I have been holding on to these pics for a while. The first engine that I have installed cross bolted main caps in has successfully made trips to the track and lived. Knock on wood

Few more.

And more.

here we go again....

Sorry, I don't understand your meaning.

i've had this done before and it worked quit well; especially with light weight components.

Looks real nice. It always seemed like a good idea to me, but I have heard some negativity about this conversion. Don't know why. I think that some have found that it hasn't stopped any of the cap walk that it was intended to stop. Most say that the weak link is actually the block webbing, not the caps. I had Best Machine aluminum caps installed in mine. Maybe an aluminum 4 bolt cap with a girdle? But then, the cylinders wouldn't handle the power that the bottom end could handle. Anyway, like I said to start, looks great. Let us know if you notice any cap walk after the season.

One of my 440 blocks has the ProGram cross-bolt conversion; the other one has been fitted w/ aluminum main caps and will also have a CRE girdle added to it.

My only suggestion for the ProGram deal is they will be a LOT easier to remove if they'd been drilled & tapped for a slide hammer to pull 'em straight up from the block. Otherwise, it's been a major PITA to work 'em back & forth enough to free them up from the block when I've had to remove the crank.

And, yes, this is the sort of post that's liable to bring out all the folks who don't like this approach. Moparts... feel the love.

I'm indifferent on the modification.... but I guess deep down I have my suspicions as to what degree it actually helps. Guess for the cost involved I'd go with the aluminum main cap route. What HP level are we pushing that poor old OE block to?

Looks good !

I have tried using a girdle. Didn't work for me. Now I will see what happens when I increase the cap strength. I haven't tried aluminum caps yet. I have a hard time understanding how they would stop cap walk. I think it may be making it harder to detect. But I do intend to try some in the future.

Thank you!

Thank you!

I like the 4 bolt caps... will it STOP cap walk... no
but it does stabilize the cap better... but the cap is
still bending/bouncing to give you the cap walk... thats
weight and/or detonation... I have 1 SB that has 4 bolt
mains(not cross bolted) and I like that block.. it has
shown to be good over the years.. the outer bolts are 3/8
but the caps are massive.... billet steel
EDIT
looks like you might have to grind the side washers
to clear the pan(just guessing on that.. but looks close)

PLEASE do us a favor. Don't just come back a year from now and say "oh ya it works" like many of our members that attend 3 Mopar races a year and run 10's. I would for once love to hear how quick the combo was, weight, and how many passes till it expired. I made it 275 passes with no concrete, no girdle, and only a set of 440sourse billit 2 bolt main caps. When I took the engine apart I found a crack up thru the block. This combo ran 8.60's -8.90 at 2400 pounds. This was with a .055 over 4.125 based 440 block

I see from the pics it's a 400 block.

Is it the cold weather casting with thicker mains?

They DON'T.........nothing does

No problem. This car makes more passes in one weekend than most people get to make in a year. That is when we win

Average 400. I wouldn't want to use a good one for a bracket engine

. Great to hear but I can't believe guys don't have any idea how many passes they put on their combos. I love the info and learn from it so I log every pass. Instead guys will say I ran this for five or six years and it held up great. But they only put 20 passes a year on their car. Lol

I have a similar block. Don't know whose caps they are, but it uses 3/8ths bolts also. Do you know the torque sequence and spec for these caps?

Monte was surprisingly terse in his reply, but the benefit of the aluminum main cap (as he has explained before) is that it absorbs some of the shock transferred to the cap that a steel cap will pass on to the block. Think of the rebound difference when striking a metal object with a dead-blow hammer vs a normal hammer.

I tighten up the big mains first to the spec then I use

45# on the 3/8.. I have the ARP main studs so I use that
spec for them
EDIT
mine also have 3/16" dowl pins in them for alignment and
maybe it helps other things.. I dont know

from my experience on a 470 with bill miller rods, light ross pistons, half fill, that the bottom end was darn near bullet proof. there wasn't any evidence of cap walk or metal transfer and i believe that the dissimilar metals helped in that respect. the key here, in my opinion, is the quality of the machine work. if the part of the cap were the cross bolt ties to the block is machined for a "snug" fit then the rest is easy. a loose fit will screw up the end play in the crank when the tie bolts torqued down. this engine i messed with wasn't a mega horsepower thing, about 650hp, but during freshening up the bearings could have been reused. this told me the bottom end was stable. don't let the moparts naysayers prevent you from getting your head out of the "box"!

I have over the years many times questioned the engineering merits of the typical girdle. It was never clear as wimpy as they are, as to what stiffness they really provided. The only explanation ever offered that might make some sense, which I have no way to verify, is if the crank is weak, and it flexes under extreme load with every revolution, it would want to, in the explainer's words, rock the cap(s) front and rear, and since the girdle is mounted the farthest distance from the crank on top of the cap, the girdle would reduce the cap from rocking, which maybe the same as "cap walk". The alum explanation for reducing harmonics makes some sense to me, but if alum is moving/flexing, it is slowly reducing its fatigue life.

I've never been a fan of drilling through the side of the block to add side bolts due to the loss of material in the main webbing The Mopar 426 Hemi blocks where designed and cast for that

What we all refer to as "cap walk" is really not that at all. What we have is a lack of clamping force and that lets the cap "bounce" and is what creates the fretting on the faces. As myself and others have stated, you even see this on iron Mega-Blocks, that have ductile caps and are cross bolted. These blocks are actually MADE for the cross bolt cap, like the HEMI, yet does not eliminate the issue. So the thoughts of an aftermarket cap, placed in a block that was NOT designed to do that, is not going to stop it either. The better blocks survive the issue better.......because, well, they are BETTER blocks, but the problem itself is NOT gone. Girdles, cross bolts and all the other stuff, that are an attempt to "lock the cap down" simply don't work. Now do they help?........that's all a matter of speculation.

Do the aluminum caps "fix" the issue?.......absolutely not, but it is my impression and others, that alum absorbs some of the movement and puts less stress on the main webs. Again, NOT a fix, just another form of bandaid.

So how do you "fix" the cap bounce........in a factory design B block, the simple answer is you don't. Your only hope is that the block is beefy enough to take it and that design includes Mega-Blocks, HEMI blocks and so forth. So how COULD it be fixed? In my opinion, that would take a total redesign of the bottom end, with much larger and beefier main webs, bigger studs and enough material to accept a splayed angle, 4 bolt cap like other brands

If you work under the premise that there are two types of stock blocks when HP levels go above 600HP- those that are cracked and those that will crack - you accept the fact that stock blocks have limits - anything you do to them is a band-aid that might extend the life of the block some. Its a coin flip at best. But until somebody steps up and starts making aftermarket iron blocks again - band-aids is what we will use! I have used the ductile Mopar caps with decent results - I have used the program caps also - nothing stops cap walk maybe reduces it some - I do have a 512 RB with the aluminum caps ready to go - I will see how that works!

Never thought of it that way. So the rotational side forces from the crank and rods is actually trying to push out of the journal bores at a given point in rotation. A side to side push would also explain how the block webbing cracks. Maybe the aluminum caps already have a better "preload" when clamped down, and springs back a further distance than steel, which is why there is a higher resistance to evidence of cap walk. Lighter components (rods, crank counterweights) would lessen the damaging side forces. If this is correct, then my next question is: How much can you rifle drill the center of a rod journal before you compromise strength?

That`s what THEY say but what about the expansion and contracting deal being alum. in an iron block.......

The cross bolt mains must not be to bad of a design, lots of OEM have gone that route. Ford Chevy. Im pretty sure the TFX block still has cross bolted mains,a few more bolts of course.

Both Ford mod motors and the LS series engines have 4 bolt caps + 2 crossbolts. Chrysler's 3rd gen Hemi is only 2 bolt with crossbolting but the main webs appear to be stronger than a B/RB engine.

new engines were designed with this design.... not an after thought.

On the stud girdles, I don't see the 1/4" thick ones which support stock caps doing much other than being a 1/4" oil pan spacer.

The BCR Aluminum caps and 1/2" thick girdle is a different system. The caps are designed to span the width between the oil pan rails, and they bolt to the girdle further away from the main stud bolts, almost like cross bolted caps, but with the girdle being held down by the oil pan studs.

Most all alum blocks have steel caps

Well the good thing is we can all agree that the main caps need to be upgraded. I'm not trying to promote any system of doing that. I view this as a learning PROCESS! First off think about what cap walk is. Under a load the main cap is forced down. This caused the sides to pull in. No longer held tight by the register the cap can move around. We see the same elongation happen in a connecting rod. Rod bearings are designed to allow for this. Think of the cap register as more of a way to preload the cap. This is why blocks with loose registers have more cap movement. Mopar blocks are not the only ones that suffer from cap movement. Ask a machinist how they fix the problem in other blocks and most of them will say that they use a stronger cap and force them tighter into the register. Think about this as well. Have you ever seen aluminum caps used to increase strength on any other engine block??? (again not saying they are a bad investment) I trust the machinist that have worked before me. Someone had to be the first to use aluminum caps and I'm sure they had a good reason. I just don't think they made that reason clear. I do intend to use aluminum caps in the future. For now I'm testing the cross bolted caps. After doing the machine work to install the caps I do not feel that I have removed any material to weaken the block. The cross bolts are 5/16 and they torque to 24 ft.lb. Just enough to help support the register.

I still follow another belief….aluminum caps DO work as a SHOCK absorber, but only allow more dimensional shift with the main bores when stressed - shifting the fall out to the crankshaft…..Best fix for getting all you can from a oem block @ 750 – 800 hp and get reasonable life? ……get rid of harmonics….or as much of it as you can.

Cap chatter is a vibratory frequency that actually transfers material from one surface to another, the bounce that is mentioned. This vibratory frequency is as much or more of the problem than anything else. The clearance with the registers is definitely important and once this cap walk problem generates, the registers will only get more clearance....blocks fail and ect.

A stock block, professionally machined with a good set of studs (properly installed), NO FILL and even stock caps.....yep......stock caps......have made many, many laps over many, many years doing this without ONE failure. A couple hundred passes were also made on a throttle stop killing ALL throttle at .001 - .01 out…..nothing worse on hammering the bottom end than that.

Was just stating my curiosity about the different metals expansion rates and figured it would have to influence bearing clearances somehow but maybe not......

The aluminum caps were worth 5 lbs off the front of the car. I think I heard some older Cadillac iron blocks came with aluminum main caps?

That may be part of the reason they use them. If they expand faster they should register tighter as the rest of the engine is coming up to temp???/

I still follow another belief….aluminum caps DO work as a SHOCK absorber, but only allow more dimensional shift with the main bores when stressed - shifting the fall out to the crankshaft…..Best fix for getting all you can from a oem block @ 750 – 800 hp and get reasonable life? ……get rid of harmonics….or as much of it as you can.

Cap chatter is a vibratory frequency that actually transfers material from one surface to another, the bounce that is mentioned. This vibratory frequency is as much or more of the problem than anything else. The clearance with the registers is definitely important and once this cap walk problem generates, the registers will only get more clearance....blocks fail and ect.

A stock block, professionally machined with a good set of studs (properly installed), NO FILL and even stock caps.....yep......stock caps......have made many, many laps over many, many years doing this without ONE failure. A couple hundred passes were also made on a throttle stop killing ALL throttle at .001 - .01 out…..nothing worse on hammering the bottom end than that.
[/quote]

Yep.
I think most of the aluminum cap supporters don't think into it deep enough, and you stated it very well.
Kenny D says it best... keep the crank rolling forward(not downward) and your engine will live a long life regardless of how much power you're making.

Alum. caps seem like a Mopar thing only. Am I correct about this and if so why?

Because everyone else has an abundance of aftermarket block manufacturers

Personally I don't think the cross bolting will hurt and will help it live. Yes the Hemi is beefier in the skirts for their cross bolt arrangement but I still I think it's an improvement for Wedge, even with the skimpier skirt.

I guess that makes sense.................

Lets see, the B and RB motor wedge was design in 1957 with no intent of racing those motors, the 426 hemi blocks where designed in 1963 with the full intent of being a all out race motor so they designed extra material in the oil pan rails and main ribbing for cross bolts I disagree with drilling through the sides of the wedge blocks through the main webbing support to add one skimpy bolt per side

I'm not using that style w/ the intent of it "beefing up" the load capability of the caps; IMO, and as I've seen described elsewhere, the ability of the girdle to tie the #1-4 main caps together and also to the pan rail should improve torsional rigidity of the mains.

Especially since the aluminum caps do crack on occasion (I've seen three different ones do it, and they weren't all the same brand, either):
1. If the aluminum helps absorb some of the shock and...
2. The girdle keeps the mains tied together so they're not swaying back and forth as much which would contribute to work hardening...
3. it should be a win-win band-aid on a stock block making under 700 HP.

FWIW, I have done some digging online for documentation that might describe in more detail the types of stresses crankshaft main caps experience, but haven't found anything that really covers it like I'd like. You'd think somewhere out there that somebody's done FEA and simulations of those loads, or figured out some way to attach sensors to various parts of the bottom end to detect and/or measure the extent and directions of the typical loads, to help people understand the nature of the beast better.

The crank is ALWAYS trying to push itself out the bottom of ANY motor. So the more power you make, the more force you have trying to help it push itself out. That is the only direction the cap sees any stress.

The other problems are crank flex and harmonics, but those two can be addressed with better cranks, lighter components and balancing.

I am wondering if the 4 7 cam lobe switch does any
better on the cap issue... its suppose to run smoother
which to me should help.. since it changes the firing
order.. maybe you would know Monte

I always run a 4-7 swap cam and in some instances even the double swap, which ends you up with a Chevy LS firing order. If you just look at the motor and run the firing order in your head, the LS order makes perfect sense from a balance standpoint.

Now, do we SEE any differences in the parts, that's hard to quantify, but they usually pick up power, which should tell you the motor runs "easier".

Again, it is just strictly a lack of clamping force and you will not fix that...........but anything that makes the assy lighter and smoother can't hurt

And, of course, NOBODY wants to be the guy in the magazine w/ the blowed-up 440 on display for the whole world: http://www.hotrod.com/how-to/engine/1405-breaking-news-dusted-plymouth-duster/

Yep, 2 broken caps AND 3 cracked cylinders =

That pic says alot for busted blocks, I had read this through and thought maybe if people posted pics of there busted blocks and there combo maybe we could get a grip on what really might work and what doesnt and whats alot of wasted cash.

To me its when the push on the crank is happening... at
the top of the firing stroke or the bottom would be the
points that would lift a cap.. anything on a angle of
the crank throw just causes it to spin.. so if the firing
order is smoother it would tend to spin easier(from what I
heard)... it would have the other cyl firing at better angles

You can use girdles, cross bolts, alum caps, billet caps but you still only have 2 bolts holding / clamping the mains. Ive ran um with stock caps and alum caps. they both cracked. Both engines were a half fill and used ARP studs.

You can make them live for awhile, but if you detonate or push 600hp+, eventually they will crack.

Being that I run SB I dont worry about it.. the SB doesnt
have a issue like the BB... I was trying to discuss what
the issue might come from... yes the cap is lifting.. but
is it the angle of the throw(top and bottom).. basically
trying to figure cause and effect.. even some of the 4 bolt
(not the side bolts) still have it... so is it the angle of
the throw that gives all the lift to the cap(or lack of angle
I might say)... but if the different firing order might help..
just thinking out loud
EDIT
ANd I dont lkie ductile iron caps... if I'm running a
aftermarket cap I prefer steel or alum.. ductile iron
cracks easy

From the looks of this, I will GUESS that the caps broke first. Then the stud is trying to hold the half a cap on the block. That will put a lot of side loading on the stud which transfers to the block. Cast irons are weak in tension. I'm not sure what grade gray cast irons were used in a block. This link has an interesting chart on the SAE grades with the Brinell hardness.

https://en.wikipedia.org/wiki/Gray_iron

Assuming we are using the SAE J431 G3000 grade, median hardness of 214 HB, then the tensile strength should be around 32ksi. I'd never seen that chart of hardness to tensile strength. I guess that's why my machinist engine builder in Tampa hardness tests every block he does.

Compare those values to Austempered Ductile Iron (ADI). Here the Yield Strength is around the 30ksi level, but the Tensile Strength is in the 55-65ksi range. Cast irons don't yield much, hence the brittle fracture on the main caps. Stretch a steel bolt and you can measure the elongation or necking of the bolt shank. I'd say that the ductile irons are a better main cap material than gray cast iron.

http://www.ductile.org/didata/Section12/12intro.htm

Feel free to disagree. I welcome an intellectual discussion, just keep it professional and not a bunch of name calling that is common on here. Hopefully the idea is to put our collective knowledge together and hopefully we can all learn from this thread. One of those synergy deals.

Big Block Chevy's have the same firing order as a Mopar and this is a non issue...........Why, because the HP blocks are 4 bolt with the outer bolts splayed. More clamping......it's just that simple. All the other is just a bandaid attempt to get a weaker designed block to last longer, as has been covered many times.

Kinda like Hospice..........will maybe make you feel better for a while, but the end is near

When I said ductile iron I might have been wrong.. I
was referring to the iron caps on a stock block...
they are brittle... drop a part of that iron and see
if a chunk breaks off vs a steel part that dents

I've seen stock 400 main caps break in two like that 440 did, I've also seen several RB blocks with the main webbing cracked between the #1 and # 3 cylinders and that #2 main cap I have built two different 400 stroker motors with both a 4.25 stroke and a 4.300 stroke crankshaft that took a lot of abuse with no fill and the old set of Mopar brand ductile iron caps with ARP main studs The first motor had 4 ductile iron sleeves in it due to deck damage on one side and pitting in two cylinders that wouldn't clean out at 4.375 bore size on the other side, it was a low compression pump gas motor that made over 600 HP at 5500 RPM using a stock type Eddy six pak intake and stock type vacume 440 6 pak carbs It started out with a set of mildy ported big valves 906 heads, it ended up with a set of Indy SR heads with a single plane Indy 400-3 intake and a Holley 1050 CFM #9375 Dominator carb, that combination made 727 HP on a DTS engine dyno in Klamath Fals, OR at 4300 ft. elevation I traded that car off several years ago and it is stll running with those main caps and studs The only reason I've tried the 440 source aluminum main caps now is that Mopar stop selling thier ductile iron main caps several years ago and I've used up the supply I had in stock I'm building another 400 stroker E85 motor now that should make over 800 HP on E85 with the CNC ported 440-1 heads with a set of paired shaft Jesel Rocker arms It has a set of the 440 Source aluminum main caps and ARP main studs, no fill or girdle on it It sonic tested oaky on the cylinders walls but it will end up with one sleeve in it also due to pitting

I agree. Cap failure, then comes the spread load on the saddles. A steel cap would not do this.
The fact that the crossbolt conversion caps shown are steel, gives me a warmer feeling about them. Add in the cross bolting, and how can you really say it's not a nice up-grade? If you can do the work yourself, it seems a sane as anything else.

I used the most ghetto of all "bandaids" (I hate that saying. Doesn't everyone have bandaids at thier house?) Anyway... I milled the humps off of the caps and built tool steel straps to hold all the pieces together when they failed. Guess what? They didn't fail. Know why? Accurate and late(relatively speaking) ignition timing. Roll that crank clockwise baby!!!!

Last stock block I broke...........the first thing to go was the block itself. Noticed an oil pressure fluctuation and pulled the motor to have a look. Caps(alum) fine, crank fine......block broke all to hell in the webs.

Many want to blame it on detonation and say if you keep it out of detonation, it will be fine........No it won't. It's about the power level. Now, detonation WILL hammer a motor, but if it is hard enough to break caps and blocks, you will also see that amount in other areas.

As somebody else said.......these are 40 year old passenger car blocks. They were NEVER engineered to be all out race motors, at the power levels that can be easily attained these days.

At a significant power level, a stock block is a crap shoot. It might last one pass, ten passes, hundred passes, thousand passes...........you simply never know

I have managed to split one ([censored] my names AL as well), all my fault with a lean nitrous tune, 528, steel caps with girdle running 9.2/9.3 @ 144 in a 3500lb 63 Maxi Plymouth.
You live and learn, I have not run nitrous since but then again Im not drag racing at the moment either, I do beat crap out of my NA engines at events and the street.
I now have ali caps in the 528 and steel in a spare 547, girdle not being used.

I went with a slightly different girdle system on this engine. A lowdeck 3.900" stroke deal. Made 780hp with a fairly big roller. J.Rob

My old 505 engine was cracked when we pulled it apart. The engine was running fine but after 100+ dyno pulls we decided to pull it apart and look over everything. Several of the main webs had visible cracks. I just took the parts and moved them to another 440 block.

Andy's story should bear a little weight. This is a dyno mule. Probably NEVER mistreated, run lean, had the snot beat out of it, or anything else. But it made a good bit of power and even with it's relatively easy life, it beat the webs out...............Make power, they break eventually. It's really that simple. EVERYTHING breaks eventually, it just depends on what life span you expect............We beat the main webs completely out of a $6000 Donovan alum block after 5 years. But it had no telling how many passes, pushing 2000hp through it.

I have always been a proponent of the aluminum cap method, as well as alum rods and a light rotating assy. Not because it "fixes" anything, but because I think this is the cheapest and most effective "bandaid" for the situation. I think the alum caps absorb some of the beating, as well as the rods. You also have lower initial cost investment and machining vs girdles, pro-gram caps, or about anything else. So as we have pretty much covered, NOTHING is going to "fix" the problem, so choose the method you think is the best and that you are willing to pay for.........but you also need to accept the fact that whatever method you choose, it will likely fail at some point

I have been lucky but stopped pushing my luck and bought an alum. block.