ARP main studs

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75greenduster

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I just tried to put the oil pump on my 360 on. The ARP main studs dont even allow this to come close to happening. Is this a normal thing or should they have included a shorter stud?
 
Haven't ever installed them myself but I've read guys having to cut down the stud before to make them clear. Some even said they had to grind down the nut.
 
Where's the interference, between the oil pump and the stud itself or the oil pump and stud nut? Did you tap all the main cap bolt holes? Send a pic if you can. I'm hoping that you had the block align bored with the studs in place, otherwise don't install them.
 
Had this exact problem when I put studs in for my 360. I called ARP and bought one of their bolts for the rear main cap. I definetely wouldn't grind the nut and stud down. It has to be as thin as the original bolt head for the pump to fit. ARP knew about the problem when I called them, but they didn't say why they don't put this info in the box of studs. I thought this was a good option for my setup. I guess you could fabricate a spacer for the oil pump, that also would work as long as you had oil pan clearance for that. Don't know if there is enough clearance there or not for something like that. Or you could machine down the main cap, I don't know what that would do as far as maintaining good overall strength.
 
I ground my stud, nut and pump to get them to clear. You should not mix studs and bolts on the same cap, if you are going to use a bolt on the rear main use two bolts.
 
I used ARP bolts on my 360 which also came with fairly thick hardened washers. The height of the bolt head and washer caused an interference with the pump. I left out the washer on the bolt under the pump.
 
The stud itself is taller than the nut, so the first interference would be with the stud, but even if I cut the stud down i think the nut would interfere too. As it is I dont think I could make enough room by simply grinding on the pump, and yes the holes were tapped and the block was align honed.
 
Yes, the stud is too long. If you went for the ARP kit with 12 pt nuts, the nut will fit under the pump with no mod, but you will have to trim the stud down about 1/2" IIRC. It is easy to do. Install the cap with one stud, then install the pump with no gasket finger tight. Measure the height from the pan rail to the pump body. then, pull the pump and install the stud in that position. Measure up for the pan rail the same amount, and mark the stud. (whiteout or teflon threas sealant works well..) Take it out, trim it off with a cut off wheel (very hard stuff...), and use a thread file or chaser to make sure the threads are ok. Then, clean all the parts, and install it. The 6 pt nuts are a PITA, so I'd try to find one of those nuts if possible. I dont have any extra or I'd send you one. ARP doesnt ell you in the catalog about that...
 
340mopar said:
I ground my stud, nut and pump to get them to clear. You should not mix studs and bolts on the same cap, if you are going to use a bolt on the rear main use two bolts.
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Well I did what I did because that was what ARP recommended to do. I called their tech line after I ran into this problem. They did not say anything to me about grinding the bolt or stud down. I would think that the heat introduced with grinding or cutting would have an effect on the machining process that ARP goes through at least the proccesses that they go through to get them to stand up to the abuse. I don't know for sure how heat would affect the bolts or studs. On a side note I have put over 30,000 miles on this engine, and never had a problem. I did rebuild it recently but there was nothing wrong with the engine when I took it apart I just wanted to go faster. This time the shortblock was assembled at Hughes Engines a proffessional mopar builder, Dave made no mention about me mixing bolts and studs and that was going to be a problem. Not trying to start an internet war here, just explaining myself.
 
I called ARP. They strongly advised me against cutting or grinding on the nut or bolt. As someone already stated they seemed to know about this problem. I have no clue then why they sell this kit knowing the oil pump probably wont fit. They agreed to send me two bolts free of charge, so I think I'll go that way instead of trying to alter the stud.
 
Well, I agree with doing what ARP says...Especially if they are sending you the hardware. But, I can say, I held it in my hand while I cut it, and it never got hot enough for me to have to put down. It gets hotter when the engine is running..lol. But, I go slo, maybe that's why...Best to be safe and do what your comfortable with.
 
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