Broken block repair

[Rustyrodknocker]

Well I got my 383 project home and the ear is busted off the back where the starter mounts.
I couldn't find the missing piece. It may have been broken for years. The bell housing does have a stud in it at that hole. I am going to try to repair it by most likely brazing a piece from another block on there.

Has anybody had to repair one of these?
Mine is busted thru the hole which I'm sure is fairly common.
If anybody has a junk block that they would be willing to lop the ear off of I would be interested in it.
I would rather salvage this original 65 block than replace it.

 

[Davea Lux]

You can also repair it by brazing a stud into what is left of the hole and using a nut to secure the starter. These bolt holes broke out when the lower bolt got loose and the engine kicked back against the starter. They also broke when somebody with gorilla arms tried to force a cross threaded bolt. Brazing on any block is tricky as you can create micro fractures. Might want to consider using a stitch welder to secure the stud, it will take a bunch of passes, but it keeps the heat down so nothing cracks.

Dave

 

[Xenon]

To start with, that hole is NOT for the starter....
That is for a bolt to go thru to secure the transmission to block...
"Brazing" anything on a cast iron block is a bad idea...
Cast iron is hard and brass is soft.. Unlike metals do not play well with heat/cold deferential...
Plus brazing is not that strong especially there which is a major stress point...

 

[65CopCar]

When I went to Lincoln Motorsports welding class, they taught us that brazing is the preferred method of cast iron repair.

But I do agree that brazing is weak and not sure that the repair would work well by just brazing. However, maybe reinforcing it somehow first? Kind of how gears are repaired. Drill some holes and stick some dowels in it then braze the dowels and finish the tooth. Many a gear has been successfully repaired that way.

 

[Big_John]

IMHO, everything I've ever seen about doing a repair on something cast iron with damage like that is best done with brazing. Welding it would be stronger in theory, but you'll have to pre heat the block and really know what you are doing to get as good of a repair. Then you take the risk of cracking it somewhere else.

The question of strength has been brought up... Remember two things here. this point on the bellhousing is not where most of the strength is by simple design. It's an ear sticking out. Braze is a lot more forgiving and a lot stronger than people give it credit for. Yes, it's not as hard as the cast, but not as brittle as cast either. Next is remember what you are bolting up... an aluminum transmission bell housing. I'll say it again, aluminum. I don't think it has to be that strong.

Then there's the braze repair. Geez... I've seen a lot of braze repairs on cast iron on machinery that is going strong after many years of service. How about broken bench vises? Seen quite a few big vises fixed like that.

I think that block could be built up with braze and drilled/ground to work.

So, here's what I would do... Find another freaking block. It's not worth the time and money to fix this one.

 

[tallhair]

Time for a 440

 

[twostick]

IMHO, everything I've ever seen about doing a repair on something cast iron with damage like that is best done with brazing. Welding it would be stronger in theory, but you'll have to pre heat the block and really know what you are doing to get as good of a repair. Then you take the risk of cracking it somewhere else.

The question of strength has been brought up... Remember two things here. this point on the bellhousing is not where most of the strength is by simple design. It's an ear sticking out. Braze is a lot more forgiving and a lot stronger than people give it credit for. Yes, it's not as hard as the cast, but not as brittle as cast either. Next is remember what you are bolting up... an aluminum transmission bell housing. I'll say it again, aluminum. I don't think it has to be that strong.

Then there's the braze repair. Geez... I've seen a lot of braze repairs on cast iron on machinery that is going strong after many years of service. How about broken bench vises? Seen quite a few big vises fixed like that.

I think that block could be built up with braze and drilled/ground to work.

So, here's what I would do... Find another freaking block. It's not worth the time and money to fix this one.

I think his dilemma is it's a 65 block. It uses a 1 year only orphan motor mount on the driver's side and not all later blocks have the place machined for it to bolt to.

Kevin

 

[tallhair]

Will the 66 mounts work with a later block and stub frame or not?

I had a 64 casting, 65 model year 413 engine in my 70 RR for a while. It used same motor mount as the prior 383 If I recall correctly.

 

[Big_John]

I think his dilemma is it's a 65 block. It uses a 1 year only orphan motor mount on the driver's side and not all later blocks have the place machined for it to bolt to.

Kevin

If that's the case, then it's understandable. I'd look into brazing it up. Half of the hole is still there. I think that cutting it off and brazing a new section on is not the way to go though. The strength is still there from the block, what you really are looking for is to support the head of the bolt and pull the bell housing against the block. I've seen this damage with guys just putting a big fender washer on the bolt head to make it work. Not a great repair by any standard, but it worked... I think we've probably all seen bolts missing too.

You know... The car probably went through life with this... If it's brazed up, the worst possible thing that could happen is the braze crack. It won't be a catastrophic failure if that happens. In fact, you could try it before you do any engine work by bolting a trans up to it. I'll bet it won't crack if done right.

 

[twostick]

Will the 66 mounts work with a later block and stub frame or not?

I had a 64 casting, 65 model year 413 engine in my 70 RR for a while. It used same motor mount as the prior 383 If I recall correctly.

I believe the early block will work with 66 and up but not the other way around. Lots of if not all later blocks have the boss cast in the block for the mount to bolt to but some don't have it spotfaced, others have it spotfaced but not drilled and the rest have it drilled and threaded but to a smaller size. Some applications used it to mount the power steering pump bracket to, trucks maybe.

Kevin

 

[Rustyrodknocker]

I appreciate that this is getting some traction and people are offering feedback.
I'm fairly adept at brazing and welding and have a formal education in the field.
I thought that some may have seen this type of failure before given the design of that ear.

Who knows how long it was broken, could have been decades. As mentioned we have all seen missing bell housing bolts.

I will repair it by some means since there is really not much to lose. It has a portion of the hole left that provides location which is handy but the casting lacks any cross section there which probably contributes to it's failure.

From a functionality stand point, joining a new section with the stud in it is probably the the most structurally sound. Next might be cutting it back beyond the hole and adding a replacement piece from another block.

As far as success or failure of repair goes. I think if it survives the process it will survive being in service.

Back in the 90's when I was going to school on the subject I had an instructor that spent some time covering repair and he had a strong appreciation for the craft. He said that in general casting repair the industries success average was only about 50 percent. However at the top end of specialty repair where the replacement cost of the casting was thousands of dollars the average was nearly 100 percent. Those castings are typically the best made and no expense is spared in creating ideal conditions for the work. The castings are perfectly clean, the alloys are spec'd and the preheat procedure may include welding in an oven.

But back to this greasy old Chrysler. This is the only 65 block I have and the car is wearing its original paints and original dents and will not be restored other than seat upholstery to match the rest of it's great interior.

If somebody has a junk block I would be interested in the donor piece. I"m not going to cut one off any of mine as they are all good cores.

Please throw out any other ideas and I will report how it goes.