8BA center main ?
 

I have a complete 8BA I planned to use as a core to rebuild. I would not turn over, so I took the heads and pan off. The combustion chambers & valves looked ok. When I took the pan off, I found that the center main bearing cap had broken.

What would cause that that to happen ? Everything else looks good. I don't want to spend any more time and effort on it if is not a good core.

Thank you Fordbarners.

Re: 8BA center main ?
 

When I was in high school in 1959, I blew the center main cap off of my '51 Ford. It made an awful noise, so I shut it down immediately. After getting it up on blocks and removing the pan, I found half of the center cap still held on by one bolt. The other bolt was where it should be, but the other side of the cap was half in the pan, with the rest blown out through a 1" hole in the pan. The bearing shell was still on the crankshaft. After looking at this carefully, I pulled it apart, and surprisingly, the crank and even the bearing shell looked good. Not knowing any better, off I went to the local junkyard and collected a bunch of center main caps, On my way home, I stopped at the local parts store and got some plasti-gage. To my utter amazement, the first cap I tried fit well and the bearing checked out in spec. I even used the original bearing shell. I brazed the hole in the pan and put it back together, and it started right up and ran great, with no noises or anything. I drove the car for a couple of more years until it got so rusty, my dad had it hauled to the junkyard.

A couple of weeks later, a friend with a '52 Ford said he needed an engine, so I told him about the good runner that was in the junkyard. he went up and bought the engine and put it in his car. He ran it for another couple of years and sold it. A year after that, I bought that car off the local Chevrolet dealer's used car lot at a real good price because second gear was out. About 6 months later the engine was using a quart of oil every 50 miles or so. I pulled it apart to put rings in it, and lo and behold, there was the brazed pan from 4 years earlier. I put some used pistons and a set of rings from Sears, and drove it another year or so, when I sold it to another friend for his little brother.

I swear this is an absolutely true story. I remember that my dad told me it couldn't be fixed, but in the ignorance of youth I went ahead anyway. I think this says more about Ford's manufacturing tolerances than my mechanical skill. If you can find a cap that fits, you may be able to fix it cheaply. Oh; how did it happen? I was approaching a stop light that had just turned red and shifted into second at about 50 to "rap the pipes". With 4.11 gears, I think that was a bit much for it!

It takes a lot to kill a flathead.

Re: 8BA center main ?
 

I'vused old caps many times in repairing flatheads. Yes, old hank made some good stuff.

Re: 8BA center main ?
 

ol ron - how do i tell the difference between the front main cap and the center one?

Re: 8BA center main ?
 

The front main bolt holes are off center front to rear.

Re: 8BA center main ?
 

, Good idea to uz plastic gauge.

Re: 8BA center main ?
 

It sounds like maybe the engine might be okay as a core. Still curios as to what might have caused it. I have no history on the motor. Thank you Fordbarners.

Re: 8BA center main ?
 

The front main will have a little "tit" on it while the second doesn't.

Re: 8BA center main ?
 

The center main takes a beating more than the front and rear, mic the crank in any engine with a lot of miles on it and the center main will be worn more than the front and rear. I've gived caps to people with broken caps and they got away with it. I'll send you one and you can try it, I've never found one that the parting line on one side don't have a little lip, You ought to mic the housing bore or at least plastic gauge it, If you put the crank in the block without the rear seal and can spin it with your hand you'll probably get away with it. Walt

Re: 8BA center main ?
 

Reread my first post. I blew mine by forcing the engine to over rev beyond it's capabilities.

Re: 8BA center main ?
 

Check the bearing web and pan rails for cracks. my 50 F-1 did the same thing, but it also broke the crank in half. A local commercial engine rebuilder had a cap that required a light center line hone and a good merc. crank. I installed a bearing cap strap to beef it up a little.

Re: 8BA center main ?
 

Thank you all for your insight. I didn't know that the center main cap took a beating compared to the front & rear. I get it, makes sense when you think of the pressure and possible "whip" on either side of it compared to the front & rear.