View Full Version : Wedge TR8 Oil Pressure

07-24-2004, 09:49 PM
My oil light has been flickering then coming on at idle after the engine warms up. Today was very hot down here (95) so do you think I need to switch to an oil that's a little thicker? I've been using 10W30 Mobil 1 full synthetic, the car has only 40k, what are you guys using?

07-25-2004, 09:42 AM
My experience with the TR7 prompts me to advise not to assume a minor problem like oil viscosity. Low oil pressure bears looking in to. On my 7 the oil light came on dimmly, when hot at idle and it meant the main and rod bearings were bad. Had I replaced them at the first indication I might have saved an engine rebuild. (or not) /ubbthreads/images/graemlins/blush.gif)

07-25-2004, 10:07 AM
Dale is right check the actuall pressure first(bad sending unit??)to make sure there is nothing major going south.Then for hot weather 20/50 is what most use.(Castrol, Valvoline, ect)
I know a man who made it to 220k with his TR7, when we took it apart the head gasket was the only major problem.He used Castrol 20/50 and went 3k on a change, and the lower end was like new it was amazing how litle wear there was on the cam too.
MD(mad dog)

07-25-2004, 10:27 AM
Even though you were inquiring about the TR8 I'm sure the advice would apply concerning oil press. As to oil reccommendation I do like the 20-50 for the TR7 switching to 10-40 in the winter. Brand and such is not as important as frequency of renewal. Better to go with less pricey and change it often than to expect much out of a more expensive oil.

07-25-2004, 03:46 PM
Thanks Guys for the help, I think these V8s are more high volume and low presure. So maybe just changing to the thicker oil will help. I'll also test it with an actual gauge.

07-29-2004, 07:44 PM
Don't despair, I've been following this issue for a year now, ever since I got my TR8 and ran into the same issue. I switched to 20w50 and poof, no more light. Of course, I had to ask if this was addressing the problem or just the symptom. I posed the question on a number of forums (v8buick.com/ and there are a couple of Rover/Buick 215 forums on Yahoo) and the general concensus came back that these engines run a low O.P. Still not satisfied, I installed a professionally rebuilt Buick 215 in my 8 and guess what?...oil pressure warm at idle is 12-15 psi, never saw higher than 40. As far as I'm concerned, this is an unusually low pressure, but then, an engine design with 45+ years on the road can't be all wrong. And yes, stay away from the synthetics, they're good, but just too thin to build pressure. BTW, install yourself a good reliable gauge so you can deal with real numbers.

07-30-2004, 03:44 PM
Thanks Cheapsnake, looks like you have done your homework on this subject. I may go with a 20-50 synthetic blend and see if that light stays off at 700rpm idle in 95F.

07-31-2004, 07:53 PM
I'm not sure about this, but if the oil pump is built like the Buick V6, it is a very simple job to fix the pump. There is a kit that comes with the pumping vanes and a steel shim for the bottom. This is usually the part that wears out and lets your oil pressure drop at idle. Changing to a 20/50 will work, but I would work on the problem instead of looking for a cheap fix (nothing against cheap fixes though.) This would be an ideal place for a graemlin with 2 cents because that was mine. /ubbthreads/images/graemlins/savewave.gif

08-01-2004, 01:07 AM
If I remember these engines correctly......the Rover V8 right?........a little low oil pressure when hot at idle is no big worry.....a thicker oil may do it, but at tickover these V8s do run low pressure. Of more concern would be if the temperature gauge was in the red.....then you panic, because that is a big no-no with these.

08-04-2004, 12:03 PM
One last thing on the subject...there is an outfit in MI that fabs a hi pressure kit for these oil pumps. Do a search on D&D Fabrication. I think they run about $60 and are intended more for racing purposes. And mailbox is right, the pumps are quite easy to get to, if you don't mind lying on your back.

Bob Buxbaum
08-04-2004, 08:40 PM
When I bought my TR8 a couple of years ago I did not have the advantage of an oil pressure sensor that actually worked! I did a complete mechanical refurb of the car and warmed up the engine while I was at it. EVERYONE that I spoke with recommended 20W50. So, Castrol GTX 20W50 went in the engine after the rebuild. I also installed a good oil pressure gauge. Guess what?!?! Five psi at 700 RPM!! After a little research I found a kit to "shim up" the oil pump. It turns out that there are a couple inherent "issues" with this engine. First, they tend to hammer out the front two cam bearings. Some said that they had NEVER heard of such a thing, but mine had bearing pieces in the sump when I tore down the engine. Hopefully when yours was rebuilt they installed new bearings. Second, the pump housing does wear both inside the pump and the pump cover. I found a kit to resolve this and it came with a new cover plate and a set of REALLY thin shims that look like gaskets. They are designed to "tighten" things up. Results? TEN psi at 700 rpm!! But, hey, that's TWICE the pressure, right? The oil pressure should increase 10 psi per thousand rpm. However (again), TOO much pressure and oil will start to come out of places that it shouldn't. There are adjustable high pressure valves for the TR8/Buick 3.5 if you need one. E-mail me at snaponbob@comcast.net if you need the where/what/when/how details of where I got this stuff.