I decided that while my engine was out that I would check the cylinder head studs were free as it was easier to do than in the car. The last time they were out was about 10 years ago and when I refitted them I put Copperslip on them so did not expect any problems. One stud on both banks was stuck fast and ended up with the stud shearing just below the nut. After soaking the stud in all sorts of cocktails it was no further in moving. So I had no option but to twist the heads off thus shearing the stud lower down. The stud would still not hammer out and so I drilled a small pilot hole in the centre of the end of the stud and then redrilled to make a well. Soaked the stud in a pool of penetrating fluid and used an old SDS masonry bit in a hammer drill placed in the well of the stud and after about 30 mins out came the stud. There was no sign of any Copperslip and I think that as the engine got hot the grease melted and found its way round the threads as there was some goo in the thread hole bottoms. The studs that were stuck were held securely by the fragments of copper that remained after the grease had melted. I am thinking of fitting bolts in on re-assembly and taking them out one by one every year to keep them free, that way it should not take any longer than removing the spark plugs.
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An excellent idea Bob, that has to me only one real flaw....
What if during the course of your routine stud maintainence you introduce a fatigue factor and you shear a stud possibly at the bottom end...... a previously useable, reliable engine now needs a majorish stripdown, or are you promoting the yearly replacement of the studs?
A well worn phrase I have always used is "if it ain't broke, don't fix it..."
Russ
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when i get my counsellors permission i will tell you about my stud removal nig.......................................NURSE! NURSE......MORE VALIUM:shock::shock::shock::shock:Comment
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kryten wrote:Hi RussAn excellent idea Bob, that has to me only one real flaw....
What if during the course of your routine stud maintenance you introduce a fatigue factor and you shear a stud possibly at the bottom end...... a previously usable, reliable engine now needs a majorish stripdown, or are you promoting the yearly replacement of the studs?
A well worn phrase I have always used is "if it ain't broke, don't fix it..."
Russ
I was hoping you would reply to this as your experience is appreciated. I was thinking of bolts rather than studs so that they could be removed with a socket. If the worse came and a bolt sheared it would be a head off, but hopefully the seizure would not happen if they did not stay static for too long. Any opinions on the Copperslip?
Bob
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mad cyclist wrote:Permission granted Nickwhen i get my counsellors permission i will tell you about my stud removal nig.......................................NURSE! NURSE......MORE VALIUM:shock::shock::shock::shock:Comment
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Bob
Personally, I'm really not happy with the use of Copperslip in this instance - there is a galvanic reaction between copper and aluminium in the presence of moisture accelerating the white oxide buildup that nips the studs in, and therefore should be avoided as there is very likely to be a small amount of moisture creep in to the space between the stud and head.
You need something non-reactive - I've only ever lightly oiled the studs - and only lightly. Heavy oiling, grease or similar could create a hydraulic effect in the block that would mean either the stud doesn't go fully into the block and therefore is a weak spot for pulling the thread out, could bake in not releasing the stud as grease doesn't like that environment, or with the bolt, could hydraulic lock allowing you to believe the bolt is fully torqued when it isn't.
Russ
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Bob,
I think the idea of using bolts not studs sounds good and I can see your thinking. Please let us (forum) know how it works out.
Ido not think you will need to takethe boltsout every year. I have just taken the heads off to replace a head gasket (rebuilt engine 5 years ago) and the studs and boltscame out, no problem.I would take them out every 3 years.
Regards
Colin
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Thanks Russ, I have got to agree about the Copperslip as it did me no favours and I knew you would have the answer about the chemistry. The answer would probably be to seal the aluminium sleeve that the bolt goes through or to have a better finish on the studs i.e. Teflon. I see that Rimmers do 2 different quality studs now but I can't believe that they sell a better quality product than anybody else,
Colin I was thinking more of a metric year.
Bob
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kryten wrote:Russ,Personally, I'm really not happy with the use of Copperslip in this instance - there is a galvanic reaction between copper and aluminium in the presence of moisture accelerating the white oxide buildup that nips the studs in, and therefore should be avoided as there is very likely to be a small amount of moisture creep in to the space between the stud and head.
My engine was rebuilt at 130,000 miles in 1992. Stud shanks were smeared with copaslip.In 2002 at170,000 milesI had cause to strip it again. Heads came off easily, all studs and bolts came out without fuss. Put it all back together and againcoated the shanks of the new studs and bolts with copaslip. Last year fitted new heads and the same experience.
For me it would be copaslip every time. But not on the threads as this distorts the torque readings.
If worried about galvanic reaction, then Molykote 1000 would be a good option. This is whatis used offshore instead of copper based compounds for flange bolting.
http://secure.silmid.com/varius.engi...&code=LUBH
Search under Molykote Pastes
Dave
Dave
1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.Comment
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Very useful link Dave - a much better solution than copperslip and unlikely to react with anything...... had some bad experiences with copperslip (copaslip) contamination causing all sorts of issues but your Molykote might just be the practical way forward.
Russ
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kryten wrote:i bought an engine off ebay a few years a go and the studs narrowed down in in middle from the thread up, i presume so ther is less in contact with the alloy head.Very useful link Dave - a much better solution than copperslip and unlikely to react with anything...... had some bad experiences with copperslip (copaslip) contamination causing all sorts of issues but your Molykote might just be the practical way forward.
Russ
rgds Nick(2stags)
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What we need to do here is get the studs and bolts made out of Titanium then they will not corrode or react with the aluminium.
The aviation, oil & gas and racing industry uses Titanium fasteners due to the high tensile strength, lightness and it's anti corrosion properties.
I will ask one of my customers how much some would be and what batch sizes he can make.
Stuart
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stustag wrote:I'd definitely be interested Stuart. I'm in the process of rebuilding an engine and need new studs, mainly because the existing ones were renewed about 5 years ago, are inferior quality and snapping :XWhat we need to do here is get the studs and bolts made out of Titanium then they will not corrode or react with the aluminium.
The aviation, oil & gas and racing industry uses Titanium fasteners due to the high tensile strength, lightness and it's anti corrosion properties.
I will ask one of my customers how much some would be and what batch sizes he can make.
StuartComment
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It seems there are different opinions on the use of copperslip, obviously depending on the experiences had.
As I have mentioned on earlier threads I was lucky when I removed my heads that all the studs and bolts came out quite easily, there was no obvious sign that any kind of grease had been used before and only a little white corrosion residue. I don't know how long it had been since the heads were last off so not much help there.
I used copperslip on the new bolts and studs, (nickel plated) which seemed a good idea, at the time at least!
I would be reluctant to remove them again unless necessary, they are supposed to be torqued down in order after all. Also in my case some of the stud holes had been helicoiled and the studs sit at different depths, so I'm not sure about using bolts instead of studs.
This is going to be a really long term experiment Bob!
ZF 4 spd box, Datsun shafts, SS exhaust, 38DGMS weber 158.9bhp, BMW MC Tomcat seatssigpicComment
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Stuart,
I'd definitely be interested in Titanium studs if you were having a batch made up.
Kind regards
Colin
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