Oil line modification

[Cowboy]

What is the deal with the oil line modification i hear about? I am building my 79 360 with 9 to 1 compression, MSD ignition, Comp cams extreme energy 256 cam, Stock heads, edelbrock air gap RPM intake, Holley 670 truck avenger carb, and some small tube headers. I just got the block back from the machine shop (.030 over bore) and i was wondering if i should do the oil line modification. All the past threads for this have old links. What is all involved in this modification? Is this mod available in a kit? If so from who? Any other suggestions for my build are always appreciated.

[JeremySmith]

It's supposed to send more oil to the rear crank bearings sooner. When I tore my engine down, thats where the most wear was, so I got a kit. It's available from Performance American Style, but it looks like a couple bucks of fittings and tube from a good hardware store. Here are a couple pictures of it installed:





If I remember right - the kit consisted of:
(2) 1/8"NPT to 3/8 flare adapters
(2) 3/8" flare ends
(1) 3/8" flare 45
18" 3/8" copper tubing

[billyrb]

You can certainly piece together a kit yourself, but for the hassle, I would spend the $25 and get a ready-made kit. You simply drill a hole in the back of the front oil block in the intake valley, and another hole between the #6 and #8 cylinders, so that pressurized oil is shot down onto the rear bearings. But, the drawback here is that your engine is already back from the machine shop. To do this without risking leaving metal shavings in your engine, it would need to be torn down and go back to the machine shop and get tanked / cleaned out again. Now you can use several magnets, shop vacs, compressed air, etc.......but you still risk small shavings getting into your oiling system (as in, I wouldn't recommend it).

Also, make sure you do the following:
1. ensure that your timing gear has the oil passages open and all the flashing has been removed
2. make sure the oil slinger is installed in the correct orientation
3. make sure that you are using a set of matched cam / dizzy gears, or if in good condition, reuse both of the originals (I'd recommend the new, matched set......www.bulltear.com has them)
4. pack the timing gear housing full of petroleum jelly before assembly.....this builds pressure in the system instantly and will help maintain it for initial startup.
5. buy one of gwamp's priming tools and prime the engine prior to initial firing
6. make sure your dizzy is dead on, and not 180 degrees of

[82Waggy]

In my opinion this mod is a red herring.

Everybody installs it as a band aid to what they think is a fault with the stock system when they tear down their worn out old engine and discover that the bearings at the tail end of the crank are worn. Well, when the pressure drops below the minimum necessary to feed the whole engine due to excessive bearing wear and oil pump wear those bearings are the first to starve, but think about it.

When the system has pressure the bypass tube is equalized on both ends, since it is tied back to the same system at both ends. With equal pressure at both ends there will be no flow through it. Additional volume maybe? Additional potential volume perhaps but since the feed paths to the bearings are smaller there cannot be additional flow through them simply because there is more volume available ahead of them, not without additional pressure. And with additional pressure to push more oil, the stock gallery is still larger than the bearing feed paths and therefore more than adequate by itself.

Even when your engine begins to wear and the pressure drops, this drop will be equal throughout the whole system so the tube is still of little use.

I also look at the bypass tube as a potential source of leaks itself - especially a poorly installed one. A copper tube and compresssion fittings subject to vibration and hidden under the manifold so that it cannot be inspected. If it goes you will loose all pressure.

Maintain a properly built system and you will be fine.

If you want to keep more oil going to the bearings, run reduced diameter valve pushrods so that you do not pump all your oil up top and run the risk of unporting the pan pickup. An extra capacity pan with baffles is also of value, expecially in Jeeps that see unusual attitudes and slosh the oil around.

JeremySmith, if you can straighten out the tube as it goes into your fittings or simply remove the mod and plug your holes - those kinks are going to catch up to you one day. I doubt you will be able to fit a valley pan over that either without hacking it to bits.

[Cowboy]

Will synthetic oil or an oil additive help to keep the bearings lubed? I don't think i am going to do the oil line mod. I agree with 82waggy that the system would not help. I have also read about a drilling holes in the lifter valley to improve oiling the cam lobes. Is this necessary?

[Ronson]

Has anyone heard about redrilling the cam bearings with a smaller orifice and then installing them so that the old orifice isn't doing anything? An old drag racer was telling me about doing this mod in the seventies, but I've never heard it mentioned here...

[82Waggy]

Drilling holes in the lifter valley is more to improve drainback to the pan than it is to lube cam lobes, but it adds windage and probably does not help drainback all that much. This also suggests that too much oil is being pumped up top through the pushrods, so once again smaller ID pushrods would help keep oil down. Deburring existing drainback pathways would be a good idea however.

Cam should get plenty of lube from existing drainback down the center of the valley as well as bleed by the lifters and windage.

Bulltear.com offers cam bearings drilled with smaller passages, but I would still rather use the smaller pushrods to keep oil down and keep the cam bearings well lubed.

Highly recomend Mobile 1 in something like a 25W40 (forget what they have exactly that is close). Tore down a 69 390 that lived on this stuff and found no appreciable wear anyplace. All bearings still looked good, pump still good, no obvious cam lobe wear, minimal bore wear (cleaned up .020). BUT - break in your motor on dino oil with Zinc in it, like Delo, Kendal, or the AMC oil that Bulltear also sells, and don't forget to use the cam lube at installation and prelube the engine prior to first start by spinning the pump with a drill and turning the crank with a wrench until you get oil through all rockers and good pressure.

[billyrb]

I am sure you meant to say, 'Oil Pump Housing' when writing about packing the housing full of petroleum jelly

Yep, that is what I meant. I was thinking about the timing gear flashing issue and wrote that instead of oil pump housing. Good catch!

[Elliott]

As far as the lifter valley oil line mod, I am not convinced it is really needed although I added it to my last 401. Plenty of these motors put on major miles and they typically die for reasons other then lower oil pressure to the rear of the block which is symptomatic of other issues than the actual galleys IMO. In any event I wouldn't worry about the copper tubing flare fatiguing over time and cracking, worst case event you still have more oil going to the rear mains. Over the years their have been various "interpretations" of what oiling mods the AMC motors needed which haven't proved to actually resolve intended issues, the distributor gear lube mod for one... eventually people figured out that there are many issues related to distributor gear failure in the AMC motor and the oil line mod did nothing to resolve any of them. "Red Herring" is a pretty good term to describe these methods of trying to resolve issues more commonly related to worn parts, poor maintenance, shoddy machine/block preparation, misalingment of bearings, etc. I will note however that Indy Cylinder Head did redesign the oil galleys on the AMC block they "reproduce" in aluminum. If you keep your oil pump in excellent condition, your machine work/block prep/assembly is done correctly and you don't suffer from poorly manufactured parts such as timing gears or the odd Summit cam then oiling mods are probably not going to be much of an issue unless you routinely drag or possibly have a defective block. JMO

[jeepsr4ever]

"What is the deal with the oil line modification i hear about?"

There are several oiling modifications for the AMC V-8 Engines.
I suspect the one you are thinking about is the added line to the rear mains/rods.

AMC did a really poor job designing, casting and machining the V-8 engines.
The rear mains and rods are starved for oil, especially if lifer/bores are worn or cam bearings are worn.
An internal 3/8" (or larger) line from the front oil gallery feed to the rear oil gallery will supply the rear mains/rods with a steady supply of oil.
This simple modification will increase your oil supply to the back rods, mains and cam/lifters by at least 50%.

This modification is mandatory for anyone thinking about high rpm or heavy loading of the engine.
There are several places that have the kit, but the best one I've worked with is from http://www.AMCLives.com part number is MOKV-8.
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"JeremySmith"

Your line is in the correct place, and is of sufficient size, but copper tubing will fatigue and fracture over time.
The kink in the line at the rear oil gallery fitting could be problematic, and I wouldn't let it pass if it were an engine in my shop.
You would be better off high temp, high heat, steel braid reinforced rubber line with crimped ends (one swivel end). Custom made at hydraulic shops, and most NAPA stores.
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"4. pack the timing gear housing full of petroleum jelly before assembly.....this builds pressure in the system instantly and will help maintain it for initial startup.
5. buy one of gwamp's priming tools and prime the engine prior to initial firing"

I am sure you meant to say, 'Oil Pump Housing' when writing about packing the housing full of petroleum jelly.

Assembly lube is a better idea than petroleum jelly.
Priming the engine just before starting will clear the oil pump anyway, other wise the assembly lube will be beneficial to a fresh engine, where petroleum jelly will melt on contact with the oil.
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"In my opinion this mod is a red herring."

Everyone is certainly entitled to their opinion.
Gauge the oil pressure at the rear of an AMC V-8 engine sometime and then get back to us.
I find that engines with even moderate wear show little or no oil pressure at the rear of the engine when the rear oil galleries are tapped.
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"Will synthetic oil or an oil additive help to keep the bearings lubed?"

Yes.
A quality synthetic oil will certainly help with the reduction of wear in an engine.
I suggest you break the engine in with petroleum oil first, then switch to synthetic.
It has been my experience that synthetic oil will prevent rings from seating and critical wear patterns from forming on mating parts when synthetic oil is used from first start up.
About 2,500 miles should do nicely for a break in, then make the switch if you like.
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"Has anyone heard about redrilling the cam bearings with a smaller orifice and then installing them so that the old orifice isn't doing anything?"

Drag racing only mod.
Keeps oil from collecting in the top end during high RPM operation.
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"Bulltear.com offers cam bearings drilled with smaller passages, but I would still rather use the smaller pushrods to keep oil down and keep the cam bearings well lubed. "

Smaller cam bearing openings will just reduce oil to the cam bearing surfaces.
The same effect can be achieved by slightly misaligned the cam bearing oiling holes in relationship to the oil gallery supply holes.

The upper end, push rods and rockers, are supplied from the lifter bores, not the cam bearing galleries. See image below.


The upper end oil is injected around the lifters, which has a recessed band to allow an oil supply to the lifter inlet hole in the side.

Oil pressure forces oil into the lifter when it's on the cam's base circle.
When the lifter is compressed, an internal valve is closed, and the oil is pushed up the push rod to the rocker arm, and if someone has properly inspected and installed the rockers, out the rocker arm hole and down the rocker arm to the pivot and valve stem friction surface.

This valve stem friction surface is often deprived of adequate lubrication.
Roller tipped, stamped steel rockers fixes this problem without the expense of full roller rockers.

Alot of good stuff but I would add that AMC blocks are very well machined. You should see the tolerances on the blue prints. They are also casted very well even though they went through a bunch of tooling changes.

The rear line will not change the amount of flow to the rear mains untill you have an insufficient flow of oil or the system burps which happens when your extended rpms above 5000rpm or you are running low on oil. It is a decent modification however many engines do not require this mod.

The smaller hole cam bearings benefit much more than just drag racing motors as they restrict oil to the cam bearings the allow more to flow past the cam bearings and increase the chances on rear 3 4 5 mains and 8 7 6 5 4 3 rod bearings to survive some serious rodding.

I alos do not agree with the petrolium jelly in the oil pumps and now Melling, Sealed power and others do not either. They have changed their instructions that come with a K85 or 228-61285 (or any AMC V8 equivalent) oil pump and now state to soak the gears in clear oil instead of packing the pump with vaseline. A AMC pump will pick up oil dry when its primed but may scratch the delicate surface of the oil filter adaptor so a little light lube should be used. We used to spray the pumps down with a heavy dose of teflon for priming however Teflon is now a possible human carcinagen so we now use LPS1.

Valve stem friction isnt deprived in a AMC V8 usually. The valve covers and the valley line fill up with oil extremely fast and flow back is very inhibited.

You can get away with alot of mis-doings on these engines becasue they are tough but some boundaries if crossed will leave your stranded and PO'ed

[82Waggy]

"Junk Yard Genius"

AMC did a really poor job designing, casting and machining the V-8 engines.

82Waggy

Horsehocky!

The rear mains and rods are starved for oil, especially if lifer/bores are worn or cam bearings are worn.

An internal 3/8" (or larger) line from the front oil gallery feed to the rear oil gallery will supply the rear mains/rods with a steady supply of oil.

This suggest that leakage past cam bearings and lifter bores is to such a high rate that they outflow the pump - the leaks cannot pull oil from the pump so there must be some pressure from the pump, and this pressure must be equalized throughout the system before there can be any flow through the leaks. Once again, no additional flow through a bypass tube that has equal pressure on both ends.

I'm not saying that such leakage will not result in insufficient pressure to feed the whole engine properly, just that the bypass line is of no benefit.

Gauge the oil pressure at the rear of an AMC V-8 engine sometime and then get back to us.
I find that engines with even moderate wear show little or no oil pressure at the rear of the engine when the rear oil galleries are tapped.

There has been at least one test run on a dyno that found no measurable difference in oil pressure from one end of the lifter gallery to the other - therefore, with equal pressure on both ends a bypass line will flow nothing. Without an increase in head pressure, there can be no additional flow through the bearing paths from the lifter gallery to the crank just because you increase the size of the feed path ahead of them .

"Has anyone heard about redrilling the cam bearings with a smaller orifice and then installing them so that the old orifice isn't doing anything?"

Drag racing only mod.
Keeps oil from collecting in the top end during high RPM operation.

"Bulltear.com offers cam bearings drilled with smaller passages, but I would still rather use the smaller pushrods to keep oil down and keep the cam bearings well lubed. "

Smaller cam bearing openings will just reduce oil to the cam bearing surfaces.
The same effect can be achieved by slightly misaligned the cam bearing oiling holes in relationship to the oil gallery supply holes.

The upper end, push rods and rockers, are supplied from the lifter bores, not the cam bearing galleries.

The idea being that reducing flow to the cam bearings increases potential flow to other places like the crank bearings. So also is the theory of running reduced ID pushrods. In fact, both of these mods should increase system pressure due to the corresponding reduction in leakage, in which case it would follow that the crank bearings would receive an increase in oil flow. The reduced ID pushrod mod has the added benefit of reducing the amount of oil pumped to the top of the engine and thereby reduces drainback requirments and potential unporting of the pan pickup.

[Cowboy]

Would going with bulltears high volume oil pump spring that increases oil flow by 30% along with their reduced diameter push rods flow more oil to the rear of the block. Would there be a need to add their larger capacity oil pan to this setup? From what i have been reading it sounds like flowback to the pan is slow. How can i increase flow back to the oil pan?

[TexasJ10]

"In my opinion this mod is a red herring."

Everyone is certainly entitled to their opinion.
Gauge the oil pressure at the rear of an AMC V-8 engine sometime and then get back to us.
I find that engines with even moderate wear show little or no oil pressure at the rear of the engine when the rear oil galleries are tapped.
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.

I think Ken Parkmen did exactly that and oil pressure was exactly the same at the front and rear. In the same thread Jeepsr4ever pointed out that the issue is really related to those unusual circumstances when either high RPM's result in all the oil ending up at the top of the engine due to slow drain back or the more common circumstance in the offroad environment where steep angles may prevent sufficient oil from being delivered to the engine. With an oil line mod SOME oil will be delivered to the rear in these circumstances, where without it the rear could be starved completely. This is the only explaination that has ever made since to me. Adding a little additional oil typically cured the problem with off road angles. In the thread I saw it was pointed out that much of the wear people see in these engines on the rear bearings is the result of everyday start ups since the oil is delivered to the rear last. To prevent this a preluber is more effective and some prelubers are designed to inject additional oil when rpms are high and or offroad angles result in temporary insufficient flow. The preluber may be the better solution with every day benefits. Personally, I wouldn't drill into a freshly machined and cleaned block to add this modification to a non-raced AMC 360.

[TexasJ10]

Well, Like I said, everyone is entitled to their opinion.

"With an oil line mod SOME oil will be delivered to the rear in these circumstances, where without it the rear could be starved completely."
"it was pointed out that much of the wear people see in these engines on the rear bearings is the result of everyday start ups since the oil is delivered to the rear last.

I'd say ANY oil is good oil when it comes to the rear rods and mains!
It doesn't matter the circumstances of the oil starvation, the fact is there IS STARVATION!
And the rear oil line upgrade helps stop that loss.

.

Yep
I guess you realize that we are agreement on the prevention of oil starvation. I'm not sure why a response ws necesary.

[82Waggy]

If you want to keep more oil going to the bearings and slow the pumping of oil to the top of the motor to reduce running the pan dry, use reduced ID pushrods (Bulltear) - Simple drop in installation.

If you want to address off angle sump pick up issues, improve flow to the oil pump, and further reduce running the pan dry, run an 8qt pan with a swivel pickup and external feed line (Milodon).

If you want to improve oiling to the rod bearings, run full groove main bearings (ACL).

If you do not mind drilling and tapping holes in your block and hacking your valley pan up for clearance, install the oil line mod (Homer Simpson). As long as it does not leak it won't hurt anything.