A moving part is eliminated and replaced with a fixed object. Action vs. no action. I will take the jet. While few and far between, I have read stories about the stock ball and spring combinations sticking shut.

I would hope that one would clean it while the engine is apart. Aside from that, if theres enough build-up in the oil system to cause it to stick, then you have problems. I am very regular with oil changes, and both engines of mine that I have torn apart had spotless oil passages.



What you want to do is your call, but make the choice knowing both sides to the story. Which is exactly the reason I posted what I did. Like I said, everything is a compromise. Which side of the compromise you want to move towards is your own call, not mine. Im just want to make sure you have enough info to make the choice thats best for you.

Mazderati, you're a little confused. You're thinking of the thermal pellet behind the front pulley bolt. Mazdaspeed 7 is correct about the oil jets, and as well, the stock oil jets never fail, they just run out of capacity.

hi can someone tell me what is ment by shimming and exactly how it is done. https://www.nopistons.com/forums/pub...1047683358.gif



Regards

Erdin

Basically it's the term used for stiffening up a spring by adding flat washers to the end of it. Arguably, the proper way is probably replacing the spring with a stiffer one instead.



B

You might be right about the thermal pellet. At least that sounds like it makes more sense.



I would still opt for the replacement of the ball and spring combination with the jet. The more reading I do, the more the higher capacity oil pump and related accessories look like a must if the engine is not already equipped with them.



I do believe the ball and spring combination stands the risk of sticking shut, especially with a sludgy and unmaintained oil pan and motor.

Have you ever taken apart the stock oil jets? They can not stick closed from contaminated oil. Your OPR and front cover Bypass valve work in indentical ways, and they would have to fail at the same time as the stock oil jets.

Its not gonna happen.



This is a racing modification. I would never do it on an engine making less than 400hp. Oil temperatures (I can only say this for sure for a second gen) are not problematic at those levels using the stock oiling system (with an RB 85 psi OPR being the only oiling mod).

plus pumping all that extra oil takes power https://www.nopistons.com/forums/pub...#>/biggrin.png

I agree. I limit this to those motors that want to see 400+ type figures and/or use the RB 80/85psi regulator (FC). This is definitely a limited application mod in my opinion.



B

I just found two independent sources on rx7club.com that say differently. For what that is worth, who is to say.



The bottom line is that I would do the modification, most likely, on any engine that I were to build. To me, if the drop in oil pressure at idle can be cured via other methods, it's a win-win situation. The motor is apart, the jets are easy to do and the modification would aid in keeping the engine cool so why not.