bloc

Hello all,

It is common knowledge that the exhaust manifold-to-head bolts are prone to breaking. Has anyone considered using a stud and nut setup?

I have quite a bit of experience with VW and on their manifolds they use the same thread size and pitch for a stud, plus a copper-coated pinch nut that very rarely has problems with removal.. even after multiple hundreds of thousands of miles.

Any reason I shouldn't do this on my L92?

clinebarger

ARP bolts!

handyandy496

iTrader: (9)

Bolts not studs.

bloc

That's my question.. why bolts over studs? They are used in that application successfully on so many other vehicles.. yet the OEM bolts, presumably torqued correctly at the factory break on LS engines very often.

spy2520

iTrader: (3)

ARP does make studs for this application as well

bloc

Yes they do, and the set is about $130

Toyota hardware which would probably work fine is $24
VW, with the copper coated nuts that won't corrode or gall is about $35

So why not use studs again?

spy2520

iTrader: (3)

If you know of some that fit for cheaper than ARP go for it. I imagine the cost of the ARPs is probably the only reason they are less common. I do own the ARP set.

clinebarger

The ARP bolts are cheaper & I have never seen one break, The stock Cast manifold flange is split in the middle allowing it to move around to much (Scrubbing the gasket & putting to much stress on 3 bolts)

I've put several ARP bolt kits on 2500 & 3500 trucks & breaking bolts became a thing of the past.

I'm not saying bolts are better than studs given they are the same material(I know they're not). On my car (W/ L92)......If I used studs on my headers, I would have to extract all the studs before I could remove the headers, That would be a PITA for little to no benefit over a good ARP header bolt.

If your using headers with good 3/8" 1 piece flanges, I bet new OEM bolts would work without issue, Me......I like good hardware!

bloc

I'll be using hooker cast manifolds that do still have the split with this swap.

in your opinion, does that change the bolt/stud recommendation?

brobinson216

iTrader: (11)

The broken bolts are normally a result of worn or broken motor mounts, snap when the engine twist and the exhaust stay put.

clinebarger

I would still run ARP Bolts.

Project GatTagO

iTrader: (7)

I am using the Hooker cast manifolds and ARP studs. No issues for 2 years. I did it for the bling factor, because nothing looks sexier than stainless hardware on rusting cast iron manifolds

Andrew