Will this rear main cap work??

[PPI Typhoon]

Just picked this up off Ebay for $20 for the whole set.

are there differences in the rear main caps that I need to be aware of??

Pardon my ignorance with this.

 

[PPI Typhoon]

Re: Will this rear main cap work??

Oh, and no, I'm not using the rest of the caps. I just want it for the rear main cap. I will be getting the Pro-Gram caps from RPM next week.

 

[TurboTony]

Re: Will this rear main cap work??

No, that looks to be a rear cap from a two piece rear seal block.

No reason to change the rear cap anyway. It's quite a bit of machining to make it fit correctly and the stocker will stand up just fine.

Tony

 

[ed hess]

Re: Will this rear main cap work??

nothing wrong with using the rear main cap for a 2 piece seal, provided you are using it on a 2 piece block. the reason is if you compare the bolt holes on a 1 pc rear cap vs a 2 pc rear cap you will see the bolt holes are staggered on one and straight on the other.

now suppose you have a 2 piece cap and 2 piece bowtie block and you want to use a 1 piece crank.

you can machine off the rear seal extension on the 2 pc cap and tap the extra needed holes on the rear of the block for the 1 piece seal adapter to fit.

any doubts?.... this is exactly what we have done on the new motor?

hth

ed

 

[PPI Typhoon]

Re: Will this rear main cap work??

No, that looks to be a rear cap from a two piece rear seal block.

No reason to change the rear cap anyway. It's quite a bit of machining to make it fit correctly and the stocker will stand up just fine.

Tony

Problem is that with the stocker, I would have to take that off the existing motor, which is running fine.

I'd like to build this motor completely without having to take out the existing setup until needed.

So by what you say about the bolt holes, is this also for a 2-piece??

 

[PPI Typhoon]

Re: Will this rear main cap work??

Well I hope so for that second picture. It says it's off a 91-94 S10 4.3 block

I also hope because I just won them for $4.99

 

[TurboTony]

Re: Will this rear main cap work??

What is on the block that you intend to use?

If it was missing it's main caps altogether I'd recommend finding a block with the correct original caps intact. It usually is a pita(read spendy) to fit a new rear main cap because of the thrust surface, it must also be milled/matched to the block half.

Any old 4.3 non balance shaft block will do, just swapp out the other three caps for billet ones. That's all I did one mine. :tup:

Tony

 

[PPI Typhoon]

Re: Will this rear main cap work??

What is on the block that you intend to use?

If it was missing it's main caps altogether I'd recommend finding a block with the correct original caps intact. It usually is a pita(read spendy) to fit a new rear main cap because of the thrust surface, it must also be milled/matched to the block half.

Any old 4.3 non balance shaft block will do, just swapp out the other three caps for billet ones. That's all I did one mine. :tup:

Tony

I have a block out of a Sy, but it didn't come with the main caps. :tdown: I have to pay for the 4-bolt conversion, get it machined for that as well as the caps, so I don't think there is any problem having it machined a little more.

 

[ed hess]

Re: Will this rear main cap work??

Problem is that with the stocker, I would have to take that off the existing motor, which is running fine.

I'd like to build this motor completely without having to take out the existing setup until needed.

So by what you say about the bolt holes, is this also for a 2-piece??

dan

i had mike lee order me a program cap for 1 pc crank. when it arrived i found the bolt hole dif between straight and stagared. when i called program about this they told me they didnt have a cap that could work.

if you lay the 2 rears together then you will see what i mean. the holes wont line up. if they do then I would be very surprised!

so what i am saying is if you look at the spacing of the holes from the rear of the cap you will see one side is set back further on the 1 piece cap (stagered) whereas the 2 pc cap the bolt holes are the same lenght from the end of the cap (straight).

so the 4 bolt caps you have can only bolt into a 2 pc block.

but you can machine off the rear seal area of the 2 pc 4bolt main cap and then install a 1 piece crank using a 1 pc crank seal adapter if you machine the rear of the block for the adapter bolts.

ed

 

[PPI Typhoon]

Re: Will this rear main cap work??

dan

i had mike lee order me a program cap for 1 pc crank. when it arrived i found the bolt hole dif between straight and stagared. when i called program about this they told me they didnt have a cap that could work.

if you lay the 2 rears together then you will see what i mean. the holes wont line up. if they do then I would be very surprised!

so what i am saying is if you look at the spacing of the holes from the rear of the cap you will see one side is set back further on the 1 piece cap (stagered) whereas the 2 pc cap the bolt holes are the same lenght from the end of the cap (straight).

so the 4 bolt caps you have can only bolt into a 2 pc block.

but you can machine off the rear seal area of the 2 pc 4bolt main cap and then install a 1 piece crank using a 1 pc crank seal adapter if you machine the rear of the block for the adapter bolts.

ed

Thanks Ed. I think I see what you're talking about now.

I'll just resell the main caps that I bought last night.

But what about the ones I just bought off the S10?? That looks different without the seal extension and not the 4 bolt setup as you were talking about.

I can't quite tell in the pic though about the staggered lines, however, these are off an S10, so it should just be the same block I'm using now.

True?

 

[ghettosled]

Re: Will this rear main cap work??

the second pic of the rear main caps looks right.. and since you have to line bore the block anyways to install the other splayed caps, it's probably not a huge deal to do the 4th and final cap.

I would only strongly suggest against doing this if you had a block which was only missing the rear cap and you didnt plan to change the others.

You should also find the 1 piece rear main seal adaptor since you'll need another one of those.

 

[PPI Typhoon]

Re: Will this rear main cap work??

the second pic of the rear main caps looks right.. and since you have to line bore the block anyways to install the other splayed caps, it's probably not a huge deal to do the 4th and final cap.

I would only strongly suggest against doing this if you had a block which was only missing the rear cap and you didnt plan to change the others.

You should also find the 1 piece rear main seal adaptor since you'll need another one of those.

Yes I am going to have the block converted and getting Pro-Gram 4-bolt caps from you, so I have to get line bored anyways.

Turns out that GM doesn't sell rear main caps by themselves. You have to buy an entire block to get them. :squint:

Thanks for the tip on the seal adapter, I'll start my search :tup: