HarleyTechTalk

Did a cam swap on a 2018 CVO Road Glide 117, installed latest oil pump per service bulletin, cleaned and reused stock cam plate. Bike made it through a couple of test rides, dyno tune and a 600+ mile ride from central Ohio down to the tail of the dragon (2 days through the back roads of Kentucky). We pulled over for gas and he asked me to listen to his bike, there was definite lifter noise and with a little throttle it quieted right up. Took it to Smokey Mountain HD the next day, their mechanic agreed it must be collapsed lifter. Said they couldn't do a lifter swap that day but he wouldn't be afraid of riding it back to Ohio since the noise quieted right down with minimal throttle. Got home and swapped out the Wood's for a new set of S&S. Started bike and had a noise I didn't like from the cam chest area, tore it down the next night and when I pulled the chain tensioner there wasn't any oil behind it and timing chain was severely worn. when I cracked the cam plate bolts loose then oil started coming out the feed hole for the tensioner.

My thoughts:
1) oil pressure relief valve stuck
2) the check valve that feeds the oil cooling system stuck open
3) piston oilers loose, got about 12 oz out of the sump plug

I believe I'm dealing with an oil pressure issue
Has anyone else seen anything like this?

Put a manual gauge on it and see if it is low at idle. 

Quote from: kd on May 19, 2023, 09:31:05 PMPut a manual gauge on it and see if it is low at idle. 

I would but bike is apart right now

Check to make sure you didn't get some debris in the little oil passages and plug it also check you don't have a stuck piston oiler. It doesn't take much and seeing this problem " after" doing cam work makes it suspect. First place the oil goes is the lifters and to the piston oilers. Take the noisy lifter apart and look for dirt.  Bob

So a little update with a long post

Had some time Sunday to get back into this. I opened the factory service manual to the oil flow description and used my solvent tank to check flow through all the passages in the cam plate, no issues found. I checked out what I could of the passages in the engine case and didn't see anything to worry about. I pulled the oil pump apart and no signs of any oil starvation, scoring or anything like that. I looked at the relief valve and saw this:

I thought I found something. After removing the roll pin the valve slid out with just a couple of light taps on the side of the pump body, no signs of scoring sticking or any of that sort of thing. Bore and valve were spotless as you would expect a new pump to be. That eliminated the relief valve theory for me. Next I removed the oil cooler check valve, no signs of trouble there, that eliminated that issue for me and a new S&S valve will be installed.

At this point I went back to the tensioner, piston moves free, no binding where the shoe pivots, spring is pushing piston back out. I try to blow air through the oil feed hole with a rubber tipped blow gun, air wont go through the tensioner, hold the shoe in so it's compressed and try to blow air in again, tensioner wont move. I disassembled the tensioner and tried to blow air through the housing and its plugged up. I notice there is what looks to be a seat for the spring in the bottom of the housing

I remove it with some effort and it's a check valve

I took a O-ring pick and the ball moves freely in the valve, I can now blow air through the housing so I reassemble the tensioner and it works with air pressure. I never found anything in that check valve or the housing, I can't explain it but it works with air on the bench, I even bolted it back up to the plate and ran solvent through the feed passage and sure enough I had solvent flow through the tensioner. Oil pump, cam plate and tensioner have been replaced with new S&S parts.

At this point I'm thinking the piston cooling nozzles are not the issue because I thought there would be more oil in the sump if they were leaking enough to cause an oil pressure issue. They will be checked and most likely replaced since he has decided to do a big bore kit now. Here is the oil drained from the sump before the cam chest was torn back down.

 Also to note I have yet to find one spec of metal anywhere after going back into the cam chest, which in my mind supports that the actual oil pressure was not the issue. I'll cut the filter open and check there too but I'm optimistic that it will be clean.
That leaves the tappet noise, I believe that with all the slack in the timing chain that the cam at idle was being counter rotated by the valve springs and kind of rocking back and forth at idle causing the tappets to slam back into the cam and then the noise would quiet with a little throttle because the acceleration would take up the slack and drive the cam. The noise was definitely not just one lifter. I went to disassemble the Wood's lifters that were originally installed to check them and they were still pumped up even though they have been sitting for almost two weeks. No issues found with them so I cleaned them up, reassembled and I'm going to give them another try
I'll update when I get time to get the cylinders off which I hope will be later this week

Didn't have time to put this in my post this morning

One thing I wanted to see was oil flow to the tensioner before I buttoned up the cam cover. So I got out my starter button and turned the engine over, before I installed the new S&S tensioner, I got a lot of air and some assembly lube from the oil pump, but never saw oil like I wanted to. Tried this several different times Sunday afternoon between letting the starter cool and the battery recharge. I installed the tensioner and tried a few more times WTF!! It was time for dinner so I put it away for the night. Woke up several times Sunday and Monday nights with this on my mind. Sometime last night in one of my wake ups I came up with the idea of "reverse" priming the oil pump. I would take the pressure sender out and put some oil in that port and it would run down to the pump, I could turn the engine over backwards and prime it, or at least I thought. So at 3:30 this morning I couldn't sleep anymore and went out to try my theory. Pulled the sender and thought I wonder if it's getting any oil through here, hit the starter button and after about 5 seconds I had oil flowing out the sender port. Good I thought, so I reinstalled the sender and tried turning it over again BINGO! I had all kinds of oil doing exactly what it was supposed to. A few more short bursts with the starter button verified the lifters were being fed (push rods still out because top end is coming down). So I didn't have to try my priming the pump theory and my questions had been answered. The trapped air between the pump and the filter must have been keeping the pump from picking up. Two things I'm puting on my list when having the cam chest apart is I will always check tensioner function with air before I install them and I will always prime the oil system before installing the cover. Hope my experiences will help somebody some day.

Thought somebody was making aftermarket piston cooling jets but I'm not having any luck

S&S sells them for Twin Cam. You might check if they have M8 units. 

Got back into this on Sunday and took the top end apart, found some interesting things with the front cylinder. there is some discoloring in the bore, but its on the sides, in line with the wrist pin, not the front or rear where the skirts ride, nothing to note on the rear cylinder except the bore has a heavy glaze





Also found the spigot cracked at the rear of the cylinder



It has definitely been inhaling some oil, I wasn't able to run an external breather on this one because he wanted the Fuel Moto AC/DC air cleaner and the backing plate is plastic with looks to be brass sleeves inside it and there is a gusset cast into the plastic where I normally would drill and tap for a 1/8'npt #4 AN fitting. I vented the oil pan "T-Man Style" at the filler neck and used a S&S check valve

Front cylinder

Rear Cylinder


Front combustion chamber and exhaust port have more carbon like the front cylinder has been burning some oil



Rear is more like I would expect to see



Tested the piston cooling jets and the front begins to leak at 3psi and full open by 7psi, rear opens at 14psi like it should

At this point I guess I should go back to the beginning, I got a call in February and he told me that he believed the bike sumped. Everything he described was all the textbook symptoms of sumping. I told him not to run it and he put it on a trailer and brought it to me. I drained 48+ ounces of oil out of the CPS and another 6 out of the sump plug. Yeah it sumped. I drained 4 quarts out of the oil pan. He said he added a quart after he got home that day but never started it after I told him not to. After a bunch of questions I asked him I found out he had just serviced the bike himself but couldn't tell me how much oil he put back in it, he did say he rode it probably another 70 miles to get it home after he noticed signs of sumping. I put 4 quarts back in it and took it out for a couple rides, I'm only 1/4 mile off of a 55mph state route so I was able to do a couple of hard redline runs and then get it back in the garage pretty quick shut it down and drain the sump. I got next to nothing at the CPS and 6 ounces out of the sump plug, both times I test rode the bike. At this point I believed that he just overfilled it and I recommended doing external vents on air cleaner and oil pan and updating the oil pump to the newest version, bike has a early 2018 build date. At that point he decided he wanted to do a cam too while we were in there. I checked compression, with the throttle body removed, and got 195 on both cylinders, I removed the push rods and did a leakdown test, I don't have a flywheel holder for the M8 yet so pistons were at BDC and leakdown was less than 5%. Oil pump, cam & Lifters, push rods, throttle body, air cleaner and mufflers were replaced. And that should take us back to the first post in this thread

Quote from: Ohio HD on May 23, 2023, 12:25:09 PMS&S sells them for Twin Cam. You might check if they have M8 units. 

They do now

https://www.sscycle.com/products/piston-cooling-jet-kit-for-m-series-and-m8-engines/