Center main blowout

[Frank Miller]

I helped a friend pull his motor to see why it was rapping. We knew there was a main bolt that had fallen out but that's it. The motor was still on the hoist when we pulled the pan and that is as far as we got. Half the cap was in the pan with a broken bolt. When we tried to loosen the other bolt it broke off the same way. I have never seen anything like this but my experience is limited. I think the bolts never got fully torqued to the cap due to bottoming out. That is just a thought.
It's out of warranty and don't ask who put it together. Mistakes happen, he's not doing them any more and he's a good guy.

[Lawrie]

They dont look like ford bolts.
Lawrie

[alanwoodieman]

wrong bolts, no split washer or wrong bolt (too long) and bottomed out in block and when torqued wrung them off. second block I have seen do this the other was a NOS from Carpenter

[mercman from oz]

Doesn't look good ?

[tubman]

I had this same thing happen on my '51 Ford in 1959. The only difference was that the bolt had not broken. As I remember it, the chunk of the main cap laying in the pan was an almost exact duplicate of the large piece you show. Back in those days, I needed the car to drive back and forth to school, so my main objective was to get it fixed and not wonder what happened. I went to the local Junk Yard and got three random center main caps and fitted them up with some plasti-gage from the local auto parts store. The first one I tried (with the original main bearing shell!) provided the proper clearances, so I put it back together, torqued the main caps, and went down the road. The engine ran fine in that car (and a subsequent '52 I put it into).

Another difference is that what ever happened put a slight hole in the pan that I brazed shut. The engine in this car had been "rebuilt" to the tune of $185 about a year earlier. Seeing this, and looking back, I have to believe that improper torque on the main bearing bolts was the cause. As I said above, the similarity of the broken cap pictured to the piece I recovered from the pan 52 years ago is eerie.

EDIT : After thinking about this overnight, my memory became clearer and what happened to me was not the same. When I dropped the pan, The large chunk was still where it should have been (bolted onto the block with one bolt),and the remainder of that cap had disintegrated, putting the hole in the pan, leaving several chunks in the pan. The other bolt was still screwed into the block, just that there was nothing there to hold anymore. The remaining chunk of the bearing cap was almost identical to what the O/P has shown.

[earlyride]

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I had the same thing happen to me on my 8ba merc. The main broke in half along with both bolts. Lucky for me I came a cross another main that worked without having to line bore

[Frank Miller]

thanks guys. I did not notice the lock washer missing. That could be it.
The next question is, how best to get the broken bolts out?

[alanwoodieman]

"if" they are both bottomed out it will be a challenge. I would take a short bolt of same size , drill a center hole all the way thru it and use that bolt as a guide to drill the ones in the block, looks like enough threads to do this, start with about 1/8" and work your way up. did not say what engine , if you need a center cap or a few to work with and can't find them around you let me know I will send you a few.

[Ol' Ron]

I take responsibility for this engine, as I built it for a fellow about 15 years ago. It's a 258, max#1 cam, and that all I can remember. Not sure where the original block assy came from, but it was bored cleaned valve job with rotators and reassembled. Plaed on the dyno and broken in. OIl pressure and temp were OK and engine was picked up buy the new owner. I bought the original engine from him and just put it in the stash with the rest of them..
Did I make a mistake?? Not sure. I was building allot of engines back then, and from the bottom they all look the same. But, when installing the crank you have to take special attention to details. I have no idea how many miles were put on the engine before this happened and the owner isn't really sure either. I'm sending him a box full of center mains, hope one fits, have no idea on how to remove the broken bolts, nothing to weld to, easyouts??. hope for the best.
Gramps

[Bored&Stroked]

My guess is that the cap broke first - then the bolts were taken out.

[19Fordy]

Got to admire "Ol' Ron" for stepping up. Thanks.

[Desoto291Hemi]

I’m not gonna blame Ron .
15 years is a while,,,,,and who said the bolts were not tight?
We don’t know that,,,,,I’m not blaming anyone.
Some times parts just fail !
Also,,,,these are cast main caps,,,,which failed first,,,,,the cap or the bolt ?
There can be defects in castings that arise later,,,,or a stress riser that can appear over time .
Also,,,,,detonation can play havoc with the mains,,,,,not just the bearings.

I have witnessed it first hand,,,,,,a perfectly good bolt being screwed back in,,,,,with hardly any pressure,,,,,and bink !
I was just glad it failed then and not later.
I am sorry that it happened,,,,,,but,,,,15 years is quite some time,,,,,who can say what really happened ?

Tommy

[Ggmac]

When I have a blind hole and the broken bolt , I first try left hand drills . Start small but expect to go to 3/8 and hope a 3/8 will catch and work the broken piece out . Set the clutch on the drill so you dont break small drills . On old Jaguars i start with 1/4 and then 3/8 . Let the piece cool , if it hasnt snagged the piece a little dry ice in the 3/8 hole with a propane torch ready . Get the appropriate easy out ready , warm the block and try to remove . Atthis point they usually can be removed . I hope the jag procedure can work on the flathead .
Good luck .

[VeryTangled]

Originally Posted by Frank Miller

The next question is, how best to get the broken bolts out?

How much have you fiddled with it Frank? Can they spin as they are? I'd try a transmission pick. If you're very lucky they will turn.

If they are bottomed into the block the tension is still there and plan B, C and D are in play.

I like the idea of using a hollowed out bolt(s) as a pilot for drilling. You've got access to a lathe to get that bolt centered up.

[alanwoodieman]

by the time this "see if this works" get thru the thread we should have the process down pat--so let us know what was done and the outcome. good luck!

[flatford8]

I think the hollowed out bolt for a pilot is an excellent idea. I’m gonna remember that. Yes, let us know how you progress...... Mark

[miniceptor86]

Originally Posted by 19Fordy

Got to admire "Ol' Ron" for stepping up. Thanks.

Yes sire!

[tubman]

Not that it matters, but the bolts in my engine spun out easily with my fingers. Still, I think that if you can get anything to "catch" on the broken portion (left hand drill, a slot ground in the bolt for a screwdriver, or the last choice, an "EZ-Out"), they should come out.

[Ol' Ron]

Put some 50.50 mix on them and let it soak in for a while. I too like the pioleted drill method something to remember. I'll have thse caps shippedm out tomorrow.
Ron

[Scotty's 52 F3]

Can you take some pics of the face of the fractures? On the bolts and the cap? Might get an idea what happened first and how fast it happened.

[Baggs]

I’d suggest taking a file to the corners of the cap and block areas , just the ends to take a possible high spot/ burr off. I do it with all my main caps and block, as well as the rods, even after the rods have been resized.

I have to trust the surfaces being flat, no way I have the equipment to check it.

I just use a small fine file, maybe 1/8 inch wide, to put a polish so to speak. It was how I was taught to ensure no cocking of caps when tapped down in place and torqued.

May or may not have caused the issue.

[Flathead]

The center main bolt holes aren't really blind, there is a window in the block where the bolt ends, and I'll bet that bolt would spin out with a reverse drill. These engines are old and nothing lasts forever so bad things will happen no matter who worked on it. If it went for 15 years it was likely put together right.

[Bums F-1]

I lost a center main cap.the crank also broke in half.that gave me a
reason to buy a Merc. crank. For peace of mind I installed a center
main strap.

[VeryTangled]

Originally Posted by Ol' Ron

...I built it for a fellow about 15 years ago... Did I make a mistake?? Not sure. Gramps

Hehe, this is a very honest perspective from Gramps. I'm pretty darn certain I did stuff 15 years ago that was a mistake. Yup. Pretty certain. I tried hard but ...

[chain drive]

they make a welding rod called stud rod you can go into a blind hole weld on the bolt it will not stick to the sides we weld on broken bolts all the time with it keep building weld up out of the hole and weld a nut or flat iron on the weld and they turn out has alot of nickel in the rod very strong good luck

[tubman]

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Originally Posted by chain drive

they make a welding rod called stud rod you can go into a blind hole weld on the bolt it will not stick to the sides we weld on broken bolts all the time with it keep building weld up out of the hole and weld a nut or flat iron on the weld and they turn out has alot of nickel in the rod very strong good luck

Basically, this sounds like a good idea and I was thinking of suggesting it myself. I do have a question, though. I have always used "High Nickel" content rod to weld cast iron. This makes me wonder about your statement "it will not stick to the sides". Can you explain this?

[Frank Miller]

Ron did not need to step u[ but he did. talk with any engine builder and they have stories about mistakes. Quite a few about the front plug being left out of the oil galley. An old radio guy once told me, the difference between a novice technician and an experienced technician is the experienced one has already burned someone else's equipment. So whether it's engines, radios or marriage there's a lot of mistakes out there. Maybe I should add kids too. :-)

[Bob C]

Originally Posted by tubman

Basically, this sounds like a good idea and I was thinking of suggesting it myself. I do have a question, though. I have always used "High Nickel" content rod to weld cast iron. This makes me wonder about your statement "it will not stick to the sides". Can you explain this?

X-Tractalloy

X-Tractalloy is a special application welding electrode designd for extracting broken bolts, studs and taps from threaded holes.

• Saves time and money - reduces downtime and labor by getting parts back into service quickly.
• Versatile - X-Tractalloy will also remove broken screw extractors, taps and broken drill bits.
• Strong - tensile strength exceeds that of Grade 2, 5, 8, 8.8 and 10.9 bolts and stainless steel.
• Nonconductive flux - ceramic-like coating insulates threads to prevent damage from welding.

[JSeery]

That's interesting information.

[tubman]

Yes it is. https://www.youtube.com/watch?v=L4zohssWS7I

[Bored&Stroked]

Yes - that is really interesting stuff . . . will have to pick some up and give it a whirl. Might help with broken off studs in these dang blocks!

[Kurt in NJ]

First I would use the piece of bolt, put it in hole and try to unscrew by hand, I get 80% of bolts broke like that out that easy
I have also use arc welder rod with some tape to center rod to remove bolt down 6" hole

A left hand drill sized for easy out-- start drilling, most likely it will remove bolt piece before you get it drilled enough to use easy out

[Russ/40]

I don't think a mistake was made. I had the same thing happen to an engine I built. Took two more owners and about 20k miles before the center main cap broke. Notice, it's almost always the center main. These parts are old, and, who mags main caps? Maybe that should be another MUST check to go along with pressure testing.

[tubman]

I thought I had an unusual occurrence, but from the posts here, this looks to be more common than I ever thought. Maybe this is why all current V8's use 5 main bearings.

[Lawrie]

And the new model A engine
Lawrie

[Tony, NY]

Originally Posted by Bored&Stroked

Yes - that is really interesting stuff . . . will have to pick some up and give it a whirl. Might help with broken off studs in these dang blocks!

Seems to be very difficult to find. Video is from 2011. Let us know where you find it.

[Wat-0]

https://www.tbcdistribution.com.au/p...-miscellaneous

[Dlistro1950]

Update. I cleaned the pan. Buried in the sludge was a washer. So it did not fail because washers were neglected...and it matches the others. The cap just failed. I think Ron did not do anything wrong. The cap failed! Ron sent me caps and I just returned from Ron SanGiovani's and he lent me some as well. Between them, I hope to find a match and return the others. I need to check the length of the bolts after I pull the broken off bolt remainders from the block. I doubt that the bolts were too long.

Thanks for the help guys.

Dick Listro

[Desoto291Hemi]

Thank you for posting your findings .
I think you will find it was just a cap failure,,,,seems it happens more than we realize.

I’m not blaming anyone,,,,but some were quick to blame it on Ron without any real evidence,,,,and sometimes all anyone really has is their reputation !

So glad to see so many stand up guys here,,,,as well as yourself,,,,it makes you have confidence in your fellow hot rodders .

Tommy

[earlyride]

After that happened to me I installed a speedway main cap support, figured it couldn't hurt, so far so good. Has anyone else used one of these?

[cdan34]

Maybe some one posted this and I missed it. It looks to me like there wasn't enough thread on those bolts and they tightened up before clamping the main.

As mentioned they could have bottomed out also.

[34PKUP]

Originally Posted by cdan34

Maybe some one posted this and I missed it. It looks to me like there wasn't enough thread on those bolts and they tightened up before clamping the main.

As mentioned they could have bottomed out also.

Doubtful, as any 8BA I have seen has the holes tapped right thru (no bottom) and the threads don't start until appox. 3/8" below the surface.

[tubman]

Two words : Three mains.

[Bored&Stroked]

Originally Posted by tubman

Two words : Three mains.

Just takes a few "band aids" - and then you can throw horsepower at 3 mains. This is the girdle I designed for our 1940 Flathead Cadillac we run at Bonneville. We've made 650 HP on alky - and the bearings still looked great.

I'm designing one for the Flathead Ford as I write - but it will be for a 5 main crank (with 2 girdle/ghost mains in it).

GirdleAndMains2.jpg

[jimvette59]

Metal fatigue does happen. Has a qualified Metallurgist examined the parts ?

[saltracer]

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We have used these from Ebay on our last few engines. Dave Tatum sells an aluminum version also.

[Scotty's 52 F3]

A pic of the fracture face will tell a lot.

[Ronnieroadster]

Originally Posted by Scotty's 52 F3

A pic of the fracture face will tell a lot.

Ive seen the bearing cap in this post. And also the main bearing that was in the cap. You can see a definite etched mark in the rear of the bearing shell where the crack was located. To make such a mark this crack was there for some time how long is the mystery. The owner came by my shop looking for center main caps I was able to loan him eight caps maybe he will get lucky and find one that will work. If what some have posted a cap form another block will work you certainly need a good amount of caps to try and hopefully get lucky time will tell. The owner also has plasti gauge to check clearances if he finds a cap that appears to work. He understands the complexity of this.
Heck I think he should buy a lottery ticket if he finds a cap that works.
Ronnieroadster

[Bored&Stroked]

Thanks Ron - from lookin at the picture and seeing a 'shiny area' around the cap break - suspected that the cap cracked first, then finally the bolts let go. If the guy gets away with finding the "magic cap" and the crank isn't hurt - then he is a whole lot more fotunate than I'd expect to be! I'd probably be collecting the lower end of the engine in a wheel barrow! LOL. Give Laura my best - hope you are doing well!

[Ol' Ron]

I sent him 5 caps and some stock bolts.
Gramps