oil temp vs water temp

[JBCOBRA]

Hi Madd
I totally agree with everything you said. Especially if your builder recommends a certain weight of oil. Not all engines are designed for 10/30 however. So there is a yin and yang thing.
The goal would be to make enough pressure, close to 60, but not exceed the pump relief pressure valve.

[Excaliber]

It is my understanding that many FE's, when rebuilt, have the relief valve modified for a higher pressure set point. Of course, it's hard to say with any given engine, but mine was done that way, it relieves around 80 psi.

[madmaxx]

Excellent point, and I know nothing about big blocks. I know very little about stroked small blocks but I know they have very tight tolerances, .002" in main bearings, utilze needle bearings in hydraulic roller lifters, the size of the oil hole in the lifters is tiny not to mention the hole on the roller rocker arms to lube the valve tip etc. I would have serious reservations about using anything heavier than 10W30. I think you nailed it, whatever the builder indicates. I know Roush, KC and Ford recommend 10W30 in their stroked small blocks.

I have personnally seen the difference in 20W50 and 10W30 on rocker arms with an engine running. The 20W50 overflows the rocker arm cavity and it would appear there was a ton of oil as compared to the 10w30 that pentrates through the rocker arm bearings and valve tip hole. Obviously the 10W30 was doing a superior job of getting oil to the bearings while 50% of the 20W50 was just overflowing and draining back into the head.

Originally Posted by JBCOBRA

Hi Madd
I totally agree with everything you said. Especially if your builder recommends a certain weight of oil. Not all engines are designed for 10/30 however. So there is a yin and yang thing.
The goal would be to make enough pressure, close to 60, but not exceed the pump relief pressure valve.

[elmariachi]

Originally Posted by madmaxx

Excellent point, and I know nothing about big blocks. I think you nailed it, whatever the builder indicates. I know Roush, KC and Ford recommend 10W30 in their stroked small blocks.

Then what are you doing over here discussing FE engines?

My builder (here in sunny Houston) and the dyno guy (both with lots of FE experience) told me to run either 10W-40 or straight 40W racing oil with a high zinc content for my flat tappet/solid lifter FE. I am running a blueprinted Melling 57HV pump and get the idle and running pressures noted above, and my bearing and rod side clearances were in spec. My pressures and temps are very predictable in relation to one another.

If the OP Jon (saltshaker) comes back maybe he can tell us what weight oil he is running because a heavier viscosity oil will run a bit hotter.

[patrickt]

Originally Posted by elmariachi

If the OP Jon (saltshaker) comes back maybe he can tell us what weight oil he is running because a heavier viscosity oil will run a bit hotter.

Uhhh, maybe the oil is cavitating with hot spots. Perhaps a little Water Wetter in the oil would reduce the surface tension of the oil molecules and solve the problem.

[elmariachi]

Originally Posted by patrickt

Uhhh, maybe the oil is cavitating with hot spots. Perhaps a little Water Wetter in the oil would reduce the surface tension of the oil molecules and solve the problem.

I would think Amsoil's Oil Surface Detensionizer would be a better choice, no?

[patrickt]

Originally Posted by elmariachi

I would think Amsoil's Oil Surface Detensionizer would be a better choice, no?

Huh. Never heard of such a thing. You got a link to that snake..., ehhrr, Oil Surface Detensionizer?

[RodKnock]

We haven't had a good "Which weight of oil is best?" discussion in a long time. Where's that guy eating the popcorn thingee?

I've always been a "centrist" kinda guy, so I split the difference when I last changed my oil. Instead of using 10W-30, 10W-40 or 20W-50, I'm using 15W-50.

[patrickt]

Originally Posted by RodKnock

I've always been a "centrist" kinda guy...

Uh huh, that's like an "epicene" type of guy.

[JBCOBRA]

My builder specifically built my engine for 20/50 high zinc dino oil.
Roush builds motors specifically for 10/30 with tight tolenances. So putting 20/50 in there is not a good idea.
Engine builders have their own recipes for tolerances etc...
There is no "one size fits all" scenario.
Just for kicks I tried 10/30. Lost 10lbs of pressure. Switched back to 20/50 and was right back to 25 idle about 60lbs driving. Right where it should be.
Have about 15k on the engine. Never a problem, and the oil flows on the rockers perfectly.

[Scufty]

Must say I get kinda a kick outta a comment like "my builder specifically built my engine for XXX oil" HA Ha HA
Come on really? the guy is building your engine for a specific oil?
Humm

[Marvin]

Don't know if engine builder built my engine for any specific grade of oil but he did say use Pennsoil 50w racing oil winter and summer?

Cannot find any so may need to use 25-50?

My oil cooler is not connected nor is my oil temp guage, not sure I need either have 12 quts oil and water temp 85-90.

marvin

[DAVID GAGNARD]

Originally Posted by Scufty

Must say I get kinda a kick outta a comment like "my builder specifically built my engine for XXX oil" HA Ha HA
Come on really? the guy is building your engine for a specific oil?
Humm

Not soo much a specific brand of oil, but a specific weight of oil based on the clearances in the main and rod bearings..........

David