Putting on the head today I noticed that the ARP nuts were not grabbing enough threads on the stud. The picture shows how they looked after torquing them to 60 ft lbs. I doubt bringing them to 100 ft lbs will make up the difference. I measured the studs after removing the head and they extend 67mm from the block. I hand tightened the nut without the washer and it looks better but Im pretty sure I need a washer of some sort.

What are my options? Are there lower profile nuts/washers I can use?

 

Remove the stud and measure it end to end. Each block/head combo has a different length. If that's a stock 951 block and head, then chances are you just screwed the studs down too far into the block. Your goal (for a stock 951) is for the studs to stand about 72mm above the deck, with solid thread engagement in the block (say 10mm worth). Don't torque the nuts the way you have it in the picture. The pressure will be concentrated on too few thread and you risk stripping the bolt or nut or both...

 

Also, it looks like you have grease on the threads. You'll want to desolve all of that off (break cleaner works well) and coat the threads with a light coat of engine oil. The torque value is listed with oil as the thread lubricant, grease will have a different friction value and throw off the final stud tension.

 

This is not a stock block and was used with these studs for years. I don't have the nuts/washers that the previous owner used. I contacted ARP to get the fasteners and didn't think to measure the studs beforehand. So if stock height is 72mm and mine is 67mm I have to recover the 5mm somehow. I was thinking of thinner washers and a lower profile nut.

 

Then that suggests you screwed the studs deeper into the block than necessary. Back them out 5mm and you'll have your extra height. Before doing so, I'd pull one out and measure it end-to-end. It should be about 192mm for a 951 block/head. If that's what yours measure, then you should have no problem getting full thread engagement in the block with a full 72-73mm height above the deck. If the nut still does not fully engage, you can uncrew the studs a bit as needed as long as you still have ample engagement in the block. Only other variables are the head gasket (extra thick MLS?) and the washer/nut thickness. Looking for skinny washers and nuts shouldn't be necessary and doesn't sound like a good idea!

Edit: if not a stock block, what was it to start with? A 2.5 block, 2.7, or 3.0? And which head are you using? I have a list of stud lengths for most combo's somewhere...

 

I didn't install the studs they were installed in the block when I got it. I figured the motor was running fine so I never thought to pull them. The studs have RTE (Raceware?) stamped on the end and I have ARP nuts. ARP nuts were easier to find.
2.5 block with 102mm dry sleeves... so 2.6
Stock head.

46&2 -- I used the ARP nuts and followed their instructions to use the ARP ultra torque assembly lube.


Thanks!

 

For reference, the stock and raceware (yes RTE) nut/washer combo are about the same overall -- around 13-14mm together (give or take). I can't imagine the ARP nuts are that much taller (though not sure its wise to mix and match anyway). Something isn't adding up here. Did you take the motor apart with those studs in place? If so, what head and what nuts/washers were on it?

Raceware does not recommend using lock-tite on their studs, so they could have inadvertently screwed themselves in further (or a machine shop might have done so).

Best course of action is to pull them out (they should come out easily) and measure end to end. If they are 192mm +/-, then screw them into 72-73mm height and be done with it...

 

Also make sure you don't have something stuck between the head and deck, like a ref sensor wire or vacuum hose... (it happens).

 

Did you take the motor apart with those studs in place?
-- The head was off the block when I got it.

what head and what nuts/washers were on it?
-- Great question. Ill try to get that info.

My ARP nuts and washers are 17mm tall.
I only have the bottom end assembled. Its on a stand in my basement... new build, no wires or hoses yet.

I REALLY don't want to remove the studs.

 

If they are raceware, they come out very easily -- nothing like the factory studs that are cemented into place. Double nut one and it'll come out by hand or with light pressure from a box end wrench. Seriously, try it...

 

I just tried the double nut on 2 studs, no go.

Needed more torque than I was comfortable with not using a stud puller.

 

Hmmm, well if they were installed according to the instructions they should screw out with minimal effort. I suppose you could get a collet style stud remover, but have to believe thats overkill. Regardless, if the studs are only 67mm high off the deck, then one way or another you're going to need to back them out some. I know of no 'thin' head nut/washer combo that is up to the task.

 

Thanks for the info Tom. I did a bit of searching and dug up one of your old threads...

"Well, on a whim, I just called raceware. I expected to a receptionist who would dump me into to sales support voicemail after not being able to understand my questions. Instead, the guy who answered the phone was great. When I asked him the install height for Raceware 951 studs, he was able to answer without even looking it up -- 73mm above the deck. He said Raceware nuts are a bit thicker than stock, so the 73mm spec gives you a few mm's higher than stock. He said they have seen variations in the depth of the factory threads, so you can't really expect to install the studs all the way into the holes everytime and get a workable stud height. He also said that the teflon sealer is used solely to keep the stud from turning when being torqued, without creating all the hassles of removing loctited studs. Thought I'd pass that along for the record... "

So it looks as if Ill be pulling the studs. Ill get a stud remover and find a heat source just in case. As long as I'm neat about things, can I leave it assembled while pulling the studs?

 

I'll see if I can dig up a spare and measure, but suffice to say to stock nut/washer and raceware nut/washer are pretty close in thickness -- raceware might be a mm +/- thicker -- but nowhere near enough to create the problem you are having? Not sure what you mean about keeping it assembled? If you are asking whether you need to disassemble the bottom end, then absolutely not -- as long as the head is off everything else can stay put. Unless someone did something stupid, the only thing holding those studs tight is crud in the thread and maybe some dried up thread sealer. That all should break loose without heat or the exessive forces needed for factory studs. The ultimate set up for stud removal is a collet style remover (snap on) and a t-bar breaker (to avoid side loading the studs) along with heat applied to the side of the block where the studs are. Easy for me to say from thousands of miles away, but racewares shouldn't need any of that...

 

The oil pan to pistons are assembled along with water pump and oil pump and balance shafts. Yesterday I was going to install the head, cam housing and belts but that plan ended quickly. A friend of mine had a craftsman style stud puller, not collet type, and I gave that a shot but still no go. I don't have a T breaker bar and the side load was too much using the Craftsman puller. Not sure what these Raceware studs were installed with but it maybe some form of loctite.