Can you have too much oil pressure ???

TVR Beaver · Post by **TVR Beaver** » Mon Apr 07, 2014 9:25 pm

I re-built my engine last year and I'm still running on 20-50 valvoline mineral to bed in. Obviously with new bearings etc it's a tad tighter but also I had V8D fit a helper spring to the oil pump before the re-build to give it a boost...

So on the gauge its running at around 45 at tickover up to 60 PSI full chat when cold...
This drops to about 40 at tickover when hot and still 60 PSI at full chat... but its at 60 as soon as its about 2K..... mind you, its still not red hot out there is it...

I ran it all last year like this with no detriment....

Its a Serp engine so crank driven oil pump and I know it will rob a few BHP but I'm not bothered about that... question is, will it do any damage?...
should I remove the helper spring and lower the pressure a bit??

SimpleSimon · Post by **SimpleSimon** » Mon Apr 07, 2014 9:34 pm

My serp motor run at 55 psi hot anyway stock over 2.5k rpm before coming out with over 100k and backed up by my diagnostic mechanical set and idle 25psi if you think 10 psi for every 1000RPM then your on the money with the RV8

be interesting to see what its like on the freshen up as my cam bearings had seen better days

TVR Beaver · Post by **TVR Beaver** » Mon Apr 07, 2014 9:49 pm

Interesting. I wonder how helper springs work? They obviously just bring up the lower RPM pressure and not the final blow off pressure?

kiwicar · Post by **kiwicar** » Tue Apr 08, 2014 6:13 am

Hi
If the oil ways were thoroughly cleaned out during rebuild then all should be OK. Adding bypass spring pressure does nothing for engine life or performance the system relies on good flow to cool bearings and carry heat away. From your description it sounds like your engine builder knows this and has done the sensible thing and just put a standard one in.
I have run with high pressure external pump on my race engine (100psi at 2000 revs and up), but that is from a very high flow pump, it makes very little difference even that high(I did it to get extra cooling) apart from it finds every place it can to leak out. I am now running about 60 psi at 1500 and 75psi at 2500 and up, the flow is less as I reduced the rate the pump rotates as well as the bypass pressure, I am getting a little more carbon in the oil but it leaks oil less, which I think is a good thing.
best regards
Mike

TVR Beaver · Post by **TVR Beaver** » Tue Apr 08, 2014 7:29 am

Hi Mike.. I was the builder... but I left the pump valve set up as it was before the re-build with a helper spring in there.....

The oilways are fine and it ran 2500 miles last year like this....

I would have thought pressure and flow go hand in hand... you will get better flow at a higher pressure so I was happy in this thought...

but then thinking could I damage anything?.. the unit is oil tight so no issues there... but running at max oil pressure all the time (60psi on the gauge)... could it cause any problems?????? ....

One area was the pump drive key I thought about... when it was balanced they ground this down a bit... okay, maybe they are way OTT to start with... but would have thought is was that close to the ctr line it would be a bit of a non-issue?...

SimpleSimon · Post by **SimpleSimon** » Tue Apr 08, 2014 8:24 am

To be honest I dont consider 60 psi to be high/excessive oil pressure even for the RV8 which is more volume than pressure reliant

topcatcustom · Post by **topcatcustom** » Tue Apr 08, 2014 9:13 am

I was talking to a very experienced engine builder about this the other day regarding my old Nash engine. He rebuilds historic Aston engines and many others, and said that too much oil pressure can actually remove the coating on the bearings, although this may not be that case with more modern shells, as materials have changed a lot over the years?

TVR Beaver · Post by **TVR Beaver** » Tue Apr 08, 2014 9:22 am

yes.. that was my thoughts.. chemical milling of the white metal .... LOL... can it happen????....
.
and it 60 PSI on the gauge actualy 60 PSI in reality.. how accurate is your TVR gauge to the mechanical one you checked it with

SimpleSimon · Post by **SimpleSimon** » Tue Apr 08, 2014 10:07 am

TVR Beaver wrote:yes.. that was my thoughts.. chemical milling of the white metal .... LOL... can it happen????....
.
and it 60 PSI on the gauge actualy 60 PSI in reality.. how accurate is your TVR gauge to the mechanical one you checked it with

about 4/5 psi on average but this is with a new old stock sender

and you dont need to worry about 60 psi stripping the bearing materials

...

TVR Beaver · Post by **TVR Beaver** » Tue Apr 08, 2014 10:26 am

I think mine was new, old stock... I replaced it about 3 years ago and it did read about the same as the original one... but maybe best checking it with a mechanical one... will see whats about

also

what about hydraulic lifters.. have you got solids or hydraulic?... I would think high pressure would affect these?...

SimpleSimon · Post by **SimpleSimon** » Tue Apr 08, 2014 3:02 pm

I did have hyd now have solid

SimpleSimon · Post by **SimpleSimon** » Tue Apr 08, 2014 3:02 pm

I did have hyd now have solid

TVR Beaver · Post by **TVR Beaver** » Tue Apr 08, 2014 3:28 pm

Think Ill take it out.. see what it does... TBH its a small spring inside the std big one.. so probably does not do a lot???

kiwicar · Post by **kiwicar** » Tue Apr 08, 2014 8:40 pm

Hi
instantaneous/ localized oil pressures in plane bearings are high . . . sort of 3000- 10000+ psi in the film between the crank and shell along the line of the crank the odd 5 or 10 psi from the pump makes no odds to the bearing, what you see as related damage to the shells is from bits of shell being plucked off the surface when load suddenly comes of the shell, called cavitation erosion.
best regards
Mike

TVR Beaver · Post by **TVR Beaver** » Tue Apr 08, 2014 9:59 pm

Well I took it out (5 mins of a job

) and its now running at 45 / 50 PSI according to the gauge at full chat?... does not drop much for tick over but it is a cold night out there so probably didn't get the oil hot in my 5 mile spin....

it's quite a weak spring but obviously does make a differance ....

so what to do... leave it out and see how it goes... or pop it back in and have a few more PSI?

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