[DM3]

Need some guidance...

68 400, built by a motor shop. Lots of Butler Performance parts, Howard cam, windage tray, etc....

I was running a small LS oil filter since the headers would not fit the standard Wix 51258 oil filter. I have been driving this car now for months, and maybe I was not paying attention, or something went wrong, but I noticed the oil pressure was just over 100 psi while driving and around 60 while idling. Being a little freaked out after talking to a few guys saying it should be 30ish idling and 50 to 60 while driving, I decided to take off the oil filter and put on the largest I could fit.

Here are my findings, all at the oil filter housing:

Original set up I have been driving for months (over 80 mph on the highway)

Wix 51042XP filter digital Gauge cluster w/ oil pressure sender 50ish at idle and 100 driving

Napa 1042 filter installed mechanical gauge at oil filter housing 80 / 100

Fram PH25 (slightly smaller then the recommended stock size) mechanical gauge 75 at start up / 80 warm / 90 @ 2000 continuous rpms.

I looked through all my paperwork and can not find the type of oil pump installed by the shop, that is a call being made tomorrow.

The car runs like a beast even though I am still breaking in the tremic 5 speed, so I have not really put the car to the test yet. I have drove over 80 to 90 mph for about 10 minute shots on the highway, but no rough driving or burnouts, etc.... Motor just turned 1000 miles last week.

Any suggestions? If any additional info is needed, please let me know and I will post it.

[tom s]

I would be really worried about that much oil pressure hot while driving.Tom

[grivera]

Well first you need to verify your oil pressure sending unit and gauge are accurate. Try a different gauge. Is it a stroker? JBP uses 80 psi pumps in those and May have recommended it - May be a contributing factor. What oils viscosity are you running.

[DM3]

I am gonna call the shop and Butler tomorrow and see if I can figure what pump was used, that is the only receipt I do not have.

I unhooked the gauge cluster sender and attached a mechanical pressure gauge.

I am running Pennzoil 10W 40.

Originally Posted by grivera

Well first you need to verify your oil pressure sending unit and gauge are accurate. Try a different gauge. Is it a stroker? JBP uses 80 psi pumps in those and May have recommended it - May be a contributing factor. What oils viscosity are you running.

[b-man]

Moving to Pontiac Street forum for more exposure since this issue really isn’t specifically related to ‘67-‘69 Firebirds..

[PunchT37]

I`ve used those PF61 type filters for years on my 455 with an 80# pump. Sold that motor to a member here. He`s happy.

[dataway]

Something jammed on the spring side of the relief ball?

[DM3]

Yesterday I switched to 10w 30 at the recommendation of the shop, after the motor warmed up, it idled at 40 but went up to 85-90 rpm when holding 2000 rpm for a gauge that reads up to 100 psi. I switched the manual pressure gauge to one that reads up to 400, at idle it was steady at 30 psi., 80 psi @ 2000 rpm.

Shop how has said try 5w 30. I think the next move is to pull engine and check the pump.

[25stevem]

Yes do that!
The last thing you want is to have a filter blow open due to that unnecessary level of oil pressure.
It can also make life hard for the rear main seal depending on what type your motor is built with.

[ID67goat]

Originally Posted by DM3

I switched the manual pressure gauge to one that reads up to 400, at idle it was steady at 30 psi., 80 psi @ 2000 rpm.

This is close to what I was reading on a 428 with 80 psi pump with engine at operating temp. Cold, it was around 20 psi higher than the above stated values at idle and 2000rpm.

[DM3]

I spoke to the builder this morning, they use Melling 54sd pump which would be 60 psi.


They have suggested trying 5w 20 (not 5w 30) to see if that helps lower the driving psi. If not, he said, just pull out the motor and bring it to them.

The last thing I want to do is pull a motor and I just installed the TKX 5 speed.

Originally Posted by ID67goat

This is close to what I was reading on a 428 with 80 psi pump with engine at operating temp. Cold, it was around 20 psi higher than the above stated values at idle and 2000rpm.

[DM3]

Also going back to the WIX 51042XP filter since I can not get a standard size oil filter to fit due to the headers. Once we have the oil issue resolved, I will 'modify" the header since I only need about 1/4 of space to get the oil filter on.

[grivera]

did the builder advise what the oil clearances are? mains/rods?

[25stevem]

Also even with the 60 psi pump make double sure the builder used a HD pump driveshaft and not a general replacement.

I would also want confirmation from the builder that the motor had .0025” on the rods and .0025” to .0028” on the mains.

Such clearances would be as good as it gets for a 400 that could buzz to 7K if need be!

[Brianbigoats]

you could use a oil filter relocation kit to get the bigger filter on rather than modify the headers

[johnta1]

I'd hook up a gauge at the port by the distributor. See what it shows?

[DM3]

No, they want to inspect the motor.

Originally Posted by grivera

did the builder advise what the oil clearances are? mains/rods?

[DM3]

That is now on the list to do.

Originally Posted by Brianbigoats

you could use a oil filter relocation kit to get the bigger filter on rather than modify the headers

[DM3]

Can anyone provide a pic of this?

Originally Posted by johnta1

I'd hook up a gauge at the port by the distributor. See what it shows?

[Joe's Garage]

It's the threaded port to the driver's side of the distributor.

Usually got one of those goofy square hole pipe plugs in it, unless someone has already taken it out.