Drilling S3 Cam Cover Bolt (Done)
#16
See attached pics below - thats from getting a water pump bolt out, but same principle. Depending on how deep the sheared shank is, you may even be able to leave a thread on the guide to hold it in place rather than having to use vise-grips.
Just cut the head off an appropriately-sized bolt, leaving enough shank to hold it in place (and possibly a thread or two), then on the bench, center punch it and drill through it.
Then when drilling the first thin hole with the left-handed drill bit (using plenty of cutting oil too), just use the guide to make sure its centered.
Pics attached are:
1. Guide, and the extracted M6 shank
2. Holding the guide in place with vise-grips for drilling
Hilton.
#18
I've got a stupid question. I've removed and reinstalled the valve covers on my '85 5 or 6 times over the years. I've never broken one of those bolts. FWIW, I've never tried to remove the lower portion of the bolts. How do you all keep breaking them?
#19
To the OP. Use one of these and it will save you alot of WYAIT's and fguture headaches. Your problems will be over.
Last edited by Fabio421; 03-01-2010 at 09:55 AM.
#20
Mine appear to have been serviced once and possibly overtightened and/or loctited at that time.
The car then sat 10 years. I was knowledgeable of the potential problem of breakage but despite best efforts one broke.
Also, another one backed-out with the top portion (on the lower passenger side against the firewall).
There was no way to reach the underside with a counterhold wrench. And it wouldn't clear the camshaft, effectively pinning the cover in place. I had to unbolt and move the motor itself. Looks like the upper was loctited into the lower.
Getting them on and off now is easy.
The car then sat 10 years. I was knowledgeable of the potential problem of breakage but despite best efforts one broke.
Also, another one backed-out with the top portion (on the lower passenger side against the firewall).
There was no way to reach the underside with a counterhold wrench. And it wouldn't clear the camshaft, effectively pinning the cover in place. I had to unbolt and move the motor itself. Looks like the upper was loctited into the lower.
Getting them on and off now is easy.
#22
Got the hole profiled better, and about the same diameter as the helicoil drill bit, then ran the Helicoil tap. The oversized tap is shown below, alongside a bolt-sized 6 X 1.0 tap for reference. (I never knew about helicoils till I adopted this sport) . Its not as deep as original, but it's gonna have to do. Am not going to risk StrekStrekStrekStreking it up again.
I realise your post is a few months old. I wouldn't worry about it. The original scenario was a steel bolt into aluminium. hence lots of threads needed as the alu is soft. You now have a steel bolt into a steel thread thus only 5 or 6 threads needed to generate the full strength (or thereabouts) of the bolt. Re the helicoil into the aluminium. The outside of the helicoil is approximately an M8x1 thread thus is 8/6 times stronger than the original for the same number of threads. Combine this with the benefit of not turning a steel female thread into a male alu where the aluminium can be easily damaged/gall etc. I'ld say it is better than the original.
#23
Three Wheelin'
Joined: Dec 2005
Posts: 1,822
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From: In the boatyard installing the mast and engine, we don't need a crane, we harness the mesquito's! Yeah!
#24
Interesting thread.
When I was a young lad learning at "the knee of the master", if you had a drill run off centre at the beginning, get a nice sharpened centre punch and chisel out a small groove on the side of the hole where you want the drill to move towards, and then carefully start drilling and the drill will track towards the centre. If you do it in small incremental grooves you can gradually get the drill to the centre.
The best method is to use a centreing guide at the start.
When reassembling parts I was also taught to apply an "anti-scuffing past" to endure that the nuts, studs etc., are easy to get out in the future. This procedure was "hammered home" even if you knew that you would not be diss-assembling the equipment in the future. Remember do not use carbon based products on aluminium.
Easy outs are a pain if they fracture, as described above. Heat, penetrating fluid and if necessary "freezing" and especially left handed rotating drills are all good method to get broken studs out.
Tails 1990 928S4 Auto
When I was a young lad learning at "the knee of the master", if you had a drill run off centre at the beginning, get a nice sharpened centre punch and chisel out a small groove on the side of the hole where you want the drill to move towards, and then carefully start drilling and the drill will track towards the centre. If you do it in small incremental grooves you can gradually get the drill to the centre.
The best method is to use a centreing guide at the start.
When reassembling parts I was also taught to apply an "anti-scuffing past" to endure that the nuts, studs etc., are easy to get out in the future. This procedure was "hammered home" even if you knew that you would not be diss-assembling the equipment in the future. Remember do not use carbon based products on aluminium.
Easy outs are a pain if they fracture, as described above. Heat, penetrating fluid and if necessary "freezing" and especially left handed rotating drills are all good method to get broken studs out.
Tails 1990 928S4 Auto
#25
When I refinished my cam covers last year, 175K on the engine never opened, I bought the newer bolts and was going to replace the two piece design., All the original bolts came off without a hitch, tried to loosen the first stand off piece from the head. It wouldn't budge, so thought the better of it, left them alone and sold the new style bolts. Used anti-seize on reinstall and shouldn't have any problems when I have to remove them again in 175K miles.
#26
A few notes on this.
If you have broken off bolts get the proper tools for removal.
I use the following extractors, and have never broken one,
All of those are IRWIN in the pictures, I also use craftsman.
Although my first choise is to weld on them as the heat helps to break down the bond.
That said the 2 piece bolt design shown by the OP is not a good one. I would strongly recommend that if you break one of the 2 piece, or need to remove the base that you buy new (upgraded from Sharky) style bolts.
On the same hand, if you need to remove them, use a small propane, or butane torch and heat the area up around the bolt BEFORE attempting to undo it. Do not heat the bolt, just the aluminum casting.
Then use a small electric or air, LOW POWER impact driver. The repeated hammer motion is much easier on the bolt for getting it out.
And again if you remove the early style bases (85/86) then throw them away and buy the new style bolt.
I have yet to get any left hand drill bits, but I will be getting some soon.
If you have broken off bolts get the proper tools for removal.
I use the following extractors, and have never broken one,
All of those are IRWIN in the pictures, I also use craftsman.
Although my first choise is to weld on them as the heat helps to break down the bond.
That said the 2 piece bolt design shown by the OP is not a good one. I would strongly recommend that if you break one of the 2 piece, or need to remove the base that you buy new (upgraded from Sharky) style bolts.
On the same hand, if you need to remove them, use a small propane, or butane torch and heat the area up around the bolt BEFORE attempting to undo it. Do not heat the bolt, just the aluminum casting.
Then use a small electric or air, LOW POWER impact driver. The repeated hammer motion is much easier on the bolt for getting it out.
And again if you remove the early style bases (85/86) then throw them away and buy the new style bolt.
I have yet to get any left hand drill bits, but I will be getting some soon.