Wanting to install OE cross bolt caps

[Urgefor]

Fun fact.  If you search for "machine shop" on this forum, you get 14 pages of results to check out. 

I'm looking to have some OE cross bolt caps that I purchased a few years ago installed into a '64 block that was cast with the thicker main webs as well as the casting for cross bolt caps on #2, 3 and 4.  I'm in central Iowa and don't have much faith in the machine shops around here since the last one this block was at installed the cam plug backwards resulting in an oil leak.  I did find a post from Jay detailing his experience with girdle and cross bolt main cap machining which really makes me want to find someplace that can do the job and do it correctly. I also found this thread from 2019 inquiring about shops in the KC area but have no idea how current that info is since it is almost 4 years old now.

Anyone know of a knowledgeable/trustworthy machine shop around central Iowa that isn't 1/2 way across the country that could do something like this?

On a side note, I pulled out the micrometers and measured a cap currently used in the block and one of the cross bolt caps.  I measured from where the bolt seats on the cap to where the cap mates against the block.  I'm certain this isn't a definitive measurement, but I was after some sort of basic comparison.  The cap currently being used measured 2.521" and the cross bolt cap measured exactly 2.5". I did this since my paranoia kicked in and the thought of "Did I purchase a set of useless cross bolt caps?" ran through my head as I was working on the game plan to get them installed. 

[GerryP]

Gessford Machine.  Hastings, Nebraska.  The FE authority.

[jayb]

Main bearing caps are not interchangeable block to block, and if you install your crossbolted caps on your block you will likely note an "edge" where the bore of the block overhangs the bore of the cap on one side, and vise versa on the other.  The only way to correct for this is to cut the caps down so that the bore of the block no longer overhangs the bore of the cap, and then rebore the whole main saddle.  If the overhang is too much you may not be able to correct for it.  I'd suggest measuring for that overhang before you go too far on this; a little geometry will tell you how much will have to be removed from the cap.

The Pro Gram caps are easier to fit because the cap bore is undersized, so the cap bore overhangs the block bore on both sides, not just one.  No trimming of the cap is required.

[Urgefor]

Thanks Gerry.  I'll give them a call.

Jay,

Understood on the main cap swap.  I'll check into the overhang as you noted.  Do you happen to know an approximate limit of how much can be cut from the cap?

[pbf777]

I pulled out the micrometers and measured a cap currently used in the block and one of the cross bolt caps.  I measured from where the bolt seats on the cap to where the cap mates against the block.

     As stated previously, it may not prove so simple to just "swap" a set of main caps from one block to another.  In a quick preliminary test for possible swap compatibility compare the measurement from the registering edge of the cap to block surface, to the crankshaft saddle bore (as best as one can  ), this of both the original cap and the possible substitutes, both left and right sides.  How far off are they?  This presenting the crankshaft saddle bores' position, left to right, in reference to the block registers; a distance sum that was not an overly critical consideration in Fords' production of the blocks and therefore as indicated previously, at times there will be an excessive sum of differential in the distances that one must decide just how much irregularity one will except, to it just ain't gonna work!   

    We have executed this operation many times in the past and I preface accepting the job with that even if in my opinion we achieve a "it'll work just fine" outcome, but there still may be 'some' displacement at the parting line, both measurable and visible, that if the customer expects a "perfectly" round bore, including at the 3-9 o'clock parting line of the cap and block, just forget it!    You can't (reasonably  ) put metal back where it was already removed previously!  And you can't just cut any amount off the cap surfaces to shrink the bore as if only with the "cross-bolt" variety you'll create a no-go misalignment with the horizontal cross-bolt fasteners, and having to slot the side holes in the block opens-up possible new problems   

    Though sometimes, it does finish out just perrrrrrfectly!   

    Scott.

[jayb]

Jay,

Understood on the main cap swap.  I'll check into the overhang as you noted.  Do you happen to know an approximate limit of how much can be cut from the cap?

Based on a little trigonometry, you need to take about .070" off the cap mating surface to correct for only a .002" misalignment, where the block edge overhangs the cap.  Nobody who align bores a block is going to want to take that much off, so what would likely happen is a much smaller amount will be taken off the cap, and the align bore won't touch all the way down the one side of the cap where the block overhangs.  Again, not an ideal situation.  You have to trade this off with how much power you expect to make, and the more power you are looking at, the more problematic this becomes.  Back in the day, when we were all happy to approach 500 HP, this probably wasn't a big concern, but nowadays when 700+ HP is relatively easy, it would make me squirm a little 

[Urgefor]

And you can't just cut any amount off the cap surfaces to shrink the bore as if only with the "cross-bolt" variety you'll create a no-go misalignment with the horizontal cross-bolt fasteners, and having to slot the side holes in the block opens-up possible new problems   

The cross bolt aspect is the part that will be the most forgiving in this particular situation.  As noted in my initial post, this particular block is a '64 that (from what I've read anyway) was cast in a 427 mold, sans the 427 cloverleaf casting of the bores, so it has the reinforced main webs and the "as cast" bosses for cross bolt caps.  I'll look into the measurements you noted as well as Jay's.

[Urgefor]

As luck would have it, I really didn't need to put much effort into measurements.  I bolted the caps into the block to check things out.  I can say they looked pretty.    #2 was very promising to the point that I briefly thought about purchasing a nice digital radius gauge to determine how little overlap there was.  Unfortunately the overlap increased considerably on #3 and more so on #4.  Luckily though, that wasn't the worst part.  The absolutely insane overlap for the thrust bearing seat on #3 is without a doubt a show stopper.

On a side note, I know a guy that has some interesting conversation starters.  They even play well with others as shown in the attached pic.   

Thank you again Gerry, Jay and Scott. The input is appreciated.

[67xr7cat]

Ford did a lot of mix and matching of different core parts. Just understand this is most likely just a 390 block other than the main webbing.  Before putting money into that block I'd get it sonic checked and magged.  A pressure test is a good idea too. The cross bolt caps can be fit to pretty much all blocks.  Having the 427 webbing of course makes for a nice factory install of course.

As for the caps, sometimes they are close, sometimes can be off a lot.  When test fitting them try 2 & 4 in both and all can be tried forward and reversed to find the best match up.  After finding the best fit up just stamp them for position and orientation. 

[Urgefor]

The block is sound and not new to me.  I've owned it since '87 or so and it has basically become my side hobby. When time and interest (on my part) increase, I like to work on minor improvements here and there.  It is currently torn apart so I can address my son's idea of painting an engine block. He used it for his engine rebuild project when he was going through an automotive program a few years back and painted it chebby orange. Kids these days. I'm aware it isn't anything special, but I like the idea of the cross bolted mains since the block is a little out of the ordinary.

[cjshaker]

They aren't too unusual for a C4 390 block. I've been running that same block for about 30 years now. First as a 390 for about 25 years, now as a 445. They're good blocks.

Your offsets on the caps don't look bad, so it's probably doable. Like mentioned, Gessford is probably one of the closest that would even want to do it. Whether or not it's going to be worth the cost, that's another question. There's a lot of work involved to do it right, and labor isn't cheap these days.

[pbf777]

The cross bolt aspect is the part that will be the most forgiving in this particular situation.

    True, but just don't loose track of the requirements of.   

    In your photo of the thrust-main's displacement, the initial concern is in the left to right deviations of the bore; front to back (if that is one of what your intent was of displaying) is mostly only critical of this thrust main and accommodations for this is addressed via the bolt hole.   

    In my previous posting I stated that:

   
   You can't (reasonably  ) put metal back where it was already removed previously!
   

    But it still is possible; as before new after-market caps were made available, we have done this before by 'spray-welding' (I did Tig a few but the other finishes out better    ) built-up (generally just one side) and then re-machined them to better locate the cap, this if otherwise off center in a totally unacceptable manor, though still very well may display a minor offset (better than it was before!  ), but hopefully the goal was that even so, it would be deemed as functionally acceptable.

    Remember, that at the parting line there is a sum of eccentricity presented, provided by the bearings, and alignment concerns here is one of the reasons for its' incorporation.   

    Scott. 

[fekbmax]

As for the caps, sometimes they are close, sometimes can be off a lot.  When test fitting them try 2 & 4 in both and all can be tried forward and reversed to find the best match up.  After finding the best fit up just stamp them for position and orientation.

[cammerfe]

I put 427 main caps in a C4 block while doing a build-up series in Mustang illustrated a few years back. The block started as a 330-390 PI engine. I knew the guy who bought it new and tracked it down.

All the machine work was done in Jack Roush's Prototype Shop. At that time, they were also building all the NASCAR engines there, as well. The bores on the block were well-centered and there was lots of iron available everywhere for machining.

I bought a set of 427 main caps at a swap-meet at Milan. They came with crossbolts and a whole handfull of spacers. Tossed the bolts and used as many of the spacers as we could make fit. Since the level of workmanship required torquing everything down after machining for size and alignment and then inserting the spacers with no more than thumb-finger pressure, we ultimately had to make a couple to get the right fit.

It was necssary to hone the mains after fitting, and the crossbolt holes in the block were drilled after the caps were cut and honed. The nubs inside the block skirt were a pretty good match. In fact, the only eyebrow raiser was that the tapped holes in the outside of the block skirt for the manufacturing-process carrier were slightly in the way. We simply ignored them, and the HD washers on the head-ends of the crossbolts covered what little was left after the drilling and spot-facing were complete.

If I were to do it again, now, I'd undoubtedly use a new block, but this was long enough ago that such a thing didn't exist. But it surely is doable.

KS

[Urgefor]

As for the caps, sometimes they are close, sometimes can be off a lot.  When test fitting them try 2 & 4 in both and all can be tried forward and reversed to find the best match up.  After finding the best fit up just stamp them for position and orientation.

Swapping of caps didn't provide any benefit.  Interestingly enough, #2 cap on #4 main saddle and #4 cap on #2 main saddle appeared (via visual inspection and dragging my fingernail across the parting line as I had done previously) to have the same amount of deviation. i.e., #2 cap and #4 cap on #2 main saddle appeared to produce identical results.  Reversing the caps was a no go since they would not even seat into the block if using the bolts to pull them down. That produced an overlap on one side and a gap on the other of 1/16" or so. I could use a soft mallet to seat them of course, but installing the bolts wasn't going to happen.  While I wanted to use the OE caps, there isn't a need to use them so I'm fine with the Pro-Gram Engineering/Billet Speedworks billet caps being the next step in this adventure.   

In your photo of the thrust-main's displacement, the initial concern is in the left to right deviations of the bore; front to back (if that is one of what your intent was of displaying) is mostly only critical of this thrust main and accommodations for this is addressed via the bolt hole.   

Out of curiosity, how would the bolt hole(s) for the thrust main be modified to account for the front to back deviation and still allow it to fulfill its intended purpose?