Main cap bolts?

jeepmonster

Been looking for new main cap bolts for a 343. What ARP bolts will work? I have heard big block 2 bolt main bolts from Chev are the same, but I have also read that some ford are the same? Can someone clear this up? I don't want to re-use my original main cap bolts and would rather not use main studs for my application. A few Vendors out there have said they have ARP main bolts but when I ask them for a part # I never get a reply. :-| Why is this such a mystery? :idea:

jeepsr4ever

check out arp's web site and measure the bolts they will definately have a reference for you... I cant remember what pt# they are either 111!!!

jeepmonster

Update: I cros referenced the number that some of the AMC vendors list for the AMC ARP main bolts and discovered that they are the same number as the SMALL JOURNAL small block Cheverolet kit 8) 114-5001 Mystery solved. I also discovered why the vendors don't want to give out the part number-they sell them for almost 3 times the price of summit! =D>

radamx

the main bolts on a AMC are 1/2 inch .The main bolts on a small block chevy are 7/16 . I do use big block chevy studs in all of my engines.

jeepmonster

radamx wrote
the main bolts on a AMC are 1/2 inch .The main bolts on a small block chevy are 7/16 .
I do use big block chevy studs in all of my engines.

I'll have to check the dimensions of the part # to be absolutely sure, my guess is that these particular chevy bolts are 1/2" upgrades over the stock chevy bolts and happen to be the same as the stock AMC 1/2"??

jeepmonster

jeepsr4ever wrote
check out arp's web site and measure the bolts they will definately have a reference for you... I cant remember what pt# they are either 111!!!

just checked out the website at ARP. The downloadable catalog on their site is from 2003?? Couldnt find actual specs for the bolts either.

jeepmonster

radamx wrote
the main bolts on a AMC are 1/2 inch .The main bolts on a small block chevy are 7/16 .
I do use big block chevy studs in all of my engines.

Just checked out the ARP site to try and get some cross referencing nailed down but the catalog on their site is from 2003? and the specifications for the bolts are not listed. It is possible the vendor number I saw was for a big block 2 bolt chevy application as the first 3 sets of numbers for the part number are different but the last 4 are the same for the small journal SB. It makes more sense that the 2 bolt big blocks are the actual ones being sold by the vendors since they are 1/2" as you have noted and the stock AMC bolts are 1/2". My builder DID check a stock big block chevy main bolt on my 343 but he felt that it wouldnt thread down as far as a stock 343 bolt, in essence the big block chevy bolts are a wee bit shorter.

I am sctracthing my head as to why ARP would make AMC head bolts and Rod bolts but not the all important main cap bolts?? 111!!! #-o

RonSon

I just looked in a 05 catalog and that is not a part # anymore. Give me the dimensions,including the grip length, and I can call them. They find stuff thats not listed for our application all the time.

Dusty

FYI I used 351 Cleaveland 2 bolt main studs in my 401. they worked perfectly right length etc. might as well upgrade to studs at this point vs bolts :?

jeepmonster

Dusty wrote
FYI I used 351 Cleaveland 2 bolt main studs in my 401. they worked perfectly right length etc. might as well upgrade to studs at this point vs bolts :?

I don't think studs are going to make much difference over a an ARP bolt for my application. + studs are a bit more work and often require line boreing to the mains. My 343 does not need line boring now and that is just going to be another expense that might be needed with the installation of studs. It would be nice to have a strong upgrade bolt instead for my application. I guess if I were building a 7000 RPM strip motor that would get torn down after every season the studs would be a good investment wich is why they are so popular, they save wear on the main bolt holes in the block and make R/R much easier. But initially they "could" end up costing more in machine work. My machine shop builder frowns everytime I mention them. :?:

Rogue Racer

You leave an incorrect impression about using main cap studs. If your block is machined correctly, installing studs is nothing more than screwing them in place; there is no additional machine work needed. To properly install them, you need only to screw them in finger tight, and I do mean FINGER TIGHT. The most common reason when people complain about studs not lining up with the holes in the main caps is that the studs were double-nutted, or some other sort of manipulation to hold them, and then torqued into place. When you do that, often the stud gets cocked in the threaded hole and the then will not align with the main cap. If a stud will not align with the main cap hole when properly installed, neither will a bolt. In those cases, I have found the main cap to be machined incorrectly and it needs to be corrected regardless of the type of fastener. If your block currently has main bores in alignment, the use of studs will cause less distortion than 1/2" bolts torqued to 100 ft/lbs. Incidentally, I have used big block Chevrolet studs from ARP in my AMC motors and they fit perfectly. I agree that the Cleveland Ford studs should work, too.

Dusty

Rogue is correct, all we did was put them in. had no distortion nor any issues with maincaps shifting etc, fit perfectly :lo1l:

tufcj

I used Milodon studs in my 390. They listed an AMC application, and were cheaper than the ARPs by a few bucks. Opened the box, and all the nuts said ARP on them. The only problem I saw was that the studs stick out enough that you can't screw in the oil pickup (#3 I think). I had to take that one out to install the pickup. The instructions with the Milodon studs said no more than 10 Ft/Lbs of torque to put the studs in the block. Bob tufcj

jeepmonster

tufcj wrote
I The instructions with the Milodon studs said no more than 10 Ft/Lbs of torque to put the studs in the block.

Bob
tufcj

That's what scares me :!:

jeepmonster

Rogue Racer wrote
You leave an incorrect impression about using main cap studs. If your block is machined correctly, installing studs is nothing more than screwing them in place; there is no additional machine work needed. To properly install them, you need only to screw them in finger tight, and I do mean FINGER TIGHT. The most common reason when people complain about studs not lining up with the holes in the main caps is that the studs were double-nutted, or some other sort of manipulation to hold them, and then torqued into place. When you do that, often the stud gets cocked in the threaded hole and the then will not align with the main cap.

If a stud will not align with the main cap hole when properly installed, neither will a bolt. In those cases, I have found the main cap to be machined incorrectly and it needs to be corrected regardless of the type of fastener.

If your block currently has main bores in alignment, the use of studs will cause less distortion than 1/2" bolts torqued to 100 ft/lbs.

Incidentally, I have used big block Chevrolet studs from ARP in my AMC motors and they fit perfectly. I agree that the Cleveland Ford studs should work, too.

 On the ARP web site it specifically states to align bore the mains as part of the procedure for installing their studs.  They make no mention of align boring the mains for their bolts, and from what I interpreted in the gide on the ARP website  it is due to the way studs distribute clamping force on the main caps relative to bolts.   FWIW my original main bolts were still very snug on tear down, so I don't see how studs are really going to make any difference over a bolt that is a stonger upgrade over the stock bolts anyway.   So I am still looking for ARP bolts instead of studs that will fit.  Studs are a convenient option, but I just don't think they are needed for my application, a nice upgraded bolt should be just fine. :lo1l:

Gremlin4ever

I am balncing & blueprinting my engine for durability reasons. AMCs are not that plentifull to just throw it together and go like those chevy guys do. I have had several long discussions with Gary (Grimes Automotive Machine) in Alpharetta, Ga and he tells me that studs in the mains are very smart upgrade for any engine no matter what it will be used for. He says when studs are used, the mains MUST BE aline honed because they clamp a greater area on the main caps. .001 has to be honed out of the caps because the studs make the whole caps work instead of just the bosses where the bolts/studs go through to the block like the bolts make the caps work. Mine are ARPs without a part number which brings me to the conclussion that they hid that from me to charge me more now that I read that earlyer.