dyno results and A/F ratio

[Craig 94 TA GT]

That's a good thought...I'll check on it. However, I think I know what the problem is.
It's most likely #7 that's leaking. That's because when a bolt originally snapped there, I had to drill out and heli-coil that bolt hole. Well, it turns out that the heli-coil might have adjusted some (from constant tightening, untightening), meaning it might be sticking out a tiny bit. So this may be preventing the gasket from seating properly on the head. I'm going to once again remove the header and try to cut off the excess coil sticking out. I'm almost certain that's the problem...but wasn't the problem previously because it was seated fine.
I also closed the cutout and plugged up the left tip with shop towels and saw exhaust coming from the back area of the header. So it's either that, or the EGR as you mentioned.

[Craig 94 TA GT]

Well, I'm about to give up. The heli coil broke and it looks like the threads are probably damaged. I tried a temporary-second-to-last-resort trick. I used SLPs individual gasket and placed it between the missing bolt primary and the Percy, but no luck. My last "cheap" resort is to find some super high temp RTV sealant and stick a bead around the problem area. If that doesn't cure it, it's time to price out one of Lloyd's packages. After all, I'm not going to pull the heads for nothing.

BTW, out of curiousity, can they repair heli-coil striped threads? If the heads are off, is there something like aluminum filler that can fill up the bolt hole...then it can be drilled for a new hole?

[Craig 94 TA GT]

Well, I know the bolt hole is one thing, but I think I have a (another) theory as to why the ticking never got better, nor worse no matter how I tightened it.

This picture shows the flange, where you can see through to the other side: http://s94938520.onlinehome.us/pictures/flange_cuts.jpg

Well, guess what...each gasket, the Percy's and Felpros have port holes that are bigger than the header hole. Here's how I remembered the sizes to be.


So, unless I'm just not thinking straight, the head's exhaust port will spit the exhaust right out of the hole...since the actual seal is past the holes, and not covering them. That's why the ticking wouldn't stop

I know there is no clearance around the bolt holes, so I'm afraid to arc weld it. So I have a temporary fix. I put copper RTV around the flanges, between the "cut" and the inner flange. Then, put some aluminum foil on top of the RTV...since I know the RTV will melt when the 1000+ degree gases directly. I'm for the RTV to cure, then will see from there. Otherwise, I have to take the header back and tell them that the "cuts" or "holes" are leaking.

[Joe 1320]

That is an easy weld, but ultra copper rtv will seal it. I've used it on forced induction motors with a hotter exhaust gas temperature and it seals just fine. btw.... that would definately cause a leak if the weld isn't sealing it from the backside.

[fastTa]

If you use Ultra Copper to try and seal the header, you will kill the O2 sensor on that side almost instantly. Also it is very doubtful that the Ultra Copper will hold up to the temps. I've seen some people use it on header flanges on SBC's, LT1's, and LSx's and it disintegrated in less than 2 weeks. It is only meant for intermittent high heat, not constant prolonged high heat.

Take that header back to the machine shop. They owe you a fix. It needs to be re-welded to properly fill in the cavities, and then re-machined to to be even with the other flanges.

[Craig 94 TA GT]

Hmmm...thats what I was afraid of. They're probably gonna say something stupid like...it had to be cut down that far due to the warping, and it isn't our fault that SLP didn't weld them well. I'll still call and ask. Otherwise, it's time to use the old Lincoln 250/250 arc welder. I'll definitely inspect and plan before the welding starts

I'm curious to know though...why some people have no problems with the RTV, and others have had major problems. It seems like 75% of people, including Joe, said there were no problems. However, the highest RTV out there is the Copper 700*...and the exhaust gases reach, what a constant 1300+? Doesn't make sense to me
I have a feeling my hillbilly job of RTV + aluminum foil + cracks in flanges = lucky to hold for 2 days.

[Joe 1320]

If you use Ultra Copper to try and seal the header, you will kill the O2 sensor on that side almost instantly. Also it is very doubtful that the Ultra Copper will hold up to the temps. I've seen some people use it on header flanges on SBC's, LT1's, and LSx's and it disintegrated in less than 2 weeks. It is only meant for intermittent high heat, not constant prolonged high heat.

hmm.... it's been on the turbo to downpipe connection of my GN since 98 and it still seals.

True..... they should weld it.

[Craig 94 TA GT]

Well, I just started it up after for the RTV under the aluminum foil to cure. No more ticking at all!! I can't believe my aluminum foil/RTV hack job worked. Well, just temporarily. So RTV under aluminum foil won't hold up to the heat either?

[fastTa]

Hmmm...thats what I was afraid of. They're probably gonna say something stupid like...it had to be cut down that far due to the warping, and it isn't our fault that SLP didn't weld them well. I'll still call and ask. Otherwise, it's time to use the old Lincoln 250/250 arc welder. I'll definitely inspect and plan before the welding starts

I'm curious to know though...why some people have no problems with the RTV, and others have had major problems. It seems like 75% of people, including Joe, said there were no problems. However, the highest RTV out there is the Copper 700*...and the exhaust gases reach, what a constant 1300+? Doesn't make sense to me
I have a feeling my hillbilly job of RTV + aluminum foil + cracks in flanges = lucky to hold for 2 days.

The EGT's as measured 3-4 inches from the flange can vary anywhere between 750-1500 degrees F from idle to WOT. EGT's also vary greatly depending on ignition timing, compression ration, and A/F ratio. Normally LT1's are around 800-950 at idle and 1200-1500 at WOT. Suffice it to say, RTV of any kind doesn't stand a chance. I guess 75% of people must have that magical RTV. And like I said before, RTV obviously doesn't belong anywhere near the exhaust of a car that relies on O2 sensors to adjust a/f ratio. Even the supposed "sensor safe" RTV contains small amounts of silicone.

[Craig 94 TA GT]

Since I do have one bolt holding the #7 primary now, I think I'm going to search around and see the best way to go about fixing it. Either ship them to LLoyd or AI and get them fixed (if possible) and P&P, or buy a used set of fully inspected heads, then ship them off to them. Or even buy a used set of fully ported heads.

Meanwhile, the RTV is surrounded by aluminum foil, so in my opinion, if it melts, it has nowhere to go. Meaning it shouldn't (but not saying it's possible) get into the exhaust path into the O2. I hope it can hold for the time being of getting P&P heads, or these fixed and P&P. I did drive it around this morning, and to my surprise, there is no ticking at all. But once the EGTs reach xx amount over xx time, yea I know it's over.

Thanks Kevin and Joe for your help

[Joe 1320]

Meanwhile, the RTV is surrounded by aluminum foil, so in my opinion, if it melts, it has nowhere to go. Meaning it shouldn't (but not saying it's possible) get into the exhaust path into the O2. I hope it can hold for the time being of getting P&P heads, or these fixed and P&P. I did drive it around this morning, and to my surprise, there is no ticking at all.

The aluminum foil trick works, eh?

[Craig 94 TA GT]

Yea Joe, it really works well!

Thanks, bud for your advice. I picked it up from a post you wrote weeks ago. I would have never thought of it