Which would you do? 8mm rockers or 10mm

[3400-95-Modified]

So I have a second set of 3500 heads and with everyone having rocker issues and loosing threads I was wondering what you would do if you were me... Now I already had issues on the exhaust threads on my current set of heads and I heli-coiled them and everything has been great since then. So the question is, do I just heli-coil the 8mm threads in the heads for the rockers and keep using the same style of rocker and just know that I shouldn't have a problem... OR do I heli-coil them to use the 10mm rockers?

Is there any proof that either set is any stronger or reduces deflection?

[Superdave]

who is everyone? I've only heard of it actually happening once or twice..


Mine have always been fine with just some red loctite on the threads.

[3400-95-Modified]

I've just seen it posted 3 or 4 times and a few posted stuff over on bnet... I was just wondering if it was worth the time to heli-coil them since I did have issues with the exhaust threads from going in and out with bolts. Also I was just wondering if there was any benefit in the 10mm ones over the 8mm.

[ForcedFirebird]

If you want piece of mind, just coil the 8's. I have never had an issue but have seen heads pulled apart that looked like the were tightened too much or partially cross threaded. As long as you follow procedure, I don't see an issue with 8's unless the threads are already damaged.

Not as bad as cracked upper manifolds, though, lol. I think some people might be using an impact or breaker bar to tighten them. We get cracked ones all the time, and even sometimes people buying ported and cracking them on install

[MidnightriderZ24]

If you want piece of mind, just coil the 8's. I have never had an issue but have seen heads pulled apart that looked like the were tightened too much or partially cross threaded. As long as you follow procedure, I don't see an issue with 8's unless the threads are already damaged.

Not as bad as cracked upper manifolds, though, lol. I think some people might be using an impact or breaker bar to tighten them. We get cracked ones all the time, and even sometimes people buying ported and cracking them on install

have a machine shop install time-serts. i did mine myself with the parts and tools from work, more work and money but if u drop big money on heads its worth looking into with higher spring pressure and rpms.

[ForcedFirebird]

have a machine shop install time-serts. i did mine myself with the parts and tools from work, more work and money but if u drop big money on heads its worth looking into with higher spring pressure and rpms.

Time-Serts trump helicoils for sure, but aren't as easy or cheap to install for a DIY'er. The late nicksil BMW blocks use Time-Serts once a HG is blown, have one at the shop needing them now.

[Superdave]

I'd personally rather stick with 8's and use an upgraded ARP stud. Time-Serts look cool though.

[TGP37]

If you want piece of mind, just coil the 8's. I have never had an issue but have seen heads pulled apart that looked like the were tightened too much or partially cross threaded. As long as you follow procedure, I don't see an issue with 8's unless the threads are already damaged.

Not as bad as cracked upper manifolds, though, lol. I think some people might be using an impact or breaker bar to tighten them. We get cracked ones all the time, and even sometimes people buying ported and cracking them on install

All hail the mighty torque wrench! I bought a nice one and treat it like gold.

The thought of an impact on the plenum is like OMG. After tightening I could see the plenum lift right up, bolts and edges left behind......that'll be a funny pic.

[3400-95-Modified]

I may go with Time-Serts... they don't look any harder to install vs helicoils.... the only extra step I see is the countersink. Kit is only $67 with 5 inserts.. Just gotta check the length but they seem to be about $1.38 each depending on how long you need, so max could be around $17 for the inserts. Honestly that's not that expensive when a heli-coil kit runs $25

Dave, there are upgraded ARP rocker studs available?

[Superdave]

No idea, I don't have any around that i could measure... maybe Ben does.

[3400-95-Modified]

Oh, by the way you replied I thought maybe you knew of a set that worked already. I'm sure we could find something to fit. But I don't even know how to remove the bolt from the rocker... I'm guessing its just a shoulder somewhere down below holding it in, but I've never tried to pull one apart.

[ForcedFirebird]

Once you have the rocker removed from the head, the bolt will thread out of the fulcrum.

[3400-95-Modified]

good to know.. never really tried it, I didn't think it would be that easy.

[bob442]

piece of mind 10mm, my stock 8mm had no play in them, and they ended up causing some valve train noise...somehow, i swapped to some 10mm's i found at the wrecker, quite now, maybe it had to do with some deflection, maybe not, but the 10mm bolt is larger, so no need for ARP bolts (IMO) and you have to drill and tap for helicoils anyways, so go get some 10mm rockers and never think about it again.

My 8mm never stripped out, but i never over tourqe'd them, i have fixed 2 cars with stripped out threads on 8mm rockers. one of which was over tourqe'd for sure as 2 rockers were already heli coiled

[3400-95-Modified]

Well my only issue with that statement is I am currently running 8mm rockers and never had any noises or issues like that... I'll probably just do the Time-Serts and be done with it.