JMortensen

Put a couple old valves in the chamber, that will keep damage to the seats to a minimum. As far as how far to unshroud, get the head gasket that you're going to run, put it on the dowels on the head, and scribe a line around the valves on both sides. That line then becomes your limit. Go past the line and you'll expose the underside of the fire ring, and then you'll blow the gasket. So work your way out to the line carefully, and if you're feeling really cautious leave a little margin between your scribed line and the edge of the chamber when you're done. As far as how to blend the seats with the roof of the combustion chamber, I tried to minimize the triangular shaped bumps between the intake and exhaust seats. You can also eliminate all of the casting marks around the valve seats, my E31 had a ring around each seat maybe 3/16" outside of the seat itself. You can transition that ring into the surrounding metal to make it nice and smooth. You should also grind away any excess spark plug threads that may be exposed. Get the How to Modify book, and study the pictures HARD. Be careful, and take it slow and you'll do fine.

Well to be honest I think my car was faster at autox with the SUs than it was with the Mikunis, but that was because I had 3.70 gears at the time. SU's would be a last resort, but it is still a possibility if all else fails. Don't tell me the PO of your old car bondo'd the weld joints!!! Man, that'd be about the time I went looking for another shell. I don't think these gussets are large enough to use in the main hoop to halo junction. I could do a bar there instead. I'll have a look at that area. I think I'm going to use them in the diagonal for the main hoop, and maybe see if I can use them here and there. I'd like to get 3 spanning the V to dash bar junction.

Thanks for the pics Steve. After seeing those pics I'm pretty confident that the triples will work, I just may have to go to the Mikuni manifold, and I can't move my engine back. I'm already running a cable. I'll probably just run with no air cleaner since the quicker this engine goes bye bye the quicker I can justify the swap. Anyone have an opinion on the tiny gusset issue?

Looking at the Frisselle pics again I think he raised the carburetors (or rather raised the ports in the head and tilted the intake manifold to get a straighter shot at the port). I understand this was pretty commonly done back in the day, I know it's discussed in the How to Modify book. Anyway, fingers crossed that it will fit as is without any mods or different manifolds, etc. It's going to be close... I went up to Joe's this morning and got 20 gussets. Pretty cool place, they make everything in house, they have a full machine shop and a NASCAR style car. Looked like there were about 10 employees total. Very friendly people. I got to take a quick look at their race car, it was pretty impressive. Anyway the gussets are tiny! I think about the gussets that you commonly see like in the back of a Coleman catalog and they are probably about the same, but these are taco gussets. Maybe this is all you need... I dunno, they just look so small...

It's an I6, until I blow it up, then I'm going to swap in an LSx. I've seen other cars with the intake in place that cleared a bar similar to mine. If I have problems I might have to get a different intake manifold or something like that, but I'm hoping that I don't have those issues. I just went out and took a look and it appears that there may be a fitment issue there. I've got some options (shorter intake manifold, lower the engine, etc) and I'll see how bad a problem it is. If it's really bad I'll just prepare for the swap...

We'll see how my car fares on the scales, but I don't have too much more than your standard 6 point ITS style roll cage in mine and those guys get down to 2250 if I remember correctly. I have a pretty standard ITS cage built roughly off of katman's article from way back when. He says 65 ft of tube in his cage, and that should weigh in at ~104 lbs with 1.5 x .120 DOM, but I used heavier 1.75 x .120 wall tubing that should add a little weight (+31 lbs at 1.59 vs 2.08 lbs/ft). I also added subframe connectors (+12 lbs), the X from the strut towers to the rockers and weld in strut tower bar (+10 lbs) and the V from the strut towers to the dash bar (+8 lbs). The extra bars in the cage were done with 1.65 x .065 DOM @ roughly 1lb/ft. In addition I removed the dash and heater box, so I'll get some weight back vs the ITS car. By my rough calculations it looks like I should be adding ~165 lbs to the bare chassis, which is a 1st generation Z and people have gotten these things under 1900 lbs race weight. I know that bj's car was built with a similar intention for low weight to mine, although I can't say for sure how much his car should weigh vs the ITS machine. I know he has gone a bit nuts with the hole saw in the quest for light weight, so I can't really factor that in. BJ, did you save all your little disks you cut out to weigh them??? All I can say is if my car weighs more than 2500 lbs when I get done with the engine swap I'm going to bust out the sawzall and get rid of some weight!!! I'm expecting something like 2200 lbs with the 6 in there, give or take. I'd like it to be less than stock with the V8 when that eventually happens, but the 6 will be in there for a while I'm afraid. The goal IS low weight. That IS what makes these cars so potent on the road course.

I'm pretty sure the casting is the same. Most USA P90a heads got hydraulic lifters. Some got mechanical lifters. I think all imported P90a have solid lifters. The questions that surround the P90a heads have to do with how large a cam they can cope with and the possibility of having to replace expensive lifters when they go bad. Search some more and you'll find threads on all that stuff. There are also threads on converting the hydraulic heads to solid lifters. Search "timesert" for that...

I just ran out of welding gas... damn it!!! Well, I guess that means its time to give an update. I've welded the .060" plates to the firewall. I didn't have to make them really grossly huge to cover the gaping holes I cut, they're only 6" x 5". Also added some gussets to the windshield area. 4 gussets in the corners between the dash bar and the A pillar bar and the halo, all about 6" long or so. On the inside I was trying to do 3 pieces, a middle and two sides that would cover everything. I found that I had a very hard time making the middle piece fit the tubes correctly, so I ended up doing a 5 piece setup with a wide center piece and then 2 pieces on each end that fit the tube. I was about 3/4 done welding the sheetmetal patch to the cowl when I ran out of gas. I'm going to have a lot of seams in there, so I figure I'll seam weld the interior, and then use seam sealer inside the cowl box to finish it off before painting. This inside bit is a real PITA. Maybe its just me, but I have a really hard time making the cutout bit fit tightly around the tube, and my spacial reasoning is a bit lacking here too. I kept trying to put the patches around the tube upside down...

After reading some of the threads on stainless I think I would try it with a mig. I'd just get 100% argon (seems to be the recommended gas for mig and stainless) and take it slow. I guess the question is how perfect does it need to be? Yours is a race car, so I'd figure if it doesn't leak that's the important thing. I have actually welded stainless to regular steel on accident with a 220V Miller and I had no idea that it was stainless until the guy who was loaning me the welder told me. Welded just like regular metal in that limited experience. Probably did 20 welds like that, they all came out fine. Also with regards to the MM and sheet metal welding, I usually run my 135 between 2.5 and 3 on the voltage and 25 to 35 on the wire speed and I can run a nice bead on sheet without blowing through. I wonder if you might be doing something else wrong that was causing your previous blow-throughs, like maybe pointing the wire directly at the work instead of coming in at an angle...

Last time I bought them I don't think there was a Kevlar option. They were just metal masters. Definitely not the organic ones. I think Axxis had organic and metallic back then. It was the pad that Nissan Comp used to sell, and man did it suck.

Metal Masters have to be the worst "performance" pad on the market, in my experience anyway. They consistently warp rotors and I had a brand new set that was properly bedded in start chunking in 5 laps. Had decent luck with the R4, but it's not really streetable IMO. The R4S is good for autox but that's about it. There is a pic in my gallery of the R4S pad I punched a hole in after the lining either detached from the back of the pad or got totally burned off at a track day. My next set is going to be either Blacks or HP+ pads, still not sure which. I think I'm going to be autoxing for a while so I'm leaning towards the HP+. Coffey used Blacks on the ROD and he had smaller brakes than I've got so I doubt I'll ever need more than the Blacks. From the reports my friends have given me the blues really eat rotors, although they work good if the pad temp is way up there...

Alright, I emailed Cary about this, he gave me some info and I made a decision as to the A pillar bars. I'm not going to do the additional braces. As Cary pointed out, it's a bit redundant with the upper frame rail doing basically the same thing, and I've already reinforced the upper frame rails, so I think it's not going to be worth the effort. So today I'll finish welding the strut tower V and start patching. FWIW I looked at the Frisselle car pictures and it's tough to see exactly what is going on because the dash covers up the cage where it comes through the firewall, but it looks pretty bizarre. It's not even close to the same on the driver's and passenger's sides of the car. I guess it worked, and to some degree you can't argue with success, but it's pretty funky...

Put a spacer under the shorter insert. It shouldn't be very difficult to make a spacer, just find an appropriate sized piece of tubing and cut to the correct length. That welded gland nut sounds pretty scary... makes me wonder what the rest of the car is like.

Looks like you're doing a really nice job with it. You might consider making the center part removeable so that if you have to drop the trans out you don't need to take everything from the header on back out.

That's called "lucid dreaming" and you can actually train yourself to do it. Pretty cool stuff. I had a friend who was pretty into that whole thing read books and all that crap.

If you're running on the ragged edge and need to know EXACTLY what the a/f ratios are, get the wideband. If not, the narrowband will get you in the ballpark.

Not really. I just grabbed the sheet metal flange that the weatherstrip hooks onto and bent it out of the way. I haven't bent it back yet, but at worst a hammer and dolly should make pretty quick work of it. I didn't make one big square cut, unfortunately. I was trying to get by with the smallest hole I could possibly make (believe it or not) so I cut the hole, then cut it bigger, then cut it bigger still. I can't reassemble all that stuff anymore. It would be more of a pain than just patching it. Yeah, I would definitely stitch rather than seam weld all that stuff. At present I'm leaning towards several small .060" gussets rather than the long sheet gussets with the flanged holes. I haven't absolutely decided one way or the other, but that's where I'm leaning at the present. That might be a good one to learn from. I still have the .pdf that they were using to sell that car, I'll check it for pictures of this area. I don't think it would be hard to get the bar in that position, its again just going to be a pain to patch the cowl and firewall. Thanks for the feedback.