# Exhaust Gasket, Gap Seal



## BigJim (Sep 2, 2008)

I am just getting around to fixing my exhaust manifold for the 10th or what ever time. I took my manifold back off today. I put a new 80 grit sanding belt on my 89 inch horizontal sander and sanded the fool out of the manifold trying to flatten the flange. I have one spot about 1/2 inch right at the outside port that has .006 " gap. I have sanded til I am blue in the face and can not get that spot gone.

The rest of the flange is dead flat but this one spot just won't clear. I have to different Fel Pro gaskets, one is a fiber gasket with metal in the middle, I think. I do know it is fiber. I also have another Fel Pro that is two separate metal gaskets made together. How much of a gap will the fiber gasket seal. I hate like the dickens to have to take this manifold back off again, it is not an easy one to R&R.

I will sand some more on it tomorrow. Any help I sure would appreciate. If there is a link I can ask the question that would be great also.


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## chandler48 (Jun 5, 2017)

You have an 89" horizontal sander. I thought I was tool "poor", but that takes the cake. Wow. Is it stationary, or do you move it across the block/manifold? And is it the manifold that is weird, or the block?


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## Fix'n it (Mar 12, 2012)

engine ?


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## Old Thomas (Nov 28, 2019)

Is there a Mr Gasket header gasket made for your engine?


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## BigJim (Sep 2, 2008)

chandler48 said:


> You have an 89" horizontal sander. I thought I was tool "poor", but that takes the cake. Wow. Is it stationary, or do you move it across the block/manifold? And is it the manifold that is weird, or the block?


Chandler, maybe I stated that wrong, it takes an 89 inch belt, I think. Anyway it has 48 inches of sanding surface and is stationary. I have to hold the manifold flange against the belt to sand.

Fix, I really don't know what year engine it is, but it is 2.5 Nissan. It was supposed to have a 2008 SE R Spec V engine in it, which is a 200 HP 2.5 but it isn't. When I rebuilt the engine I found out it wasn't a SE R Spec V engine, I think it came out of an Altima which is why I sweat blood getting that sucker back in the car.

I just checked and the specs say I can have 0.0276 inch gap so I may be ok. 

I also just looked and I see what looks like sand in one port of the manifold. That is what caused the Altima engines to go down the tubes. The exhaust manifold/catalytic converters were too close to the exhaust and fried the catalytic converters turning the insides to sand. That sand type stuff got sucked back into the engine and the rest is history. Nissan would not honor the blown engines so folks were just stuck with a car with around 64,000 miles with an engine that was trash. 

This engine isn't supposed to have that problem. The catalytic converters are made into the exhaust manifold. So now I am also looking at maybe the engine going down again. Nope, I will not put that manifold with the converters back on if I find out that is what is happening. I will use spacers on the 02 sensors to fool the brain to thinking all is ok. Man I hate this car.


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## BigJim (Sep 2, 2008)

Old Thomas said:


> Is there a Mr Gasket header gasket made for your engine?


I will check, if I go back with this manifold, I appreciate the information.


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## Brainbucket (Mar 30, 2015)

Maybe header gaskets with the soft middle to conform with the headers. I don't know if they make them for your car but here is an example. By the way, these lasted 20 years on my 550hp 454
















Earls 29D04BERL Header Gasket Set, BB Chevy, Pair


Header Gasket Set, 396-454 Chevy Big Block 1965-90, (1.83" x 1.72" Ports), Pair - Designed and manufactured for Earl's by Parker-Hannifin Corporation, these seals are the first High Performance Seals developed to solve automotive sealing problems using Aerospace Technology. Uses Aerospace...




www.speedwaymotors.com


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## ukrkoz (Dec 31, 2010)

Amazon.com


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## BigJim (Sep 2, 2008)

ukrkoz said:


> Amazon.com


ukrkoz, I checked on that, it is made for mufflers, it can't take the high heat of the manifold. I do appreciate your suggestion, thank you.

BB, if those gaskets will hold on that bad boy, they will hold on anything. I appreciate the suggestion.

I have wrestled with this situation and researched about every place I could find last night. I am afraid to put this manifold with the catalytic converters built in back on. There is sand looking particles in one of the ports which is the catalyst deteriorating. This was the reason the Altima engines went down. This is an Altima engine in the little car so it looks like the same thing happening on this engine.

I am between a rock and a hard spot. I can't afford another converter, this one is not that old at all. If I sell it with a gutted converter I could get in trouble, If I put this converter back on I am sure the engine will go down the tubes. We want to sell this one and see about getting a different car or small truck. At this point, I really don't have a choice but to put the gutted converter back on. Man I hate this car. lol Here is what the manifold looks like: It has 4- 02 sensors in this unit.


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## SW Dweller (Jan 6, 2021)

are there copper gaskets available for the application? I have had good luck with them in the past


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## Old Thomas (Nov 28, 2019)

I have had good luck with copper gaskets on perfect dead flat surfaces. On imperfect surfaces I had leaks with copper. Then I use thick header gaskets or take the manifold to an engine shop to get it machined flat.


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## keenxxx (May 5, 2018)

I work in the trade and if a replacement is out of the question ($$) I will see if the local "machine shop"can surface the flange. On older long tube headers the flanges would warp, We would cut the flanges so they would independently tighten. Should not have to mess around w/ multiple gaskets on an OE exhaust manifold.


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## BigJim (Sep 2, 2008)

Today I had planned to install the original manifold. As I got into flattening that flange I noticed one of the tubes had a crack completely all the way around, so much for that one. I continue to sand the flange on the other manifold we bought last year. Finally got it right. I used a Fel Pro fiber gasket that had an aluminum core. I think it will work ok this time.

I did look for header gaskets but had no luck. After finding the original manifold was trash, I had no choice other than just keep going with this one. I appreciate all your help, I will let you know if it spits a code or not.


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## Brainbucket (Mar 30, 2015)

🤞🤞


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## ukrkoz (Dec 31, 2010)

Actually, if you really look around, there are similar compounds rated up to 2400 degrees for EXHAUST manifolds. I somehow just could not find the right sample, though I have cna of it in my garage. Lazy to go check. 

There you are:









Amazon.com: Blue Magic 8024 ThermoSteel High-Temp Metal Repair - 24 oz. : Automotive


Buy Blue Magic 8024 ThermoSteel High-Temp Metal Repair - 24 oz.: Adhesives - Amazon.com ✓ FREE DELIVERY possible on eligible purchases



www.amazon.com






Welds cracks and holes in iron and steel
*Withstands temperatures to 2400 degree Fahrenheit*
*Strength increases with heat*
*Fills cracks and holes and pits*
Great for boilers, stoves, BBQ's, furnaces, heaters


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## ukrkoz (Dec 31, 2010)

Also, bite a bullet, take exhaust to pro shop that has large plane grinder. Not sure, what exactly is the proper term for those. They are large machines that have stationary rotating grinding wheel and entire support moves back and for underneath it. Thus, wheel makes perfect flat surface. Your exhaust flanges are warped from heat. For purpose you have, I'd have just sealed it and , you know.....


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## BigJim (Sep 2, 2008)

ukrkoz said:


> Also, bite a bullet, take exhaust to pro shop that has large plane grinder. Not sure, what exactly is the proper term for those. They are large machines that have stationary rotating grinding wheel and entire support moves back and for underneath it. Thus, wheel makes perfect flat surface. Your exhaust flanges are warped from heat. For purpose you have, I'd have just sealed it and , you know.....


Chattanooga where we live, there are few machine shops, I know of one and they aren't too well equipped. I did ask them and they couldn't surface it. I appreciate the suggestion, and I appreciate the link to the high temperature material, I have it bookmarked. I did a lot of research on a lot of products that were advertised to work on exhaust systems and manifolds, most if not all I saw failed. I didn't see the one you linked. If it becomes necessary I will sure give that one a try. Thank you.


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## Fix'n it (Mar 12, 2012)

so, you have an exhaust manifold that you can't get flat, .006" ?


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## BigJim (Sep 2, 2008)

Fix'n it said:


> so, you have an exhaust manifold that you can't get flat, .006" ?


I finally got the flange flat, I bet I took off 3/32 of an inch in all. I got it all put back together the spacers on the 02 sensors was going to hit the fan shroud so I cut a relief. Worked good, and now ready for a road test. I will let you know it if spits a code.


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## ukrkoz (Dec 31, 2010)

BigJim said:


> I finally got the flange flat, I bet I took off 3/32 of an inch in all. I got it all put back together the spacers on the 02 sensors was going to hit the fan shroud so I cut a relief. Worked good, and now ready for a road test. I will let you know it if spits a code.


What code? Exhaust leaks do not "spit code". I had 2 flange bolts missing on my Tahoe, one per side, to major exhaust leak, and there was no codes for months.


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## BigJim (Sep 2, 2008)

ukrkoz said:


> What code? Exhaust leaks do not "spit code". I had 2 flange bolts missing on my Tahoe, one per side, to major exhaust leak, and there was no codes for months.


My code reader gave an exhaust leak as a potential cause. I did a pressure test and sure enough there was an exhaust leak. I knew it couldn't be anything else, I have replaced every sensor on that dern engine, I even turned the knock sensor around so it would still be grounded, but not send a signal that something was wrong. I have the high dollar plugs in the engine and they are only two months old. I am not getting oil in the plug tubes so that isn't causing a misfire. The exhaust leak was the only thing left.


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## Brainbucket (Mar 30, 2015)

ukrkoz said:


> What code? Exhaust leaks do not "spit code". I had 2 flange bolts missing on my Tahoe, one per side, to major exhaust leak, and there was no codes for months.


Yes they do. Your just lucky.


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## ukrkoz (Dec 31, 2010)

Well, duh. You have O2 code, with one of the *possible* causes being exhaust leak. Which I did have on my Tahoe but, considering 144 000 miles, O2 was replaced and that was it. The only way I found there was leak, was smell of exhaust inside, when standing still at, say, red light. F-rs who pulled engine out and put it back in were lazy enough not to reinstall 2 flange bolts, ones on the subframe side, as it's rather tight spots.


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## BigJim (Sep 2, 2008)

I found out one thing for sure, you don't want to inhale the dust from the guts of a catalytic converter.


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## Fix'n it (Mar 12, 2012)

i've gutted a few = no question about it.


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## BigJim (Sep 2, 2008)

We took a little trip today to see how the manifold fix went. We were getting 19 mpg before fixing the manifold, we are getting 35.5 mpg now. Just hope that dern light stays off. It sure has a whole lot more power now. It is hard to believe this little 4 banger has the same horse power as the old 283 Chevy small block.


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## BigJim (Sep 2, 2008)

Well, so much for that, went to the store about an hour ago, check engine light came on. Did I say I hated this car?


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## BigJim (Sep 2, 2008)

This afternoon I did a code reading and it said the Cotten pickin car, spit the code P300, random misfire. My code reader said it could be bad plugs, bad fuel injectors, coils or a vacuum leak. Plugs are the best NKJ available and are about a week old ($64 at rockauto) The injectors are new, not 6 months old, top of the line injectors. All new Denso coils, not cheap ones and they are about 3 months old. I did a smoke test today and there is no vacuum leak that I could see. 

Heck the dern car was getting 19. something mpg, before I changed out the manifold, now it is getting 35 mpg. I am going to drive the blame thing until something breaks. I don't know what else to do.


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## ukrkoz (Dec 31, 2010)

BigJim said:


> Well, so much for that, went to the store about an hour ago, check engine light came on. Did I say I hated this car?


That's how it is. You hate her, she hates you back. Show some love....


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## ukrkoz (Dec 31, 2010)

A Nissan, huh..
They leak down oil from lifter tappets and this can cause timing shift causing misfire.
I do not recommend lifters job, it becomes cost prohibitive if you want to sell the car. Basically, it needs head job. If it's mechanical, you will not have true error code pointing at it. It's hours of diagnostics, including compression test. 
We had Infinity once. Son did. Not for long.....


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## BigJim (Sep 2, 2008)

ukrkoz said:


> A Nissan, huh..
> They leak down oil from lifter tappets and this can cause timing shift causing misfire.
> I do not recommend lifters job, it becomes cost prohibitive if you want to sell the car. Basically, it needs head job. If it's mechanical, you will not have true error code pointing at it. It's hours of diagnostics, including compression test.
> We had Infinity once. Son did. Not for long.....


That Infinity is just an over grown Nissan. lol You may be on to something about needing a reworked head. When the engine went down before I rebuilt it. It had gotten to the point where metal had just barely started sticking to the cams at the journals. I had to hone the journals and the cams to remove what little was there. In doing so, my oil pressure is lower than I want it to be but still good enough that it won't lock the engine if at idle for hours.

Replacing the head is not in my future though, I have put too much into this car now, I will never recover what I have in it. I appreciate you help. Oh I did do a compression check, all cylinders were right together. This car has a really fast take off, it isn't lacking in power for sure.

I am going to check the codes again after while when it quits raining.


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## Brainbucket (Mar 30, 2015)

Are your spark plugs gaped correctly? If it's doing a p0300, random misfire, keep driving it. It should identify the cylinder. If you have a scanner that can read fuel trim, that will help. Seeing what it's doing. Adding fuel or removing it.


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## BigJim (Sep 2, 2008)

Brainbucket said:


> Are your spark plugs gaped correctly? If it's doing a p0300, random misfire, keep driving it. It should identify the cylinder. If you have a scanner that can read fuel trim, that will help. Seeing what it's doing. Adding fuel or removing it.


BB, the crazy part is the cel went off and it has done this a time before. I didn't gap these plugs as it said gapping them would ruin them. These are NGK DILKAR6A11 plugs, as much as the cost I figured they would be good ones.

I just checked, they say they do need to be gapped. I will check them tomorrow.


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## ukrkoz (Dec 31, 2010)

I'd say, pull ECU fuse, remove battery cables and touch cable clamps together. This depowers everything, drains any back up power in the system.
And let it sit overnight.
It might be just the fluke code leftover. When I bought my beloved Tahoe and we had it scanned with intelligent scanner, it showed 67 codes sitting in memory that regular scanner will not pick up.
Unfortunately, and I apologize for doing this to you, you made basic DIY mistake - started tossing parts at code without doing in depth diagnostic and pin pointing source of error.
I bought and sold many cars off craigslist and noticed that, error code tends to return 10 minutes before potential buyer will show at your place. Just saying.


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## BigJim (Sep 2, 2008)

UK, that is some good information, I will give that a try. I will check to see if the gaps for the plugs are right today also.

The FAS was oil coated from to much oil on the air filter, a wire was broken on one of the 02 sensors. The new one had a cut wire when I bought it. I don't know why I though to slide the sleeve on the 02 sensor up to look at the wires but sure enough, one of the wires was cut, not broken.

I turned the knock sensor around and reinstalled it so it would not send signals to the ECU, I did replace the cam and crank sensors though, too hard to get to the crank sensor after all of it back together.

I appreciate the information, it is worth a try for sure. Now to find that dern fuse. lol


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