The coolant seals were moved. If I could fill them in with devcon or other steel putty and smooth it perfectly flat, could I mix an S5 front plate with an S3 rotor housing?



While we're on the subject, what is the difference between S4 and S5 oil pumps? How can I tell the difference visually? Is there a difference? Finally, is the 20B oil pump the same as S5?

There is no difference between s4 and s5 oil pumps. There is a difference between 20b and s4/5 oil pumps. 20b and FD pumps have an extra passage in the pump body to feed more oil to the outer (top) half of the pump. The iron has a corresponding recess in the pickup port. S4 irons must use a s4/5 pump but s5 irons have enough casting around the pump surface to die-grind the appropriate recess for the 20b/FD oil pump. The oil pump internals are all the same size from s4 onwards (apart from the non turbo versions).



I have heard of people doubling up water seals to use early housings with later irons. I have not tried it myself so I can't comment.

yep the fc engines all use the same 2 pumps, the na engines use a smaller pump. kahren has a thread with pics somewhere

look in my P-Port build thread, I have done the exact thing you are looking for

This is for a 4 rotor 12A project. Jeff Bruce said I could get away with an S5 pump on the street, which was my goal to not have to use an external oil pump/dry sump.



From what I understand, I should try to pick up an FD pump and an S5 front plate and port the passage. Then double up the coolant seals and it should work.



Banzai, I looked but only found the slide throttle thread.

here you go Jeff



https://www.nopistons.com/forums/index.php?...ic=51440&hl=oil

Thanks. That's a great thread filled with excellent info. I'll use those pics when I port the passage.



One last thing. Is it safe to double up coolant seals?

Different people give different answers.



Daryl Drummond told me he didnt ever have a problem doubling up on seals, but if time/money/resources permitted he would fill. Which is what I did

Ah, thankyou! That solves the oil volume and pump issue. Then since we'll be filling the ports up with devcon or some other steel putty anyway, I'll try my hand at filling in the coolant seal recesses in the iron as well; time permitting.

I looked for an S5 plate at my local place but all they had were S4 and older.



New questions. Can I use an FD front plate with a 1st gen front cover and rotor housing? Will a 12A stationary gear fit correctly and all that?



Figured I'd kill two birds with one stone and just get an FD oil pump and front plate when I go to Atkins next month.