To ARP or not to ARP
- Thread starter fmorelli
- Start date
What was your reasoning for using a cometic head gasket? I was under the impression that these engines had fairly well sealing head gaskets and blowing gaskets or head lifting was not a serious issue, at least not below 750whp. Wouldn't it be 'best' to stay OEM?
Cometic - I was already getting head back from Tony and he had it available, so I figured the insurance didn't hurt for short money.
I know ... could have done same with ARP bolts from him at the time, but just didn't cross my mind.
On power ... I've gotten different feedback from different folks. Some cite numbers like you have. Others seem to have issues closer to where I am going. It's a bit of a
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True. Guess what, wrong parts for the job won't make a proper install relevant.
Reality is often one does not know if there is an install issue. That includes being a mechanic in the shop seeing the result of a failure - it's often not clear. Of course many mechanics like to divine a black arts opinion to demonstrate their clear and superior knowledge; been there enough times when working with others.
What we do know - when we are pushing 2x the stock envelope - is that engineers design with some headroom, and YMMV. That's a fact. So really a lot of these questions are around ... enough headroom or not vs account for that.
I have the crank bolt capture setup, but not the spline solution, and my engine is not coming out to have the crank machined. One could argue that would be a wise move at this power level. But unfortunately it is a judgement call based on a read of effort/cost vs risk. :-(
Yeah from personal experience the capture doesn't do much and is just like a $100 piece of billet thats a money maker for companies. My capture came right off with the crank pulley when I spun my first oem hub when I put my first motor together and cheaped out. Pinning the crank is the best way to get the hub to not spin. Splining it is second best
I said this MANY times when that piece came out.
Do a search and you will see.
It would only work if the crank was pinned and there was an issue with bolt backing out. Then and only then would it lock the bolt in place.
You can't lock a bolt to a piece that spins as a whole unit.
That's like a bolt and washer threaded into a nut. Tack weld the bolt to the washer ( crank capture design) and think the bolt is actually locked into place...it still can and will spin loose, TOGETHER.
But glad somebody else sees it LMAO !!!
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This was golden. I was unaware of these updates! Has this been discussed here before and I missed it?
Note he says "post N54 production" ... remember N54 was in the Z4 until 2016. Curious when this update came out.
i bought it a few weeks ago. It was released in 2019. The contact surface for the friction discs is massively bigger.
All crank hub fix sellers and advocates are silent on this as they want to sell you the pinned, 1-piece whatever stuff.
Get some Loctite 468 extra for the contact surface of the parts to the shaft itself and you add extra strength.
I just did these arp studs. What a pita!! I got them from other than vac(boosted projects iirc). M11's torqued down no problem. Got all bolts to 50ftlbs and then the m11's to 75ftlbs. But when i tried to go more on the m9's the front 2 just spun. So took the head back off and got a new head gasket since it was torqued. Lucky I got oem from fcp and sent it back for warranty. Added helicoils to front. One was fine, the other spun still. Got time certs but they have sent wrong size and my studs wouldnt screw into them. Talked to the guy I bought them from and they sent the right size but by that time I added a 2nd helicoils to the spinning bolt and it caught. Got all 4 m9 studs to 35ftlbs. And after everything was torqued down I hit them with a 90degree angle and just went with it. Hope it holds, im in the process of buying a new cyl head and having it ported and will remove this head and go with the new and I just bought the m11 studs and time certs to do the conversion when its time.
The m11 are fine size, the m9's need to be longer. The nuts barely make it on the studs. I m guessing the vac ones have longer m9's ?
When i first spun the m9 I pulled it out and all my threads were on the stud, I twisted them off it was like a spring.
Anyway just going to go with my 20psi max base map on my 6266 until I get this head done and on and secured properly. I just built the bottom 1/2 of motor but I dont trust those head studs. They worry me
The m11 are fine size, the m9's need to be longer. The nuts barely make it on the studs. I m guessing the vac ones have longer m9's ?
When i first spun the m9 I pulled it out and all my threads were on the stud, I twisted them off it was like a spring.
Anyway just going to go with my 20psi max base map on my 6266 until I get this head done and on and secured properly. I just built the bottom 1/2 of motor but I dont trust those head studs. They worry me
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Sorry to hear about your issues. Yes this has been the discussion - that VAC is the place to get N54 ARP studs because they custom order from ARP and spec the correct size stud for the job.
For those following along, I believe John means Loctite 648 (note transposed numbers).
Did you took all the measurements of the studs prior installation?
If so, please share them.
99.9% sure those studs don't have 35 mm thread.
I talked to arp and they told me the same. That vac buys certain sizes from arp and makes their own kits.
I did not measure them unfortunately. But i believe the company I got them from sent me another couple when I messaged them hoping for a solution. If I can find them I will measure them. Things are a little hectic in my garage right now. I got shit everywhere lol
I did not measure them unfortunately. But i believe the company I got them from sent me another couple when I messaged them hoping for a solution. If I can find them I will measure them. Things are a little hectic in my garage right now. I got shit everywhere lol
Thanks, it's good to have some hard data to know what we exactly need.
FYI: Stock head gaskets can be re-torqued several times if not heat cycled.
FYI: Stock head gaskets can be re-torqued several times if not heat cycled.
I dont understand why companies just can't sell the proper m9 stud would not be hard at all
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