If you are not familiar with the Eccentric Thermal Bypass, it is a thermo-wax controlled plunger thingamajig in the front of the eccentric shaft that Mazda used to cut off oil flow to the rotors during warm up. Basically, it's a device aimed at warming up the engine more quickly. The down-side is that it can fail and, it seems, to usually fail in the bypass position, overheating the rotors and causing damage to the engine. Mazda used the thermal bypass in all 13Bs from 1986 on, including the RENESIS.

We don't like the thermal bypass and suggest it is a good idea to eliminate it functionally on all rebuilds. Some companies sell a machined insert to replace the device, but we feel that is absurd when a few pennies in lockwashers will do the job just as well. To be exact, all that is required are three 5/16 inch (or 8mm) lockwashers placed over the end of the bypass. When Rob attended the factory New Model Training in 1985, back when he was a Mazda dealer shop foreman in San Jose, this is the method the Mazda techs showed him.

Doing the mod requires removing the pulley hub bolt, behind which the thermal bypass resides. For this reason, we recommend you only perform the mod during an engine rebuild or if you are taking off the front cover for some other reason. Regardless, care must be taken not to allow the thrust bearings to slip. While there are ways to do this in the car (which I won't get into here), ideally the engine would be out of the car on an engine stand, with the front cover pointed up.

We are pleased to offer an Eccentric Thermal Bypass Elimination Kit (3 lockwashers and instructions) to anyone who wants it, free of charge. We will even mail it to you at our cost. No strings attached. It is a 42¢ value...with 39¢ of that in postage. Or, you can download the instructions and get your own washers. Either way is fine.

If you want one, PM or email me with your name and mailing address.

 

I'm serious about mailing these kits out for free. If you want one, shoot me a PM, email or call.

 

Wow.... just the factt hat you would invest your time in something like this is impressive. Guess it shows that you really do look out for the rest of us.

 

Yes i agree i think that you are doing the forum and the rest of the RX7 community a great justice no matter how small a deed it is.

One question do you think any of the current engine issues with the renesis could have been caused by this... Just wondering?

 

Thanks. As for the RENESIS, I don't think the thermal bypass is a real issue. The valves tend to fail with age and Mazda has been using them for 20 years now, so it's unlikely they would suddenly make a bad batch of them. Even now, it's not because they fail frequently but simply the tragic consequences of a failure that make us err on the side of caution and eliminate all possibility. I beleive the current issues with the RENESIS involve compromises made between lubrication and emissions. Mazda must meet emissions and it seems they may have reduced internal lubrication to realize it...but that's just speculation. Since they are under warantee, we don't see many of them in the aftermarket yet. The short apex seals also seem to be an issue, but again I cannot say that with certainty. The RENESIS is still an impressive feat of engineering.

 

tried to pm you but rx7club is not allowing it, please pm me. I'm interested in the kit for a 13bt

thanks

 

Yeah, sorry. When they made me a moderator of this sub-forum, they seemed to have disabled my PM privileges by mistake. Not only can't I recieve them, but I can't send them either. Email me at <sales@pineappleracing.com>.

 

Poetic .......

-S-

 

Shot you an email. Send me some. Thanks

Chris

 

What would be the symptoms of a failed Pellet? I have low oil pressure while cruising but really only when its cold outside, around 45psi, stock gauge. If there is a lot of throttle fluctuation or gear changing then it will hang right at about 60psi, stock gauge.

Chris

 

Usually, the thermal pellet dies quite suddenly and will result in a 10-15 psi drop in pressure, as well as making the pressure "sluggish". The pump can often still hit the regulator pressure (~60 psi), but then it will sink back down at lower RPMs. Don't rely on the stock pressure gauge...you need a mechanical gauge to be certain of the actual pressure.

 

Yea I've been looking for a nice gauge. Thinking about an ISSPRO in the very near future.

Chris

 

Well, you don't need a nice gauge...just an inexpensive mechanical one that you can plug in to verify the operating pressure. Just install it in the engine bay and remove it when you are done. Running mechanical gauges inside the car can be risky. Never do it with fuel and think twice before doing it with other HOT liquids...one failure of a connection inside the car can scar you for life. All it takes is a cracked/loose fitting, bad line or a collision. They do make "isolators", but it adds expense and complexity. I would much rather have mechanical gauges in the engine bay (temporary or permanent) and run nice full-sweep electronic gauges in the cockpit.

 

^ I will definatly use this advise in the near future. So as fas and the Eccentric thermal bypass do all 13b's have this useless device?

 

GSL-SE and earlier 13Bs did not have the thermal bypass; 1986 through the RX-8 have them. They are not litterally useless...when they work, they do warm the engine up quicker so that emissions are reduced. In that sense, it is like a pre-cat. When the engine is up to operating temperature, it does nothing whatsoever for emissions. It's job is only transitionary. The problem with the bypass devise is that it can fail and cook your engine, so it is not worth risking in our opinion. Mazda, however, has pretty rigerous standards to meet and this was the only way.

 

Im so in. This is definatly a reliability mod. Ill send you a email right now Blake.

 

It's on the way...

 

Great. Thanks Blake.

 

No problem. Your post brought the subject to several more people's attention, apparently, because three more kits went out the same day when we normally go weeks without anyone asking.

 

Greetings from Greece.
I believe that my pellet has failed so....is there any chance to send me this elimination kit???
I am willing to pay for the shipping costs.
I thank you in advance.

 

Sure. It's only USD$0.84 for airmail letter post, so don't worry about paying the shipping. Alternatively, I could email you the instructions and all you have to do is find three 8mm lockwashers.

 

Please do so!!!!
Pm me please!!!!
By the way...what is a lockwasher???
Thanx

 

Blake, the link to the instructions on your intial post isn't working .

 

Thanks for pointing that out...another relic of the old site. I updated the link in the original post and for good measure, here it is again:

https://www.pineappleracing.com/inst...ypass1a-s2.pdf

 

just sent an order and requested these for my FD

*dances*