cross bolt conversion cost

[c9zx]

All of the input from everyone is great information, it's appreciated. Component weight and RPM keep being mentioned, that makes sense. The crank is a Scat 4.250 "cast steel" (60 lbs.), the rods are Molnar H beam BBC (742g), the pistons will be Mahle Power Pk (519g). Brent is doing a solid roller cam for it. Target peak power 6200-6300 RPM, Max RPM 6600. Let me know if more data change your input or advice. My machinist (Gerold, at Brand Racing Engines, OKC) is very capable. Is machining the thrust bearing cap crazy difficult?

[AZ428STCKER]

We have a 428 block that's been cross-bolted with BSW caps and 2 more in the works. Bostick Racing out of Yuma Arizona did the machine work, decked, align hone, blocked filled, clearance for main caps, for around 1300$. I know of two other guys that have had their blocks done at bostick, and both run 428's in stock eliminator running north of 600 hp over 7000 rpm with a jerico 4 speed. One of them won Class at Indy in C/S a couple years ago. That's with the stock 3.98 stroke not the 4.25 you'll be using though.

[e philpott]

thrust bearing just requires more steps and doesn't really help the bottom end like 2-4 does , my own DT2 390 block is cross bolted with Pro Gram caps

[My427stang]

In the end I think a pinned cap has more benefit than a cross bolt in most cases based on where it helps ground the cap

     Now there are solid "pinned" and then there are hollow "Doweled" locating mechanisms and I'm not sure which you might be contemplating?   

     But just for thought: Of the "pinned" type, utilizing say a solid ground steel pin of something less than 3/8", such as utilized in the 385 series blocks, and 5/16" in the BOSS 302, these engine examples with 4-bolt mains, in extreme applications they just loosen up and often are found just laying in the bottom of the oil pan!     And then the problem with the "hollow dowels" is that it is impossible for one of "seamed & rolled" material makeup to be round and as for the "solid-round & ground" type it's still a challenge for them to be "perfectly" round, so in either case flexibility is the solution for reasonable fitment possibilities and still both generally act on limited surface areas.   

     Scott.

     
   

I am talking solid dowels, and being captured no way to fall in the pan. Will have 7/16 cross bolts as well, unlike the 385s.

[pbf777]

I am talking solid dowels, and being captured no way to fall in the pan.

     The concern wasn't the issue of the dowels actually being in the pan, as that in itself really isn't likely to be a problem; rather it's the fact that this provides evidence that the pins are being pushed and shaken, in motion to the point that they migrate out of position, and in the instances provided literally dropping out and therefore even if retained longitudinally are not capable of providing accurate location of the cap or significant support to the block in service.   

     Scott.

[My427stang]

I have a 429 CJ in the works now and all are tight, can’t argue if you’ve seen it but I’d likely blame a non skirted block with all fasteners in a single plane or more likely balance issues before I would blame the pin design, especially on the external balance versions

That being said if on a standard block you do not like pins, do not like cross bolts, all you have left is component weight, balance and a tight register to keep the caps in place. At 600 ish HP and 6500 rpm, that can show serious fretting on 2 and 4. Just the way it is

Easy to throw stones but these things can work, sone guys can break a bowling ball in a sand box, and some guys can start at theoretical paralysis by analysis but cross bolt conversions have been around for years and a combination of a pin and a cross bolt is in every Pond block and if the cap and main design allows it, only adds to stability and transfer of harmonics

[frnkeore]

There are X bolt bossed C5AE A blocks, too. There is one for sale, here in Oregon.

[FERoadster]

As Frank stated some of the C5 blocks have the cross-bolt bosses like the C4 blocks. I've got a C5 that has been cross bolted.
Richard >>> FERoadster

[MeanGene]

There are C5AE-A blocks that are 390's, and 427's. Last center-oiler, with the change requiring a new casting number being the 4-bolt engine mounts. This one came out of a V-drive boat, had the C4 crank, nut n bolt rods and bumper tops- which, if you look closely, they worked

[c9zx]

Just an update on availability of the BSW billet main caps. I spoke with them today. He said he would be doing a run of them in about 2 weeks. He said he would contact me when they are ready. Chuck (S)

[oldiron.fe]

    to wc while observing skirt/block movement --did ford test or have ideas to reenforce blocks--or dampen  the movement-- better balance-over bal/under bal / weight of assy.---   were any block fills
     
    used to change/dampen movement-- any further work on subject

       
     when gapp/rousch built the 427 sideoilers in greatest numbers was any added inspection for blocks for their builds/work


      john-oldiron         thanks for any comments

[oldiron.fe]

           please refer reference #25 to reference #14 comments thanks wconley-john-oldiron                                                                                                                                                                                                                                                                                                               

[WConley]

john-oldiron

Gapp-Roush was before my time there, but I never heard about any special things they did to their lower end structure on the 427 blocks.  I did get to know Ray Paquet.  He didn't do anything radical to the structure of his cross-bolted 427 blocks either (aside from rod journal diameter/width and oil system detailing).  The lightest possible reciprocating components and selecting for most consistent cylinder wall thickness were his focus on the block side.  There was a bit of block fill if I recall correctly, but that was mainly for cylinder wall stability.

Now as for general bottom end stability, nothing beats a bed plate.  That's where the caps are tied together into a massive plate structure that makes up the bottom half of the block.  It's pretty much a must-have for any modern max effort engine. Deep skirts with four or six bolts + cross bolting will get you a long way as well.  Those solutions will pretty much kill the bottom end wobbling that we were seeing.  You also want to lighten the reciprocating assembly as much as possible, and fully internally balance the engine.  We ended up building a "world class" four cylinder demonstration engine with a bed plate and all of the above tricks.  It was as good or better than anything out of Japan or Germany at the time.  Of course it never made it to production      As far as block fill, I have noticed some modern engines have shortened water jackets for improved structure.

I doubt you'd find a modern Formula One engine without a bed plate.  There are several production engines out there now that use them, especially if turbocharged.  At Ford, the Ecoboost V-6 Engine in the latest Ford GT, along with some Ecoboost four cylinders got bed plates.

[galaxiex]

I don't know what a bed plate is...
So I did a search and found this...


Ford PowerStroke diesel.

Also....
Apparently bed plates are common in marine engines.

[WConley]

Yup - That's a good example on a block that wasn't originally designed for one.  A bed plate ties all of the main caps and pan rails together with a stiff structure.  Of course if you design the block from the get-go for a bed plate, it will end up cleaner and lower profile.

Here's one on a Honda K-Series four cylinder: