stroker_valiant
Well-Known Member
I was reading in a post a couple days ago about if a person were to go with main studs rather than bolts, the block would need a line hone job done. Why is this? I tried to research it to find out, to no avail...
main studs vs bolts
- Thread starter stroker_valiant
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POS Dakota
Anti-Socialist
I would like to hear from some BUILDERS on this myself, because I have my own opinion based on my own experience. Not saying I am right or wrong...
Case in point, my 360 in my truck...
It makes about 340ish whp n/a (through an od trans which is about a 23 pct loss) to begin with and I have nitroused the living crap out of it for years on the factory main bolts without a single problem. Engine still runs just fine. The rings are a bit tired now, but being shocked about this would be kind of dumb on my part.
This is easily well over 400 whp and a lot of flywheel torque with high shock loads in a heavy vehicle, so by that virtue I would think for someone with the average 450-550 horse N/A 408 in a light A-body with a lot less torsional stress and not near as much shock to the caps, main bolts, especially the aftermarket ARP BOLT is all that's necessary.
If anyone would like to outline what makes studs so much better than a bolt besides the "they promote even clamping force" statement I hear repeated everywhere, I am all ears.
I understand a line hone might correct any main bore distortion brought on by a fastener that exerts a "different" amount of clamping force on a cap, be it more/less, or a different load distribution, but so far I never get a good enough answer.
I see a lot of people going through the extra expense and hassle of line boring, and studs when I'm almost certain it's not necessary in their case. what I would like to hear is some kind of established guideline for when you DO need them, and when you DONT need them instead of all the ooga booga that flies around where everyone thinks they need them.
I dont think everyone does need them, and I think if you are at a point where you do need them you should be using an r block with 4 of them anyway. But what do they come with? Oh yeah....Bolts! lol
Anyone?
Good question stroker valiant, and I hope this spurs some good discussion we can benefit from.
Case in point, my 360 in my truck...
It makes about 340ish whp n/a (through an od trans which is about a 23 pct loss) to begin with and I have nitroused the living crap out of it for years on the factory main bolts without a single problem. Engine still runs just fine. The rings are a bit tired now, but being shocked about this would be kind of dumb on my part.
This is easily well over 400 whp and a lot of flywheel torque with high shock loads in a heavy vehicle, so by that virtue I would think for someone with the average 450-550 horse N/A 408 in a light A-body with a lot less torsional stress and not near as much shock to the caps, main bolts, especially the aftermarket ARP BOLT is all that's necessary.
If anyone would like to outline what makes studs so much better than a bolt besides the "they promote even clamping force" statement I hear repeated everywhere, I am all ears.
I understand a line hone might correct any main bore distortion brought on by a fastener that exerts a "different" amount of clamping force on a cap, be it more/less, or a different load distribution, but so far I never get a good enough answer.
I see a lot of people going through the extra expense and hassle of line boring, and studs when I'm almost certain it's not necessary in their case. what I would like to hear is some kind of established guideline for when you DO need them, and when you DONT need them instead of all the ooga booga that flies around where everyone thinks they need them.
I dont think everyone does need them, and I think if you are at a point where you do need them you should be using an r block with 4 of them anyway. But what do they come with? Oh yeah....Bolts! lol
Anyone?
Good question stroker valiant, and I hope this spurs some good discussion we can benefit from.
stroker_valiant
Well-Known Member
Well I did go with the ARP studs, I didnt need them, but I didnt have the factory bolts and got a good deal on the studs. I plastigauged and everything checked out just fine.
Guitar Jones
aka Angry Johnny
The prevailing wisdom is that the studs may locate the caps in a slightly different spot thus throwing the line bore just slightly off.
I put main studs in my crate short block when I got it but didn't have it line honed. No problems after 10 years. I also installed ARP rod bolts in the conn. rods without having them resized. I'm not reccomending this mind you, I just didn't have time to have the machine work done.
I put main studs in my crate short block when I got it but didn't have it line honed. No problems after 10 years. I also installed ARP rod bolts in the conn. rods without having them resized. I'm not reccomending this mind you, I just didn't have time to have the machine work done.
I believe studs have an advantage by way of the surface area involved in distributing the axial load. Now I'm gonna have to tear the house apart to see what the Machinery's Handbook says on the matter. Some of the brain cells tasked with storing information on threaded fasteners may have been sacrificed to Bacchus over the years.
POS Dakota
Anti-Socialist
I've heard this from a few people too. just changing them over and not bothering with a line hone with no negative results.
moper
Well-Known Member
The cap, block, and fastener work together. The factory bolted the cap in place, and that bolt exerted a certain amount of holding force which distorted the cap a little. Then the main bore was cut and honed. The issue is when you change the fastener the amount of distortion changes too. Not to mention the studs sometimes do not fit the cap holes right and the holes need to be enlarged very slightly to get things to work. Plastigage is not a valid measuring method... It's better than nothing, but it's like setting the pointsw with a matchbook cover.... Yeah, it's better than nothing, but it's not that accurate. The way the bores distort is usually at the parting lines, where the bore get's tighter as the sides draw in. Platigage can't measure the clearance there. Also some bearings have more eccentricity and may not be a problem. The bottom line is unless you use a dial bore gage to measure the bores at three points, you may not see the change. But the bearing will. Bolts-forbolts may not change much. But studs preload the caps a bit more than any bolt, and much more evenly, so the distortion gets much worse.
stroker_valiant
Well-Known Member
Well that was just the answer I was looking for, thank ya very much sir.
DustingBlimps
Bloody knuckles
Also when you're assembling, it's a LOT easier to check stud threads for damage/dirt/etc than it is to clean out the inside of a block hole.
You get foreign material in there, that gives a skewed torque reading and your bolt isn't "home". You wouldn't know unless you were checking for stretch anyway.
But like you say, I agree that studs are overkill for most people.
Main bolts don't tend to blow out in my experience, bearings do.
I'm sure 10,000 will reply now and say, no, it happened to them!
Even ARP makes a blem or two, I'm sure.
You get foreign material in there, that gives a skewed torque reading and your bolt isn't "home". You wouldn't know unless you were checking for stretch anyway.
But like you say, I agree that studs are overkill for most people.
Main bolts don't tend to blow out in my experience, bearings do.
I'm sure 10,000 will reply now and say, no, it happened to them!
Even ARP makes a blem or two, I'm sure.
DustingBlimps
Bloody knuckles
When you go studs what do you do about the stud that blocks a wet sump oil pump?
My pump body would have a stud about 1/2" deep into it with the stud in place.
Do people replace this stud with an ARP bolt instead? What is done?
My pump body would have a stud about 1/2" deep into it with the stud in place.
Do people replace this stud with an ARP bolt instead? What is done?
moper
Well-Known Member
No, you need to use the 12pt nut ARP kit. Then for that position you trim the stud, leave off the washer, and grined the taper off the top of the nut. I've done this several times and sometimes the pump needs to be ground (still) to clear, but others it didnt... Same Melling pump every time...lol. Others I know just run the bolt in that spot but I never felt right about that.
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