registered vs dowl pin main caps?

[bc]

What is the best way to locate main caps, registering them or using dowl pins? And why?

[MadBill]

There's more expert knowledge than mine here, hopefully to be heard from, but I'd say:
#1 Dowels with splayed outer bolts
#2 Dowels with straight outer bolts
#3 Dowels with no outer bolts
#4 Registers
My reasoning is that the gas loads push the crank down, which pulls in the edges of the caps, making registers useless except fo helping position the caps for machining.

[OldSStroker]

There's more expert knowledge than mine here, hopefully to be heard from, but I'd say:
#1 Dowels with splayed outer bolts
#2 Dowels with straight outer bolts
#3 Dowels with no outer bolts
#4 Registers
My reasoning is that the gas loads push the crank down, which pulls in the edges of the caps, making registers useless except fo helping position the caps for machining.

Bill,

We recently had a discussion on this subject. I'd appreciate you views on any/all of the following:


Are you assuming dowels press fit in both block and cap? For assembly/disassembly purposes, if you used a press in only one component, which would it be?

What diameter dowels would you use on a SBC or equivalent engine? Where would you position the dowels?

Do the extra dowel holes weaken an already marginal main web on say a SBC production block with four bolt/stud holes it?

Should you see fretting on the block if the cap is moving under gas loads in a non-dowelled cap?

Would it make any sense to accurately machine/hone the inner stud holes in the caps and centerless grind the studs to use them as the dowels?

Thoughts?

Jon

[RRBD]

You can sneak in a set of dowels in the center three mains on a two bolt SBC block. I have put them in the block(pressed fit) and then reamed the caps for a slip fit. I have used 1/4" dowels each time. We used them on a dyno mule 536 BBF (two bolt) during testing for the Engine Masters as well.

Scott

[SchmidtMotorWorks]

I have seen some people use tubular dowels on the same center as the screws. There are some metric ones with very thin walls.

If I used solid dowels I would press them into the caps with small holes all the way through to knock them out if needed.

[Mark Workman]

I put them in the block with a press fit, but use internally threaded pins for easy removal when necessary. Pull 'em out with a slide hammer.

[bobqzzi]

I have seen some people use tubular dowels on the same center as the screws. There are some metric ones with very thin walls.

If I used solid dowels I would press them into the caps with small holes all the way through to knock them out if needed.

Any suggestion where to buy hollow metric dowels?

[talon]

try buying these at DME, Holochrome, Hasco - should have the metric ones and DME has them in there metric catalog

In the mold industry these are known as tube dowel

here is a link to DME

http://216.91.69.172/DCatalog/pages/K18_frame.htm

you could also Google for tube dowel

[SchmidtMotorWorks]

The mold tube dowles are kind of thick, I think the thin one's are called something else like sleeves or ring dowels.

I know I linked it somewhere at home, if I find it I'll post it tonight.