New Exhaust Manifold

[BLDFW]

I just installed a new exhaust manifold on my 8n. Maybe it's just me, but it sounds louder than I would have expected. I can still hear detonation or what sounds like leaking at the manifold but it's bolted down tight with the applicable new gaskets in place.

Is that normal? Maybe it's just normal sounds?

 

[Lamont7777]

Local expert who deals exclusively in N tractors and sells new and used parts says he is having a problem with the quality of the new manifolds. He was telling me that many of them are twisted and either had to be machined again or sent back. Said the surface mating to the block was not flat or straight. Might ck and see.
Monty

 

[souNdguy]

any signs of soot leakage?

 

[Bob Harvey]

How good are your ears ? A COMMON problem with these engines is a deterioration (loss) of metal at the #4 exhaust port, again COMMON, the block is erroded at that point, and the manifold is the same-erroded in that area. There are MANY posts on how to correct the block issue, and the same amount on how to deal with the manifold. HTH

 

[ASEguy]

I use a stethoscope. Just take out the metal portion and use the hose. If you have one you will easily find it with one. It might even save you some removal time. I use them for intake leaks as well.
Hope this helps. Gerard

 

[BLDFW]

(quoted from post at 16:19:15 05/04/12) Local expert who deals exclusively in N tractors and sells new and used parts says he is having a problem with the quality of the new manifolds. He was telling me that many of them are twisted and either had to be machined again or sent back. Said the surface mating to the block was not flat or straight. Might ck and see.
Monty

My neighbor, a member of the local Model A club, helped me work on it was wondering the same thing. I was very disappointed and wondered about the quality when I opened the box ordered from PA, USA only to find a big "made in Taiwan" stamped on the lid. On first fit we had to grind down some of the casting seams in the bolt channels to get sufficient clearance for the socket head.

Anyway,I'll be seeing him again later this morning and will ask about a machine shop that can machine it smooth just to be sure.

 

[rustyfarmall]

(quoted from post at 16:01:11 05/04/12) I just installed a new exhaust manifold on my 8n. Maybe it's just me, but it sounds louder than I would have expected. I can still hear detonation or what sounds like leaking at the manifold but it's bolted down tight with the applicable new gaskets in place.

Is that normal? Maybe it's just normal sounds?

There may or may not be a problem with the new manifold, but just keep in mind that the OLD manifold was most likely all sooted and carboned up on the inside, and that soot and carbon WILL absorb noise.

 

[BLDFW]

(quoted from post at 19:24:24 05/04/12) How good are your ears ? A COMMON problem with these engines is a deterioration (loss) of metal at the #4 exhaust port, again COMMON, the block is erroded at that point, and the manifold is the same-erroded in that area. There are MANY posts on how to correct the block issue, and the same amount on how to deal with the manifold. HTH

Yeah, the #4 port on the manifold was shot but fortunately the block surface was pretty much intact and damage free! I read through a fair number of the posts in my early research and decided it was better to order a new one rather than to try and glue, paste, caulk, paper, bubble gum, or otherwise rig it thus fighting an ever losing battle. Fix it right and be done with it!

I'll admit spending money the right way up front is relatively new concept for me these days. Guess I've learned something over time. A penny spent is a pound of exasperation saved (not to mention cutting the eventual costs by 2/3's )! :lol:

 

[BLDFW]

(quoted from post at 06:50:25 05/05/12)
There may or may not be a problem with the new manifold, but just keep in mind that the OLD manifold was most likely all sooted and carboned up on the inside, and that soot and carbon WILL absorb noise.

Thanks! Yes, that thought also occurred to me when I first started it up. I'm thinking I'll run it a couple of times more and then pull the manifold off to see of there are signs of sooting/burning on the gasket set. I'll probably still have it machined down.

 

[KKRRSS]

dont forget that a poor pipe to manifold seal will do as you are describing. Several threads on here about getting a good seal there.

 

[BLDFW]

Well, I figured out what the problem was.....
The lower side of the manifold was actually resting on the top edge of the lower side block access plate rather than on the block itself. It was such that you couldn't see it when you looked. Everything looked normal.... It wasn't until I pulled the manifold off and looked closely that I could see new soot marks on the block, odd markings on the surface of the manifolds and, of course, the burned out section on the new exhaust exhaust gaskets.

We started comparing the two manifolds to see how that could have happened and found the lower casting on the new manifold to be thicker or wider than the original so no matter what we did, it would not clear the access plates. GADS!! Anyway, I took the manifold over to a local machine shop to have it planed again just to be sure it wasn't warped or otherwise not perfect and made the trek to Tractor Supply to get a new set of gaskets.

My buddy is grinding down the lower outer edge of he manifold to insure it clears the plates. I supposed I could have removed the plates, installed the manifold and then reinstalled the plates but I didn't really want break the seals on them. I'll be putting it back together either this evening or tomorrow and will let you know how it goes.

 

[Bruce (VA)]

(quoted from post at 15:04:57 05/08/12) Well, I figured out what the problem was.....
The lower side of the manifold was actually resting on the top edge of the lower side block access plate rather than on the block itself. It was such that you couldn't see it when you looked. Everything looked normal.... It wasn't until I pulled the manifold off and looked closely that I could see new soot marks on the block, odd markings on the surface of the manifolds and, of course, the burned out section on the new exhaust exhaust gaskets.

We started comparing the two manifolds to see how that could have happened and found the lower casting on the new manifold to be thicker or wider than the original so no matter what we did, it would not clear the access plates. GADS!! Anyway, I took the manifold over to a local machine shop to have it planed again just to be sure it wasn't warped or otherwise not perfect and made the trek to Tractor Supply to get a new set of gaskets.

My buddy is grinding down the lower outer edge of he manifold to insure it clears the plates. I supposed I could have removed the plates, installed the manifold and then reinstalled the plates but I didn't really want break the seals on them. I'll be putting it back together either this evening or tomorrow and will let you know how it goes.

" the lower side block access plate"

Those are the valve covers.

Did you call the seller & tell them they are selling junk? Even if you don't get a refund, there has got to be some satisfaction in telling them that there quality control sucks.

 

[Hobo,NC]

(quoted from post at 05:45:37 05/09/12)

(quoted from post at 15:04:57 05/08/12) Well, I figured

The seller did not make it,,, its still may not be a quality issue with the manifold,,, originals do loose weight over time its the nature of the beast... Till someone comes up with a NOS manifold we will never know... I have seen my share of studs that retain the side covers bent UP :shock: all they need is knocked down :wink:,, I would have checked it cuzz I have been their done that ,,, A hose of any kind held up to yer ear and ran around the manifold would have found the zaust leak while others were look'n for their doctor tools...

Why would anyone machine a new manifold,,, If I even had the thought I would check it with a straight edge before I went to grind'n away...

Anyway its a good catch and a good read when the issue has been found..
I like follow Ups I can believe...

 

[R Geiger]

(quoted from post at 10:45:37 05/09/12)

(quoted from post at 15:04:57 05/08/12) Well, I figured out what the problem was.....
The lower side of the manifold was actually resting on the top edge of the lower side block access plate rather than on the block itself. It was such that you couldn't see it when you looked. Everything looked normal.... It wasn't until I pulled the manifold off and looked closely that I could see new soot marks on the block, odd markings on the surface of the manifolds and, of course, the burned out section on the new exhaust exhaust gaskets.

We started comparing the two manifolds to see how that could have happened and found the lower casting on the new manifold to be thicker or wider than the original so no matter what we did, it would not clear the access plates. GADS!! Anyway, I took the manifold over to a local machine shop to have it planed again just to be sure it wasn't warped or otherwise not perfect and made the trek to Tractor Supply to get a new set of gaskets.

My buddy is grinding down the lower outer edge of he manifold to insure it clears the plates. I supposed I could have removed the plates, installed the manifold and then reinstalled the plates but I didn't really want break the seals on them. I'll be putting it back together either this evening or tomorrow and will let you know how it goes.

" the lower side block access plate"

Those are the valve covers.

Did you call the seller & tell them they are selling junk? Even if you don't get a refund, there has got to be some satisfaction in telling them that there quality control sucks.

I had the same problem with a manifold I got from this site and Had to grind it down to get the valve cover to fit. I called and told them and they said they have not heard of the problem before.

 

[BLDFW]

(quoted from post at 19:03:29 05/08/12)

A hose of any kind held up to yer ear and ran around the manifold would have found the zaust leak while others were look'n for their doctor tools...

Where were you when I needed you?

(quoted from post at 19:03:29 05/08/12)
Why would anyone machine a new manifold,,, If I even had the thought I would check it with a straight edge before I went to grind'n away...

Since I had it tightened down while not flush to the block and then it was run for a while, it's entirely possible the extended exposure to high heat could have wracked it.....so rather than risk going through the whole exercise again, to order online or drive 25 miles for yet another set of exhaust gaskets, etc, etc, etc, I opted to err on the side of caution, to run it across a planer and KNOW that it's right and be done with it once and for all.....or until it needs it again, whichever comes first.

Pretty, eh?

 

[BLDFW]

UPDATE: My buddy took his grinder to the lower edge of the port openings to insure it would clear the side access plates (aka valve covers :wink: ).

I cleaned up the block surfaces and mounted the new manifold again, this time making double sure it cleared the valve cover plates. With everything put back together and tightened down, she started right up! She ran a whole lot smoother than before when it was sucking exhaust air. We fiddled with the carb settings until she was running optimal and quiet. She ran great at all speeds and sudden throttle adjustments.

GLAD that exercise is over!!

Thank you to everyone who provided feedback!! Glad you're all here to provide the benefits of your experiences, good or bad! It's all good!

 

[R Geiger]

(quoted from post at 00:35:27 05/10/12) UPDATE: My buddy took his grinder to the lower edge of the port openings to insure it would clear the side access plates (aka valve covers :wink: ).

I cleaned up the block surfaces and mounted the new manifold again, this time making double sure it cleared the valve cover plates. With everything put back together and tightened down, she started right up! She ran a whole lot smoother than before when it was sucking exhaust air. We fiddled with the carb settings until she was running optimal and quiet. She ran great at all speeds and sudden throttle adjustments.

GLAD that exercise is over!!

Thank you to everyone who provided feedback!! Glad you're all here to provide the benefits of your experiences, good or bad! It's all good!

This shows where I had to grind. I had put the manifold on before the valve covers. then the covers would not go on. the studs were not bent and I don't think I could have bent them enough to work.

 

[BLDFW]

(quoted from post at 09:00:51 05/09/12)

This shows where I had to grind. I had put the manifold on before the valve covers. then the covers would not go on. the studs were not bent and I don't think I could have bent them enough to work.

Wow, yours was really off. Mine wasn't as obvious as yours. We did the same thing by laying the gasket out and grinding down to it. We also had to grind out two surface areas inside the bolt passages to get the socket head to clear.

 

[Hobo,NC]

It looks all over the place,,, what brand is it...