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Hey all, so I got hold of a nicely machined but unassembled FD 13B, bridgeported by a place in Houston. I had to obtain a few misc parts to install it in my 85 GSL-SE. I'm using all the stock components from my 6port RE-EGI motor and got it installed to the car a few days ago.
After engine assembly I tested the water jacket seals using a pressure tester that I left in place for an hour and it never moved from 20psi, so I figured that's all good.
The engine uses the S5 rotors, and Houston included the apex seals and corner seals, but I had to obtain new side seals. I also had to get new oil control rings.
Everything went together great, and there was no binding, and as I stated it held pressure just fine.
So, I got it running this morning using the pull start method. After the usual clouds of smoke cleared up, it suddenly started running poorly, seeming to misfire, and the oil pressure dropped. The operating temp had gotten to normal.
Did my oil seals blow already?
I hate rotaries at this point. I've done many piston builds and even if things aren't perfect they always run and you can tweek all the things til it runs great. I've never experienced this much misery until rotary engines.
just sayin'. I'd sure love to drive my RX7, but if this build doesn't take then I'm giving up on these things. It's too hard to get parts anyway.
Your engine build seems fine, s5 rotors are compatible with REW housings. Do a compression test. Then I would suggest giving up, getting a nice 350 or even 383 small block, swapping it in a weekend and having an absolute blast
Seems to me that there are a few issues. One being oil pressure and the other being the operating condition. It also does not appear to be an FD/REW engine.
If it started running poorly after it stopped smoking, you probably didn't blow any seals. It is normal for the oil pressure to be lower at idle, and once the engine is warm. What were you seeing for oil pressure at idle?
Looks to me like a fair amount of RTV was used in the build.. One problem area can be the O ring between the front cover and the block.
You used the O-ring with the plastic retainer? The gasket plus RTV in this area increases the possibility of that O-ring shifting which results in low oil pressure. I don't mess with the paper gaskets anymore, as the later style steel gasket is cheap, superior, and does away with that pesky o ring.
A set of clean or new plugs is a good idea after that first run, and a compression test is a good step to rule out other issues.
If you glued the apex seals short, it is possible that the glue has not broken and once the assembly lube was burnt off you have lost some compression. Not that it would reduce oil pressure, but what was the clearance on your side seals? If they were tight, it is possible that they are binding once hot or have damaged the corner seals.
If you can rule out some issues with a compression test, perhaps we can provide some more suggestions.
Thanks all. The GSL-SE runs great now thanks to RAD Potential's suggestion to ditch the EFI for a Weber 48/IDA setup. The fuel injection was flooding things and fouling the plugs. It's just too difficult to obtain new parts for that system and trying to get the factory OEM RE-EFI running properly isn't gonna happen. A Weber is perfect for the BP. I have reliable quick starts cold and hot, good brap brap brap idle, and super good acceleration. She screams. Perfect oil pressure, perfect compression, perfect cooling. Things are just simpler now. I do have to premix now, but whatever, it's worth it.
I still have the original 13b block that I rebuilt using pre-1983 semiPP housings and will do a similar setup. Maybe I can swap it in when this motor is ready for a refresh.
It makes sense. The GSL-SE is a 40yo EFI system when many cars were still using carbs. It's overly complicated and a bitch to make work and keep working.
I'll keep you all posted if anything comes up, but I'm good for now!
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It makes sense. The GSL-SE is a 40yo EFI system when many cars were still using carbs. It's overly complicated and a bitch to make work and keep working.
It also wasn't designed to run a bridge ported engine with higher compression rotors. Glad to hear you found a good carb setup that works for you! If you ever decide to do EFI again do some kind of aftermarket one rather than trying to convince one of the stock ones to work (even the later model ones)
07-03-22, 03:15 PM
