Thoughts on Motor Honey?

[rang-a-stang]

Don't laugh at me. Well, I guess you can, how would I know?

Background:
My 401 is up and running after my rebuild but my oil pressure is not high enough for my liking. I am going to re-do my oil pump in the coming weeks but I want to drive my rig in the meantime.

Situation:
All new bearings, rings, seals, lifters, and cam. Fresh oil (conventional 10W-40 with ZDDP additive) and fresh filter (Baldwin B9). Using my stock gauge (mechanical gauge is on the way) I have about 45PSI cold cruising and 20PSI at hot cruising. Hot idle is barely 10PSI.

Question:
For discussion sake, I have hear Lucas Oil Stabilizer is similar so that is on the table, too. I used Motor Honey back when I was in high school 25 years ago to raise oil pressure in my tired old VW engine and it worked great.

What do you guys think of me adding this stuff to my oil to temporarily raise my oil pressure?

[SJTD]

Why not use heavier oil like 20-50 rather than trying to thicken the 10-40

[babywag]

Do NOT use any crap like that! Motor Honey or Lucas etc.

Can't base this on fact but being so thick I would worry greatly about lack of oil on cold start to bearings.
It's a band-aid for worn out motors to quiet them down.

[joe]

Background:
My 401 is up and running after my rebuild but my oil pressure is not high enough for my liking. I am going to re-do my oil pump in the coming weeks but I want to drive my rig in the meantime.

What oil press you getting at idle and at road speed? These are not high oil pressure motors. As-in don't require big pressure numbers. What you using to read oil press, the stock elec gauge or after market mech? Is your 401 overbored within factory recommended specs? When experiencing your not happy with oil pressure what's the temp gauge reading?
I'm not a fan of many aftermarket oil additives. Just cause you toss in some oil thickening goop to make the gauge read better does not guarantee the oil w/goop is actually getting into the bearings. Oil isn't designed to just coat bearing surfaces to reduce friction/heat. It needs to "flow though/past" the bearing surfaces and remove the heat generated. Never used Motor Honey so don't know if it actually blends well with modern multi-vis oils to help or hinder??? It may just give you a false sense of security via the oil gauge. I dunno? If you decide to try it, do keep a good eye on your coolant temp gauge. It'll may give you a clue if the goop is helping or hindering. I do remember way back (60's-70's) folks ran STP/Motor Honey etc but that was back in the straight weight oil days, not multi-vis oils. If your bearing specs and oil pump specs are within factory spec you shouldn't need to run crazy thick oil or added goop. I'm curios...how many miles on the motor before rebuild and when you did your rebuild did you include new cam "AND" cam bearings? Worn cam bearings and main bearings will result in low oil pressure. If you decide to use the goop and your temp gauge is reading ok you're prolly not doing any harm. On the other hand factory FSJ gauges are for entertainment value only. Even with factory gauges on your pushrod motor you should be getting at least 10 PSI per 1000 RPM. If less than that you got a problem and it ain't the oil. Modern "brand name" oil is pretty darn good stuff and doesn't need user installed additives.
Best of luck.

[brielly]

First, I wouldn't trust your gauge to be accurate. Your pressure may be just fine. If it would make you feel better you can certainly add motor honey, STP or lucas but without a mechanical guage you're just guessing and may not need to do anything.

[FSJunkie]

Verify that pressure is accurate before you freak out.

I ignore stock electric oil pressure gauges so much that it actually got me in trouble.

I didn't believe the gauge when it slowly worked it's way down to zero then stayed at zero....in the span of five minutes....while I was driving 75 MPH up I-135. I thought the gauge, which had a history of not reading properly, was failing. I kept driving. The engine seemed fine by all other indications.

It had no main bearings by the time I came to a stop at the end of the off ramp. I spent the rest of that vacation towing my dead classic car 1200 miles home behind a U-haul van.

Wasn't an AMC or an AMC engine.

[Ristow]

Thicker oil will decrease flow. Yes, it will give good gauge, since the pressure port is right at the pumps exit, but you are doing nothing to improve actual oil delivery. You are actually making it worse in most cases.

The big diesels have gone from 15w40 to 10w30 over the ast 10 years. All the old timers get all nervous over that “thinner” oil, and it does lower pressure a bit,but samples come back better than the old oil, due to faster flow.

[babywag]

modern oil is good stuff and way better than back in the day.
10w-30 is all you should need.
15w-40 or 20w-50 is way too thick/heavy imho it isn't a race car
additives like lucas or motor honey are a band-aid or snake oil, I don't use them

I'm actually debating switching to 5w-30, now that it's warmer I get almost 70 psi w/ 10w-30

[Ristow]

Fords are 5w20 on the gas motors now.

[babywag]

Lotta new motors run 5w-20 and last 300k.
I ran rotella 15w-40 for little while in mine didn't agree w/ me or motor.
Rattled like hell on cold start, reduced flow (higher OP) and man oh man the detergents scrubbed that puppy out!
That was before rebuilt pump...

[PlasticBoob]

You have new cam bearings too?

[SJTD]

Thicker oil will decrease flow. Yes, it will give good gauge, since the pressure port is right at the pumps exit, but you are doing nothing to improve actual oil delivery. You are actually making it worse in most cases.

If he is bypassing oil in the pump itself due to wear, thicker oil should increase pressure, and therefore flow, in the whole system.

If pressure at the gauge is higher it's higher throughout the system.

[rang-a-stang]

20W-50 added this weekend. I haven't started it since I put it in.

What oil press you getting at idle and at road speed?
... What you using to read oil press, the stock elec gauge or after market mech? Is your 401 overbored within factory recommended specs? When experiencing your not happy with oil pressure what's the temp gauge reading?
...I'm curios...how many miles on the motor before rebuild and when you did your rebuild did you include new cam "AND" cam bearings? ...Even with factory gauges on your pushrod motor you should be getting at least 10 PSI per 1000 RPM. If less than that you got a problem and it ain't the oil.

Using my stock gauge, I have about 45PSI cold cruising and 20PSI at hot cruising. Hot idle is barely 10PSI. 401 is .030 over bored. Temp readings when I am not happy with the oil pressure are about 200 degrees according to my EFI computer's Temp Sensor, factory gauge is right in the middle. Motor had an unknown number of miles on it. It was not the factory motor from my rig and had been re-ringed at least once but never bored and still had AMC bearings in it (though they were DEMOLISHED). Yep, new cam AND cam bearings. You mention 10PSI per 1000rpm; I am on the borderline there. That's why I am nervous.

Verify that pressure is accurate before you freak out...

First, I wouldn't trust your gauge to be accurate. Your pressure may be just fine...

Mechanical gauge in route to re-verify.

I hear you Ristow. My hope is that after I replace my timing cover/pump again, then verify my pressure again, that I will be OK to run thinner oil because I will have pressure closer to Tony's. I am not intimidated by thin oils but I am intimidated with damaging a brand new set of bearings during this break in period. I am worried that either
a) Machinist used the wrong clearances and I am bleeding pressure past my bearings or
b) I did a poor job on the oil pump
c) All of the above. Which is a serious possibility.

You have new cam bearings too?

Yes, sir. New cam, Main, and rod bearings. New lifters, push rods, and rockers, too.

If he is bypassing oil in the pump itself due to wear, thicker oil should increase pressure, and therefore flow, in the whole system.

If pressure at the gauge is higher it's higher throughout the system.

That's what I am hoping... I did open up the oil passage IAW Ristow's write up so I know it's capable of extra flow but if my clearances are too big and my pump is jacked up, I am in a world of hurt.

Oh Mr. Mechanical OP gauge PLEASE Tell me my stock OP gauge is reading 10 psi low....

[babywag]

If he is bypassing oil in the pump itself due to wear, thicker oil should increase pressure, and therefore flow, in the whole system.

If pressure at the gauge is higher it's higher throughout the system.

Thicker oil that increases pressure does it because the oil is harder to pump through system. Flow isn't increased rather the opposite flow is decreased.

Marc
What rpm is idle? Idle speed makes a difference. Some GM bins have pretty low idle speeds like ~525 range which would = low hot oil pressure reading.
But you likely changes that already?

[rang-a-stang]

Thicker oil that increases pressure does it because the oil is harder to pump through system. Flow isn't increased rather the opposite flow is decreased.

Marc
What rpm is idle? Idle speed makes a difference. Some GM bins have pretty low idle speeds like ~525 range which would = low hot oil pressure reading.
But you likely changed that already?

Idle was 750 at last OP check. This BIN I lowered it to 650 but have not started on this BIN yet.

My Machinist receipt says Mains are .0023 (plus or minus .003) and rods are .0026. 1979 Service manual for 360 says the correct clearance is .0017 to .0020 on No 1-4 mains and .0025 to .003 for the rear main. I do not see a clearance for the rods. This means I am out of tolerance and that may be the source of my low OP.

Does anyone have a service manual with 401 tolerances? Are they the same? I am hoping the Steel crank needs slightly higher clearances? I am about soil myself if they are the same or tighter....