Intake removal?

[DodgeDan]

Hello,

 

I am trying to remove the intake manifold on my '39 Dodge so that I can replace the gaskets in order rule out sucking air at the intake.  I have all the brass nuts off the studs and the four bottom bolts out that bolt the intake to the exhaust manifold.  Should this just pull/pry off now, or do I have to remove the entire exhaust manifold as well to get the intake off?

 

Dan

[TodFitch]

Intake and exhaust should be removed and re-installed together. There are 13 nuts holding the combined manifold assembly to the block, don't forget the one hidden on the intake below the carburetor.

 

When you re-install, have the bolts between the intake and exhaust loose so that both manifolds can seat properly against the block. Then tighten the bolts holding the exhaust to the intake.

 

There maybe other ways of doing this, but the above seems to be the easiest to assure a leak free assembly.

[Don Coatney]

As Tod said 13 is the magic number. May require a light thump from a rubber mallet once all fasteners have been removed. 

 

[DodgeDan]

Thanks guys, much appreciated.  I have the exhaust pipe disconnected now and I am working on all the stud nuts.  When I removed one it started to leak out coolant, it looks like two are into the water jackets?

 

Dan

[ChrisRice]

yes one at the very front and one at the very back will leak coolant out.  i just removed mine the other day.

[TodFitch]

Thanks guys, much appreciated.  I have the exhaust pipe disconnected now and I am working on all the stud nuts.  When I removed one it started to leak out coolant, it looks like two are into the water jackets?

 

Dan

Only if you have a 1935 or later engine, those of us with a '33 or '34 engine don't seem to have that issue.

[DodgeDan]

Okay I have them both off now.  I was able to remove that plug in the intake too and replace it with a capped fitting so I can put my vacuum gauge on it now.  I have a new gasket set, including the intake to exhaust manifold gasket, so now it's time to scrape and clean and prep the surfaces, I'm going to paint them up too while I have them off.  I have silver high temp header paint for the exhaust manifold and high temp black engine paint for the intake manifold.  Then when it's all back together I'll install the newly rebuilt carb.  Thanks again for the help.

 

Dan

Edited August 30, 2014 by DodgeDan

[Niel Hoback]

   When I did that a couple of weeks ago, I bolted the manifolds together with the new gasket in place, but only tight enough to snug the nuts up. Then I put the manifolds on the block without the gaskets and tightened the bolts and nuts enough to insure that the manifolds were both flat to the block. Then I tightened the four through bolts holding the manifolds together enough to keep them from moving, maybe ten ft.lbs.  Next I took the manifolds off of the block and put the new gaskets on the block and reinstalled the manifolds.  Tighten the manifold nuts and bolts to 15-20 ft. lbs. and finish tightening the four manifold connecting bolts.

[DodgeDan]

Good advice, much appreciated!

 

Dan

Edited August 30, 2014 by DodgeDan

[Niel Hoback]

Don't forget the Permatex #2 on the two long bolts.

[DodgeDan]

Will do on the Permatex #2.  Hey got another question... where is the bimetallic spring located that operates the heat riser plate in the exhaust manifold?  Now that I have the manifolds off I wanted to check it and I'll be damned if I can see it?  There is a metal plate inside the square center section of the exhaust manifold, there is a counter weighted lever on the outside that moves with it.  No spring anywhere that I can see, shouldn't that plate open and close with manifold temp?

 

*** I just read the tech section on heat riser and now I see why... mine is totally missing! ***

 

Dan

Edited August 30, 2014 by DodgeDan

[Young Ed]

Spring should be behind the lever on the outside and go to a stud on the intake. Atleast thats how it is on the newer ones I'd assume 39 the same.

[DodgeDan]

So I cleaned up and repainted both manifolds today.  I need to order a new heat riser spring, then I'll be getting it all back together.

 

Dan

[meadowbrook]

On this topic, I'd like the groups wisdom on gaskets. This does not directly apply to Flatheads but my dad and I are working on a 57 T bird and noticed the gasket for the intake manifold to head joint is available in 2 favors, dry or with a graphite coating. Should some kind of sealant be used on them? I think the graphite coated one should not, but any thoughts? The manifold is aluminum, so I tend to think the graphite would be useful to allow some movement between the iron head and aluminum manifold.

[Niel Hoback]

I think you are right. There is no other reason for graphite on a gasket.

[DodgeDan]

I am actually curious on the topic as well.  Back in BOCES we were taught to only apply sealer to one side of the gasket.  With the two manifolds that I will be putting back on soon, as well as the intake to exhaust gasket, do I need or should I be using any gasket sealer?  I had planned on doing what I have always done and apply it to one side to hold the gaskets in place.  I figured on using some Permatex #1 on the manifold to block flanges and #2 on the intake to exhaust.  Just on one side. Any thoughts or recommendations?  Also, how about the carb gasket?

 

Dan

Edited September 1, 2014 by DodgeDan

[Niel Hoback]

I wouldn't put any sealer on the side with graphite on it or you will defeat the purpose of the graphite. A thin coat on the other side wouldn't hurt, but I doubt that its necessary.

[Plymouthy Adams]

if your machined surface are not rusted and pitted you should not need a sealer...the gasket material will correct for the milled surfaces..If you are heavily pitted or pocked with rust...consider a light cleanup of the surface on a grinding machine..

[_shel_ny]

My shop manual makes no mention of using a sealant when installing the manifolds other than to use a suitable sealer to coat the threads of the bolts that go into the water jacket.

 

 

 

 

EDIT:  add pic

 

         movement is expected

Edited September 1, 2014 by shel_ny

[Dave72dt]

graphite gaskets do not get or need sealer. They are designed to allow some "slippage" on the contact surface because of the expansion rate and amount, commonly used between dissimilar metal and aluminum surfaces. Aluminum manifold and iron heads, use the graphite. On the exhaust manifolds, run a straight edge across the block or head surfaces and the manifold. You want them both to be flat at the mating surfaces. You'll often find exhaust ports on the manifolds eroded and then have poor contact and heat transfer, causing leaks and blown gaskets.

[DodgeDan]

These look to be graphite, so I'll go with no sealer then other than on the threads into the water jackets.

 

Dan

Edited September 1, 2014 by DodgeDan

[DodgeDan]

Well, I got it all back together.  New carb and carb gasket, all new manifold gaskets, new heat riser control spring, plus I put on a new muffler since I had the exhaust off and mine was shot.  Started her up and she still runs pretty bad.  I put my vacuum gauge on the new vacuum port fitting that I installed in the intake and the needle on the gauge is fluctuating wildly.  I looked this up on a chart on how to use a vacuum gauge and it says that this points to loose or worn valve guides.  So... this may be more than I am able or wanting to get into.  This sucks...

 

Dan

[DodgeDan]

Does anyone know what kind of undertaking it would be to replace the valve guides?  Any special tools required?

 

Dan

[Plymouthy Adams]

Page 149 of the Plymouth service manual discusses what size guides that are available, reaming proceduare, installation orientation and the tool need to complete the job for R & R of the guides..

[Don Coatney]

Suggest you also read the instillation instructions found in the recourses section of this web page.