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To stud or not to stud mains?

1K views 26 replies 14 participants last post by  Cobra 302 
#1 ·
Is it worth studding the mains on a 4bolt main BOSS block?
Are the supplied bolts good enough?

I need to buy a $21.95 bolts to hold the oil pump pick up tube.
For $60.00 more I can get the studs.
Only the center studs are supplied.

http://www.summitracing.com/parts/ARP-154-5602/

 
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#4 ·
In my opinion I would stud every thing you can on a motor..I built my motor with main and head studs..The are MUCH stronger than regular bolts since you fully engage the treads in the block..Most race engine I have since have studs..If you don't race OR you are not going to use boost from a turbo or S/C then you should be OK with regular bolts..
 
#5 ·
In my opinion I would stud every thing you can on a motor..I built my motor with main and head studs..The are MUCH stronger than regular bolts since you fully engage the treads in the block..Most race engine I have since have studs..If you don't race OR you are not going to use boost from a turbo or S/C then you should be OK with regular bolts..

I race the car at the autocross once to twice a month.
I am also going up on the boost to about 14-15 pounds on the S/C.
 
#11 ·
The lower end is mostly affected by rpm's. If you're running a solid lifter cam, then use lower end studs. If it's a hydraulic cam, then your rpm's are limited enough that it won't stress the bottom end that much.

If studs were needed, companies like Dart and Worl Products would equip them that way. Otherwise, word of failures would spread.

OTOH, sometimes you just do things because they help you sleep at night.
 
#12 ·
Is the block machining finished? I considered switching to studs on a new Motown block and found there are mixed opinions about switching without also doing an align hone.

The definitive comment I got was, "it will probably work OK". I kept the bolts.

Kerry P
 
#13 ·
Is the block machining finished? I considered switching to studs on a new Motown block and found there are mixed opinions about switching without also doing an align hone.

The definitive comment I got was, "it will probably work OK". I kept the bolts.

Kerry P
I got the same advice from my machine shop. Main journal alignment checked (and align-honed if necessary) with whatever fasteners you intend to use.

Sean
 
#16 ·
http://www.summitracing.com/parts/ARP-154-5602/

That part number is for the 69/70 Boss blocks. I would call ARP to see if they are compatible with the FMS Boss 302 blocks. ARP makes lots of stuff that doesn't get into their catalog. I would call a local sped shop or ARP direct to see what they can do for you.
 
#18 ·
http://www.summitracing.com/parts/ARP-154-5602/

That part number is for the 69/70 Boss blocks. I would call ARP to see if they are compatible with the FMS Boss 302 blocks. ARP makes lots of stuff that doesn't get into their catalog. I would call a local sped shop or ARP direct to see what they can do for you.

Good catch you are correct.
I called them, they don't have a part number for main studs on the new Boss blocks.
I would have to measure a few things for them and they would put something together.
 
#21 ·
Ford racing makes this kit for the new block.
I may have to go with the ford racing studs.

I would bet a small wager that they are made by ARP..



http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=11289
Yep,
There are many many benefits to using studs over bolts.

Although can you use studs on splayed main cap ? Seems like the cap wouldn't sit down over the angled studs.
The splayed side of the main caps use a bolts and not studs..All four bolt mains are like this..Look at the picture above..
 
#23 ·
I don't quite recall if it was ARP fasteners that had the article, but for most high-torque applications, they recommend studs over one-piece bolts. The reasons, all else being equal such as type of steel used and same thread pitch, is when you tighten a main bolt, you subject the treaded stud to two forces: the inline stretching as you draw the head of a bolt onto the clamping surface, and the twisting of the same shaft. This ultimately fatigues the shaft.

By using a stud, you only need to finger tighten the stud into the block, when you torque the nut, you subject the stud to ONLY the inline stretching, and NOT the twisting.

For that reason, I've always use studs for both main caps and cylinder heads.
 
#24 ·
I don't quite recall if it was ARP fasteners that had the article, but for most high-torque applications, they recommend studs over one-piece bolts. The reasons, all else being equal such as type of steel used and same thread pitch, is when you tighten a main bolt, you subject the treaded stud to two forces: the inline stretching as you draw the head of a bolt onto the clamping surface, and the twisting of the same shaft. This ultimately fatigues the shaft.

By using a stud, you only need to finger tighten the stud into the block, when you torque the nut, you subject the stud to ONLY the inline stretching, and NOT the twisting.

For that reason, I've always use studs for both main caps and cylinder heads.

You are correct I found the same information on ARP's catalog.
I am ordering a few things today from MAX.
I'm glad he got me the free 2011 Ford racing catalog. I have a few things to order:sneaky2:.
This build never ends.
 
#25 ·
Sounds like you already did it - good move in my opinion. A couple of saying I like that apply here

"You can pay me now or pay me later" - studs are good insurance

"You only get one chance to do it right the first time"
 
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