Exhaust-like Noise 1937 Series 60

[jackworstell]

Our 1937 series 60 runs very well   but there is a noticeable noise that sounds like an exhaust leak.
But we've searched and can't find a leak.

The car has a stainless exhaust system including the muffler.   I've read several times that stainless systems
make more noise than steel systems.
QUESTION,,,,could this "extra" noise from a stainless system sound like an exhaust leak ?

Jack  Worstell    # 7558      jlwmaster@aol.com

[jackworstell]

Thanks  Art.   I;ll be going to the garage Tuesday and will check on this then.  I think you have hit the "nail on the head".

Jack Worstell

[Steve Passmore]

You will be very lucky if it has only burnt away the manifold.  I have had to have the block itself skimmed on 4 engines.

[jackworstell]

OK

[jackworstell]

It will be next week until I can get around to removing the manifolds.    At
this point I'm convinced that it's the exhaust cross-over  "weak spot".

QUESTION  Looking ahead....I have spare manifolds but they are for 1940-1948 engines.  The parts book
shows a different manifold for 1936-1939   346 engines.
......Does anyone know if 1940-1948 manifolds will work on a 1937 engine ?

QUESTION  If the block itself should also be damaged.....if the damage is not
too bad would it be possible to braze the surface cavities and then dress them down
to make a suitable repair ?

Jack Worstell

[tripwire]

Jack, the later manifolds are different. 

Someone else will chime in with opinions re: brazing the block.

[Steve Passmore]

The later manifolds have no provision on the underside for the 37 PCV type fittings, and you will have a different angle to the carb when fitted. The carb angle changes as bodies got lower.
It's an idea I haven't explored, this brazing thing. I don't know what effect it would have on components around that area. If it did work you would still need to remove the heads to be able to accurately file the surface.  I did try some years ago your JB weld in an emergency, and about a year later when I dismantled the engine it was still good, although, I was not impressed with how hard it set. It sanded just like body filler but I guess if it lasted a few years?

[jackworstell]

Thanks Steve....useful info.   ( is there anything you don't know about 346 ci Cadillacs.........? )

I thought about JB weld...it works great....but I didn't think it would hold up to really high temperatures.
QUESTION.....exactly where on the engine did you use JB Weld ??

Jack Worstell

[Bob Schuman]

Jack,
I used Pyro-Putty 2400 for this repair on my 40 LaSalle several years ago with very good success. It can be found on the internet. It is like JBWeld, but was recommended to me as much better for this type of repair. I was able to hand-file the hardened Pyro-Putty to a flat smooth surface without needing to remove the heads, only the manifolds. 

[jackworstell]

Thanks Bob...I had forgotten about Pyro Putty.

I take it you used it to repair  damaged surface on the block as a consequence of an exhaust
leak in the exhaust cross=over under the intake manifold ?

Jack Worstell

[harry s]

I used Pyro Sealer which is about the consistency of Permatex to repair a slight leak in that area. You apply it at assembly which eliminates any sanding or shaping. My repair was done 5 or 6 years ago and no problems (so far).
Harry

[Dan LeBlanc]

Here's a video we did back in 2014 when we were trying to figure out where the noise is coming from

https://youtu.be/9xK4djKxgmM

[jackworstell]

Thanks to everyone...great info.

Next week we'll take off the manifold and see exactly what's going on.....

Jack Worstell            jlwmaster@aol.com

[Steve Passmore]

quote author=jackworstell link=topic=151024.msg401635#msg401635 date=1532781976]



QUESTION.....exactly where on the engine did you use JB Weld ??

Jack Worstell
[/quot

You see where Art has his finger Jack? it's that point of contact on the block. You will see it when you get the manifold off.

[jackworstell]

Before we go to trouble of removing the intake, exhaust, carb etc etc ....to see if the exhaust cross-over is the source of the exhaust noise............   I wanted  to see if we have a spare intake on hand which will "bolt on"

So I checked the spare 1940-1948 intake  we have,,,,I know it's different than the intake on our
1937 series 60 but I thought it might bolt on anyway.

I found that the 1940-1948 intake measures 5" from bottom surface ( goes against the block ) to the upper surface
( where the carb bolts on.....but the 37 intake is something like only 4".....

I was surprised...I thought the latter manifold would be lower...it's the other way around ?

So it looks like the 1940-1948 intake won't work...the carb will set too high

Jack Worstell        jlwmaster@aol.com

[Steve Passmore]

That's where the carb surface angle changes over the different years Jack. As the engines took on a different angle.  The later engines slant more in later cars so the manifold has to 'kick' up at the back to compensate.  They still fit and can be used though, only you would have to alter your PCV system which is under your manifold, and the carb sits on a weird angle.

[jackworstell]

We pulled the manifolds on our 1937 series 60

What we found was that the gasket surface on the exhaust cross-over UNDER  the intake manifold
had  deteriorated just as several of you had predicted. Only the inner edge ( closest to the center of the engine ) was damaged. The corresponding gasket surface  on the block was also damaged.

This no doubt was the source of the exhaust noise......which was very noticeable...surprisingly so....considering
the small amount or surface deterioration.

Since the damage is limited we are going to try to fix it with JB high temperature gasket sealant
( this is not a "two part" product).  I would guess that this is along the lines of Pyro Sealant but I'm not sure about this.

By the way...I compared the 1940-1948 intake manifold to the pre 1940 intake manifold
To my surprise.....the earlier manifold is close to 1" LOWER  than the latter manifold....I had assumed it would had been the other way around.

Jack Worstell       jlwmaster@aol.com

[Steve Passmore]

It's the angle that changes Jack, to tilt the carb slightly.  I wouldn't rely on JUST gasket sealant personally. I would use their setting two-part, then the sealant. Just my 2 pennies worth.

[jackworstell]

UPDATE

,As several of you predicted...the exhaust leak was in the exhaust cross-over which is cast into, and as part of,  of the intake manifold.   
Both ends of the cross-over were leaking.   Only the in-board surfaces of cross-over "flanges" were leaking...the outboard surfaces of the two "flanges"  had not deteriorated. 

The corresponding surfaces on the engine block had also deteriorated. 

  Luckily none of the deterioration was severe...but still bad enough to cause a loud exhaust noise.

We fixed this using "Quik Steel"   and  JB Weld High Temperature  Sealer/Gasket Maker  ( red.  100% silicone, red in color) 
  The "Quik Steel" we bought at a local auto store.....it is a one-part product and I would guess about the same as "Pyro Putty"

The exhaust leak is fixed.....but how permanent is repair is remains to be seen.

Jack Worstell     jlwmaster@aol.com