If the OP wants to monitor oil temp and pressure, he should install the necessary hardware to do so. I, for one, want to know. The HD oiling system is based on volume, not pressure which is why HD has developed two "hi flow" upgrades to the early OEM pump with increased flow and scavenging capacity. IMHO, the increase in scavenging is more important than the increased flow capacity.

An oil pressure gauge that measures 0-60 and a temp gauge that measures 0-300 are all the OP needs. I am not familiar with the location of the sending unit on the Evo motor but that is where I would connect the pressure gauge. On a twin cam the oil temp sensor is located next to the drain plug in the pan; don't know where that location is on an Evo.

 

Not that I would be interested in the info, but it would be simple and not to expensive to install RTDs in the oil pan and a couple on each head to give one a digital readout of temps. I had an oil temp gauge and found it to be of poor reliability. It also gave me something else to worry about when on the road. I used the Harley oil temp gauge system. Failed twice in about 18 months.

 

Agreed upon catalytic converters. I myself am ANTI-EPA as they get. However, theres a slight problem I see occur a lot.

When getting into tuning, this is where my lack of expertise with Harley and their software will shine haha, however... Take this for an example of why fueling to quench the cylinders is a bad idea and why temperature and pressure are CRITICAL (why I can come off as a total *******)

Ford with their 6.4 and 6.7 emissions compliancy have a regenerative exhaust, because these systems require fuel to help burn the soot out of the exhaust, the EPA in all of their wisdom decided I HAVE A BAD IDEA lets burn the soot out of the exhaust of a diesel truck! an engineer at FoMoCo Said, I CAN TAKE THAT BAD IDEA AND MAKE IT EVEN WORSE! Common rail fuel injection system, high fuel system pressure, upwards of 20,000psi coming out of the tip of the injector... Because we can have the PCM energize the injectors to "fire" on the exhaust stroke we can put slightly atomized fuel through the exhaust to go down into the DPF (destroys pickups fast aka trashcan of doom) to ignite to burn the soot out! GREAT IDEA! EH! WRONG! What exactly happens when we do this? Well... For starters, What is fuel pressure coming out of the tip of that nozzle going into that cylinder? Ok, so what you're saying is we're going to inject many 1000s of PSI of fuel into a cylinder, on the exhaust stroke... What happens? Cylinder will cool down. Yes. Fuel has a quenching effect. What cools down first the cast iron block and cylinder or the aluminum forged piston? The piston! Add in many 1000s of PSI of pressure, you can cool a piston down that also has jets spraying oil into the bottoms. Piston swell goes down, fuel washes past the rings, fuel gets into the crank case. Fuel dilutes the engine oil. What happens when we dilute oil with fuel? We lose the lubrication properties of the oil! What happens from there? We have friction bearings in the turbo chargers, they're the first to be affected by this. They corkscrew and send fragments down the drains. The drains drain right into the valley of the block into the camshaft and the lifters. Lifters get wiped out, cams get scored. In extreme cases the lifters will spin in their bores and wipe the block out (cant sleeve the lifter bore and there are no aftermarket suppliers of an oversized lifter like say an oversized piston) and in really bad cases say you have an injector nozzle leaking ever so slightly, overfuel the cylinder, wash the cross hatch out of the bore OR better yet, melt the piston down til all you have left is a connecting rod and wrist pin. Those are my favorite!

If the engine made it that far and you got lucky and had a tech like me work on it, I remove the pedestal (the drains) clean the junk out of the valley and inspect your camshaft and lifters. If all is well, I say a hail mary and button it back up. Now these engines create immense amounts of heat. So much so that when hacks don't reinstall the heat shields on top of the turbos, the oil will cook in the oil feed lines sludge up and restrict oil going into the turbos (these feed lines were revised later on as that also happened with the presence of the heat shields)

So how is Harley cooling the engine? Are they firing the injectors on the exhaust stroke? If you richen the fuel to air mixture, and you overfuel dramatically say you had a carb set up you would have fouled plugs smoke etc... Beings there are cats in the stock pipes, a cats job is to burn/convert unburned hydrocarbons into rainbows and unicorns to emit from the tail pipe to please CARB and EPA. Look at the stop sucking oil thread, where the guy used a spray bottle and water, sprayed water into the throttle body to de-carbon his valves and milky oil puked out in his driveway... Why? Cooled the cylinders probably went overkill with the water... when usually 10-20 sprits of a squirt bottle in a fine mist would have done... probably went a little too carried away and cooled the internals down just enough to get water into the crank case It happens, I learned from doing it years ago what can happen when too much is used, but also gave me an excuse to put forged I beam rods in. Water+oil=Shot bearings, and prematurely worn out valve guides.

Major downfall is with the idiot gauge in a 6.4. I had plenty of oil pressure! No, you have a switch that sent a signal to your PCM back to your IPC that moved the gauge to the middle once the sensor detected a pathetically low amount of oil pressure. Scan tool I can see pids, and if you were to see your oil and coolant temps youd probably fall over from a heart attack. And that's with an unladen truck... Not a fully loaded towing rig... I made my own gauges and saw HUGE discrepancies in oil pressure coming from the gearotor pump to the top end of the engine (5.4 3v V8s, the biggest engineering disasterpiece I will touch on shortly)


3v 4.6 5.4 6.8 V10, are plagued with oil pressure issues. As simple as running the incorrect or an aftermarket oil filter, or go a couple thousand over on your oil changes will cause a plethora of issues. I have worked with an engineer once on how to fix this problem short of denying customers warranty repair work due to mile guard oil filters from fast lube shops. These filters in particular will literally fragment and shoot through the oiling system. These engines have hydraulic timing chain tensioners (HEY a problem that Harley also has too) and in the 4.6 and 5.4-cam phasers. Phasers advance and retard the cam timing to act as an EGR system, hang the exhaust valve open slightly as the intake valves begin to open draw in a little exhaust gas there ya go. No need for a nipple on a manifold with a steel pipe going to a DPFE or EGR valve in the intake.
they have a hydraulic/electronic solenoid that controls the advance/retard of the cam timing. Problem is... The oil gallery that feeds these phasers and solenoids, are TINY! once they get clogged up with debris, sludge, or junk oil filter particles, its done. Need a new engine. OR remove engine from the truck, strip it down and send to the machine shop to be hot tanked...

Why not run kerosene in the oil like we used to do years ago to break sludge up in an engine? Well, bright idea at FoMoCo, lets use an overhead cam! We can line hone the cylinder heads for the camshaft to use as a bearing! Starve the top end for oil, corkscrew the caps and heads, game over. Send tiny fragments of cast aluminum through the drains in the head, after ford agrees to pay for cylinder heads and cams, even though You as the tech changed the oil before starting, you didn't remove those tiny particles that made their way into the crank case working through the oil system... Those particles, I have found in vehicles that had cylinder heads replaced, made their way into the chain tensioners, lose tension on the timing chain tear that slipper up that applies pressure to the chain (literally a synthetic rubber slipper) and the chain will walk slightly from lack of tension, chew the front cover up, and really make a mess of the engine, OR 50-100 maybe 1000 miles after cylinder heads, now a cam code comes up, top end has noise, you go in and replace the cam phasers as advised. Get done with a road test... Uh oh code came back... Scratch your head, re-time the engine, try again... Code returns 10 miles into a road test... Oil gallery that feeds is plugged up somewhere... No fix for that except to replace engine at that time...

IF and that's a BIG IF I were to own a 4.6/5.4, I would make it my duty to know what the oil pressure is at all times going to the cam phasers... and run strictly FL820 filters and change the oil 3000 miles on the dot. Roller bearings, the cam followers (rocker arms of an overhead cam set up) have needle bearings that fail from neglect. Sludge destroys fords. Sludge is what essentially? Break down of oil from heat, combined with dirt/debris. Worked with an engineer for a cure, revisions were made after not only me, but 100s maybe even 1000s of other techs had run into this same problem because ford doesn't like to pay a lot of money out on warranty repairs do the bare min, and pray it gets the owner through warranty period... To fix it properly would be to drop the oil pan and inspect the pan for metal filings and the oil drains from the heads down for debris.

But I buy Chevys. They have pushrods and more room to work under the hood. So in a nut shell, I would make sure that this air cooled engine were to have proper oil pressure at all critical areas at all times in a proper temperature range at all times. Regardless of synthetic, synthetic blend or standard dino blood.

I love the nostalgia of an air cooled pushrod Vtwin. However, liquid cool one of these 103s and go on up, would blowing a head gasket be more detrimental? Absolutely, but I bet they'd run a whole lot cooler, and probably make a whole lot more power. One of my old KX250 race bikes popped a head gasket during a race, I had just about enough of racing at that point in time, I kept the bike for trails, I removed the liquid cooling from the bike filled the cooling ports up and it ran great, but as it got hotter, it became a pig... opposed to before with liquid cooling it ran consistent and had plenty of power whether it was 5 minutes after cold start or 5 hours of grueling demanding racing.

 

If the gauge and sensor are quality pieces of hardware, they won't fail. Knowing oil pressure and temp or head temp is nothing to worry about but if one has $5k-6K invested in a motor, establishing a baseline for both is worthwhile.............

 

"Bikes these days are far better made"???? IMHO, the Evo was the last decent engine Harley made. The junk bearings and other crappy critical parts put in today`s twin cam engines refutes that claim....

I rest my case for an Evo. Anybody think a twin cam will do this?

 

Perhaps you weren't there while Evos were still current? They were far from perfect, we have just grown to love 'em in retrospect.