I'm replacing some of the tension bolts in my rebuild, I mistakenly ordered ribbed bolts for the replacements and noticed how different they are from the 'smooth' bolts my S4 had... It appears these ribs have been added to help tolerate vibrations, after doing some research I found this web page:



tension bolt info



Do any of you coat your tension bolts with RTV when installing as racing beat recommends? What about using thread-lock on the threads to help prevent them from walking out from vibrations?



Any reasons to chose the S4 bolts over S5? It looks like the ribs could weaken the bolts.

My 13BT has the ribbed bolts, and I've never had any problems with them. You'll need to be making SERIOUS power before you ever have to worry about tension bolts. I've never used silicone on the bolts, but I know people who use ATF.

Do you use the engine oil on the sealing washer and threads like the shop manual says?

The guy at T&R who helped me put my motor back together used ATF. He likes it better than motor oil. We didn't use any silicone on the bolts, but it's a good idea to do it if you want to.

That is what I did, and mine is running just fine.

How is your engine running btw? Are you done with the break-in period yet?

It is running really well, I only have 800 miles on it so, I am not done with the break in peroid yet. I am not taking it past 4000rpm. The motor is running really strong though. It pulls really hard from 3000 to 3500(were I have been shifting) and that isn't even at half throtle. I am really happy with mine, and I think you will be with yours too. https://www.nopistons.com/forums/pub...#>/biggrin.png

i dont think they did it for power i think they did it to tune out an rpm related resonance in the bolts. the ribbed ones are better, but ive nver had a problem and ive had my smooth bolt motor well over 8500 and many several occasions with no problems



mike

I just heard back from my crack dealer (henry over at mazdatrix), here is what he had to say regarding the tension bolts:



The reason for the ribbed center part is that at high RPM's 8+ the tension bolts can get harmonics which would sometimes snap the tension bolt and then it would fly out towards the flywheel and cause big problems. It is a safety precaution. For your application I would use all ribbed bolts.



So, I'm being a good addict and ordering 16 more ribbed S5 tension bolts.

I've heard the ribbed ones are mainly for HER pleasure.