All forward momentum ground to an immediate stop

[nbn]

2 years ago i sent this engine to the machine shop to be rebuilt.

Finally got time to put it back together. Set the engine in the car, and realized I never checked/adjusted the valves. I pulled the passenger inner fender, side covers and started the process. 

Then I found this....crack in the tappet bore!

How does this even happen? 

Edited Friday at 05:10 PM by nbn

[JBNeal]

OUCH 👀

Can those cracks be welded?  Did the machine shop find anything when they magnafluxed the block?  Can't sat that I've seen cracks in this area before...

[Ivan_B]

You should've carefully inspected and tested the engine right away... I've also had a very bad experience with someone "rebuilding" a motorcycle engine for me, once. After that, I had to send it to another shop who discovered all sorts of "things" inside Now I know better...

[kencombs]

That looks terrible.   But, I'd bet it has existed since the block was cast.   I'd run it as is and this is why:   There is no oil under pressure in that area of the block.   There is almost zero load on the tappet bore, just an up/down motion with a minimal side load from the cam contacting the lifter base.   As evidence I offer the fact that I've never encountered a worn bore, even in engines with many, many, many accumulated miles.  And have never heard of anyone else finding one.  

 

Yes I know it is a lot of work to remove and replace the block if it doesn't work out, but I'd gamble on it working fine.  After all there is a lot of machine and assembly work done and salvaging that is worth the gamble in my mind. 

[oldodge41]

My$.02 is,I also would run it if I were into it as far as you are. Easy for me to say, I know, but I would.

[nbn]

7 hours ago, kencombs said:

That looks terrible.   But, I'd bet it has existed since the block was cast.   I'd run it as is and this is why:   There is no oil under pressure in that area of the block.   There is almost zero load on the tappet bore, just an up/down motion with a minimal side load from the cam contacting the lifter base.   As evidence I offer the fact that I've never encountered a worn bore, even in engines with many, many, many accumulated miles.  And have never heard of anyone else finding one.  

 

Yes I know it is a lot of work to remove and replace the block if it doesn't work out, but I'd gamble on it working fine.  After all there is a lot of machine and assembly work done and salvaging that is worth the gamble in my mind. 

 

6 hours ago, oldodge41 said:

My$.02 is,I also would run it if I were into it as far as you are. Easy for me to say, I know, but I would.

Glad to hear your thoughts on this. I stopped by the machine shop and his thoughts were the same. He was a bit perplexed as to how it could have happened. 

The machine shop owner gave me 3 options. 1) try to have it welded and repaired in place, 2) pull the engine, find a replacement block and he'll eat machining cost to get another engine going, 3) run it as it is and if there is an issue on the next year, revert to option 2. This is after I've sat on this engine for 2 years after they did their work.

We'll hopefully fire it up this week.

[DonaldSmith]

There are special taps and screws for bridging cracks in cast iron.   They were used extensively in repairing the cast iron dome of the Nation's Capitol. 

Instead of the threads having a nice in and out profile, the screw threads are more like Christmas tree branches. all sloping in the same direction,

so the screw does not pull put laterally. 

 

(This would do well to demonstrate how well versed I am with trivia, but does not attempt to posit how strong such screws would hold the sides together in this case. 

But what else to do on a lazy Sunday?  Gotta keep the site going.  And I got to use "posit" in a sentence. )  

   

[Los_Control]

@DonaldSmithis talking about the lock and stitch method.

This looks like a pretty nice system and wonder about cost .... sure it is not cheap.

 

Seems the problem with fixing cast iron is heat vrs cold = cracks 

I like the old timer saying ..... we did not know we could not weld cast iron, so we just went ahead and did it anyways  

Kids use to do it all the time creating split manifolds for dual exhaust .... they learned tricks like heating the entire exhaust manifold in a fire pit, and then welding it while it was hot and let it all cool down at the same time.

 

I like what Tony did here with a cheap 110V fluxcore welder .... it does not get that hot like acetylene or stick welding .... short little steps at a time.

 

Anyway you go though, would have to pull the engine ..... I vote to run it and see what happens.

Edited Sunday at 03:41 PM by Los_Control

[oldodge41]

I am impressed by the response from your machinist. Sounds like a stand-up guy. Keep us posted as to how it all works out.