what he said ,had to shim caps to get clearances. got it running for a grade,but would'nt want it in my car
Pull the pan and check each rod. They have side clearance, so you should be able to move each one side to side a little on the crank. If you have a tight one back it off. Confirm the right cap is on the right rod or rods. On the mains, make sure the caps are in the correct position. If they are loosen one at a time, trying to rotate the engine with each one. Starting at the rear with the rope seal.
main caps and rod caps were "hopefully" re-installed in their proper position, but we will check, students were advised as to proper way to do it, but you know how that goes rings were right out of the box, no file fit... cam bearings were student installed and the cam rotated fine... we will take it back one step at a time and let you know what we find out...thanks for the help
probably too tight bearings or rings. My dad had this problem one time when he was young. don't do what he did. he put it in anyway and thought it would wear in. he tried to start it by towing the car and letting the clutch out he broke a few teeth of the rear end ring gear so then he had to fix the engine and the rear end.
put it on the stand and pulled the pan, checked end clearance on the rods and found one didnt feel right, sure enough it was on backwards, flip it around and everything is groovy, turns over like a dream...start slowly torquing everything back down, get to the very last main cap and .... I just about puked... time for a new block
Looks like that piece has been gone a while if you can't find it. Probably in the past someone tried to bump the cap loose before the bolts were out. I'm with Rich, if this is just an exercise, run it, hunt up another block later if it's going somewhere.
Don't know a alot about engines, but is that really that serious where you need to replace the block? It looks like the threads are still intact, and the cap could go back on without a problem. Would it be a problem with torque specs because of the missing metal. Or other issues?
I'd put the cap back on and run it and never think about it until I knew I had to. Bet i never would.
i thought i was the only one that shit like this happend to. i say run it, a friend of mine had a 302 ford with a crazy knock, he ran it for a long time (not hard) we took it apart later down the road and found one of the main caps was broken in half! aparently it happends to the 289-302. i know its a completely diff motor but you get the point....so you gonna run it???? baby it on the test stand for a bit
I think I would agree with the others here who have said run it. If there are enough threads left to torque the cap on properly it will likely hold and the engine would live as long as it would without that small piece missing. Its an end bearing so that should help with it not being a problem. Maybe we are wrong in that line of thinking. I would bet otherwise though.
Run it, thats not a crucial part of the block and theres plenty of surface left for the main cap to seat into. why should all us flathead guys get the honor of running cracked blocks lol!
I suppose the run it / don't run it argument comes down to the application. If its a sports or race motor, it's as you say new block time. If it's a road motor or merely an excercise in building I guess I'd risk it. No matter what you decide, damn I'm sorry finding that sort of stuff stinks.
Not really clear picture , but it looks like that cap has been moving on the block, like it has galling on the machined surface, as if the cap was loose when it was last run. Just my 2c worth.
If I remember correctly those Y-blocks are all fine threads internally. You'd be supprised by the abuse that they can take or how well run. We ran our with one bank on rocker arms off the engine. I say run it not enough material missing to make a difference...
wow, never even thought about trying to run it this way... there are no threads left in the block, at least as deep as the bolt needs to go, seems to me like these yblock main bolts dont thread very deep into the webbing?? never though about putting a stud into it, that may be the way to go... you guys present some interesting options, we'll see what happens, thanks-
I'll bet having the main cap on backwards caused a lateral load on the bolt, which blew out the chunk. Maybe drill and tap the web a little deeper, and use a stud as budd suggested. If you went this way, you could jb weld the chunk back in place, (make sure the mating surfaces are cleaned). Hold piece in position till cured using a flat bar bolted to the main cap mounting surface. Just remember to use something like wax paper so the clamping bar isn't bonded too.
You have to see what thread you have there and if it can be drilled and tapped deeper first. Then the stud plan comes into play. Another viable option, there are oversize inserts that could be installed. You have to use the recommended drill & tap, and then install the insert. Then you could go back to a standard cap bolt or use a stud. I'd make up a guide block to guide the drill and tap, a good student project though. Bob
Helicoils will work as long as the hole is not too sloppy (no ex-wife stories please..). I would use a thread locker product on it. Thread inserts are last-resort remedies for badly stripped out holes, I still prefer them over standard helicoils for applications like this one. Bob
If I'm reading all this correctly, rear main was installed backwards. Not even gonna ask aout the piece missing. No threads in this bolt hole? Helicoil it, do it right while you have it up on the stand. Take the rod caps off, push the pistons on up into the bores, pull the crank, cover everything, install your helicoil, vaccuum wipe and clean all pertenate areas, and reassemble. Be sure and test rear main clearence with some plastigage. Cheap insurance, then put back together. Find the little goober that smacked the cap surface and rap him across the nuckles with a 12 in/ flexable ruler! Ha!
Since the bolt hole is stripped out , the helicoil will tap into the fresh material BECAUSE that insert has to thread in. When inserting, apply loctite to outside of helicoil insery. Let dry. Get yourself a new fresh bolt with good threads, test the fit. If that bolt is really tight, grind a thread cutter on the end of that bolt....some of the loctite has leeched into the helicoil threads, run that bolt in removing the crust outta the threads.....then assemble the motor.......
Its not the rear main, its the very front one, again you guys have given us some good options, I'll keep you updated, thanks-
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