Oil pump O-rings and pump coupler

XK-Engine
#1

I’m assembling my 1967 4.2 engine for my 420 sedan. I for the life of me get the oil pipes on without cutting the seals. I lubed them well, beveled and polished the end of each tube and still cuts them 3 seals total. I even applied heat the the oil pump to try to expand the aluminum slightly. Looking at my factory originals, they were cut but not as bad as my new seals. The suction seal fits tight so I removed the small piece of rubber that was cut and reinstalled. I will probably change that seal again. The oil pipe groove is cut with a slight bevel intended to be there to compress the o-ring some…

I plan on getting seals from work and match my old seals to the aircraft MS seals we have at the shop. Anyone use a sealer, lock tite or such as added comfort?

Second is the oil pump coupler supposed to float 1/8 inch? That’s how it was, but seems to be a shady design as it will favor the pump side.

#2

Yes the coupler has free play. I had to revert to my press to get the oil pipes into the body.

#3

I squeezed my pipes in the managed to get my inspection camera in the pressure pipe at the block end and found the seal cut. I removed the oil pump cover to check the suction side. Again it was cut. It would probably have worked and the rubber would hopefully get caught in the filter. I’m probably just too picky.

#4

I just installed mine, the first time it deformed the seal and pushed it out of the groove (took them apart a couple times to check). I just used Permatex Assembly Lube and gently rocked the tubes in so as not to pinch or damage the seals.

I didn’t use any sealer as I figure the suction/pressure will prevent much oil from going around the o-rings.

#5

I used assembly lube, silicone grease, oil and it trashes them every time. The rocking aids in cutting them easier. I was tempted to put the old seals in. I just can’t get myself to do it yet. That’s my final plan if other seals don’t work.

#6

Does the new oil pumps have better grooves for the O-rings? I’m using my original pump that is perfect with near new clearances.

#7

I figured it out. It’s my original pump and the way the groove is machined. I have an old XJ6 pump and all fits fine. The groove is machined without the chamfer. I guess I’ll order a new genuine Jaguar pump, lock tab and drive coupler.
I only want to be in this engine once!

#8

SNG only has the 4.2 pump which requires different o-rings and the inlet is larger than the XK tubes. Be sure to order several sets of rings and the oil pump adaptor pipe:

#9

My engine is a 4.2. Thanks!

#10

Alternatively you could look for o rings a size thinner and keep everything original, as long as the tubes are an almost impossible press fit it won‘t cause problems?

#11

I was thinking the same after my post. This car has been a money pit. Thanks!

#12

Alternatively, is your old XJ pump badly out of spec, or could you mix and match?
Either way you’ll find a good solution.

The coupler is not only short but also favors the thrust side of the four flats a lot since it’s a bit loose. Then again it mustn’t bind and take into account light misalignments and tolerances. And somehow the two times I put new o-rings into a pump the tubes were almost impossible to slip in. Good luck!

#13

Not sure about the o-rings. Are they too fat? Mine slipped it with no problem with a bit of oil.

Yes the coupler floats freely. You want it to, to minimize the chance of a bind. If it binds, it detonates. Ensure that after torquing the 3 bolts, when you lift it, it has no resistance, and plops back down when you release it. If it doesn’t, then loosen the bolts and try again.

#14

It floats freely. O-rings are too fat for my original pump. I’m going to see if some aircraft o-rings from work will fit better tomorrow. I had a generic o-ring that fits the inlet side good, but I don’t trust it in service because its from an old Chinese kit I had laying around for years. I’m sure I’ll come up with something.

#15

There are two different sizes of o-ring. The first ones I tried were from the gasket kit and they were too big. I got a second set of green ones that came with the new pump that fit much better.

#16

Yes I’m aware of two sizes of o-rings. My 1967 pump needs slightly smaller o-rings. The 1974 oil pump the fatter rings fit fine. Worse case mix n match… I got O-rings from work I’ll try tonight when I get home.

#17

Hi Jagman, I’ll bet I know where those O rings were made…no one makes rubber products worse than the Chinese. Doesn’t matter what the application, their rubber is awful. Also a 420 owner. and the stripped yellow/brown like OEM sold by a west coast supplier is horrible. In a 420 you use a lot of it.
Well after one year, every connection was leaking and actually sweating through the hose. Don’t waste your money.
Regards,
Allen
I have sections of the real deal NOS OEM low pressure brake hose, Nothing like the aftermarket at all.