How far up the creek am I??

[O'Shell]

So I just got done checking my rear main bearing with the plastigauge, and I was putting the cap back on all bolts in and semi-tight.. Started to torque the bolts, at about 90lbs this happened to the first bolt I had the torque wrench on. Replaceable? What all is involved with replacing it? Where is the best place to get one?

 

[Southeast Overland]

I have a spare if you need it - shoot me a PM.

 

[Toyrod]

The cap is machine-matched to the block. You will be looking at complete disassembly and a line-hone at the machine shop.

ps. You are at the headwaters!!

 

[cruisernerd]

make sure your torque wrench is accurate. i got one brand new that was out 15lbs.

 

[cruiserbrett]

You are looking at complete engine disassembly to correct that. The cap you pictured is bolted to the block and then a large line bore machine cuts the final main bearing bore diameter, which is finished with a hone. So that cap is specific to that block. even .001" out and you will wipe out bearings.

Sorry to see that that happened!!!

looking at the edge of the remaining lip on that hole, what created the rough bevel in the surface? To me it looks like something caused the hole to spread open at the top and forced the failure of the casting. show a pic of the bottom of head of the main cap bolt that did that.

 

[FineWynsFJ40]

Possible to weld and re-machine the hole & counterbore?

 

[3jvj]

JB weld.











Just kidding.

 

[goneballistic]

you just convinced me to not check the rear main bearing on my temp donor engine that's going in my 40. that sucks man.

 

[carb]

my f1 rear main cap did the same thing as yours. The sad part was i just spend 1600 bucks at the machine shop on the motor. I v out the broken parts and welded them with ni rod for cast iron. put in back on did the same thing.So off it came .after looking at it i decided to weld it again but this time a made a strap that went from hole to hole on the bearing cap and left the end long and heat them with a torch to bend them down to support the sides of bolt hole. then i tack welded the strap to the cap and the tabs that supported the sides of the bolt holes . put it back on the motor and its holding great.I hope this help you. I will post a picture if i can. the motor is in and running. ho yea you will have to drill the holes after the strap is welded on . Carb

 

[rockcrawler]

You are looking at complete engine disassembly to correct that. The cap you pictured is bolted to the block and then a large line bore machine cuts the final main bearing bore diameter, which is finished with a hone. So that cap is specific to that block. even .001" out and you will wipe out bearings.

Sorry to see that that happened!!!

looking at the edge of the remaining lip on that hole, what created the rough bevel in the surface? To me it looks like something caused the hole to spread open at the top and forced the failure of the casting. show a pic of the bottom of head of the main cap bolt that did that.

x2

This is not something that is repairable unless you want to end up with bigger problems.

 

[Plowboy]

Any chance a machine shop could rework the shoulder on the cap?

 

[cjgoode]

I would also think a machine shop could do something, and if so I would have them check the whole thing, it would be an even bigger drag to get that side fixed only to have the other side break when installing.

 

[bronco69drp]

I have a spare if you need it - shoot me a PM.

pm this guy, put it on, check the clearance with plasti-gauge, if it's good run it
Had to do that with my 302's rear main cap, still running strong after 6 years;p

 

[O'Shell]

looking at the edge of the remaining lip on that hole, what created the rough bevel in the surface? To me it looks like something caused the hole to spread open at the top and forced the failure of the casting. show a pic of the bottom of head of the main cap bolt that did that.

The bolts look fine to me. IDK. It did split the casting seam and was pushed out from the top just like you said. Here is pics of the bolt heads. And the seam side.

I do not think the cap eventhough has would work anyway as my engine is an F his is a 2F. I would like to get my hands on an F cap and at least put the plastigauge on to just to see..

 

[Pin_Head]

Any chance a machine shop could rework the shoulder on the cap?

X2

machine the cap to accept a shorter Allen head or Torx cap screw, or also make a spacer tube to use the original bolt.

It is a tractor motor, not a race engine and the cap has 3 other bolts.

 

[miker]

Were you using a lubricant on the underside of the bolt head when you were tightening it? From the picture it looks like the surface on the cap is galled where the underside of the bolt head makes contact.

 

[O'Shell]

I went with Pin Heads route, I think this will work. I just hope we didn't cut to far in to the gasket seat. My next question is: The allen bolt I got has bit of a curve (see pic) is this going to push out on the hole and cause the same thing to happen?

 

[Plowboy]

I went with Pin Heads route, I think this will work. I just hope we didn't cut to far in to the gasket seat. My next question is: The allen bolt I got has bit of a curve (see pic) is this going to push out on the hole and cause the same thing to happen?

I think if you put a flat washer inbetween to take up that flair on the head of the bolt you should have no problems. just oil up before you torque down.

 

[KillerPea]

Not too much oil though. It almost looks like there was hydrolock in the bore which split the cap.

 

[Pin_Head]

Ream the inside of the hole to match the angle of the Allen scew or use a washer. It was Larry's idea. He is old enough to know and I agree it should work fine.