Thread: 3.9 v8 oil pressure

Originally Posted by PhilipA

I have found over 20 years of RRC ownership that Ryco filters have as low a failure rate of the anti drainback valve as any and recently that the Chinese ones are very good in that regard. It depends on the quality of the valves used as there are different qualities available.
I have anti drainback valves leaking in Cooper, OEM and Ryco but it only happens very occasionally and from day 1. I have also used Purolator which were very good.

I tried to get Mann from Western Filters but they claimed that Mann did not import the size for RRC a couple of years ago.
IMHO it is not worth stuffing around trying to get "unobtainium " filters.
Regards Philip A

Philip, as an interesting aside, I fitted a new Z89A to my rebuilt engine and immediately had issues with startup after an overnight (or longer) sitting. 5 seconds or so and occasionally a rattling lifter. After 500km I dropped the running in oil and replaced it with another Z89A (bought at the same time and place, same batch presumably) only to find it was just as bad. I performed an autopsy on the filter as a matter of course after the rebuild and found the drain-back valve looked OK.

Last week I dropped in to Autobarn because they were doing a $4.99 deal on Valvoline filters and I thought it's an easy way to test things - different brand altogether. They didn't have any Valvoline Z89A equivalents, but had the Cooper filters so I bought one. I told the bloke the problem and he said they don't have many issues with Ryco, but suggested I contact Ryco to tell them. Out of interest I asked to see another Z89A to compare against the Cooper and to my surprise this Z89A had a bright red rubber valve, not black like my two suspect ones. They've changed something for some reason. Might be that the Chinese ran out of black rubber, or that the black rubber was failing with the heat it's subjected to.

I fitted the Cooper today and will see how it is in the morning.

Has anyone tried this method for priming?

Fill a cleaned out standard grease gun with one half pint of Petroleum Jelly
Leave the standard grease connector tip on the gun. (for zerks or grease nipples)
Remove the Oil Pressure Relief Valve Plug
Extract the Spring from the relief valve.
Insert the grease gun in the housing fill with the half pint of Jelly.
Replace spring and plug and you have a direct well packed oil pump gear housing. with no mess.

I haven't, no. I've only had to resort to vaseline the one time. It is easy when the whole engine us upside down.

Much to my extreme annoyance, the problem persists with filter number 3. Time to look deeper.

I faintly recall a post on here some time ago that highlighted that the timing case gaskets for a crank oil pump engine and a camshaft oil pump engine are different with one hole being covered in one of the variants.

Maybe the person who posted then can advise whether this is supposed to affect oil pressure and whether my recollection is correct.
Regards Philip A

Interesting point Philip, Because I removed the crank oil pump timing case and put the v belt unit on because of all the ancillaries. Pretty certain I got the v belt timing gasket though. I think the pattern is also different despite the same bolt holes? I remember the oil gallery size on the block face being larger on the serp motor than on the v belt motor.

The screw driver trick worked for me this morning. Although I ended up getting my angle grinder out and cut out a groove on a piece of round steel. The screwdriver works on the older RV8's. Spinned it up to 40psi briefly At least I have the tool for next time. I think last time I tried to make the same thing out of a screwdriver but the slot wasn't sufficient and kept slipping. I'm going to get a new set of gears + not put any sealant on the pump gasket which is why I think I have pressure on the low side + drain back issues. I'm getting 19-20psi hot idle & 27psi @ 2700 now after changing valve & spring + 15w40 penrite oil with no additives. Not much different from before. I was using 20w50 with 500ml lucas oil. A little too thick for the cold mornings me thinks + that wouldn't help trying to build quick pressure up on first start. seeing how it will behave tomorrow morning. Hopefully within a few sec's, don't want to see 8 seconds. If it still does I'll add some lucas to help with the dry starts until I replace pump gears/gasket.

I'm going to get a new set of gears + not put any sealant on the pump gasket which is why I think I have pressure on the low side + drain back issues.

Definitely no sealant on the base plate, and make sure there are no raised bits where the bolts may have pulled in a bit. You can give those areas a bit of a file , but not the anodised part where the gears spin.

In my experience the main problem with oil pumps is when the cam has broken up and scored the walls , where the gears spin. This needs a new/repaired timing case , although I just put new gears in an 81 I had and it held oil pressure OK.
Have you checked that the oil pickup does not have a leak, either a crack from a clout on the sump or the flange gasket leaking.
I still believe that the filter or housing has to be faulty for oil to drain back to the sump or there may be something to do with the pickup, or possibly a leak in the timing cover gasket .
Regards Philip A.

I'm going to check the pressure relief valve today, but then I have no other option but to suspect the timing cover gasket. I can't see any other way that the pump can lose prime just sitting there overnight.