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Which Exhaust Manifold Gasket Set Is Best?

 
lonewolf11
V-6 Camaros rule!
Posts: 105
Joined: 04/09
Posted: 02/01/13 01:15 PM

Again time constraints. I have searched for new Exhaust Manifold Gasket Sets from AutoZone, O'Reilly's, NAPA etc and find so many to choose from. This being the 1st time for Gaskets of the Factory L98 Exhaust Manifold going back on my 1987 Corvette. Up until now I have had Shorty Header's and getting Header Gaskets from Gotelli"s Speed Shop has been a non-issue. Now that I am going back to stock it has been a challenge on which Gasket Set is best. Any help here would be greatly appreciated. I will going back to Long Tube Header's by mid-summer so for now I am using the stock set-up. Thanks.  
Gregorio Lonewolf

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pepsi68
I love my Chevy Chevette!
Posts: 1
Joined: 02/13
Posted: 02/01/13 11:22 PM

lonewolf11

I've had a heck of a time with the web-sites. I had to reregister as pepsi68.AKA pepsi1....

If you still have the stock exhaust off. Get a long straight edge and put it across the stock headers. If they are not flat they will never hold a gasket.

Get them to a machine shop and have them resurfaced. Those stainless steel headers are a pain to get a gasket to seat.

I will (assume) the headers are flat. I would go to a dealer and get the GM gaskets. Then I cut the lower bolt holes 1/2 out. I hope I didn't confuse you.    This way you can get the header bolts started and then drop the gaskets in between the header and the head. Tighten them from the center out. Then the last time if you can do it when the engine is hot.
   You may have seen them like that. Just don't over cut the hole. I've done this on my street cars and race cars. The gaskets I like are the silver ones. They are 3 pieces to a side. But thats my preference.

Bob AKA pepsi1  

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lonewolf11
V-6 Camaros rule!
Posts: 105
Joined: 04/09
Posted: 02/02/13 11:22 AM

Thanks Bob... As I am in the process of all this and with everything prepped for my application of the Cermaic Coated Paint I was going to apply today I 1st will check the "flatness" of the Factoy Manifolds. I spent much time yesterday sanding & prepping not only the Exhaust Manifolds & AIR Pipes I did the same with the Front Y-Pipe. Unfortunately here in San Francisco after weeks of sunshine we are hit with cooler weather since the fog has rolled in and at this writing of 10:15 am it looks to be foggy all day. So with the Temps down NO painting will be involved. I do all my own work out of my garage & painting inside the garage with my wife on an Oxygen Compressor 24/7 I don't want to chance a blow up of sorts. Know what I mean? The fumes get sent right upstairs thru the heater vents as the furnace is right in the garage. Your input is very helpful however & I will follow your directions presuming I go the dealership option vs Corvette Centrals set I just ran across for only $12.95 + S&H. I was so amazed at AutoZones wide selection & with so many with diminsions included I was like wait a minute, there has to be an easier way.

This just came to me, since I am doing not only the manifolds and have the Y-Pipe off as well, would having to start the header bolts before dropping in the gasket be deemed necessary or as the Corvette Central Gaskets being individual it would not matter as these won't drop in anyway but a set by Fel-Pro would be a solid 1 piece & drop in not an option unless I was to cut them. Guess doing this the old fashion way of putting the gasket on the manifold slideing the bolts thru then mate it to the head, hand tighten then wrenching? Thanks.  
Gregorio Lonewolf

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lonewolf11
V-6 Camaros rule!
Posts: 105
Joined: 04/09
Posted: 02/02/13 11:28 AM

Bob, sorry I was just browsing gaskets and see that there many types including the materials used such as aluminum or copper either round, oval or square port & some with port dimensions in making these things. Any suggestion on what materials are best? Longest lasting, best seal, the thickness & what difference thickness may make etc. what are you thoughts on this? Thanks.  
Gregorio Lonewolf

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pepsi1
V-6 Camaros rule!
Posts: 88
Joined: 01/12
Posted: 02/05/13 03:58 AM

Greg

Sorry I didn't back back to you sooner. Had trouble logging on. My moderator finally got it straightened it out.

All I meant by cutting the bottom half off the gasket bolt hole. Its for ease of installing the gasket, nothing more. If you can get the header bolts all started then slide the gasket behind them. But if you can hold the header and gasket up, do it the way you feel comfortable.

Some (1) peace gaskets will have the (2) end bolts holes cut on the bottom. I did that since I can't remember. Then many years ago Mr Gasket started doing that.

1.As far as the material to use, it goes back to how flat the header is. Then when it mates against the head and the header it has (2) flat surfaces...I've even taken gasket material and made my own.

2.I've used the cheap gaskets that come in engine kits, I've even made my own in a pinch and they worked on my race headers. So the material isn't really, a problem. Just use a gasket that covers the header opening. Make sure the gaskets isn't overlapping (ie sticking over the exhaust hole) the header opening. If it is it will eventually burn in that spot. Exhaust temperatures go from 600* to 1200* depending on how rich or lean the engine is.

Hope this helps...

Bob  

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lonewolf11
V-6 Camaros rule!
Posts: 105
Joined: 04/09
Posted: 02/05/13 10:47 AM

Bob,

I too had to log in like 4 times this morning as it kept saying incorrect password, it wasn't.

Anyway, thanks for getting back to me & I am glad your situation is cleared up.

It is highly possible I will end up with a 1 piece gasket as the Factory type don't seem to be available thru sources like AutoZone etc. I will check on Mr. Gasket & what is available as this sounds like a good starting point. I will be going to Gotelli's for the gasket. Check their website if you'd like; http://www.gotellispeedshop.com/

I have checked the flatness of the Exhaust Manifolds with a straight edge & it is FLAT! Thanks the powers that be. So what it appears to be is just a set of gaskets to make it all fit & work.

Sunday was the only day out of the last 5 that saw enough sunshine & warm enough weather (San Francisco, and yes we lost the SuperBowl, but props to the Ravens for getting the job done from the 1st whistle) without hardly any wind to Ceramic Coat the Exhaust Manifolds & the Heat Shields. May sound impractical to paint the exhuast Manifolds other than it's own natural state but they are a Grey with the Shields White. I also did the Front Y-Pipe in Grey. It actually looks good this way as far appearances go. My main objective was protecting from rust etc & protecting the pipes & the plug wires & other meltable items.

I do have to remove the Pre-Cats as my mechanic says they may cause the thing to "block-up" with the CompCam that is installed. I personally never thought Pre-cats were necessary anyway. Haven't had them on the Vette since I bought it 7 yrs ago. My first purchase was a front Y-Pipe without the Pre-Cats and installing the Shorty Header's. I have this covered however.

Thanks for your help.

Greg  
Gregorio Lonewolf

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Serpico
I love my Chevy Chevette!
Posts: 2
Joined: 02/13
Posted: 02/06/13 11:12 AM

Greg:
  Glad to hear your getting there, with your project. I've been to San Fran. a few times in my working days. The last time I was there we visited some friends in San Jose. If was just like you described a couple days. Then it was nice. You know what always got to me was the way the Fog out over the ocean looks like mountains from a distance...LOL...My brother in Fl. Gets that there also. We went to an open air flea market that was HUGE. I was able to get new Lugs nuts for our 86 Monte Carlo SS for 1/3 the price the dealer wanted.
  Apparentley they have a different taper I don't remember if it was 45* something like that. I send them home by UPS. 20 Lugs nuts, but I was still ahead of the game. Well I'll tell you I'll be logging in as Serpico. My Moderator has been going crazy trying to straighten this mess out.

Bob AKA-pepsi1  

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lonewolf11
V-6 Camaros rule!
Posts: 105
Joined: 04/09
Posted: 02/07/13 11:16 AM

Bob,

Thanks for the reply & nice story. You are correct about the Fog & looking like a Mountain Bank. It often does as it slowly rolls over the hills & in from the ocean. Sorry you are having so much difficutly with getting things straightened out with the moderator. Hope it's working for you soon.

Onto the project. I have everything in place for when I get my Disability check Saturday. There are a few items I need to get to finish this project. A few nuts & bolts, a new set of spark plugs & wires along with Gaskets as needed. May as well put new ones on since I am doing this and starting fresh is a good thing, I believe. Cleaning the Throttle Body inside & out along with doing a coolant by-pass on the Throttle Body. I have read so much about this helping to keep colder air going thru the Throttle Body so thought I'd give this a try. I'll have to post some photos of the engine bay again once I have completed this project.

The item that is puzzling me now is the hook up of this silly little Cross-over Tube that goes from the right Exhaust Manifold to the Intake that has this crazy sensor on it. The opening for this tube on the Exhaust Manifold is quite big in diameter & has a bulge to slip over & I know using a rubber hose to connect here will more than likely "melt" right away. I haven't been able to locate this Cross Over Tube, aphoto of an L98 showing this tube nor even a picture of it on any website, as to how the tube connects at this juncture. I am looking this up as on my Shorty Header's we took the AIR tubes off of my original Exhaust Manifolds to weld onto the Shorty's. Also, when this new motor was being built the builder fabricated his own & welded it all to the Header itself so will have to be cut off to get the Header off. May end up fabricating my own as well.

I will continue to do some research, perhaps Vetteweb will have it someplace in the archives... Or I'll just post for someone to be nice enough to take a photo of theirs so that I can see how the darn thing is connected. I also have NOT been able to find any for sale thru the usual resources, Corvette Central, Mid-America, Eckler's etc. Anything on Craigslist, Ebay or any other place advertising L98 parts are for a complete motor or what have you but nothing about this particular tube itself.

Thanks for all of your help & kind words.  
Gregorio Lonewolf

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