never heard back good or bad, so it must have been good.
 
Thanks Bob, but the hole is bored off center from the head bolt, but a regular timesert for 7/16s has a major diameter of .534, which is not large enough to clean up the damage done.

James that was my first thought, but with the hole off center it appears the threads for a 3/4 inch insert would not be covered by the head gasket. do you think that would be a problem?
 
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I seem to remember reading somewhere that a Model T engine had a very badly damaged hole. The hole was too big for a standard Helicoil. The hole was drilled and tapped out to accept a cast iron pipe plug. The plug was tightly installed with Loctite. The plug was dressed down to the deck, drilled and tapped back standard. Good luck with it, Ed
 
Thanks James and Ed, After reevaluating your suggestions I came to the realization my thinking on the larger insert was a little flawed, for some reason I was thinking the head bolt would need to be in the center of the insert thus putting the insert too close to the cylinder wall, after another look the insert can be off center from the bolt thus moving the insert away from said cylinder.
thanks again and it maybe awhile before I get this done but I will keep you posted on the results
Tim
 
Another option to look at is "full torque", they have blank inserts that can be drilled off center, I too have a nice block with a bad stud hole repair, I have also done repairs similar to what James mentioned
 
Ed in Maine said:
I seem to remember reading somewhere that a Model T engine had a very badly damaged hole. The hole was too big for a standard Helicoil. The hole was drilled and tapped out to accept a cast iron pipe plug. The plug was tightly installed with Loctite. The plug was dressed down to the deck, drilled and tapped back standard. Good luck with it, Ed
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Good idea Ed, a 1/4" NPT solid cast iron pipe plug would be good and of the same material. The tapered thread would make it water tight and negate the need for locktite. The solid plug could be cut flush and drilled in the original stud location. Good idea.
 
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Ed in Maine said:
I seem to remember reading somewhere that a Model T engine had a very badly damaged hole. The hole was too big for a standard Helicoil. The hole was drilled and tapped out to accept a cast iron pipe plug. The plug was tightly installed with Loctite. The plug was dressed down to the deck, drilled and tapped back standard. Good luck with it, Ed
Click to expand...

I do that to all of the stud holes before I do any other machining on my race engines EXCEPT, I use steel 3/8 pipe plugs. By doing this first, boring takes any bumps out that the tapered plug might cause in the cyl. wall.
 
Thanks guys I never would have thought of using oversize pipe plugs I have a block under the bench with this problem
learn something everyday
 
Pipe thread exerts outward force, as do the regular threads, fine if there is enough metal surrounding the area to contain the force, the "full torque" type inserts have no outward force, they will be better in thin areas that could be prone to splitting open ---but they cost morer than pipe plugs
 
Thank you everybody for your input.
I'm unable to find Full-torque's price sheet and how concerned do I need to be about distorting the cylinder if a tapered plug is installed as I'm not looking to bore the engine?
Tim
 
I have used pipe plugs to make this kind of repair many times in castings and I tightened them but never tightened them with great force; once they were milled smooth, they never moved or tried to back out.
 
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