did oil and filter this Spring using Lucas High Zinc Hot Rod and Classic 10W40 in '68 383 Barracuda. I seem to notice louder engine noise like tappets or lifters lately. Car moderately driven, no more than a 150 miles on the new oil. Very hot summer - wondering if heavier oil would be worth a try. Oil level adequate, pressure OK. I did actually add a half quart more than dipstick mark because it seemed to not take what it should and it's a chinese aftermarket stick but I don't think a 1/2 qrt too much is going to cause me engine noise..any comments appreciated.
10W40 too light?
- Thread starter Dave NEO
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About 1000 since rebuild/teardown,1010 crank, mild racing cam and cam bearings (Crane Cams Anti-Pump Up Hydraulic Lifters, COMP Cam valve springs).
That's all I got from PO who did it. I have some 15W50 I could use but like you say my not be great idea. I don't know what weight oil may have been in there when I got it. thnks for your comments.
That's all I got from PO who did it. I have some 15W50 I could use but like you say my not be great idea. I don't know what weight oil may have been in there when I got it. thnks for your comments.
New engine probably wants a thinner oil unless it was specifically built with higher clearances.
Pressure is measured at the beginning of the oil system.*
Try this for why thicker can leave some of the system without sufficient oil.
Picture trying to push molasses through to the top end.
Even warmed up, not too much is going to get there, even though there's lots of pressure at the beginning.
Now picture doing the same with vegtable juice.
A lot more will flow through.
I know, kindof silly using food products for an analogy, but its lunch time.
*for a big block it can be in the middle when gage is connected at the cross passages.
Pressure is measured at the beginning of the oil system.*
Try this for why thicker can leave some of the system without sufficient oil.
Picture trying to push molasses through to the top end.
Even warmed up, not too much is going to get there, even though there's lots of pressure at the beginning.
Now picture doing the same with vegtable juice.
A lot more will flow through.
I know, kindof silly using food products for an analogy, but its lunch time.
*for a big block it can be in the middle when gage is connected at the cross passages.
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I run 10-30 and 10-40 Lucas Hot Rod in both my cars 360 and 416. No problems.
Depends where you are asking about.
At the pump, no. If any thing it might go up since it may be more than the relief valve can blow off. We see this when an engine is cold - especially on engines where the pressure gage is located close to the pump (such as a small block or AMC).
But at the gage on the back of a big block, I'd say its definately possible. Possible because its showing pressure after the cam and crank bearings have taken their share of the volume.
In which case, lower pressure would indicate not enough volume is making its way to the top.
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72Dart6pack
Harder Better Faster Stronger.
I'd go straight gear lube. And call it good.
Jim Lusk
Well-Known Member
Might need to add some sawdust to that mixture...
j par
Well-hung Member
My first question is does it have a hydraulic flat tappet cam or a solid lifter cam? I are you able to adjust or do you have adjustable rockers? Loud lifter noise or rocker noise? Just sayin...
if bearing clearances are within spec, pressure fluctuation should be minimal at operating temps. minimal !
DesertRat
Leading edge boomer
I’m running 5-30 full syn in my fresh motor. Lucas zinc rich additive-1pint. Stock oil pump with windage tray. Hydraulic flat tappet and stock rockers. Hot idle is 40 psi and hot cruise is 60+ psi.
Yeah you don’t need heavier weight oil. Those pressures are fine. If anything the cold idle is high. 10-30w might be better.
You shouldn’t have clattering because of oil pressure if the pressure is 30 psi hot.
famous bob
mopar misfit
Have any of u guys read studies on hot engine oil? there was about no diff. in thickness between 50 wt. and 20wt. at 200 or more degrees , it all thins considerably when hot , on conventional style oil, "from bill Jenkins book." About the newer oils ????????????
Not sure what you mean by 'studies'. This is straightfoward engineering. Go look at the specifications for SAE Automotive oil grades. The grade designations are based on viscosity at 100 * C or 212 *F. An SAE 30 most certainly has a different viscosity at 200*F than an SAE 20 or 40.
If you want to know precisely the viscosity of any oil, the manufacturer's data sheets are available, or you can send a sample for testing. The relationship of oil viscosity with temperature is consistant and can be graphed with an equation using any two temperatures within reason. Yes, once an engine is warmed up, the difference between different grade oils is far less than when starting cold, but that doesn't mean its not important. Especially at high rpms and loads, an oil must be in the best working range or stuff will not survive.
Here's a graph of viscosities for four of Brad Penn's oils as an example of the differences. (graph program at Widman's website)
If you want to know precisely the viscosity of any oil, the manufacturer's data sheets are available, or you can send a sample for testing. The relationship of oil viscosity with temperature is consistant and can be graphed with an equation using any two temperatures within reason. Yes, once an engine is warmed up, the difference between different grade oils is far less than when starting cold, but that doesn't mean its not important. Especially at high rpms and loads, an oil must be in the best working range or stuff will not survive.
Here's a graph of viscosities for four of Brad Penn's oils as an example of the differences. (graph program at Widman's website)
Mattax is right on about this. There's still a difference, and it can be important.
But more importantly, it doesn't matter in this case
@Dave NEO 's engine is pushing 30 psi even when hot. His engine shouldn't be making any noise because of that pressure, it's high enough.
So the problem likely isn't which oil he's running or what viscosity it is, he should be looking for what/why it's making noise. Maybe the top end of the engine isn't oiling properly, or the valvetrain is out of spec, or the lifters are going bad, or the cam is going flat, etc.
Per post #3 it's a hydraulic flat tappet with Comp anti pump lifters and springs. Sounds like it was built by a previous owner so no cam specs.
Some are definitely louder than others, the valvetrain in my 340 with it's lunati 60404 is pretty loud too compared to more mild, slower ramped cams I've had in other sb mopars. But the noise is "new", so, something else may be going on.
new mild cam. How does not being driven enough enter into equation, if at all? I was laid up 3 weeks, then the car was in the shop mostly waiting for parts 3 weeks. FWIW, I intend to get some regular driving in from here on out.
Summit Racing Part Number: SUM-6401
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-5,500
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 234
Duration at 050 inch Lift: 224 int./234 exh.
Advertised Intake Duration: 298
Advertised Exhaust Duration: 303
Advertised Duration: 298 int./303 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.466 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Valve Lift with Factory Rocker Arm Ratio: 0.466 int./0.488 exh.
Lobe Separation (degrees): 114
Summit Racing Part Number: SUM-6401
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 2,000-5,500
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 234
Duration at 050 inch Lift: 224 int./234 exh.
Advertised Intake Duration: 298
Advertised Exhaust Duration: 303
Advertised Duration: 298 int./303 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.466 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Valve Lift with Factory Rocker Arm Ratio: 0.466 int./0.488 exh.
Lobe Separation (degrees): 114
Not being driven for 3 weeks will likely mean the lifters have drained out, so, there might have been some noise on start up as they filled up. Yes, they're anti-pump lifters but they won't hold oil forever. But that should go away immediately after start up.
Do you know what was done for the engine/cam break in?
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