damaged main cap

[Greg Willocks]

Hi my e6 has a damaged main cap , how, when, why, the hard facing has been chipped off one side of the cap where it bolts onto the block. when the bearing was replaced and cap bolted up the crank kept locking up , on investigation they discovered the damaged cap and a crack in the block that opened and closed as the thread went past it. now they say it was that way and they did not damage it by bolting it up and trying to start it with an incorrectly positioned main bearing , correct me if wrong but if it was pre existing then wouldn`t the old bearing show signs of this , would there have been some kind of noise? and why only one side of the cap ,one would think that if it was that damaged that it locked the crank up that side would of been virtually flappy in the breeze. his remedy was to file down the damaged area and shim the difference to make it equal with the other side.

would it be worth while to have the crack welded up or should the block be replaced

thanks

[blackdog2]

The late 80s had problems with the bolts not long enough and yanking a section of the block out . Ive change a lot of them . They do sell a bolt kit .

[Greg Willocks]

thanks I was told you could get longer bolts , do you change all bolts or just the one

[blackdog2]

All but check the deph of the hole and in stall the flex plates.

[Greg Willocks]

ok thanks ? what is the flex plates you mentioned

[gearhead204]

I would not pay these jokers a dime and would get my truck the hell out of there!

[Greg Willocks]

where do you get the longer bolt set , Mack or PAI

the guy is sueing me for 20 grand for the rebuild, and it sounds like it needs another, I`m not paying and he`s holding the truck.

[gearhead204]

can you get another r600 for twenty grand that fits your needs? if so I think I give him a title and find a real mechanic. just my thoughts

[turckster]

A lot of the older E6 Mack engines had a main cap issue. Main caps 2, 3, 5 & 6 were the usual suspects. Usually when I was to overhaul one of these engines the first thing I would do was pull the pan and drop these main caps. Inspect the bearings for odd wear, checked the main cap and block mating surfaces for fretting and for cracks in the main cap bolt holes.

If the fretting was bad (which would cause odd/uneven bearing wear) we gave the customer 2 options- reman engine or pull the engine for disassembly to have the block line bored. With a crack in the main threads it would be an reman engine. E6 engines with the main cap plates (2 & 3 - 5 & 6) didn't usually show this wear or not as severe.

If you had the engine overhauled and the main caps showed severe fretting and had (a) crack(s) in the main bolt holes they should have stopped and informed you. Given you some options and explained the consequence of said options if you chose not to repair properly.