TwinTurbo.NET: Nissan 300ZX forum - Re: Re: Re: Re: Re: Lets set a few things straight
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Subject Re: Re: Re: Re: Re: Lets set a few things straight
Posted by Scott ZShack Taylor on September 15, 2017 at 4:02 PM
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In Reply To Re: Re: Re: Re: Lets set a few things straight posted by Kyle(Houston) on September 14, 2017 at 06:16 PM
Message Sigh, You are clearly having some reading comprehension issues.
I have too many water logged Z's to fix and engines to build to keep explaining the same thing again and again.
I am going to explain it one last time for you without all the stupid copy and pasting.

I am not some noob Z guy. I have been doing this for 20 years too. I just can't stand this pages format so I stick to FB.

Here are my replies

I am well aware of the thread pitch. Apparently you think I don't know what I am talking about and that you know more than I. I do not need correcting on this subject. You are clearly not comprehending what I said in several instances!
The pitch of 1.75mm is the block end. that means every one turn of the stud counterclockwise will raise the stud 1.75mm out of the block. Thus raising the threads at the top of the stud. The nut height is the same because the head didn't move. This is where the available threads get reduced. Again not something I would expect a shop to do, but those fellow z guys/gals, our customers in which you refer to as "idiots", have done or may do!

I did not forget the headgasket at all. I purposely did not include it just to see if you were actually reading what I write and following the math. Glad you caught it. Just goes to show that you are only interested in nitpicking my post and not actually trying to understand it!

As for the write up and tq specs go. I never said I personally go to 120. You may want to reread it. I said that since many big power guys are taking L19 to 120, then there is no reason why the 2000's can't go to that as well. 120 is less then both fasteners yield point. (but way higher than 8740)
I know you think I am contradicting myself but I am not. There is a difference between what a bolt can handle and what the blocks threads can handle. BOTH are figured into the final TQ recommendations by ARP. In the case of the 8740's, according to ARP's engineer, the fastener itself is compromised at 83FtLbs. ARP2k and L19 are not. They can go higher than what ARP's engineer recommends the block can handle. It is why they say to TQ 2k's to only 100FtLbs and not the full 125 that they can handle! Sure there is a margin of safety there. how much? IDK. I am sure their reasoning for this takes into consideration that block castings can be different. We have seen this in other areas of the block like coolant flash and cylinder wall thickness etc.
What I was saying is that if these OTHER guys are taking L19 to 120, then you can take 2k to the same level. That is all. For that matter you can take 8740 there too if you want to disregard the yield point. The limiting issue then becomes if the block threads will handle it and will the head handle it etc. (But that is a whole other discussion)
As far as you saying the 8740 will go to 112 FtLbs? That directly contradicts what the engineer says they can go too. He was very adamant about that. And NO you have not provided any evidence from ARP that 8740 studs in the VG are recommended to 112Ft-Lbs!

So lets recap.

As far as the studs metallurgy is concerned, You can take both 2k and L19 to 125. This doesn't mean you should or that I am recommending it. If guys want to do so, they do so understanding the inherent risk involved. But that is what we do when we are pushing the envelope. Right? Lol
Just like if they want to use L19, they assume the risk!
As a shop owner, I will never recommend using a product against the manufacturers recommended use or specs unless a customer wants it done and paperwork is signed stating so. It would be foolish to do such a thing from a business perspective!

You are free to disagree with me on this. You can continue to do it your way and I will do it my way. Doesn't hurt me a bit.

A simple phone call with your studs part number will net you an actual TQ value for the 8740. But you won't likely do it because you don't want to be wrong. That's human nature. lol
Best of luck

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