Preparation of surfaces for head gaskets

[TJ 450]

I'm a few weeks away from bolting the reconditioned heads onto my 450's M117.

In preparation for this, I've got together a set of good bolts that have been thoroughly cleaned. Could there be any issue with reusing these standard high tensile bolts? I wouldn't have thought so, unlike those stretch bolts used on the all-alloy engines.

Also, I've cleaned the block surface with a razor blade and degreased... is a perfectly smooth surface required here, machining marks aside? Would there be any other treatments required?

Tim

[goldacre]

Hi TJ 450, i remember my Brother-in-law re doing a head on a Holden Astra and the problem he had was they shaved more off the head when they rebuilt it than they told him, ran like a pig until he did a compression test and got the right gasket.

Apparently there are a variety of head gasket thicknesses for some model cars to compensate for thickness lost in the head being shaved and this maintains the correct compression ratio as some cars EMC are designed for exactly that compression.

Wouldn't think this will be an issue for our 116s as i do not recall seeing a variety of head gasket sizes on AutohouseAZ and our cars fuel system is pretty robust.

Thats the only trap i know of regarding cylinder head replacements 

G

[WGB]

Hi Tim,

I think the modern head gaskets do a very good job and you should expect little trouble if the heads and decks are true.

If you really want to be totally anal a bolt re-tension after a few hundred Kays might be worthwhile.

Bill

[s class]

Make sure the threads of the bolts and the bolt holes are clean, otherwise the tightening torque of the bolts will not translate corretly to the required clamping force. 

[koan]

Make sure the threads of the bolts and the bolt holes are clean, otherwise the tightening torque of the bolts will not translate corretly to the required clamping force. 

What about lubricating threads, that affects where the torque "gets used up" as well. Should have a look at the manual to see what it says.

I used nickel anti-seize on threads of the head bolts as some of them were well on the way to seizing, also replaced all damaged and rusted bolts.

koan

[Nutz]

Hylomar Universal Blue Racing Formula Gasket Dressing is a must.

[s class]

Make sure the threads of the bolts and the bolt holes are clean, otherwise the tightening torque of the bolts will not translate corretly to the required clamping force. 

What about lubricating threads, that affects where the torque "gets used up" as well. Should have a look at the manual to see what it says.

I used nickel anti-seize on threads of the head bolts as some of them were well on the way to seizing, also replaced all damaged and rusted bolts.

Yes koan.  Maybe I didn't word it correctly.  The correct procedure is to clean the threads to ensure no debris, and then lightly oil them immediately prior to fitting the bolts - usually - so check the procedure for the engine concerned - it will probably give torque values with a foot note saying its for lightly oiled threads. 

koan

[TJ 450]

Excellent. It sounds like I'm on the right track then.

Thanks for the info.

Tim

[TJ 450]

BTW, the manual says to lubricate the bolt threads with engine oil prior to assembly.

Tim

[Ryan1980]

certainly no problem with my 450 after we replaced the head tim!

[TJ 450]

That's a good indication Ryan, although it is worth noting that your engine was very clean to begin with. All it needed was a degrease and some fingernail scraping and the head was ready to bolt on.

This engine block had chunks of corrosion and gasket remnants, as the heads haven't been off since day one. I reckon the razor blade has done the trick, though.

Tim