FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Urgefor on June 28, 2023, 09:31:08 PM
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Fun fact. If you search for "machine shop" on this forum, you get 14 pages of results to check out. :o
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 (https://fepower.net/simplemachinesforum/index.php?topic=8145) 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. ::)
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Gessford Machine. Hastings, Nebraska. The FE authority.
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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.
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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?
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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! 8)
Scott.
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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 :o
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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.
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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. 8)
Thank you again Gerry, Jay and Scott. The input is appreciated.
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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.
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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.
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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.
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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 8) ) 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.
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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.
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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
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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?
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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?
Regarding #3 thrust, it appears that either the cap is drilled off center or the block saddle is. I'm guessing the cap is. The below will need to be done on a milling machine.
Measure the cap first, using calipers, measure the thickness of the bolt hole, to the side of the cap. If both sides are within .005 - .007, then it's good. Then do the same to the block bolt holes.
To fix the cap, put it in a precision vise, indicate across the bottom, to insure it's parallel and indicate the center of one bolt hole, on the X axis. After that, indicate the center of the of the cap, on the Y axis and "0" it. You will be at the center of the cap and where the center of one bolt should be.
Using a sharp, long 1/2" end mill (make sure it can go all the way threw, w/o hitting the vise bottom) and plunge threw the cap hole. Move over to the other hole, 3.680" and do the same. To insure that there is bolt clearance move .010 more in the Y axis and plunge again.
If the main saddle is off center, then you have to disregard the Y axis above and match the offset of those bolt holes, by measuring the offset and matching that on the Y axis.
Also, the circular cuts on both saddle and cap, are very close tolerance. The dimension is .913 - .915 so, check that also.
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That is what I was assuming the modification would be. Thank you for clarifying. I take it that means for the thrust bearing cap to do its job, an elongated bolt hole isn't much of a concern as long as the mating surfaces between the cap and saddle are able to achieve the desired clamping force to keep the cap from shifting when the bolts are torqued to spec.
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Almost All the old schools guys I've talked to about this have told me you only need to do #2 and #4, they never had a problem with #3
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That is what I was assuming the modification would be. Thank you for clarifying. I take it that means for the thrust bearing cap to do its job, an elongated bolt hole isn't much of a concern as long as the mating surfaces between the cap and saddle are able to achieve the desired clamping force to keep the cap from shifting when the bolts are torqued to spec.
Yes.
One other thing, if you use the center cap, is that after the center cap and saddle surfaces are inline with each other, you will have to accurately locate the threads in the cap, to the cross bolt hole that will be drilled from the outside of the block, to be sure that when the threads engage, they don't pull the cap off to one side or the other, decreasing the thrust clearance to much, so make all the side holes 1/32" over size and spot face them.
It won't be easy to do and the machine shop will need to know what they're doing.
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I agree with Jack, the caps that need help are #2 and #4, that is where most blocks start to crack between the cam and crank bores when run hard at high HP & RPM. Easier for the machine shops to do a good job on the conversion and not have to deal with the thrust alignment when changing caps and all the work that goes with it. One of the two stocker blocks have just the number 2 & 4 cross bolt caps.
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I take it that means for the thrust bearing cap to do its job, an elongated bolt hole isn't much of a concern as long as the mating surfaces between the cap and saddle are able to achieve the desired clamping force to keep the cap from shifting when the bolts are torqued to spec.
As stated previously by another, yes, basically slotting of the bolt hole in the cap as needed is done for alignment; but be aware that particularly since we in this day and age are expecting power levels beyond that which the O.E.M. engineered the block for, loss of material sums particularly in these sort of high load/stress areas are not appreciated. As for example I have witnessed FE caps split thru the bolt hole column in the past even with only the O.E.M.'s bolt fastener preload value (though I believe the bolt engineering is part of the problem! ;) ) and most today will switch to a stud of higher strength creating even greater compressive forces coupled to the greater operational pressures! :o
Also of note: Even if not swapping the main-caps it is often encountered with the implementation of a stud fastener in place of the O.E.'s bolt that interference of the studs' shank and the bold hole I.D. (and it would be nice if ARP could better control the run-out alignment between the studs' shank to threaded sections! ::) ), and should be inspected for; as this can not only create difficulty in acquiring the proper thrust-cap location front to back for reasonable bearing/crank thrust clearance value, but also this issue can cause force to the caps right to left which can lead to distortion of the main bearing bore and/or creating a greater deflective load from the vertical pull on the threaded bores with the possibility of aiding in breakage of the block casting through the bolt holes! :o
Scott.
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Thanks for the info regarding replacement of OE bolts with studs Scott. I was definitely not aware of that issue and now I know that I should make a decision regarding main studs in relation to installing a different set of main caps.
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Posting this here as well. Any information is appreciated.
I haven't heard back from Billet Speedworks after sending a message via their contact page on their website and leaving a couple voicemails on the number listed on their site. Anyone know their current status? I'd place an order via their website and be willing to wait, but I'm not sure what to think about the lack of response from them.
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Good news everyone!!! (in my best Professor Farnsworth voice) Finally got in touch with Billet Speedworks. They will be machining caps in a few weeks with availability being mid August. Responses I received from resellers ranged from "we can't get them" to "we've had them on backorder since last December". If you have been thinking about ordering a set, now would probably be a good time. ;)
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Maybe! ???
Scott.
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Just got the shipping notification today from Billet Speedworks. Main caps are finally on the way. Better late than never. :D