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I took my engine out for paint and now that the car is done I'm preparing to put it back in. I pulled out my turbo the other day and found the used OEM exhaust gaskets in the box with it and the manifold, they had clearly been leaking in two areas, but it wasn't anything severe when the car was running and was about inaudible when the car was warmed up. The gaskets have about 12,000 miles of use and I'm wondering if they would be fine to reuse after cleaning them up since they are multi-layer or if they really should be replaced. I've got new OEM locking nuts if that is of any consideration.
I also found one of these SCE copper gaskets new in packaging in a box of parts I had around but I'm concerned about the longevity of it with the EGT's of a single turbo car. Here's a link: https://www.summitracing.com/parts/SCE-9422
As mentioned, I'm running an single turbo. It's an EFR 8374 IWG and I made a little over 400 whp on the old large streetport engine setup, the new engine is a half-bridge shortblock.
Remflex are the best and cheap for the lower exhaust, downpipe end and back. $15-16. Graphic crushable sealing gaskets. I have used these exhaust gaskets for years. These are awesome. No exhaust leaks. They are crushable gaskets that seal perfectly even if your alignment is off some. These are reusable too. Readily available from Amazon, Summit, etc. Just chose your size depending on stock vs. aftermarket diameters.
honestly though it will mostly squeeze out, and if it doesn’t then there’s a gap. How is the dried goop any weaker than a gap?
not arguing for doing it, just struggling with the logic.
I've seen it in the past where people put that copper RTV on exhaust gaskets, they had a leak after using it, then when pulling it that RTV was all burnt up and crappy looking.
Again, there is ZERO REASON for using it. It's not getting you anything or helping anything. I've used just gaskets for YEARS with ZERO leaks on many cars I've worked on.
BTW those Remflex gaskets are nice, they do work well. I've seen some so-so aftermarket exhausts that had a bit of an alignment issue and that solved it.
Those Remflex gasket are great, I use them on both side of the midpipe flange, they will eliminate any issue cause by the flange not being 100% straight. For the manifold, I would have a shop check it, they do warp even the stock brick.
I've seen it in the past where people put that copper RTV on exhaust gaskets, they had a leak after using it, then when pulling it that RTV was all burnt up and crappy looking.
Again, there is ZERO REASON for using it. It's not getting you anything or helping anything. I've used just gaskets for YEARS with ZERO leaks on many cars I've worked on.
BTW those Remflex gaskets are nice, they do work well. I've seen some so-so aftermarket exhausts that had a bit of an alignment issue and that solved it.
Dale
That’s what I get for listening to Rob Dahm, haha…
That’s what I get for listening to Rob Dahm, haha…
What about annealing the gaskets? Not necessary?
You can re-anneal copper crush washers, been there done that. Heat them up with a torch until they glow and they get soft again so they can be crushed again and seal.
Exhaust gaskets that doesn't apply to.
Again, two flat clean surfaces and a proper gasket, even a re-used on, should just be throw it on and done.
You can re-anneal copper crush washers, been there done that. Heat them up with a torch until they glow and they get soft again so they can be crushed again and seal.
Exhaust gaskets that doesn't apply to.
Again, two flat clean surfaces and a proper gasket, even a re-used on, should just be throw it on and done.
Dale
I just did that on my daily yesterday. Dealer wanted a WEEK for new ones.
Dale... post 2... "yes they are re-usable" are you referring to the OE gasket or the item linked to Summit?
most manifolds (all?) warp in the center. you should see some carbon at 9 o'clock on the front and 3 o'clock on the rear. if you put a straightedge on the manifold face you will find a bit of daylight in the area between ports. i have had my manifold precision re-ground flat but it has returned to non flat of course. the Mazda gasket is multilayer to accommodate warpage.
the Summit gasket looks interesting as does the Remflex. any additional input re these two options? i have been running the cheaper OE Cosmo gasket from Atkins.
as has been mentioned above, silicone of any knid has no business anywhere near the exhaust gasket.
The reusable refers to Mazda OEM gaskets. The Remflex gaskets can be re-used but they are designed to crush, once crushed that's that. But if you install same orientation you are OK.
I've only really found they are good on flanges that are slightly misaligned (like a few degrees) or with a slight warp.
In general, for the downpipe-midpipe and midpipe-catback gaskets, these are the winners -
the flange on my manifold shows .003 warp between the two ports. i am a day or so away from bolting it back on my engine. based on this thread i bought s Remflex exhaust gasket. i also have two new Cosmo gaskets. the last time i did the turbo manifold i used two new Cosmo gaskets. they produced a modest carbon/leak pattern between the ports... (like many other single turbos)
the Remflex instructions direct a torque of 20 ft pounds. while i understand this is to control the crush i am concerned that the studs are not under much tension/stretch. my app is about 600 hp for 30 seconds so everything is pretty stressed. i can live w a very small amount of leakage (Cosmo) but not w the nuts or studs doing something weird due to lack of tension.
i am perfectly fine w going either way based on any feedback based on experience.
Howard,
I overtightened the Remflex without any problem except the crush leaves an impression that needs to be put back with the same orientation in the future. The seal can't be beat with zero exhaust leak over time.
Mike
thanks for the info Mike... how much torque did you use. i am not concerned about re-use as they are $36 which, of course, includes both exhaust ports.
I don't remember the exact torque used. I closely watched the gasket start to deform slightly universally along the perimeter of the flange. My midpipe is custom made with a Vibrant HO metal cat, so my one ends is somewhat misaligned so needs more torque on one side for a good seal, hence the need for the Remflex, particularly on this one end.
Mike
i just spoke w the nice lady who mans the phone(s) at Remflex. she indicated there is no "technical" dept and that she was the man. it did sound like there are thousands of these out there and she said they rarely get returns etc. she sounded convincing but so did Sal. i did learn that ideally they would like to see a 50% crush so whatever torque gets that done is the number. when we got into bolt stretch it became murky. i think i will roll the dice on these. just noticed pretty good reviews on Amazon.
"is there any reason to not use their individual Cosmo type individual gaskets"
most manifolds eventually warp. the front shows daylight at 9 o'clock and the rear at 3 o'clock. my CPR design manifold has been in service since 2013 and has been precision ground back to flat a few years ago. it is currently .003 out. this is enough to pass a miniscule amount of exhaust as evidenced by the carbon deposits on the Cosmo gasket. the amount of leakage has zero effect on the flow but i would prefer a complete seal.
short of O ringing the manifold there appears to be two options. the Remflex and another that is made similar to the metallic front cover gasket... with a raised crushable rib. both look interesting.
based on more than 160 incoming motors, my observation is easily 90% of the single turbo motors had the same exhaust leak. it would be nice to actually have a sealed exhaust. Mazda no doubt recognized this challenge and engineered a multilayer gasket... perhaps it works on the dreadful OE turbo manifold but it does not seal on a single turbo system.
i will try the Remflex and if it doesn't work will try the copper metallic option. if that doesn't work it will be O rings just like numerous piston motors use to seal the block/head.
06-12-23, 11:27 AM
