455 acceptable idle oil pressure

As I understand it this is an inherent issue with these motors, it just seems too low for my liking. 1976 455 fresh build with Edelbrock heads and intake, speed pro forged pistons, comp cams flat hydraulic.

I inspected the cover throughly for wear and installed a high pressure kit (1/4" taller gears and that goofy spacer plate with dowel pins). It has only 10 psi at 900 rpm using 10w40 Edelbrock (Torco) flat tappet cam oil. This is on an engine with less than 5 hours run time. It rises nicely with rpm, 20 psi at 1500rpm, 30 at 2000, 50 at 3000 (these are all hot pressures, cold it is higher across the board obviously).

My concern is that as the engine wears in some, the oil pressure is likely to go down some and with only 10 psi at hot idle theres not alot of room for that!

Will the TA perfromance front cover solve this issue? Or is it a non issue? What should the bearing clearances be? The machine shop I had do the work said these large mains require more clearance.

Edit, I see there is several posts on this already, I will investigate those and see if I find my answer! (Im new here haha!)

 

Josh.

DON'T let your machinist tell you you need larger clearances. For a street/strip motor I would recommend no more than 0.002" rods and mains. Race only clearances can be set looser, but to keep pressure up for a street/strip motor, they must be tight.

Most here have stopped using the High-Volume oil pump. The longer gears have proven to place undo load on the cam and distributor gears, eventually causing damage. I run a standard oil pump with a high pressure (white) relief spring and have 20 psi at 750 rpm hot using 5w30. The TA timing cover/oil pump is a good choice if you suspect the pump to be the problem. But if your bearing clearances are too loose, it may even fall short.

 

Thats what I was worried about, when I gauged the mains they were closer to .003 (Around .0026-.0028 if i recall correctly). Plasitgauge isnt super accurate but the strips looked a bit narrow for my liking. Rods were resized stockers and theyare all right aorund .002.

 

The main clearance sounds like the cause. Really, the 10 psi at idle is OK, but is that with the oil really hot after a good hard run? With hotter oil, it may be lower. Generally 11-12 psi per 1000 rpm is fine. You don't need much pressure at idle because cylinder pressure is also very low.

I normally wouldn't recommend the high volume pump, but I think you need it, and to make sure oil pump gear end clearance is set properly and not too large. Adding the booster plate in addition to the hi-vol pump may help too.

If none of that makes sense let us know.

Devon

 

Yes thats hot off the highway, its also running hotter due to the rad being too small. It runs around 200 degress so thats probably not helping. Its a summer only car so I wonder if I should run 20w50 or something thicker?

 

Yep, you can try that too.

Devon

 

Re-check your gear end clearance in your oil pump. Just throwing the gears in the pump wont work well. .002 is the generally accepted clearance.
200 deg. running temp. is ok. What temp T-stat you have?

 

I personally heard Dennis Manner say "anything over 0 at idle is acceptable as long as it rises as soon as you're off idle ..."

 

it could be in your cover , my engine is set on the loose side .003-.0033 on the mains and same on the rods i have 18-20 lbs hot oil pressure with a stock pump.50-60psi from 3000 rpm and up depending on oil temp i do have an oil temp guage .this is with 15-50 joe gibbs hr1 conventional oil

 

Is there any mods to the oil system? Is the feed from the oil sender to the front cam bearing enlarged to .500? If the correct oil mods are done .003 is fine. When I build a street engine I shoot for .0022- .0024 on the rods and .0025 to .0027 on the mains and not one of my engines see anything less then 25psi @ a hot oil with 15w40. I would start by going back to the stock pump and set the end play from .002-.0025 put use 15w40 and worry more about what the psi is @peak RPM. 10 to 12psi for every 1000rpm is good. The cover and oil filter housing should be worked over if they are not. Chris

 

X's 2. Mine runs 70-80 cold at idle and goes down to 10-12psi @ 800 rpm with the engine 180-190 using 10w40 Only 2500 miles on the engine.Im not worried about it one bit.

 

Two things:

First, Jim Jones, you mentioned that you didnt like the high volume pumps but liked the stock volume pumps with a higher pressure spring. I have been under the impression all these years that the high volume wasnt as much as an issue as the pressure. While I am currently using a stock volume pump, I have run the high volume pumps in the past with regular pressure stock springs with absolutely no problems. Have I just been lucky?

Second, With this latest motor buildup, I've been running 15W40 Rotella T as well as a zinc additive. I use the Rotella T due to it supposedly having a higher zinc content. Does anyone else run it?

Thanks, Jim

 

Jim.

Years ago I knife-edged a cam gear running a high volume oil pump. After a great deal of research, and discussion with others who had a similar issue, I was informed that the increased amount of oil encountering the larger surface area of the pump gears was causing the distributor and cam gears to wear unevenly. I will add that I was using 50 weight racing oil at the time, and this may have compounded my problem. Since returning to the standard volume pump, I have not experienced any gear wear problems, even with the high pressure relief spring.

Perhaps Jim W can shed some additional light.

 

This issue is of interest to me as well, because I built my engine in the early-mid 1980s when Kenne-Bell was selling the hi-vol pump kit and saying how good it was for engines. So I included it in my buildup. Now I find out that it can destroy the cam and distributor. Is it high-rpms that cause the damaging volume of oil? Is damage unlikely if the engine is only used for street driving, with little or no racing? Or will just running the engine normally, never taking it above 5K rpm, still cause this damage?

 

The big trouble seems to be excessive wear at cold startup. With the added load due to the longer gears, damage can happen even with thinner viscosities if the engine is not allowed to remain at idle while the coolant temp comes up, thus warming and thinning the oil. Cold + RPM = excessive wear.

Devon

 

I'm running the high volume pump and have been for years. It does wear the dist and cam gears prematurely. I didn't worry in the past because it was a race only application and it seemed I was always upgrading my cam so the wear wasn't an issue. The high volume pump is seeing street use now and I will be doing a tear down in the near future to see what is going on in the wear dept. I have been using a lighter oil on the street. Rotella 15/40 vs the Castrol 20/50
I used while racing. I have been careful to warm the engine to at least 160 before driving so as not to create to much strain on the cam and dist. gears.
At this time my idle pressure with 15/40 at 180 degrees is around 15lbs @ 750.

Bob H.

 

Pardon my ignorance,but why is there such an issue with low oil psi at idle in these Buick engines?
or is it only some folks have issues due to how they build their engines?
Are the pumps that weak in these things ?
Oh and i agree that .003" on an engine with main journals this large should not effect oil psi so much:TU:

 

Not cheap but these may take care of gear problems http://www.bopengineering.com/buick_v8.shtml

 

There can be a few reasons why the engine is idling with low oil pressure. Bearing clearances, timing cover/oil pump. The fact that your engine has just been gone through we are for the moment going to remove bearing clearance from the the list. I have seen many factory timing covers that are over blue print tolerance, even many new NOS covers. The tolerance in the oil pump cavity on the prints are a bit lax in my opinion. The TA timing cover is held to a + or - .001" from high to low. Factory covers were not held that tight per blue print and personal inspection . The big plus has come from us changing the diameter in the pump cavity. I made it smaller, are go gauge is set for .002" below GM's low and our no go is set for .001" below GM's low. The fact of the matter is that we are not mass producing the covers like GM did, so we are keep a much better eye on these covers being they are machined in house here at TA Performance. Other reasons for better performance has come from us opening up oil passage ways through out the cover. When we build a pump assembly here for you at TA we also make modifications to the pump cover and booster plate. Pump is assembled, checked with a dial indicator, adjustments are made to achieve proper clearance, disassembled, all gaskets are trimmed to match, cleaned, packed with Vaseline, and reassembled. We also stamp the cover behind the heater hose connections that indicate what gasket was used, what the end play was on the gears and who did the job. Today we have phone calls from customers on how to reduce there oil pressure. Because of the calls we now send additional relief springs to help control the high oil pressure. Engines typically idle around 30psi. Depending on the build, yes it could be lower or higher. I would like now go back to bearing clearance. If one of our pump assembly's do not help your oil pressure in a new or used engine I would then think about looking deeper into the engine. Most likely the engine has to much clearance somewhere allowing oil to easily flow past bearings, rods, lifters reducing the ability to build pressure. We set clearances on most engines around .0025" -.0025". We build very few stock engines and yes I would set them a little tighter. Those engines would require a lighter pressure relief spring. We have had a few idle with close to 50psi. There are many engines out there today with .003"+ main clearance that have 30psi hot idle oil pressure with the TA timing cover. I would like to add one more option that I use a lot. Engines that you folks have that idle with low oil pressure you may try a bottle of STP oil treatment. NOT Lucas, STP. It has good additives, it helps with the idle oil pressure, helps quite up lifters. For some of you this will help.