[Half-Inch Stud]

Originally Posted by BruceWilkie

related to heat and need to retorque... I Thoughts???...Maybe kills the studs before the gasket dies ???

Well, I've NEVER re-torque Head-Bolts on a hot-run engine because I figure the organic gasket material is at it's softest, unfair to re-TQ while HOT. In fact I'd be scared to re-TQ while HOT.

Corollary: Re-torque after a complete cool-down sounds fair game. (if we Monk-like about it, not to cavalier).

[twinturrbo406]

... here are our Tiger heads with the insert ... it has turned out really nice and the surface is seamless ... it is a bit tricky blending the inserts by hand, as you are literally hovering over the alloy seats with a carbide-burr (()) but it is a slow process ... and based on the results of the others engines we've seen using this mod, i see no reason why it wont work as intended for these heads ... and it also makes for a very nice "repair" for any heads that have had any issues in this area, regardless of make ...

[Robert C.]

Very nice work.

[rompn63]

Glenn just called me this morning and said my Tigers are ready. I'll pick them up Tuesday and have them on by the weekend.

[60man]

Originally Posted by twinturrbo406

... here are our Tiger heads with the insert ... it has turned out really nice and the surface is seamless ... it is a bit tricky blending the inserts by hand, as you are literally hovering over the alloy seats with a carbide-burr (()) but it is a slow process ... and based on the results of the others engines we've seen using this mod, i see no reason why it wont work as intended for these heads ... and it also makes for a very nice "repair" for any heads that have had any issues in this area, regardless of make ...

Looking good ....Question....any thoughts on adding the additional water hole/passage above center bolt...AKA: 421 mod..?? Is it possible with insert..Would it help prolong gasket life even more ??
Would like to hear Calvin's & Glen's opinion ..Thanks

[Glenn Sedig]

Originally Posted by 60man

Looking good ....Question....any thoughts on adding the additional water hole/passage above center bolt...AKA: 421 mod..?? Is it possible with insert..Would it help prolong gasket life even more ??
Would like to hear Calvin's & Glen's opinion ..Thanks

I think extra water can't hurt. I would put the hole under the insert unless you can hit the radiused end of the insert dead center with the drill bit. The insert is tough enough that if you don't hit center the drill will wonder off to the side. Also the amount of press fit on the ends of the inserts has been calculated to stay pressed at temps up to 600 degrees even with the different rates of expansion. Drilling the into the ends would give less area of contact for the press.

[BruceWilkie]

Originally Posted by Half-Inch Stud

Well, I've NEVER re-torque Head-Bolts on a hot-run engine because I figure the organic gasket material is at it's softest, unfair to re-TQ while HOT. In fact I'd be scared to re-TQ while HOT.

Corollary: Re-torque after a complete cool-down sounds fair game. (if we Monk-like about it, not to cavalier).

The heck with the organic gasket material... my own organic material is is peril when things are hot. I havent used header gaskets in 20+ years. (hi temp red only) Used to think it was bolts backing out. Safety wire proved otherwise.(safety wire skill well learned when learning aircraft maintenance) Cured rtv only compresses to a point and I use a pretty thin amount. Only enough to fill voids and have enough stretch for expansion/contraction cycles. So... after figuring out the bolts arent turning and sealer containing seal and not leaking.(Debs street car 8 years as of last month) The bolts are stretching after heat/cool cycles??? Then hit point where they no longer stretch? Or hit point where expansion contraction equalize? Cant be rtv as it would have "glued" like loctite and not allowed much if any movement in first place and once disturbed from "sealed" would stay "loose".

Only talking header bolts or studs here and I've never put a tq wrench on them(ever in my life). Probably will If I ever need to remove them. Hmmm maybe I'll go loosen one later and see what break-away torque is then retighten to same tq. Check tq again Sunday night. Maybe learn nothing or something.

Just have to wonder about thermal cycles on heads/block/gasket/fastener. At what point do gaskets stop crushing? Heads too? What happens to fastener that is constantly heat cycled? Lose temper? I cant see how it could help itself.

Seems good maintenance to check fastener torque though.

[Half-Inch Stud]

Originally Posted by BruceWilkie

...Just have to wonder about thermal cycles on heads/block/gasket/fastener. At what point do gaskets stop crushing? Heads too? What happens to fastener that is constantly heat cycled? Lose temper? I cant see how it could help itself. Seems good maintenance to check fastener torque though.

Wonder no more: Rod bolts, Main Cap bolts, balancer bolt, rocker studs always show excellent break-away torques. No gasket, so you know the thermal cycling does not relax/ yield the fastner nor item fastened.

Head Gasket material is relaxing. Clarity is a good thing.

[Glenn Sedig]

Put 13 more runs on the heads with the inserts for a total of 21 runs. Leak down is

1----90%
2----94%
3----97%
4----99%
5----99%
6----99%
7----95%
8----98%

Don't know whats up with cyl 1, Set the car up with alcohol and had problems all weekend. Maybe the cyl got washed down before we tested it. Also the motor was cold.

Alcohol runs cooler so I don't know if the insert life will be tested with the same stress as with gasoline. We have done a set of heads for a nitrious engine so may be able to get some info on that when it is back together.

So far the inserts in my heads are holding well.

[Jeff Kinsler]

Originally Posted by Glenn Sedig

Put 13 more runs on the heads with the inserts for a total of 21 runs. Leak down is

1----90%
2----94%
3----97%
4----99%
5----99%
6----99%
7----95%
8----98%

Don't know whats up with cyl 1, Set the car up with alcohol and had problems all weekend. Maybe the cyl got washed down before we tested it. Also the motor was cold.

Alcohol runs cooler so I don't know if the insert life will be tested with the same stress as with gasoline. We have done a set of heads for a nitrious engine so may be able to get some info on that when it is back together.

So far the inserts in my heads are holding well.

wow, 99% so thats 1% leakdown?? did not know that was possible.i wish my motor would do that, it does not even do that when everything is new..you guys must have some secrets!! i have never seen any e.t on the track from minimal leakdown to up to 20 % leakdown in the center cylinders. Bruce Michale's old pontiac motor was the same way he changed head gaskets at 20% leakdown and never even saw it at the track...
guess it all depends on where the air is going...
glenn, hope you get the alcohol tune up fixed.