Thread Inserts Question

Did a couple of Helicoil 6mmx1mm inserts last night. I had previously stripped a couple of the Cam Cap holes and chose at that time to overtap to 7mmx1mm and use the slightly larger bolts. Anyway, have now put inserts in those two holes to bring them back to 6mm.

Here's the question(s). 1) Owing to the fact that the inserts are so straight forward to do, should I do the other 14? 2) Is the 12mm long insert I'm using going to provide sufficient thread for the cam cap bolts to bear on?

Thanks.

the bolts thread down 5/16-3/8 on origional holes that should be pretty close to 12mm im thinking. goodluck,happy wrenching!

Wire, thanks. At 12mm, I've got just over 7/16" of thread so it sounds ok. I might even just chase in a 6mm long insert behind the 12mm to be on the safe side. Thanks again.

ive got inserts in mine never had any problems .

Mine all have inserts.

Everyone using 12mm or 1/2" (ish) inserts?

I used 9mm for some and 12mm for some. Would not do if not stripped. Did run a 6mm tap down other holes and made sure cap bolt would go in by hand to about a turn more than it's installed length. This way I knew I was torqueing against the cap and not a load of crap in the bottom of the hole.

FWIW: The Suzuki manual for the GS1000(kz1000 copy says to clamp the camshaft in place with long nose vice grips before removing or installing the caps.

-Duck

Did the remaining 14 inserts last night, all with 12mm long inserts. Took 3-4 minutes each, very straight forward. Thanks everyone for the help and advice.

This is very interesting to me. I had all of my old cam cap threads replaced with "nutserts" way back when I first had my motor built. My old engine builder always installed them because he was sure they would eventually strip since the cams have to come out to adjust valves (shim under bucket). Anyway, I never had a problem with those, and now I am having another head done (porting, larger valves, etc..) and the new engine builder says they will never strip if you are careful with torque. I had asked him about installing "preventative" inserts and he said a definite "no". So there you have two very experienced builders with totally different opinions. My little brain says to go with the inserts.

Post edited by: 79MKII, at: 2006/03/08 22:09

The problem as I see it with the second builder's opinion is that you have to be absolutely sure that all POs actually DID torque the bolts correctly. Not a bet I'd take.

If the POs DIDN'T torque them correctly, the aluminium English) thread in the head WILL be stretched.

The reason I did all mine was because, although I was VERY careful to torque mine correctly the last time I did the job, I still stripped two of them. At that time I decided to over tap them to 7mm x 1mm. My thinking was that at some time in the future (now) I would still have enough "meat" left in the head to do the inserts.

Just my $0.02 worth.

As I already have a couple of stripped threads and the engine is out and apart, can you describe how you did this with a list of tools and parts? Thanks!

LetTheGoodTimesRoll, The most painfree place to start is to purchase a "HELICOIL" kit for 6mm x 1mm. You will need to purchase extra 12mm long inserts at the same time because the kit doesn't have enough to do the whole job. The kit includes the required drill bit, the required tap and the insert "wrench/tool/inserter".

Best way to proceed is with a naked head, all the valves etc removed. The dill shavings will be difficult to contain otherwise. Ideal if you have a drill press but not absolutely necessary.

Blow out each hole with carb cleaner and air, to get all the crap out, before you drill. You are then going to drill each hole with the bit provided in the kit. If you're not using a drill press, keep the bit totally perpendicular to the head, don't let it wiggle. Be EXTREMELY care full to dill to the full depth of the existing thread but DON'T drill through the bottom of the hole. If you do mistakenly drill through, some of the holes can be repaired using JB Weld.

Blow out the newly drilled holes again with carb cleaner and air.

Take the TAP (You'll need a small tap wrench with which to rotate the tap)and carefully rotate it in each new hole to cut you a new thread. This is pretty straightforward but you need to take your time. try to follow what is left of the old thread that's left in the hole. The pitch of the thread insert is of course still 1mm.

When tapping new threads, I tend to do maybe 1 complete turn with the tap then back it out. Then go back in with another complete turn then back it out again. At each backout, spray the accumulated swarf (aluminium cuttings) from the tap, with WD40.

Don't lean on the tap too heavily, just kind of "help" it find it's way with minor pressure.

When all the new larger threads are cut agaim clean out the new treads with carb cleaner and air.

Put a 12mm long insert on to the insert tool and screw the tool into the insert until it "locks" with the tab at the bottom of the insert. Insert the tool & insert carefully into the newly drilled hole and carefully screw down into the newly cut thread. Make sure that you end up with the top of the insert no higher than the top of the newly cut thread. If when you first screw in the insert, you back out the tool and find the insert isn't in far enough, you CAN screw the tool back in and wind it down a little further.

I tend to use a dab of Locktite on to outside of the insert.

Make absolutely sure you clean the head thororly when you're finished, you don't want a bunch of swarf all over the place.

Hope this helps you. Take your time and you will be surprized how well you will do. I think the job's worth doing. Good luck.