Just thinking out loud: could you prevent cap walk with roll pins drilled into the parting line between block and cap (parallel to cap bolts)?

I think the root cause of cap walk is a block that can not handle the power being generated. Most of the OEM muscle car blocks were designed to handle around 400HP, so what happens when you push something twice its designed capacity? A block girdle will help some, as does block filler, but they are just bandaids.

https://www.carshopinc.com/product_info.php/products_id/66507/M3840C4

Anyone try these 4 bolt mains caps?

Turn the timing back. It’s cheaper and easier.

I’m not sure how quick you want to go but sometimes we over think things. I’ve gone 8.60’s with 440 blocks and 9.70’s with 360 blocks with no bandaids. Did I have a little cap walk, sure I had some. If I wanted to do a quick stock block 440 again I would put main studs and aluminum caps on it and go racing. Save up your money and get a good block. I did.

I've even see some guys put bushings around the main studs to help prevent cap walk. it helps some, aluminum main caps on a big block are your number one add on that give you your best bang for your buck. cross bolt caps weaken the block because you have to remove the main webbing that's holding block together.

I keep mine at 34* so it doesn't detonate because that is what kills ANY engine

Gus

A man just needs to know his limitations........

In other words if the block you have isn't working for you then upgrade to a better block. If you are going to use a stock block in your project then stay within the limitations of the stock block. You should be able to build a very reliable 600 hp big block engine without having to mess with any bandaids. If you need more than that then either take your chances or step up.

I've found that detonation and poor tuning lead to cap walk even on low compression(less than 9.5 to 1 with iron heads) street engines that make power above 500 HP
I disagree on using the girdles and block filler
Not good having cement block filler due to having two different heat ranges in the cylinder walls causing block distortion around the cylinder walls
On using the current after market girdles when you look at the BB Mopar and FE Ford designed blocks that have the main webbing support ribs in the block starting down low around the oil pan rail going up to the upper main bearing webbing using a main girdle that uses the stock 5/16 size oil pan bolts does nothing to strengthen the blocks, does it
Replace the stock main caps and use main studs and spend the left over money on better parts in the stock blocks
Or better yet do as AndyF suggest, get a better block

You got it Pittsburgh. Main studs and aluminum main caps. As for those 1/4" thk. main girdles, not even a good band-aid.

Early 360, over 500HP, block filler, under 12:1, good gas, 38 degrees, ARP studs, and they stilled showed fretting. RPM plays into this a great deal.

Aluminum caps don't prevent cap walk. (not saying they aren't a good replacement for cast iron) Aluminum just doesn't allow the transfer of material at the mating surface, so there is no evidence of it. If you see peppering on the mating surfaces, you are running to much ignition advance at some point in your curve. Early timing tries to hammer the crank out of the bottom, lifting and distorting the caps. Delay the ignition and the crank rolls forward....
There is a whole lot more power potential in a factory big block than most think. Just have to treat it right.

My understanding:

Aluminum caps absorb the "shocks" so the caps shouldn't bounce around as much as iron/steel. Maybe it was Monte Smith who used the analogy of hitting something with a dead-blow hammer vs a standard hammer that doesn't absorb the hit.

Most girdles aren't expected to strengthen the block; the benefit is tying the main caps together to keep them better aligned as a unit when the rotating assembly is trying to push them all in different directions.

It's funny (to me) when there always seem to be people who p!ss on one approach or the other, since I see benefits to using them both together.

I look at teing the main studs together with the girdle as a bad thing due to the girdle trying to flex the studs, main caps and block as the firing order occurs Not a good thing, huh
Good intentions, designing producing and selling the girdle systems, don't always produce good results

Maybe not always, but there are some good running stock block strokers out there 1/2 filled and chastised. Pretty damn reliable ones too!

I agree with this cab. Every time I used a girdle the main bearings looked bad and finally we came to the conclusion that the girdle was actually moving stuff around.

And, most of the time, especially with fairly agressive lobes, you can take a stud girdle off a Chevy and they will make more power. The motion of the valve is translating all its business to other valves that shouldn't be moving.

The valve job seemed to last longer and look better on freshen up.

Tell me again how a plate with 22 odd bolts in it is flexing a 300,000 psi stud?

That's another thought I had: drill out the bolt hole in the block and cap a bit so that a bushing/sleeve can be fitted over the studs that extends into the block and cap.

Thanks for all the replies! Not that I'm having cap walk or plan to build an 800hp engine My question was just out of curiosity from an engineering standpoint: if such a simple solution with roll pins could help if someone (not particularly me) is experiencing cap walk.

Cross bolting weakens a stock block and still doesn't stop them from "walking". I remember seeing pictures on here of a Megablock that had some bad cap walk issues.

I don't think dowel pins would do much. The caps bounce, not necessarily moving them back and forth.

Just my opinion...I'd use aluminum caps and stud it.

All you can do for a stock block deal is run a center weighted crank with light bob weight, use studs and aluminum caps on a bb. Look at the new Ford Coyote blocks to see what it takes to keep everything from moving around too much. And they START with a center weighted crank!