Oil pressure dropped

[Uthud]

1997 FLHTCU 150,000 mi +/- original owner
Always something.
After much tinkering, I finally got the cruise control fixed ( separate post).
So, we are running down the road feeling fine, and I notice the oil pressure is much lower than usual. I also saw that the volt gauge registered low. Bike continued to run fine and sound fine on the way home.
The short story is that I have an appointment to have the timing chest checked and repaired. The long story follows, if you’re interested. The moral of the story is that you should replace your lifters on an evo more often than you think it is necessary.

Checked pressure relief valve. Tried (unsuccessfully) to remove screw plug to inspect tappet screen filter. Changed oil and filter- HD 20W-50 and OEM filter (as always).
Oil pressure still ran lower than normal, especially when normal operation temperature was reached.

Read some things and saw some YouTube videos saying HD changed their oil formula and their filter media? So, I changed the filter for aftermarket one- no joy. But before I dumped the freshly changed oil, I wondered if my gauge was just wrong.

Since the wiring diagram shows both the oil pressure gauge and the volts gauge involved a black wire and an orange wire, and both gauges began behaving strangely, I started looking at electrical. I used my digital multimeter to see that the charging system was ok, got the ground system cleaned and checked, moved on to power side. I replaced the main breaker just because, tracked the voltage drop problem to the relay in the fairing. I replaced the relay and socket with a nicer weather-resistant one that I found on Amazon. That fixed the volt meter, and improved the oil pressure gauge, but didn’t restore it “normal”.

I removed the oil pressure sensor to connect an oil pressure test gauge. There was a small shard of metal in the orifice. Uht-O. Installed tester, started engine, got around 55 psi. Let it run a while and pressure started dropping. Still no lifter noise. Idled down to around 700 rpm still making around 8 psi. On my test gauge. So, I’m starting to think that the dash gauge is wrong, or maybe the sensor. I was able to push a button on the test gauge to allow some oil to run out into my (clean) catch pan. Still thinking about that metal shard.
Sure enough, more small wiry shards in that oil. Shut her down and made appointment with the man.
FWIW, the lifters have around 75K miles; the cam has around 135K, other related parts have around 150K miles. Hopefully, I dodged a bullet and stopped before too much bad happened. I guess we’ll find out when the man opens up the cam chest.

 

[Justjake]

1997 FLHTCU 150,000 mi +/- original owner
Always something.
After much tinkering, I finally got the cruise control fixed ( separate post).
So, we are running down the road feeling fine, and I notice the oil pressure is much lower than usual. I also saw that the volt gauge registered low. Bike continued to run fine and sound fine on the way home.
The short story is that I have an appointment to have the timing chest checked and repaired. The long story follows, if you’re interested. The moral of the story is that you should replace your lifters on an evo more often than you think it is necessary.

Checked pressure relief valve. Tried (unsuccessfully) to remove screw plug to inspect tappet screen filter. Changed oil and filter- HD 20W-50 and OEM filter (as always).
Oil pressure still ran lower than normal, especially when normal operation temperature was reached.

Read some things and saw some YouTube videos saying HD changed their oil formula and their filter media? So, I changed the filter for aftermarket one- no joy. But before I dumped the freshly changed oil, I wondered if my gauge was just wrong.

Since the wiring diagram shows both the oil pressure gauge and the volts gauge involved a black wire and an orange wire, and both gauges began behaving strangely, I started looking at electrical. I used my digital multimeter to see that the charging system was ok, got the ground system cleaned and checked, moved on to power side. I replaced the main breaker just because, tracked the voltage drop problem to the relay in the fairing. I replaced the relay and socket with a nicer weather-resistant one that I found on Amazon. That fixed the volt meter, and improved the oil pressure gauge, but didn’t restore it “normal”.

I removed the oil pressure sensor to connect an oil pressure test gauge. There was a small shard of metal in the orifice. Uht-O. Installed tester, started engine, got around 55 psi. Let it run a while and pressure started dropping. Still no lifter noise. Idled down to around 700 rpm still making around 8 psi. On my test gauge. So, I’m starting to think that the dash gauge is wrong, or maybe the sensor. I was able to push a button on the test gauge to allow some oil to run out into my (clean) catch pan. Still thinking about that metal shard.
Sure enough, more small wiry shards in that oil. Shut her down and made appointment with the man.
FWIW, the lifters have around 75K miles; the cam has around 135K, other related parts have around 150K miles. Hopefully, I dodged a bullet and stopped before too much bad happened. I guess we’ll find out when the man opens up the cam chest.

Do keep us in the loop

 

[dolt]

Not sure the OP dodged a bullet; the tale will be told by oil in the crank case. If, when drained, metal (magnetic) swarf shows up, the "man" is likely to suggest a complete tear down to split the cases, clean out the swarf and put back together; that's the worst case. Best case is dropping the pan, clean out the swarf, replace damaged parts i.e., cams, lifters, oil pump, etc. which could leave some swarf in the internal passages in the motor. One option in addition would be a"total" oil change which would remove all the oil in those passages and, hopefully, the swarf as well. Whatever you do, do not replace lifters with OEM parts, go to Larry's Motorcycle and Machine https://larrysmcymachineinc.square.site/#EeHnxU and order lifters.

 

[Uthud]

Not sure the OP dodged a bullet; the tale will be told by oil in the crank case. If, when drained, metal (magnetic) swarf shows up, the "man" is likely to suggest a complete tear down to split the cases, clean out the swarf and put back together; that's the worst case. Best case is dropping the pan, clean out the swarf, replace damaged parts i.e., cams, lifters, oil pump, etc. which could leave some swarf in the internal passages in the motor. One option in addition would be a"total" oil change which would remove all the oil in those passages and, hopefully, the swarf as well. Whatever you do, do not replace lifters with OEM parts, go to Larry's Motorcycle and Machine https://larrysmcymachineinc.square.site/#EeHnxU and order lifters.
Cooking Fats & Oils

Swarf is a new term to me. Is that anything like FUBAR????
Anyway, thanks for your input.
I just dropped bike off Saturday morning and spoke briefly with the man. Hopefully, I will hear back from him this week. He was already thinking rebuilding the lower end. I asked him to open the cam chest and evaluate, then we’ll talk. I waffle as to how much I want to keep the bike vs. look for used something else.
I will post more when I know more.
There’s a guy with a ‘09 FLHTCUI for $6500 in town. Gear drive timing, lots of other upgrades.
64,000 miles, though.
I’d like to keep old bike, but we’re going have to see how much swarf is in there and in the pan, etc. Thanks for the new vocabulary word.

 

[dolt]

I would think you would want to get a clean "bill of health" on '97 FLHTCU for a future owner before selling and purchasing the '09? If moving to the '09, if all maintenance records and upgrades are documented, I would not let the 64K miles get in the way of the purchase if a test ride and inspection don't expose red flags.'09 was a year for several upgrades to the touring line. If gear cams have been installed, very likely other upgrades have been done as well.

 

[Uthud]

UPDATE (kinda) for those interested:
Dropped it off for July 28 appointment.
Heard back from Man that week. The good news from him was that the oil in the pan was “ok”, won’t need to split cases.
I went over the next week to put money down for parts and we discussed plans. I had given him an idea of what I wanted when I dropped it off. So, he had already made a partial parts order based on my list.
Anyway, at this point, still waiting for backordered parts.
I’ll let you guys know when it’s done.

 

[dolt]

Swarf it the metal debris the OP has encountered. I would be cautious about "oil in the pan is OK". The Evo oiling system for the touring and Dyna models is similar to the Twin Cam but filtration is just the opposite. The Evo pump feeds unfiltered oil straight from the sump into the engine for lubrication. So, if a lifter or inner cam bearing failed, that debris went directly into the sump passed through the oil pump which would explain the pressure loss and circulated through the motor. I don't know how long the motor was run but it sounds to me like the motor ran for a while which certainly pushed some metal debris into the system. I would be cautious about not verifying that metal is not circulating in the oil and would collect a sample and send it to Blackstone to verify that there is no metal circulating in the oil. The OP can Google Blackstone and they will send a collection vial and return label, test the oil and send a comprehensive report; $25 the last time I did this and for the same reason. If there is any metal circulating in the oil, it will come back and bite the OP in the ass. I wish Uthud good luck with whatever he decides to do. JMHO.

 

[Uthud]

update: just got the ‘97 back from shop today.
I had new S&S lifters, S&S lifter blocks, Andrews EV27 cam, koyo cam bearing, new cam bushing, new breather gear, and S&S adjustable pushrods installed.
Shop had heck of a time locating the S&S tappet blocks, the reason for the delay.
I was wanting a metal breather gear, but he recommended a new plastic one instead, because of the amount of wear in the bore.
The original was not broken, but it was 150,000 miles and 29 years old. There were adjustable pushrods already in it, but he put in new S&S ones.
Nothing in there was failing except for the cam. It was shedding some, which may have been what caused the abrupt drop in oil pressure, and may have been the source of the metal bits I had seen in the pressure sending unit and pressure relief valve cavities. He said that there wasn’t any crap in the cam chest when he opened it up. I have the old parts, and nothing seems trashed: lifter rollers are intact and operating smoothly, ditto the cam bearing.
He said the tappet screen was clean.
Starts, idles, and runs great. It made 73HP and 83 Ft-Lbs on the dyno, and exhaust gas analysis was in good spec.
He is saying that the “low” oil pressure is okay to run with, because engine needs volume, not pressure for the lower end and only above 3 psi for the lifters and top end. .. I have 5-7psi at idle when warm, and stays steady at over15 but under 20 psi around 2500 rpm. It will climb over 20psi up around 3500 rpm. Cold start will read over 30 psi, dropping steadily as it gets hotter. But? I think I’ll feel better putting on a new oil pump? Maybe in spring.
I’m going to trust him that the oil he drained from the pan was free of debris swarf, and hope we nipped it in the bud.
I’ll let you know if I’ve chosen poorly.

 

[Justjake]

update: just got the ‘97 back from shop today.
I had new S&S lifters, S&S lifter blocks, Andrews EV27 cam, koyo cam bearing, new cam bushing, new breather gear, and S&S adjustable pushrods installed.
Shop had heck of a time locating the S&S tappet blocks, the reason for the delay.
I was wanting a metal breather gear, but he recommended a new plastic one instead, because of the amount of wear in the bore.
The original was not broken, but it was 150,000 miles and 29 years old. There were adjustable pushrods already in it, but he put in new S&S ones.
Nothing in there was failing except for the cam. It was shedding some, which may have been what caused the abrupt drop in oil pressure, and may have been the source of the metal bits I had seen in the pressure sending unit and pressure relief valve cavities. He said that there wasn’t any crap in the cam chest when he opened it up. I have the old parts, and nothing seems trashed: lifter rollers are intact and operating smoothly, ditto the cam bearing.
He said the tappet screen was clean.
Starts, idles, and runs great. It made 73HP and 83 Ft-Lbs on the dyno, and exhaust gas analysis was in good spec.
He is saying that the “low” oil pressure is okay to run with, because engine needs volume, not pressure for the lower end and only above 3 psi for the lifters and top end. .. I have 5-7psi at idle when warm, and stays steady at over15 but under 20 psi around 2500 rpm. It will climb over 20psi up around 3500 rpm. Cold start will read over 30 psi, dropping steadily as it gets hotter. But? I think I’ll feel better putting on a new oil pump? Maybe in spring.
I’m going to trust him that the oil he drained from the pan was free of debris swarf, and hope we nipped it in the bud.
I’ll let you know if I’ve chosen poorly.

Good on you