Installed my new MREV2 and 5/16 last weekend in my 35th and have driven it enough for it to have a few warm up / cool down cycles. Notice the idle is a little more rough, so today when i was changing the oil, i checked the torque of the plenum bolts. The center 6 bolts (the ones most visible on the upper plenum) were less than 25 inch pounds. I know i torqued them to 80 inch pounds and i used the thread locker supplied by Motordyne.

Is it customary for these bolts to loosen with warm up / cool off cycles? I torqued them back down to 80 inch pounds today but I'm wondering if this is going to be a routine thing.

Or do I need to remove them and put more thread locker on them? If that's the solution, will it harm anything to remove those six without removing the all the outer bolts?

Thanks in advance for meaningful responses from the experts on this forum.

 

We had a thread like this some days back. Did you use the bolts provided by Motordyne?

 

I check mine every so often. Sometimes it does come a little loose but just torque it down in order and I think you'll be okay.

 

Did you follow an "X" pattern when torquing after installation?

 

I don't use any threadlocker and I haven't had this problem in the 3 years I've had my spacer. Torque in multiple steps by the numbers. I know it sounds crazy but start at like 20inlbs and torque in sequence then go to 40 then 60 then 80 and then recheck at 80 in sequence. I overdo it but I also don't have my plenum bolts come loose on me. Good luck

 

The bolts don't loosen or move at all, but the tension does relax after a few thermal cycles. This is normal and OK.

You only need to tighten it to spec once and it makes a good seal. Retightening is not needed.

 

Thank you for the responses.

Yes, I used the Motordyne bolts and torqued each of them in the proper sequence and also staged torque settings (40 in lbs, 80 in lbs, and so on). I am precise when it comes to this kind of thing....followed to the letter.

It was surprising yesterday when I discovered how loose they were (only the main six on top of the plenum, not the outer bolts). I torqued them back down and put some good hard miles on the Z yesterday.....yes, it was freakin awesome! I'm hoping it was just the bolts "relaxing" as one of the replies suggested. I'll check them periodically.

A little more info just for grins - When I bought my 35th it was somewhat unplanned, I immediately joined this forum to learn the problem areas and proper mods based on my liking. So far I've done Nismo wheels, Hotchis sways, MREV2 & spacer and a Nismo exhaust. It sounds and handles so sweet! I've kept it N/A because it's apparent the stock rods cannot handle lots of power, otherwise I would consider a supercharger. But I don't want to get into engine removal, breaking the rear end, tranny, etc. It's a very fun car and is deceivingly fast even with these conservative mods. The MREV2 and spacer definately make additional torque you can feel in in normal street driving RPM range. I overkill research before I implement mods, I want to know the good, bad and ugly first so I know what to expect. So, thanks again for your responses and participation on forums like this. It makes ownership of a Z alot better.