Rex4Life

Going through the TII swap into a GSL-SE. I was double checking some design issues and I'm concerned about the oil pressure control valve. Everybody talks about using the 12a/13b front cover on the TII swap--but I haven't read anything about the oil pressure control valve (the one in the front cover).

I know the 12a vs 13b (84-85) valves are different by the part numbers (but the pressures listed don't vary between 12a/13b). The 13b (84-85) and 13b TII (88) valves have the same part numbers but I'm concerned the front cover was clearanced different for the TII to give a higher pressure. I'm using a 13b (84-85) front cover--and I assume the valve is for the same.

The FSMs list the 13b (84-85) relief pressure at 113.8 psi and the 13b TII (88) at 156 psi.

However, the FSMs list the same operating pressures for all three engines (64-79 psi). What a mixed bag of crap these FSMs have.

Do you think I have a problem here? Do I need to get a higher pressure control valve? Would like to know before I put the engine in.

Thanks in advance,

Scott

Directfreak

iTrader: (2)

You just need to shim the Oil Pressure Control Valve with a few washers. I believe Mazdatrix or Racing Beat offer a part for the same thing too.

Basically

In the old engines, Oil pressure when the same all the time.

In the 86+ engines, they have like a small thermostat on the 3-shaft which tells the engine Not to get so much cooling during warm up.

You know what, I might have the two parts confused.

But I know I ended up shiming the oil pressure Valve with some about 5 washers from a coaxial TV Cable (All I had at the time).

Alex R

DriveFast7

iTrader: (1)

Wouldn't the turbo motor want a higher front oil pressure control valve psi since oil is also being used to lube and cool the turbo?

Does the turbo front psi valve fit in the gsl-se front cover?

while the motor's apart I'd also install the 85psi REAR oil pressure regulator for extra insurance.

Rex4Life

Yea I thought about the 85 psi valve but at $90 it's a little too steep for me.

I'm still not sure on what to do. The oil goes from the pump outlet to the first pressure control valve, then the air/oil cooler, then to the second pressure control regulator--then to the rest of the lube oil system. Both valves relieve into the pan. So what if the oil cooler sees a little lower pressure--will it matter?

Gotta stew on this one for a while.

Scott

nimrodTT

Check into a 3rd gen oil pressure regulator. 90-100psi and around $30 from the dealership.

ioTus

iTrader: (5)

They both looked exactly the same to me, so i just used the one that looked to be in better condition. Didnt swap anything else out.

Should i have changed the clearnance or whatever like you were saying Alex?

Siraniko

iTrader: (13)

exactly. thats what im using but be sure to shim the front cover too. idles at 40 psi

Directfreak

iTrader: (2)

.

Directfreak

iTrader: (2)

Basically you take this apart,



Place some washers in it, and close it back up. I will have less "play" and your Oil Pressure will be higher all around.

If you're using the TII one already, don't worry too much about it. It's not that big a deal.

setzep

yeah, just swap the -se one for the T2 one. The front is more like a safety relief valve, the rear controls the main oil pressure you read on your gauge.

web777

Does this work? I always thought only the older regulators (pre 79) can be shimmed.

DriveFast7

iTrader: (1)

You are correct. post 79's cannot be dissassembled.

setzep

The front one can be shimmed but the rear one looks to be a sealed unit if I remember right?

Directfreak

iTrader: (2)

Yep.

Rex4Life

All right, I think I figured this out--see what you guys think.

The front pressure regulator maintains sufficient oil pressure to overcome the maximum oil cooler pressure drop and still allow the rear pressure regulator a margin of pressure above it's control point. I know that's alot in one sentence. Basically you always want the rear regulator controlling/throttling pressure at it's setpoint. If it's inlet pressure is too low it obviously won't be able to control pressure.

At first I thought I would be OK if I just used the stock SE front pressure regulator since I am using the SE oil cooler system. Note that I am using the TII rear pressure regulator. Now here's the trick--the TII oil pump flows more oil since it has 5 cm wider rotors. So since more oil is flowing through the oil cooler, I would expect a higher pressure drop through the cooler. And yep, this means I need a higher front pressure regulator than the stock SE unit. I'm also assuming the pressure drop curve for the FB/FC oil coolers are very close to the same--probably a good assumption.

Sounds like the 1/16-1/8" shim idea for the front regulator is the way to go.

What do you guys think?

Thanks for letting me bounce these ideas off you.

Scott

DriveFast7

iTrader: (1)

You're on the right track Scott!!! That first paragraph is right on.

Not to nit pick but TII pump is 5 centimeters wider? ? ?

The 13b GSL-SE oil pump is 17.5mm wide. Widest oil pump available. 1st gen 12a's used 12.0mm wide oil pumps.

Would a T][ front oil pressure regulator work in GSL-SE front cover?

Rex4Life

Whoops, thats millimeters--sorry, I was in a hurry.

You sure about the SE being 17.5 mm wide? The second gen non-turbos are 12.5 mm. I couldn't find any specs about the SE width. In the FSMs not all of the specs are published for each series.

The 84-85 parts fiche shows the 12a/13b oil pumps to have the same part number--really curious where you got the 17.5 mm from.

And about the TII regulator in the front cover. I checked the part numbers and they are the same between the SE and the TII. But they could have clearanced the internals of the front cover a little different to get the higher oil pressure.

Man you guys are great bringing up all this stuff. I know we'll get this worked out correctly. Keep the ideas coming.

Thanks again for the help.

Scott

DriveFast7

iTrader: (1)

Yep I'm sure. It's in the book "how to modify your Rx7" which I've read for several years! I think it's also in the RAcing Beat catalog.

You can and should just measure the impeller width on that oil pump. It should be 17.5mm deep.

Rex4Life

Yep DriveFast7, you're right about the 84-85 13b being 17.5 mm, see it in my Racing Beat catalog, along with some other good info. Same table shows the diameter of all the pumps changed in 86--pre 86 was 40 mm and 86 on went to 50 mm diameter.

So I guess it is safe to say the TII does flow more oil than the GSL-SE and I'm almost sure I'll put in the 1/8" shim. Now that I have some solid info to back up the decision.

Good find on the info DriveFast7.

Scott

setzep

In addition to the T2 pump flowing more it also has a longer oil cooler witch would also add to pressure drop.

fatboy7

The front regulator is more of a safety relief valve than a true regulator. On my swap, I upgraded the rear regulator to the RB 85 psi one. With that kit they give you two washers to shim the front regulator. If you're worried about not having enough pressure for the rear oil regualtor to function properly, I'd just do the same and shim the front one.

If you worried about the oil cooler having too much pressure in it, I wouldn't worry, they are pretty strong, a couple extra psi won't hurt anything.

Rex4Life

Well I've decided I'm going to shim it 1/16".

Here's why, Racing Beat recently stopped using the shims for the 85 psi regulators-- guess they thought it wasn't necessary.

So just to be extra safe, I thought 1/16" is a good compromise between nothing and 1/8" (which we know is used for the real high pressure unit).

I feel like the 1/8" will give too much pressure and just wear out my pump.

I'll let you guys know if I run into any problems.

Scott