Stock Turbo to Downpipe

[gnonyx]

Hi All,
I'm a bit confuse since my 87 GN is mostly stock especially when it comes to exhaust stock system.
What I don't understand from the factory it never had a gasket between the Turbo and the downpipe.
Has anyone also had no gasket between the turbo and downpipe or did you did have a gasket in place?
Can I use one the following:

Permatex hi temp ultra copper gasket maker

https://gbodyparts.com/copper-integrated-waste-gate-down-pipe-gasket-p-1407.html?osCsid=c5d402cb1450ad640b5776ce70ae04cf

r7" class="bbc_link" target="_blank" rel="noopener noreferrer">https://www.ebay.com/itm/Buick-Grand-National-Turbo-to-Downpipe-Exhaust-Gasket/232478036509?hash=item3620c5521d:g:O9QAAOSwuLZY2R r7

Thanks

[Steve Wood]

It never had a gasket between the turbo and the downpipe.  It also never had gaskets between the headers and the heads.

There was no need because the turbo and the exhaust housing were cast out of solid iron and the surfaces were smooth and mated well.

If you want to, I would just put a paper thin smear of high temp rtv on the exhaust housing before bolting it down and let it sit over night before starting the engine.

Did not have one under the turbo but I sure have seen a lot of gaskets that someone put under the turbo leak like a sieve when a little smoke was generated..

[gnonyx]

It never had a gasket between the turbo and the downpipe.  It also never had gaskets between the headers and the heads.

There was no need because the turbo and the exhaust housing were cast out of solid iron and the surfaces were smooth and mated well.

If you want to, I would just put a paper thin smear of high temp rtv on the exhaust housing before bolting it down and let it sit over night before starting the engine.

Did not have one under the turbo but I sure have seen a lot of gaskets that someone put under the turbo leak like a sieve when a little smoke was generated..

Thanks Again Steve you always come through with the right suggestions
And yes I finally had someone welded the cracked headers and resurfaced the heads to the point I didn't use a gasket. I used the Permatex hi temp ultra copper gasket maker on the both headers and also on the crossover pipe.
After leaving the headers and crosspipe rtv rest for couple of days the BLM was 124. I did checked again for any leaks to which none was found, so I might have a vacuum leak if I want the BLM # to go down.
Question, would the leak between the turbo and downpipe cause the BLM # to rise?
Is it wise to get a 10mm spark plug wires for a stock ignition system or just stay with the 8mm type, and if so what brand type is good?

[Steve Wood]

Very seldom does a car read 128 on the blm's.  As long as it is +/-10, it is normally considered fine as it is well within the correction limits of the ecm.  Minor leaks are more noticeable at idle with little exhaust flow occurring.

124 means the car is slightly rich so the ecm pulled a little fuel out to dial it in.

If you are not familiar with how blms work, here is a link  http://www.vortexbuicks-etc.com/blms.htm

I would say no to a leak between the turbo and downpipe.  

Sparkplug wires, if in good condition, do not make more power when comparing different brands whether they cost $30 or $130.  Hopefully, for more money, you get more durability and more life, but there is no difference between 8 mm and 10 mm other than appearance.

Even in the more expensive ones, there is often a difference in quality.  If I change plug wires, other than for physical damage, it's because I am bored.  

I have Magnecor wires on my GN.  They have a smaller boot on cyl 6 which makes it easier to put on or get off. They are reputed to be one of the better wires.  They are also one of the more honest companies as they point out the plug wire resistance is not that important and trying to use resistance as a quality factor is pretty much meaningless in regard to high voltage DC electricity.  I think they are 8mm and have been on the car for about 25 years.  Bob Bailey pointed me to them.

My T has Taylor wires on it and they are 10.4 mm.  I bought them because I liked the color LOL.  They have been on the car about 18 years.

Many people really like the wires built by Russ Merritt.  They are sold by RJC Racing these days.  They have an excellent reputation and Russ is one of the truly straight shooting Buick guys in my opinion.  He is married to Grumpy's daughter, Melissa.  I would probably buy a set of his wires when and if I ever need another set.

[gnonyx]

Very seldom does a car read 128 on the blm's.  As long as it is +/-10, it is normally considered fine as it is well within the correction limits of the ecm.  Minor leaks are more noticeable at idle with little exhaust flow occurring.

124 means the car is slightly rich so the ecm pulled a little fuel out to dial it in.

If you are not familiar with how blms work, here is a link  http://www.vortexbuicks-etc.com/blms.htm

I would say no to a leak between the turbo and downpipe. 

Sparkplug wires, if in good condition, do not make more power when comparing different brands whether they cost $30 or $130.  Hopefully, for more money, you get more durability and more life, but there is no difference between 8 mm and 10 mm other than appearance.

Even in the more expensive ones, there is often a difference in quality.  If I change plug wires, other than for physical damage, it's because I am bored. 

I have Magnecor wires on my GN.  They have a smaller boot on cyl 6 which makes it easier to put on or get off. They are reputed to be one of the better wires.  They are also one of the more honest companies as they point out the plug wire resistance is not that important and trying to use resistance as a quality factor is pretty much meaningless in regard to high voltage DC electricity.  I think they are 8mm and have been on the car for about 25 years.  Bob Bailey pointed me to them.

My T has Taylor wires on it and they are 10.4 mm.  I bought them because I liked the color LOL.  They have been on the car about 18 years.

Many people really like the wires built by Russ Merritt.  They are sold by RJC Racing these days.  They have an excellent reputation and Russ is one of the truly straight shooting Buick guys in my opinion.  He is married to Grumpy's daughter, Melissa.  I would probably buy a set of his wires when and if I ever need another set.

Thanks again Steve,
Although I have read your description on BLM not once but many times over, I still read it again so it can soak into my head.
Right now I'm hoping the leak from the turbo to downpipe housing leak is causing the A/F to go from previous 14.7-15.1 to now 15.3-15.6

One more thing, what is the torque for the bolts for the turbo to the downpipe elbow housing?

[Steve Wood]

I am not 100% sure...I think they are metric grade 8.8 which is usually around 15 ft/ lbs

If you have a leak at the exhaust housing interface or where the stock downpipe connects to the housing, it may suck a small amount of air into the dp and affect the wide band sensor in the downpipe.

I tend to watch the stock nb sensor in cases like that as well as the blms

[gnonyx]

I am not 100% sure...I think they are metric grade 8.8 which is usually around 15 ft/ lbs

If you have a leak at the exhaust housing interface or where the stock downpipe connects to the housing, it may suck a small amount of air into the dp and affect the wide band sensor in the downpipe.

I tend to watch the stock nb sensor in cases like that as well as the blms

Thanks Steve ands I will keep you posted once the RTV has cure.
Please be safe, healthy, and enjoy the weekend