So in tearing into my 1993 22RE truck, I decided ARP head studs would make a dandy way to drain my wallet.

A club member warned of oil starvation issues. Todd with Engnbldr said he has seen it, but if I use ARP brand studs, the stud that goes into the oil passage to the head should be tapered. Other brands are not. The club member said his ARP studs had no such taper on one stud so he did not use them.

I know many of you fellers run them, so what is the skinny on this?

FWIW, I've been running these studs for 10+ years and have never heard of this as an issue, nor am I aware of any of the ARP 22R-series studs being tapered.

Not disagreeing with Todd, whose seen more motors than I have, or with anyone who has starved a motor and feels this is the cause, but I can state with confidence that this has never been an issue for me.

I will also say that ARP has a fantastic technical support line, so you may want to give them a call and ask them directly if any of their 22R-series studs are tapered.

-Jeff

I've "faced" this issue... My comments:
1) It's rare. If these things regularly caused oil starvation, they wouldn't be sold.

2) I think it might be a problem on some motors that have high valve spring pressures - motors that really need the oiling capacity up top.

3) These things HAVE to reduce oil flow somewhat - if you compare the diameter of the stock bolts (tapered) with an ARP, the ARP is larger, it's larger right smack dab in the middle of the oil supply portion of the head.

For 98% of motors, I don't think it matters... I think it might matter if you have high valve spring pressures, a head casting that has a reduced or otherwise different from OEM oil passage design, and maybe some unknown 3rd factor.

I can tell you that I had a top end oiling issue at one time. I did two things to resolve it in combination - so I can't tell you what the "fix" was - so I'm suspicious of both things:
1) reduced valve spring pressure to something reasonable, I think under 190PSI at .450 lift, if I recall right - check with Ted, he won't steer you wrong in regard to valve spring pressure.
2) Removed the #1 cylinder passenger side ARP and went back "stock" bolt. This is where the oil feed for the head comes from.


For anyone curious, you can see the taper on a stock head bolt vs an untapered ARP here:
http://lakebox.dnsalias.com/photos/1988%204runner/engine/rebuild/arpvsoem.JPG

Note, I highly recommend ARPs due to the HG issues with these motors...

Is ARP now tapering the one stud, possibly due to the problem noted? I'd be intersted to know.

That is what Todd said, but I will know in a couple days. The club member said his were not tapered and he elected to not use them.

That ain't much of a difference in taper though, at least in that image.

Wouldn't you risk warping the head if you did that, with the differences in torque values?

How much of a difference that taper makes is going to depend on the size of the oil passage in the head.

You shouldn't have warp issues using a cut stud, assuming you can torque that stud to the same value... I still think you should use these things, maybe cut that particular stud slightly... IF this was a systemic problem, the studs would be redesigned.

So you cut the stud, as opposed to using a stock bolt in that one location?

Wasn't there a thread a year back here or somewhere else where someone posted a picture of the ARP stud in question that had been machined down? I seem to recall someone had put it on a lathe and turned down the diameter slightly in an attempt to rectify the potential problem. Maybe it was a factory head bolt?

>>>*I will stick my nose in with MHO, if I may. My son Tod is a tad jittery, he got a head back with the cam line melted, had to replace it free. Yep, studs choking off the oil feed, he fixed that and she ran fine. Kinda spendy learning curve there.

*ARP has some of the finest products there is, with a well deserved reputation.

That said, the studs work just fine with most combinations. Do they help? In normal conditions it makes no difference at all, in upset conditions like tuning errors, etc, they help keep things sealed. But trust me when I say you can STILL fail a gasket if you get a cylinder too hot or something like that.

The thing to remember is one company makes a part, then another company makes a part, and as with any change or any modification it is up to the installer to check everything.

*Make note here: CHECK everything!!!

Since many different suppliers cast heads, all it takes is a slight bolt hole diameter size change or bolt hole shank size change? Either one fine by itself but the two together? Yep, one piece doesn't work with the other without a small modification.

*A bit like measuring your foot and ordering mail order shoes if you get my drift.... <img src="/forums/images/graemlins/smile.gif" alt="" />..

This is true of almost everything. Now 98% of the time, they will go in and work, if the oil clearence looks too snug, modify the stud. I have now done this a total of twice, both times with an aftermarket head of unknown origin. Our own Topline heads seem to be fine in this respect but I also have one report of maybe??

Crabby phone calls are embarrassing...

Oiling to the top is dependent on room for it to flow past that stud, a larger stud is going to reduce the volume somewhat.

Of course if you install a cam with too much lift, now you need to check the oil holes in the rocker shaft and drill an extra oil hole in the rocker in extreme situations.

We don't even produce cams with enough lift that this can happen because after about .460" total valve lift, well...Nothing much more happens..*Just MHO again.

Folks argue with me on that one, fine with me.

*:D..

So in very rare situations, we suspect the combination of the stud and a slightly off head bolt hole. The rest of the time, no problem.

On spring tensions mentioned above, the gentleman is exactly correct!! Keep the nose load under 190#. I would explain but that is another article, just write that one down...

190# will hold you to into the high 6000+ RPM range, note at this point your friendly neighborhood machinist (me) is hiding behind the big white tires?

*Tough little engines be dam*ed, flying metal hurts.

If ARP studs are handy and in the budget, go for it. One of these days I just might produce my own piece, who knows? I already have them designed.

Part of my problem is this semi-retirement stuff? Now I work ALL DAY instead of ALMOST all day....*LOL**....*EB