cylinder head

[DEmily]

Anyone know if a 1980 xs11 special cylinder head will fit a 79xs11F?

[randy]

Yes.

Randy

[DEmily]

Looking at the list of differences in models it looks like the exhaust valves were enlarged and increased duration. The piston crowns were changed as well. I thought the piston crown change may have been to compensate for the larger exhaust valves. So I guess that is not the case?

I have been having problems getting a cam cap stud to stay in the head I have. I installed a hekicoil and installed an automotive hardened stud, well, at least the parts store called it that. Everything went fine until I started torqueing down the nuts. The stud snapped just before it reached 7 lbs of torque. Had to re move this one and in doing so, I messed up the treads the hekicoil was using. Now the hole is too large to hole the helicoil. I thought about trying JB weld or something like that, but worst case, a different head.

[ratbyk]

Broken Stud

If you snapped a stud at 7 lbs of torque you had better check your torque wrench!
Ken/Sooke

[DEmily]

That was the first thing I though of too. The torque wrench is fine. Had it checked and it was 1/2 lb off at 20lbs. I believe it was a bad stud.

[Geezer]

Originally posted by DEmily
Looking at the list of differences in models it looks like the exhaust valves were enlarged and increased duration. The piston crowns were changed as well. I thought the piston crown change may have been to compensate for the larger exhaust valves. So I guess that is not the case?

I have been having problems getting a cam cap stud to stay in the head I have. I installed a hekicoil and installed an automotive hardened stud, well, at least the parts store called it that. Everything went fine until I started torqueing down the nuts. The stud snapped just before it reached 7 lbs of torque. Had to re move this one and in doing so, I messed up the treads the hekicoil was using. Now the hole is too large to hole the helicoil. I thought about trying JB weld or something like that, but worst case, a different head.

The problem you are having is because you need deeper threads to hold the hardened bolt to full torque. The fix is to stack 2 or 3 helicoil insers in the same hole. It's a little more work but not all that tricky. If the hole is competely hosed, look for something called a "keensert." I'm not to sure of the spelling on that but they hold like hell.

Geezer

[DEmily]

Hey Greezer,

Thanks for the info. When using the Kkeensert, is it neccessary to purchase the insert tool? They are quite expensive from what I found on the web.

[Geezer]

Originally posted by DEmily
Hey Greezer,

Thanks for the info. When using the Kkeensert, is it neccessary to purchase the insert tool? They are quite expensive from what I found on the web.

As I recall the insert tool was an 3/8" American tap but I haven't installed one in 20+ years. Any way you drill and tap the hole, screw in the insert with your fingers then tap down the locking pins with a hammer. You won't find a stronger fix.

Geezer

[DEmily]

I think thats just what I'm looking for. Thanks GReezer. Now I just gotta find out where they sell them at.

[TopCatGr58]

Hey there Dan and Geezer,

I just looked in my copy of MSC Industrial Supply Catalog, and they have a product called a Keylock insert, along with HELICOILS, but nothing called a Keensert/kleensert!?
Their web site is msc web site
Found under Taps/dies/thread repair section. They show stainless steel metric ones(Keylocks) that don't require a special tool for insertion. Inner threads as low as M5x0.8 @8mm deep, M8x1.0 @12mm deep, and other sizes, low as $12.25ea.! HTH?
T.C.

[DEmily]

Hey TC,

Thanks for researching that! I appreciate the info. I will check it out. I did just finish torqueing down the cap and it held. I filled the hole with JB weld Then Threaded in the heli-coils I had left. I then threaded in the new stud into the heli-coils. So the jb weld is on all contact surfaces of everything. It is suppose to hold at up to 600 degrees so hopefully it will stay put. I have used it in many applications but never a stud in an aluminum head. I plan to run it a very short time and pulling the cover again to check the stud. I will be watching it close for a while. If it looks like it is not keeping the torque I will go with one of the inserts you and Greezer have spoke of.