50% STP?

Status
Not open for further replies.
Do you know why it doesn't have good oil pressure?

STP might be a stop gap measure if you have a bearing that's shot. but if it's caused by something like a pickup tube issue or a stuck bypass valve on the oil pump, thick oil will make the issue far worse. You won't have hardly any flow.


What's your oil pressure anyway? How did you diagnose the issue?
 
Yes, cam bearings. In a 6.5 the valley is closed and entails pulling the motor, turning it upside down and maybe crank removal. Water pump, timing cover, both alt brackets, steering pump bracket... Not happening anytime soon.
 
I have used STP in a lot of worn engines, but I don't think I would go much above 20% in 15/40 oil. Also depends on the ambient temp.

come winter, not so much.
 
If the below pic accurately represents the oiling system, then I'd be loathe to do it...looks like the mains are the last to get oil, around the backs (hopefully) of the cam bearings...then the mains feed the big ends.



Go 20W50, see if it helps, then thicken a little from there if you think it's helping...in incrememnts. if you like.

But I think going thicker than that will hasten the demise of other componentry.
 
What is the total oil capacity. I would not hesitate to run (and have) at least 1 full quart (2 bottles) but would be a bit careful after that.

STP is old school VII...I have experienced easier starts with my cranky Jeep with STP in the sump. When I was a kid every oil change got a can of STP, and we were using 10w40 year round in South Dakota! Brrrr......
 
I have to ask-have you put a mechanical pressure gauge on it? The factory setup isn't very accurate, the senders aren't the greatest-I'm on my 3rd AC Delco one on my '93 6.2. I've put lots of non-diesel rated oils in both my 6.2 & 7.3 (although they were usually at least CF)-might be time for some Delo 400 straight 50-if you can find it.
 
How did you manage to take out a cam bearing? And how do you know it's a cam bearing? Are you sure it isn't cracked from a main into a galley?

The 6.5/6.2 was never a robust motor even in the later versions. I think I read even the last 6.5s in the humvees had issues dispite the block improvements.
 
I have an optimizer block, pulled it and did crank bearings. They actually weren't bad, so reassembled. I've tried 3 manual gauges. I lost the oil going down the road. It's running the high volume pump. I put a new one in. What's left is cam bearings.
 
Originally Posted By: jhellwig
How did you manage to take out a cam bearing? And how do you know it's a cam bearing? Are you sure it isn't cracked from a main into a galley?

The 6.5/6.2 was never a robust motor even in the later versions. I think I read even the last 6.5s in the humvees had issues dispite the block improvements.
The Optimizer isn't a bad engine, especially if it has the forged crankshaft (original GM was nodular iron-crack prone)-I've had two 599 block 6.2s, a '92 & the '93 in my sig-the '92 actually made it to 300K, the '93 is now at 160K, they had the beefed up 6.5 block with the smaller 6.2 bore. If those darned forged cranks weren't $1000+...
 
Status
Not open for further replies.
Back
Top