I like oil pressure. I'm nearly done building a streetported 4 port 13B and I added some shims to an adjustable rear pressure reg a little longer than 1/8" for a little over 85 PSI at 3k RPM with hot oil (I guess that's how you measure oil pressure).

The reason for this thread is to let anyone who's building an engine know that you can omit the front cover gasket and use silicon instead ('85 and older engines, and some later ones). This will crush the front cover "O" ring more which allows higher than stock oil pressure to be used without fear of it getting pushed out (or in).

Lately, I've seen a couple front plates with O rings that have gotten pushed inward which allows oil to bypass. this creates a low pressure condition at all RPM.

Who else has done the no-gasket thing? Am I the only one? I doubt it, since Mazdatrix mentions that silicone can be used instead.
http://www.mazdatrix.com/faq/oring.htm

 

I did my front cover on my cosmo 13b w/o a gasket

 

Cool! What's your oil pressure set to?

 

Is more pressure always better?

Is this only for 2nd gen engines?

 

Not always. If you run the stock OMP with higher than stock pressure, it'll push more into the carb/rotor housings. More will seep past the oil seals as well. It adds up to more oil consumption and a little more smoke at startup. The oil pump chain also wears a little faster.

It's great on older engines that came stock with the adjustable pressure regulators. That would be '71-'80. Later engines can also use these regulators because the thread pitch is the same. That would be '81-'92. I guess '93+ already had high oil pressure stock.

 

i'm so happy i found a 71-80 regulator in my stash

mike

 

Get a block off cover and pre-mix with higher pressure oil regulator. Heck if you are going to the trouble of putting a hp regulator, might as well have premix since you intend to rev high more I assume(reason for having a Hp regulator). Plus pre-mix is better for apex seals.

I have the High pressure reglator 80psi from RB. I will try the no gasket trick next time to see if anything is different with pressure. The gauge usally reads ~70psi at 3000rpm+, but the gauge is so crappy, who knows what its really at.

 

FC3S.ORG does this thing where they crush the top head of the oil pressure... and its suppose to compress the spring a little more and makes more oil pressure...

 

I dont really know what my oil pressure will be(not running yet)

I`am using a 6mm spacer(0.236")..any idea what type of oil pressure that will give ?

Hope ist high enough for my Cheesport..hehe!

 

I got another '71-'80 a couple days ago.

Yeah, this engine's getting an adaptor to block engine oil but let 2 stroke oil into the carb. They come in three versions (it's getting the 12A style because 4 port 13Bs used the same front covers).

That's a cool idea, but I wouldn't know how much to crush it. I think I'll send them one of mine when I run out of the adjustable type.

You'll probably have close to 100PSI with 6mm. I've got a 4.1mm shim (old "slot style" corner seal ground down) that came out of one of my engines. The front cover regulator spring is also longer than an FB, so I think this engine made 90PSI or more at the rear and who knows what at the front. It was locked up when I got it (spun front stationary bearing), but I plan to rebuild it soon with carbon apex seals (cause it's a '73 12A) and possibly a cheeseport for the unusualness of it.

 

Yay cheeseport!
I`ll be happy to know that someone is also going to use the idea except me.

100psi..mmmm sounds nice and high.Then i can put a badge on that says "Diesel" haha!

 

At idle its around 20-25 psi or so, it idles high at 3k its 60, and at 5000k its probally 70 or so.

 

I think my REPU engine is similar at those RPMs. When cold, it bypasses like a stocker, so I hope it's got an adjustable pressure reg in it since everything else, other than the intermediate plate, is old school. Hmm, I bet the oil pump is one of those 15mm ones. Gotta get another 17.5mm.

Yeah, I'm seriously considering the cheeseport on my '73 12A. It's already been streetported. I'm upgrading the old dual side seal rotors to '83-'85 light rotors and 3mm apex seals. Better sealing at high RPM? Well I know 2mm seals seal better at higher RPM because they're lighter. I also need carbon seals because the old chrome is attatched to the aluminum differently and looks like it would flake off really quickly with iron seals. I'd also run an aftermarket flywheel which is something of a chore to do with '73 rotors because RB specifically states that they don't sell stuff for those engines because of their characteristically poor low RPM torque. No problem. Heh, this engine will have lots more power all over the RPM range when I'm done with it. Hmm, 17.5mm oil pump, FB stationary gears and eccentric shaft, well, entire FB rotating assembly, slightly offset starter or a newer lighter one (old engines had the starters on top and they were large and heavy), '74-'78 front cover with single dizzy, DLIDFIS, cheeseport or half bridge or full bridge or something that'll put it up to 150HP if it's going into a FIAT X1/9 (those trannies can handle 150HP but not much more), or more if it's going into a 323, or 200HP if I keep the RX-2 tranny, or 175-200HP if I install it in a street bug.

Oh, don't mind me, I'm just thinking as I'm typing.