Straight 8 Exhaust Manifold

[Guest Ken Sogge]

Resellers tell me that the exhaust manifold for my 1940 Special is the same for 1939 through 1953. Is that true? If so, why are so many of the available used manifolds cracked? Didn't Buick ever figure out how to make an exhaust manifold that would not crack? Also, why are the reproduction exhaust manifold so expensive ($695 and up)? Is there a reasonable alternative here? I have had my manifold braised with bronze twice and it cracked again, right beside the repair. Help!!

[Leif Holmberg]

You are right,they fit a lot of years.

Leif in Sweden.

[Mark Shaw]

The primary reason they crack is that many don't torque them correctly and/or use a lubricant type sealer to allow the cast iron to move.

Spring washers were also used to allow expansion while minimizing torque increase. These special washers sometimes get lost and are often replaced with flat washers.

As a manifold gets older it may need to have the flat surfaces dressed up to seal properly. Most don't do this and simply use extra torque to make them seal.

One problem often leads to another....

Edited January 25, 2011 by Mark Shaw (see edit history)

[Guest Ken Sogge]

What is the recommended torque for mainifold bolts? My shop manual does not specifiy.

If I buy a NEW exhaust manifold, will it match up OK with my old intake manifold? Is there an allowance for one to be machined more than the other?

[Guest Ken Sogge]

Tell me more about the spring washers, lubricant sealers and how to obtain same. Bob's does not list either. Maybe a repaired manifold would survive with these additional considerations. I'm sure that torquing has been part of my problem here. Even after planing the manifold, I bet I torqued it too tight. Bring on those ellusive spring wahers! I appreciate the advice. Maybe there is a light at the end of this tunnel. Would I still use the intake rings? I guess I don't understand how the exhaust manifold can move when expanding. I'm sure it has to expand.

[Mark Shaw]

•Every vehicle has different levels of torque necessary to properly tighten its bolts. The standard is to use 20 to 30 foot-pounds of torque. Older engines often fall on the lighter side of the equation, so use 15 to 20 foot-pounds of torque if your engine is 15 years old or older.

•Clean off any used gasket material and coat the engine side of the gasket with copper seal or other lubricating exhaust sealant (I use Fel-Pro C5A Anti-Seize Lubricant. It is rated to 1800 F).

Torque Sequence is important too....

Install a new gasket every time you take the manifold off the vehicle. Torquing the bolts properly requires following a set pattern. The pattern helps the new gasket sit correctly against the engine blocking leaks. Hand-tighten all bolts initially. Torque the bolts in sequence to half the amount of torque necessary. Start with the middle bolts, and work your way toward the edges one bolt at a time. Repeat the process using the full torque necessary.

Check out this website for info on the type of spring washers Buick used: http://en.wikipedia.org/wiki/Belleville_washer

Edited January 26, 2011 by Mark Shaw (see edit history)

[RiKi5156B]

I have a spare 40 special manifold that is uncracked and has the factory c-shaped clamps and heatriser. I will sell it for $100 plus shipping. Rich

[Guest moto826]

thoes washers are the same as my kids motocross bike

[bobj49f2]

The Belleville washers seem easy to find, McMaster Carr sells them, in fact many different types.

[Glassesguy]

If you are a stickler for originality you will find the choke heat pipe housing on the 39 manifold

is different from all the others. It has a housing and cover on the manifold vs a simple opening into which you push the choke heat tube. Good luck finding one though as many have been replaced over the years with the manifold shown in Leif's chart.

[1939_Buick]

If you are a stickler for originality you will find the choke heat pipe housing on the 39 manifold

is different from all the others. It has a housing and cover on the manifold vs a simple opening into which you push the choke heat tube. Good luck finding one though as many have been replaced over the years with the manifold shown in Leif's chart.

Also 1939 series 40 do not have a stud after No 8 cylinder. The last stud is "missing"

New series 40 exhaust manifolds are cast in Australia. He sells them to Bobs; etc. Not cheap

[danhar1960]

What part of the world are you in Ken ???

Danny

[Guest Ken Sogge]

I have responded to Rich in La Center WA

and hope we can make a transaction.

I am in Scandia, MN (about 40 miles north of St. Paul)

How about a temp gauge? Mine came apart.

[WWS]

If anyone needs one, I have an NOS manifild still in the factory box and looks like the day it was produced.

Email me

[chstickl]

Mine was cracked too and I got it welded fine. Since it is cast iron, not everybody can do it and I recommend to let you show some previous work, how it looks. Might not be easy to find an artist who can weld cast iron. Mine was about US$30 for one crack - quite a difference to 600odd bucks.

Chris

[W_Higgins]

Even after planing the manifold, I bet I torqued it too tight.

How was it planed? Some shops use large belt sanders or a machine that's a stone-in-table type grinder. Both are essentially a hand operation and no matter how good they are it's near impossible to get a truly flat surface.

I bought a Van Norman Rotary Broach simply because I've had so much stuff ruined by shops that didn't have one (or a similar way to mill), or some of they ones that do are simply afraid to touch parts made from unobtainium.

[Terry Stock]

My experience for what it is worth.

I had the exhaust manifold for our '39 model 41 welded several times.

With each repair, the inlet manifold was refaced too. Each time it was refaced the size of the manifold inlets got smaller (they are like a trumpet). The last refit was a fine act to ensure the manifold actually covered the outlets from the head.

I eventually took the plunge and bought a new exhaust manifold - ordered through Bob's Automobilia and shipped from the manufacturer in Queensland, Australia, Ranald Grant.

I was able to obtain a replacement inlet '39 manifold that had no previous machining.

The exhaust manifold came equipped with tie down nuts and the insert rings.

The manifolds were machined and installed by a mechanic/engineer friend with some old Buick expertise about 8 years ago. He applied graphite grease to the facings as an aid in the expansion/contraction process.

No trouble so far. Money well spent although it seemed a lot at the time.

The hot box had been replaced several years previous too.

Edited February 4, 2011 by Terry Stock (see edit history)

[Guest werntonb]

Resellers tell me that the exhaust manifold for my 1940 Special is the same for 1939 through 1953. Is that true? If so, why are so many of the available used exhausts manifolds cracked? Didn't Buick ever figure out how to make an exhaust manifold that would not crack? Also, why are the reproduction exhaust manifold so expensive ($695 and up)? Is there a reasonable alternative here? I have had my manifold braised with bronze twice and it cracked again, right beside the repair. Help!!

Yeah you are right, I just used the old exhaust of my friend. That's my alternative solution for I don't buy a new reproduction exhaust manifold.

Edited February 25, 2011 by werntonb (see edit history)

[FLYER15015]

Just to throw my $.02 in on this thread regarding exhaust manifold issues.

#1. I saw on the "gearz" program on the speed channel the other night, that "Maalox" works just like "neverseize" on head bolts/studs. Just dip the stud prior to threading it into the head. also works on the nuts holding the manifold on. Makes you wonder what's in this stuff we ocasionally drink ?

#2. When reassembling my used manifold, I used a generous supply of "wood furnace door gasket glue' on the 2 slip joints that join the front and rear sections to the centter section, and to the bevel joint where the exhaust pipe meets the manifold donut gasket.

I have about 250 miles on her so far and everything is quiet under the hood.

Mike in colorado

BCA# 45728

AACA# 884416

[Erik]

I eventually took the plunge and bought a new exhaust manifold - ordered through Bob's Automobilia and shipped from the manufacturer in Queensland, Australia, Ranald Grant.

Does Ranald Grant by chance do a 4brl exhaust center?

Do you have any contact info to Ranald Grant?

[ROD W]

He is advertising in the latest Buick News about getting another batch made. Cost

approx $750 AUS plus shipping. Email : ranald14 @bigpond.com

[critterpainter]

You might check with Bobs Automobilia. Ranald Grant does NOT supply them with manifolds. Bobs are made in the USA and sell for around $695.00

Bill

[Guest Ken Sogge]

I have finally resolved my problems with the exhaust manifold.

I learned a lot from this blog. I adapted a lot of the ideas I got here and resolved the mess. I have written a step-by-step procedure for installing an exhaust manifold. It is two pages long. I will attempt to post it here. if it does not get hooked on, send me an email address and I will send it back to you as a Word attachment. Attachment did not work for some reason.

Ken

ksogge@frontiernet.net

[Guest Rede]

I have a spare 40 special manifold that is uncracked and has the factory c-shaped clamps and heatriser. I will sell it for $100 plus shipping. Rich

I am new to the forum, so please excuse my not knowing how it works.

My question is: I noticed your listing (and did see that it was posted some time ago). My question is do you still have the exhaust manifold for sale?

Thank you for your time.

[Thomas J. Bianculli]

On 1/25/2011 at 9:44 PM, bobj49f2 said:

The Belleville washers seem easy to find, McMaster Carr sells them, in fact many different types.

I know this was an old post. however McMaster Carr does still sell the washers, and they seem to be the only company I could find without a minimum order. They are in Ohio, I am in PA, and I just ordered a pack of 1 dozen in stainless steel for $12.60 and I will have them tomorrow!!!

[Thomas J. Bianculli]

I too have been victim to the manifold cracking gremlin.  Since I have been unable to find a replacement as of now, someone is attempting to repair it. THis process has given me time to clean, repair or replace everything associated with the job as well as do some research. I found the 1952 Buick shop manual and its section on manifold removal and replacement indicates the intake manifold used gaskets and the exhaust did not.  My engine by the number is from a 1948 Super, installed in my 1940 Super in 1960 or earlier. My manifold had the black gaskets on both intake and exhaust, and I do not believe the engine had ever been disassembled.  The gasket blew out initiating the job. On removal I discovered the cracks in the manifold.

 

My question is this, does anyone know if it is true that no gasket was used on exhaust?? It would seem that the absence of gasket on the exhaust manifold while the intake used  them would cause sealing problems or even cracking???  All gasket sets include intake-exhaust gaskets which leads me to believe they should be used. I have purchased a set of the copper clad gaskets and intake rings from CARS, as well as a set of Belleville Washers from McMaster Carr, the only supplier without a minimum order.

[Joseph P. Indusi]

From what I have been told and what I have read about this, the straight eights after a certain date in the 1940's were assembled with pilot rings for each intake channel and around this they slid a crushable very thin washer type of metal gasket.  The exhaust manifold surfaces mating to the head used no gasket at all but were coated with a special compound, described in the shop manual as a mixture of graphite and a heavy oil or similar substance.  The hot box, exhaust manifold and intake manifold were assembled and bolted together (just snug to allow some limited movement) using a gasket between the hot box and the exhaust manifold.  In this joint they also placed a steel ring.   There was also a gasket between the top of the hot box and the intake manifold.  Then the whole assembly was attached to the head using eight sided washers  or Belleville washers for each stud.  If you see an engine with bolts instead of studs be sure to replace them with 3/8" studs, coarse thread on the head side and fine on the manifold side.  

 The studs were tightened starting from the center and working toward the ends with about 15 lb-ft of torque on each.  Then re-torqued to 25 to 30 lb-ft.  then bolts holding the hot box to the manifolds were then tightened fully to about 25 lb-ft.   I have had to re-torque the stud nuts after a few runs at running temperature.

It helps to have the assembly planed flat on a machine or belt sander.   I have always used the copper clad gasket sets sold today,   I never tried the approach described above.   I did however coat everything, both sides of the gaskets with a mixture of graphite and 50 weight motor oil.

Joe  

[Bob Engle]

Gaskets Isolate the manifold heat from the block thus creating a greater differential thermal expansion between the two.  Buick continued the no gasket  practice into the 60's with their nail head V8's

 

Bob Engle 

[Larry Schramm]

14 hours ago, Thomas J. Bianculli said:

I know this was an old post. however McMaster Carr does still sell the washers, and they seem to be the only company I could find without a minimum order. They are in Ohio, I am in PA, and I just ordered a pack of 1 dozen in stainless steel for $12.60 and I will have them tomorrow!!!

 

Let us know how much the shipping is.

[Thomas J. Bianculli]

6 hours ago, Larry Schramm said:

 

Let us know how much the shipping is.

Hello Larry,  The total bill on my Amex is $17.87, just over $5.00 for shipping. They use UPS.  Had they used First Class  Mail it would have been cheaper.

[Thomas J. Bianculli]

18 hours ago, Joseph P. Indusi said:

From what I have been told and what I have read about this, the straight eights after a certain date in the 1940's were assembled with pilot rings for each intake channel and around this they slid a crushable very thin washer type of metal gasket.  The exhaust manifold surfaces mating to the head used no gasket at all but were coated with a special compound, described in the shop manual as a mixture of graphite and a heavy oil or similar substance.  The hot box, exhaust manifold and intake manifold were assembled and bolted together (just snug to allow some limited movement) using a gasket between the hot box and the exhaust manifold.  In this joint they also placed a steel ring.   There was also a gasket between the top of the hot box and the intake manifold.  Then the whole assembly was attached to the head using eight sided washers  or Belleville washers for each stud.  If you see an engine with bolts instead of studs be sure to replace them with 3/8" studs, coarse thread on the head side and fine on the manifold side.  

 The studs were tightened starting from the center and working toward the ends with about 15 lb-ft of torque on each.  Then re-torqued to 25 to 30 lb-ft.  then bolts holding the hot box to the manifolds were then tightened fully to about 25 lb-ft.   I have had to re-torque the stud nuts after a few runs at running temperature.

It helps to have the assembly planed flat on a machine or belt sander.   I have always used the copper clad gasket sets sold today,   I never tried the approach described above.   I did however coat everything, both sides of the gaskets with a mixture of graphite and 50 weight motor oil.

Joe  

 

[Thomas J. Bianculli]

Hi Joe, thanks for the info. I found the 1952 Shop Manual somewhere on the site and you are spot on with what they said. I was going to use Copper Permatex which retains some flexibility but now I may go with the factory method as you suggested.

[Larry Schramm]

3 hours ago, Thomas J. Bianculli said:

Hello Larry,  The total bill on my Amex is $17.87, just over $5.00 for shipping. They use UPS.  Had they used First Class  Mail it would have been cheaper.

 

That is reasonable.  There have been others that the shipping has been more than the cost of the part(s).  Thanks for the response.

[Thomas J. Bianculli]

21 hours ago, Larry Schramm said:

 

That is reasonable.  There have been others that the shipping has been more than the cost of the part(s).  Thanks for the response.

Hello Larry, I agree. In addition to that when I was looking for the washers some vendors had a minimum order like $150.00 or a minimum of 1000 pieces.

Bu the way, the washers did arrive last night as promised and should do the job.

 

Tom

[Larry Schramm]

Good luck. 

[Wayne wenzel]

On 1/25/2011 at 10:23 AM, Mark Shaw said:

The primary reason they crack is that many don't torque them correctly and/or use a lubricant type sealer to allow the cast iron to move.

Spring washers were also used to allow expansion while minimizing torque increase. These special washers sometimes get lost and are often replaced with flat washers.

As a manifold gets older it may need to have the flat surfaces dressed up to seal properly. Most don't do this and simply use extra torque to make them seal.

One problem often leads to another....

I have just purchased a 1938 McLaughlin Buick the manifold was cracked and professionally repaired and installed just prior to me buying the car.  It does have an exhaust leak, and I was very intrigued to read this post about the use of Belleville washers, sounds like they were installed at factory, is there different spring tensions and torques for these or if I get the correct hole size are they all the same tension and torque?  There was no sealant used between gasket and block, thought I might try the belleville washers first and see if that eliminates the problem or would you recommend removing the manifold using the sealer and installing correct washers?

[Bloo]

The exhaust manifold must be able to move with expansion. It gets much hotter than the head and it WILL get longer and the ends WILL move out. Anything that restricts that motion will cause the manifold to break. That is what you need to pay attention to.

 

The belleville washers just allow the manifold to move. They go on so the outer edge contacts the manifold and the inner edge contacts the nut. Soft washers could crush down and stop the motion.

 

Also pay attention to the studs and imagine the exhaust manifold getting longer. The manifold will probably hit the outside of the studs cold (to make sure the manifold won't hit the inside of the studs when it grows). If it is already hitting the inside of the studs and has no room to grow longer, you will need to do something about that.

 

Make sure the surface of the manifold is straight and flat. If it wasn't already warped, it probably warped when they welded it. Hopefully they milled it afterward, but if they didn't that could be why it leaks.

 

I don't know what sealer you refer to. You don't want to glue it down. I would do whatever the shop manual says.

 

I believe one of the Buick parts vendors has the washers. Probably Bob's.

 

Welcome to the forum!

Edited May 17, 2019 by Bloo (see edit history)

[1939_Buick]

Does the car have the rings on  the intake?

https://bobsautomobilia.com/manifold-parts/intake-manifold-pilot-ring-1934-53-s.40-50-.-mp-343/

 

Other threads

  https://forums.aaca.org/topic/297744-1937-248ci-intake-man-gland-rings/

 

https://forums.aaca.org/topic/117403-straight-8-exhaust-manifold-gasket-leak47super/

 

Edited May 18, 2019 by 1939_Buick (see edit history)

[1940Super]

On 5/18/2019 at 9:43 AM, Bloo said:

The exhaust manifold must be able to move with expansion. It gets much hotter than the head and it WILL get longer and the ends WILL move out. Anything that restricts that motion will cause the manifold to break. That is what you need to pay attention to.

 

The belleville washers just allow the manifold to move. They go on so the outer edge contacts the manifold and the inner edge contacts the nut. Soft washers could crush down and stop the motion.

 

Also pay attention to the studs and imagine the exhaust manifold getting longer. The manifold will probably hit the outside of the studs cold (to make sure the manifold won't hit the inside of the studs when it grows). If it is already hitting the inside of the studs and has no room to grow longer, you will need to do something about that.

 

Make sure the surface of the manifold is straight and flat. If it wasn't already warped, it probably warped when they welded it. Hopefully they milled it afterward, but if they didn't that could be why it leaks.

 

I don't know what sealer you refer to. You don't want to glue it down. I would do whatever the shop manual says.

 

I believe one of the Buick parts vendors has the washers. Probably Bob's.

 

Welcome to the forum!

I'm getting my engine ready to go back on chassis but am making sure I've torqued everything correctly after running engine.

I have good clearance around the studs except the last 2 at the firewall end being in close contact with the manifold(see photo). What are your thoughts on the clearance? 

I believe the washes I have are the originals? The are quitethick, flat with a small raised outer edge on the side that rest on the manifold and more rounded on the nut face. Belleville washes as I understood them have a slight curve in them. Was there ever a washer on the longer stud with the thick metal piece that clamps the end of the manifold? Not not thread left on the stud so I would imagine not

Looked on Bob's website but didnt see washers. Old Buick Parts had washes for the exhaust.

[Bloo]

I can't really see well enough to tell, but it looks fine. The plate is the sliding memeber on that stud, so I don't think there would be any belleville washers there. Those belleville washers look like good ones. I suspect they might even be original.

 

Some studs can (and probably should) be in contact with the manifold, as long as they do not block motion as the manifold gets longer. For instance it looks like the manifold is touching the long stud. The manifold will grow further away when it gets hot. I think i see a gap next to that last stud (bottom of pic). That is also good. When the manifold grows it will get closer to that one.

Edited May 19, 2019 by Bloo (see edit history)