Loctite on head bolts?

[ian_uk1975]

Thinking ahead (no pun intended) to when I re-install my heads, should I use Loctite on the head bolt threads? I've read that thread sealant should be used on any head bolts going into a water jacket. Just for 'belt and braces', is there any problem in using sealant on ALL head bolts? If not Loctite (542), which sealant would you recommend?

Cheers,
Ian.

[ian_uk1975]

Originally Posted by ian_uk1975

Thinking ahead (no pun intended) to when I re-install my heads, should I use Loctite on the head bolt threads? I've read that thread sealant should be used on any head bolts going into a water jacket. Just for 'belt and braces', is there any problem in using sealant on ALL head bolts? If not Loctite (542), which sealant would you recommend?

Cheers,
Ian.

I should add the engine in question is a 350 Chevy.

[Sidecarbod]

I don't have a clue about your engine but I do know that what you put on the threads will effect the torque reading so you would be wise to wait for someone to confirm what you should do.

(Even if you are using stretch bolts they have an inital torque setting so you do need to know for sure)

Pete

[ian_uk1975]

Originally Posted by Sidecarbod

I don't have a clue about your engine but I do know that what you put on the threads will effect the torque reading so you would be wise to wait for someone to confirm what you should do.

(Even if you are using stretch bolts they have an inital torque setting so you do need to know for sure)

Pete

Thanks Pete. I believe Loctite (or similar) isn't particularly viscous, so shoudn't affect the tightening torque significantly. If thread sealer wasn't being used, you'd probably dip the head bolts in engine oil anyway.

Cheers,
Ian.

[keane]

Ian, dont loctite the head bolts, torque them to the recommended figures and then when the engine has been run up/settled down you can check the bolts again, chances are you will have to retorque a couple which will be a problem if you use loctite, re water jackets I believe a some suitable rtv will suffice, I'm sure there will be more advice shortly. Dave

[ian_uk1975]

Originally Posted by keane

Ian, dont loctite the head bolts, torque them to the recommended figures and then when the engine has been run up/settled down you can check the bolts again, chances are you will have to retorque a couple which will be a problem if you use loctite, re water jackets I believe a some suitable rtv will suffice, I'm sure there will be more advice shortly. Dave

Thanks Dave. Bear in mind the Loctite I'm on about is a thread sealer and not a thread LOCKER. I've seen it advised not to use RTV on head bolts. I must admit, I've done several top-end rebuilds on 4-pot engines in the past and have never used anything on the head bolts and never had a problem. However, I want to follow 'best practice' on the SBC if I can.

Cheers,
Ian.

[Lloyd Barnes]

All the stuff I've read on chevy's recently has been categoric about the need to use thread sealer on the water jacket bolts. If its best practice your after then real steel do some ARP thread sealer specifically for this job. Otherwise one of the books I have also suggests RTV would be ok.

[wilf]

Can't recall if head bolts actually do enter water galleries on the sbc - they don't on a Ford sb, apart from 289s/early 302s from memory.

Once you have a head off it will be readily apparent if the head bolt holes are blind or open to the the water galleries. If the former, you won't need any sealant.

Oops - posted almost at the same time as Lloyd!

[Lloyd Barnes]

Hi Wilf

a fair few of them go straight into the jacket. As you say with the heads off its easy to see which.

Just reading the page in question they suggest sealant on all the bolts, perhaps to equalise the torque settings?

[ian_uk1975]

Originally Posted by Lloyd Barnes

All the stuff I've read on chevy's recently has been categoric about the need to use thread sealer on the water jacket bolts. If its best practice your after then real steel do some ARP thread sealer specifically for this job. Otherwise one of the books I have also suggests RTV would be ok.

Thanks Lloyd... looks like the ARP stuff is the way to go. The page on Real Steel specifically states it's for use with SBC head bolts, so that answers the question

Cheers,
Ian.