Block repair... Advice needed...

[Ford F834]

I need some advice about block repair... I pulled a junkyard 7.3 and took it to my machinist. He said the cylinders look good, but the three central main bearings spun in the block. He said it is possible to cut the block where the main caps mate and line bore the crank axis but he did not recommend it. It raises the pistons which increases the compression ratio and can cause valve clearance problems. He also had concerns about the accuracy of the long bore and engine geometry. His advice was to find a better block to build.

Anyone here have any experience with this kind of block repair? I am not all that concerned about the piston height. I have some prototype decompression head gaskets being made for me that finish at .110" thick. My target CR is 18:1 and I can always shave the pistons a little if needed. If the block really is junk I won't waste my time with it, but in Arizona the trucks never rust so finding a good engine without a truck wrapped around it isn't easy!

 

[Ford F834]

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[DaveBen]

He is right, this can cause a lot of problem$. That block is junk.

 

[icanfixall]

Sorry but that block is finished. Machining the main webs can be done but you end up with the crank closer to the center of the engine. Remember the gear drive up front that drives the cam and injection pump gear. We do have a deck height from the center of the crank to the top of the block. That dimension is 11.137 to 11.141. Our pistons come up out of the deck by 31 thousands too. The only reason pistons don't hit the heads is the head gasket thickness. Usually they miss by around 40 thousands. I bet this wrecking yard engine ws run low on oil and spun the mains. Generally speaking that ruins a block beyond repair. Sorry.

 

[Ford F834]

Thanks for the confirmation guys. I hadn't thought about the gears up front either. That just won't work. I am putting a lot of $ and effort into this truck and I want it to be done right. Good core engines are hard to come by, but there are two possibilities at the junkyard right now that I will check out on my next days off from work. I won't buy another one without opening it up on the spot. Lesson learned. In my area IDI's don't get junked for no good reason but perhaps I will get lucky with one of them.

 

[jwalterus]

Good core engines are hard to come by

and there's the tradeoff, you guys have great bodys sitting in junkyards, an those of us in rust-prone areas have scarce sheetmetal but lots of good engines and drivelines

 

[IDIoit]

when ive align bored blocks, ive always used thicker bearings to compensate.
depending how much of the cast its eaten, cant this be done?

 

[icanfixall]

when ive align bored blocks, ive always used thicker bearings to compensate.
depending how much of the cast its eaten, cant this be done?

I do not know of any manufacture that sells bearings like this.. Maybe typ4 knows of them???

 

[riotwarrior]

when ive align bored blocks, ive always used thicker bearings to compensate.
depending how much of the cast its eaten, cant this be done?

Makes 0 sense...

Most align boring I have seen just cuts main caps...not block....could be some cut block too dont know.

Thicker bearings woukd be for turned crank..how would thicker bearing move a centre line downward when both halves of bearing are same thi kness?

I am not understanding the concept...as you would need thick block halves and thin cap halves to do what you are suggesting?????

 

[IDIoit]

think of it as a reversed turning of the crank......
maybe im wrong, but it makes sense in my unprofesionall ******* mind

 

[riotwarrior]

think of it as a reversed turning of the crank......
maybe im wrong, but it makes sense in my unprofesionall ******* mind

Ok i will give u this 1 single bit to YOUR side of thought....yes...there are thicker bearings available....for ...say SBC...to run small journal crank in large journal block...those are a specialty item.

However for this instance ....and I could be wrong...there isnt a bearing available as you describe or I mention about for the sbc...the thicker bearing is still normal OD and smaller ID for a turned crank...not enlarged crank bearing web and cap....none that I am aware of...

If said thicker bearing did exist..for this specific engine and application... I would be amazed...to the extent...I may have to paint my trucks hood rooster **** pink...

@IDIoit

Make ya a deal Brian

You find said bearings specific to this engine and application...an actual part no and available bearings....

I WILL PAINT MY TRUCKS HOOD RDP...and drive it for a month like that with Brian was right stenceled on it.

However...if you cant....you have to paint up a hood in RDP and when you start driving 6door ...run that hood with Al was right on it....

Challenge made!

Accept...??????

 

[laserjock]

 

[jwalterus]

there is a solution aside from some oddball bearing......

pull a GM and throw some paramount shims in the friggin thing like they did with the 235 dippers.......

 

[riotwarrior]

there is a solution aside from some oddball bearing......

pull a GM and throw some paramount shims in the friggin thing like they did with the 235 dippers.......

Or thermql spray weld like eutalloy and repait and build up bearing journals then aline bore a d hone back to stock size....

 

[IDIoit]

***** @ the RPD challenge.
next time i got 2 free hours, ill do some researching.
i gotta drop my PSD heads off @ the shop so ill ask my engine builder.
he would be the source for specialty bearings.
as for your challenge, I DO NOT ACCEPT.

i wouldnt wish a RPD paint job on my worse enemy.
are you sure youre not hispanic with the multitude of odd ball colors you want to paint your truck?
(nowthatmytruckisalmost1or5colors,icantalktihs)