SRQ400

Man, you are getting ripped off big time. You should be able to tell if the leak is at the header flange from the sound or with a visual sign around the flange itself.
Did you new OEM gaskets? It would best if you did and give them the torque specs of 32 lbf.
Personally and in general I wouldn’t trust an exhaust shop to install headers. If they have the time then they usually don’t have the workload they need – big hint! This project should only take 2 down time days to you. One from a mechanic and one from an exhaust shop. Possibly one extra if the exhaust shop needs to order something not off the shelf.
I hate to say this – I think it’s time to start over with new qualified shops in mind.

TexasLex

Thanks for the reply and I agree with you. The weird thing is, there were no visible carbon deposits that at least I could see.

I had originally gone to the local Supra tuner to get a bid, but they had a 6 month wait and did not ever reply with a bid. I was petty sue that what I needed done was not a big enough job for them as all of the other cars there, and there wee a lot of them, were in for engine swaps. The first shop that worked on the car was not an exhaust shop though, they looked to be qualified based on the other cars I saw the times I was there to get my bid and to drop the car off. For example: 2 NSXs (1getting a supercharger), 350z getting twin turbos, etc... I think what happened is that they took care of their specialty markets of Nissan and Honda and gave my car to their flunkie mechanic. Besides warping the exhaust flange, they also managed to use the wrong transmission fluid when they swapped the torque converter, which necessitated a trip to the Lexus dealer for a transmission flush (I went to the dealer for this b/c I did not want to risk another mix-up). They also left the driver's side window down and all kinds of shop "pollution" found its way into my cars interior and on to my new light tan Recaro leather seats.

Since the first shop had used a TIG welder to fabricate the exhaust, I wanted the corrections to be made with the same type of equipment, and which led me to the second shop. The second shop does custom TT VWs and Audis. They are a very good shop, just once again, they were taking care of their primary clients first.

At this point I would have been way better off just buying a new car, but I always loved the shape of the SC and I am going to get this **** done right (that is if I first don't lose it in bankruptcy court )

GILLEXUS

iTrader: (14)

what I can't figure is how do they determine that you have a leak and where it is coming from??
How is it possible to warp the header flange? I don't think you have very many mile on it even.
Maybe it just the gasket did you use new ones?
I guess if you take off the header and have the flange cheked and tit is not warpped, then they should apay for the labor.

Pearlpower

iTrader: (2)

I would be interested in where that leak is coming from as well since I will be installing the headers on my SC shortly and have posted my concerns on the poor flange surface area. My email to SS sent well over a week ago on the condition of the headers was not returned.
Pics are here.
https://www.clublexus.com/forums/sho...d.php?t=197918

TexasLex

The warp is in the exhaust side flange. It is one that I bought from S&S, but it was straight when I got it. The "new" mechanic said it was warped when the other shop welded the exhaust tube to it. He said the gap is over an inch long and that a gasket will not hold back a leak. He has agreed that I order the stainless flanges from Lextreme and he told me to get the 1/2" ones.

I gave the first shop two tries to fix it and basicaly they lied to me because they said they checked everything over and over again, including removing the exhaust and looking inside the flex pipe for the source of the leak. If the had actually done that they would have seen the real problem. So yes, they are going to pay, they just don't know it yet.

TexasLex

The warp is in the exhaust side flange. It is one that I bought from S&S, but it was straight when I got it. The "new" mechanic said it was warped when the other shop welded the exhaust tube to it. He said the gap is over an inch long and that a gasket will not hold back a leak. He has agreed that I order the stainless flanges from Lextreme and he told me to get the 1/2" ones.

JBrady

So the problem is the EXTRA flanges that you bought to bolt to the header outlet... correct? This would be a 3 bolt flange to mate up to the header outlet which you would weld the downpipe to. You say that the shop that welded up your system initially somehow overheated the flange and it warped?

Glad to hear it is not a problem with the headers themselves.

Is it not possible to just sand it flat on a heavy duty 12" disc sander? I would definitely try this first before cutting off flanges and re-welding new ones.

Word of caution about the Lextreme flanges. They are for the earlier bolt pattern. Even though at first glance they appear the same the bolt holes are closer together and will not line up to the header outlet. As you said the extra set of flanges you purchased from S&S are the correct bolt pattern and are 3/8" thick (thicker than stock) which should be enough to sand flat for a good seal.

Hope this helps. You certainly deserve to have your car working properly after the effort you have made to do a first class job.

TexasLex

Yes, to clarify, the flanges I am speaking of are the "extra" set I purchased from S&S. The mechanic (hopefully soon to be referred to us "the good mechanic") told me that I needed another flange. I know he mentioned that the warped one looked like it also had been knarled up in a vise, so maybe this is why he said I need another one. Anyway I noticed that Lextreme has the option for one to select the year and model of their application. So perhaps he has both the old and the new style. I have emailed him to be sure the flanges I ordered are the new style. I will post a response once I receive a reply from him.

TexasLex

Regarding the old-style flanges, would it be possible to elongate/enlargen the bolt holes on this style flange to make them work with the new style flanges on the headers? Or this not an option due to the acutual position of the header's outlet tube in relation to the bolt pattern?

JBrady

Possible? Yes. Realistic? If you have the proper tools. The bolt holes are farther away from the centerline on the newer flanges. 3/8" stainless is tough to cut. Laser cutting is the norm.

Honestly, if it were me I would try to straighten the flanges you have. They should be 3/8" mild steel, the same exact flanges as the headers. Get them square if the metal is warped and then power disc sand it true. Check to make sure that the actual header flange was not warped by being bolted up to a warped outlet flange.

b1ackhawk

Thx for the posts. Do we have anyone here that has installed the headers on 92-95 SC without a complete custom exhaust?

Oliver1

I live in South Florida (Cooper City) and I need a mechanic to install my S & S Headers and Magnaflow high flow catalytics. I would also like to install a new exhaust system in 2.25 inch tubing. Does anyone know of a good Mechanic/Exhaust shop in South Florida? I have Borla Exhaust installed already. Please help.

TexasLex

Thanks for the reply. It looks like my home equity loan is going through so I ended up having a pair of flanges water jet cut from 1/2" stainless along with a pair of gaskets from 3/16" copper. I am going to have them installed and have the middle set of mild steel connection flanges replaced with stainless at the same time. The Borlas will be replaced with bigger Magnaflows then too. I will try to get some pics this time.

I had a CEL error code for ignition miss so we replaced the wires with Magnacores which made it better for a while. Now the miss is back AND the car stalls after I drive on the freeway for 10 - 15 minutes then come up to a stop light or slow down. I ordered a new fuel filter and distributor caps and rotors that I will install once they arrive. I still think it is the O2 sensor though because the problem started right after the headers went in.

The good news though is that despite all of the problems the car is way faster. I am going to get wider rear tires (which will certainly be needed once I install the nitrous that I am nearly finished putting together). Also, the "new" mechanic said he hates Apexi S-AFC and recommends a Perfect Power piggy back chip from South Africa. Then he can adjust the timing too as well as get way more specific on the fuel mapping. After this is all done I would have probably come out ahead buying a used C4 Vette, but I am a Lexus guy so ...

TexasLex

The car is back in the "good" shop right now having the new flanges welded on.
I drove the car on a 20 minute freeway trip the other night and it stalled when I got to my destination. It did the same thing when I got back to Houston. The next day I noticed the charcoal canister’s vacuum line was off the check valve, so I reattached it and the car has run OK since then. However, I have not run it on the freeway for more than a minute at a time since then. The stalling problem has been reported by others after installing the headers so I am wondering again if it may be O2 sensor related since this is the reason the others reported for their stalling. Apparently if the O2 sensors are damaged they cause the car to stall once they reach a certain temperature(?). I have driven the car several times over the last few weeks but for some reason last night the CEL went off briefly. During this time I nailed the gas and the car pulled very strongly through 2nd gear. Then, while entering the freeway, I heard a sound which I think was the engine missing once and then a few seconds later the CEL came back on. Also, it may be my imagination but it seems that after driving the car when I pull up to a stop light that the A/C blower was “pulsing” with the engine’s RPMs. I am wondering if the engine’s ground strap may be loose.

Any ideas?