NoPistons -Mazda Rx7 & Rx8 Rotary Forum

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-   Rotary Engine Building, Porting & Swaps (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/)
-   -   Oil pan gasket and front cover gasket (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/oil-pan-gasket-front-cover-gasket-69992/)

RE_TurboFB 06-15-2008 08:03 PM

I have read and hear from a few that they dont recommend using a oil pan gasket. I have used just silicon before when I did not have a oil pan gasket handy, And It did not seem to have any problems..



A few more say not to use a front cover gasket, and to just use a silicon in place of it. I have heard by doing this that it will insure that the engine will have good oil pressure....



Have any of you guys ever heard any thing like this before...???



Thanks guys!!

Stanello 06-15-2008 08:19 PM

Definitely use a front cover gasket. The oil pan gasket is up to you, I've had more success with just using RTV.

mazdaspeed7 06-15-2008 08:45 PM

I never use a front cover gasket, but you have to use a different o-ring for the oil feed. The stock ones, s4 or S5 wont work. The RA kit comes with them, but I can probably dig up the sizes if you are interested. As for the oil pan gasket, I dont use that either. Just good silicon(hondabond or at least grey rtv) and good cleaning of the flanges.

Lynn E. Hanover 06-15-2008 11:03 PM


Originally Posted by RE_TurboFB' post='902050' date='Jun 15 2008, 05:03 PM
I have read and hear from a few that they dont recommend using a oil pan gasket. I have used just silicon before when I did not have a oil pan gasket handy, And It did not seem to have any problems..



A few more say not to use a front cover gasket, and to just use a silicon in place of it. I have heard by doing this that it will insure that the engine will have good oil pressure....



Have any of you guys ever heard any thing like this before...???



Thanks guys!!



That idea about no front cover gasket is to reduce the chance of blowing out the cover to iron "O" ring junction.



The front cover has too few bolts in general, and nothing close to this junction to hold it together. A metal "O" ring works well.



And newer kits have a metal "O" ring backup ring to help with holding in the "O" ring. Some had a Teflon washer looking thing to do the same thing. Usually not a problem unless the oil pressure has been increased, or a cold start gets awway from you, and revs up a bit.. The oil pressure actually pushes the cover out from the front iron and the "O" ring escapes.



Then you can only get maybe 30 PSI with the "O" ring stuck between the cover and the land area in the front iron.



If you leave in the part of the gasket (paper) that fits around that land then leave out the rest, you get that extra pressure from the missing .018" of gasket.



Lynn E. Hanover

RE_TurboFB 06-16-2008 12:11 AM

So i can just cut out the part of the front cover gasket that seals around the O-ring and run that part. Then just leave out the rest of the gasket and use some RTV grey ..???



OR just leave the gasket out all together and run RTV Grey and a different O-ring... No O-ring retainer Or anything...????



Wow This is good stuff to know guys https://www.nopistons.com/forums/pub...IR#>/smile.gif , Because I am running higher they stock oil pressure...



Thanks!!!

j9fd3s 06-16-2008 12:48 AM

the factory doesnt use an oil pan gasket, they also seem to have the best results.



i like to use the mazda sealer 8527-77-739, but volume seems to be better than quality with the oil pan gasket. ultra grey works fine.



i'm too chicken to not run a front cover gasket, although have been using the rx8 one, its metal, and reusable, n3h1-10-502a?

Lynn E. Hanover 06-16-2008 06:21 AM


Originally Posted by RE_TurboFB' post='902061' date='Jun 15 2008, 10:11 PM
So i can just cut out the part of the front cover gasket that seals around the O-ring and run that part. Then just leave out the rest of the gasket and use some RTV grey ..???



OR just leave the gasket out all together and run RTV Grey and a different O-ring... No O-ring retainer Or anything...????



Wow This is good stuff to know guys https://www.nopistons.com/forums/pub...IR#>/smile.gif , Because I am running higher they stock oil pressure...



Thanks!!!



Keep in mind that the factory does that to avoid the expense of the gasket. It is more like a cost reduction than an engineering improvement.



That lousy "O" ring blowing out has cost thousands of engines through the years, and Mazda has put in a number of penny fixes, but never redesigned the junction so it would work under stress. They give you a piece that works fine as long as it is not stressed, but its in a sports car. The kind of thinking you get from people who are not allowed to have guns.



The next time your engine is apart, make a sheet metal disc to fit in the hole and put the "O" ring on top of the disc. If you run the OMP that disc needs a .020" hole through it to feed the pump.



Drill out the brass plug in the end of that latteral gallery. Take it to a machine shop and have an "O" ring boss fitting installed. (AN tube to boss) in dash 10. Then run a AN hose from that for your oil supply. Do not use a pipe fitting. It will crack out the gallery when you tighten it. Remove the stock fitting from the hose and braze it shut to use as a plug for the front cover. Then later, you can change it back to stock if you like.



Piece of cake.



Lynn E. Hanover



Identify the 13B in this picture.

C. Ludwig 06-16-2008 07:34 AM


Originally Posted by RE_TurboFB' post='902061' date='Jun 16 2008, 01:11 AM
So i can just cut out the part of the front cover gasket that seals around the O-ring and run that part. Then just leave out the rest of the gasket and use some RTV grey ..???



OR just leave the gasket out all together and run RTV Grey and a different O-ring... No O-ring retainer Or anything...????



Wow This is good stuff to know guys https://www.nopistons.com/forums/pub...IR#>/smile.gif , Because I am running higher they stock oil pressure...



Thanks!!!





No you can't cut the gasket out in the area around the o-ring. That would effectively shim the rest of the cover up off the o-ring and provide less squeeze than either alternative. You either use a gasket or don't. If you do not use a gasket and use the teflon o-ring combined with the rubber o-ring the teflon will get squeezed flat when the front cover is torqued down. When this happens it pushes the rubber o-ring in and leaves it no where to go other than into the oil galley. So you need to be careful not to flatten the teflon piece too much.



Like Lynn says, a metal (brass or aluminum) crush washer in place of the o-rings works well.

j9fd3s 06-16-2008 04:41 PM


Originally Posted by Lynn E. Hanover' post='902067' date='Jun 16 2008, 04:21 AM
Identify the 13B in this picture.



6 port engine, so that makes it 84-92. freeze plug under the ports in the center plate make it 86-88. its also got a non ribbed tension bolt, and theres no boss for it in the center iron



we were in pauls storage yester day, and he's got a whole box of header flanges that look just like those...

Tom93R1 06-16-2008 08:33 PM

Damn Mike, do you have all that memorized or did you look it up?





We been using the metal RX8 front cover gasket on S5 and earlier motors as well, works great! Like you, too chicken to run with no gasket.


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