Chipped Valve & Pitted Lifter

wecm31 · Nov 13, 2011

The Bike

1985 R80RT, I have had it ten years and ridden 75K km (~ 50K mi). PO was a local Airhead of some reknown. I have always used Amsoil 20W50 full syn, I believe the PO used that as well as Golden Spectro semi syn. Oil changed by me at the end of every season. Total mileage on the bike is now 140k km (~85 K mi).

Plan A

I finally got a proper compression check when I took the bike off the road (carbs off, thanks Kurt!). 125 psi right, 130 psi left. Not critically low, but not ideal. This is my only bike and I plan to ride it far and wide in coming years, so I decided to pull the heads and maybe see about redoing the top end.

The timely visit of my Ontario Airharshal David Home accelerated the schedule a bit, and parts began to fly off the bike last week. Upon pulling the right side head, the exhaust valve revealed some nasty chips missing. Wasn't leaking around the seat, at least when we poured some gas on top of the back side of the valve and held the head up, none leaked through. Still, that sealed the deal on replacing all four valves and having the heads serviced.

wecm31 · Nov 13, 2011

Scope Creep

With the heads in hand, David suggested pulling the lifters for inspection. One was badly pitted (right side exh, same train as the chipped valve), one slightly pitted, and the other two near perfect.

thanks to Mike for a previous thread,

http://forums.bmwmoa.org/showthread.php?t=50870&highlight=pitted+lifter

Not sure what applies to me... I think I have the oil under control, not sure what the original (not the PO I know) owner did with the bike when new. I have always stayed on top of the valve adjustments, never found them off by more than a few thou. And I certainly don't run the bike hard, don't think I have ever seen the tach past 6500. I pulled the oil pan and then ripped into the filter (which I usually do every change) and no chunky bits to be found anywhere. Did this pitting happen this summer or 20 years ago? AFAIK, the heads and cylinders have never been off the bike. I replaced the push rod tube seals when I bought the bike, but just slid the head/cyl assembly back enough to mount new rubber.

Here is my Pollock offering....

wecm31 · Nov 13, 2011

$64,000 Question

What now?? I have the heads all boxed up and they are going off to a regional dealer who has been in house servicing Airheads longer than my bike has been on the road. I will have them machine the seats, install new valve guides, mount new valves and hardware. New set of rings on the pistons while I am at it. And four new lifters....

I think the cam is alright, here is a pic for the brotherhood to ponder. (quick plug for iphones, you can get the lens into the most awkward places. Try that with a SLR) I was looking at the section on cam inspection in the Clymer.....looks the same. Or was the pic in the manaul of a bad cam?

And whats up with the tiger striping? The lobe surfaces are partly chromey looking, and partly coppery... Is that wear or from hardening? I see no pitting or obvious wear, I plan to drop in all the new parts and carry on.

20774 · Nov 13, 2011

Awesome pics! My amateur observations... As for the cam wear, I knew that that wear should be off center and I believe this contributes to the rotating lifters. But the uneven aspect suggests to me that the lifter and cam lobe surfaces weren't parallel to each other. Maybe that's also standard?

As for the lifter face, hard to tell from the picture, but if I had access to a professional shop that looks into metallurgy (I do at my work), they could probably tell the age of the pitting...if parts look bright and shiney (ie, new) or dull and rough looking (probably old).

toooldtocare · Nov 13, 2011

From my experience the cam looks ok, and as Kurt said, the lifters are mounted off center to cause them to rotate. I have seen lifters do this in other engines such as English cars that were not taken care well. Or, maybe that is just the way English engines were built in the first place, not designed to run a long time. I don't know, but I rebuilt a couple of them and installed new lifters and left the cam alone if they had no more wear than yours. I think you will be ok. Wayne

wecm31 · Nov 13, 2011

20774 said:
But the uneven aspect suggests to me that the lifter and cam lobe surfaces weren't parallel to each other. Maybe that's also standard?

I showed the lifter to a Mopar buddy of mine and he said the lifter and cam faces aren't parallel to encourage lifter rotation. I guess the off centre match up does that too, but the slight misalignment face to face really gets the lifter spinning. He said it would take a micrometer to prove, its not much.

krpntr · Nov 13, 2011

lifter

No zinc in the oil. Get motorcycle specific oil. Not automotive oil. Lots of previous comments on this subject.

wecm31 · Nov 13, 2011

Krpntr said:
No zinc in the oil.

I've read about the zinc issue and older engines. I have spent some time finding the right oil for my Plymouth, most new car oils not being suitable.

I have always used Amsoil MC oil, 20W50. Their zinc is not the highest, but
above modern oils.

http://www.synthetic-oil-tech.com/MC White paper-g2156.pdf

I was wondering if some foreign material landed on the tappet. Would
bad oil not make all four pit? As noted, two them are near perfect still,
one has ~ 40% of the pitting of the one shown.

AntonLargiader · Nov 13, 2011

I have some not so good news for you.

I have the same bike in my shop, and it came in with a totally trashed and mushroomed lifter and a chipped valve. The cam lobe was totally wasted. This was the left exhaust.

All of that metal went somewhere, and that somewhere was into the oil pump after some previous oil filter clogged and bypassed. The block was ruined.

The front main bearing carrier had rotated after the retention pin became unstaked. The crank was still good, but the cam, block and pump were shot.

Why not pull your transmission and flywheel, and use this as a good opportunity to renew the rear main seal and oil pump O-ring.

LOSTBOY · Nov 13, 2011

This seems a frequent problem in Monolever R80s. I don't have an explanation; the first time I saw it was in a friend's R80RT who was stingy about oil and changing it. Since then I've seen it in bikes that were well cared for. I can only speculate that this was a bad period for lifters.

I would suggest replacing that camshaft. Take a look at the affected lobes wear pattern vs the ones that are working good lifters. And as Anton suggests, inspect the oil pump. Those little pieces of cast iron can wreck the pump housing, which is machined into the crankcase. If yours is damaged a cooperative machine shop can bush the case.

krpntr · Nov 13, 2011

interesting link on oil

I am no expert on oil, but I do try to follow the advice of people who are. I change my oil and filter every three months or so regardless of the miles. I guess as soon as I can I'll be pulling my lifters to check the wear patterns. I have about 170k on my '82 R100. The heads are off and I am on an extended trip in the Huston area helping a disabled friend on a project that may last all winter. When I get home I'll be dropping the pan and pulling the transmission before the bike goes back on the road. I hope I don't find anything like what you guys found. :sick

wecm31 · Nov 13, 2011

Thanks for some input, feeling lucky to have found this now from hearing Anton's report.

Time is on my side, so the hunt is on for chunky bits. I was thinking of maybe a spline lube in the spring, move that up a bit. I will remove the trans for a boo at the oil pump and new rear main seal (have done both in the past).

Bike was running fine....no noise that I could tell. I remain unsure about the fate of the cam. The middle lobe in the pic was mated to the pitted lifter, you wouldn't know to look at it. Does the engine come out for a cam change? I have read conflicting accounts.

ISAMEMON · Nov 14, 2011

well as far as engine having to come out to do a cam, no

but you have the heads, and carbs off, your thinking of pulling the trans, and cylinders to re-ring

well not far to go to pull the engine and make it all easier to work on

I have an 85 R80RT ( bought it as a near dead bike)
I had to do the upper end, and tranny circlip and timing chain
so for me, it was a lot easier to just pull it all and do it all on the bench

I also had pitteld lifters, two
cam was fine, no abnormal wear
as far as it being specific to the "newer " bikes I dont agree. I had a 78 R80 that had half the miles of this bike and one of its lifters were pitted

I guess I am worried about what anton said of mushroomed lifter, have not seen that yet, but must say, dont want to see it either

also noticed motbins sells the lifters for about half of what the local dealer wants, so yo can get 4 from them for the price of two from dealer

ebeeby · Nov 14, 2011

Just curious, what does the pushrod end look like ?

LOSTBOY · Nov 14, 2011

Isamemon said:
well as far as engine having to come out to do a cam, no

I also had pitteld lifters, two
cam was fine, no abnormal wear
as far as it being specific to the "newer " bikes I dont agree. I had a 78 R80 that had half the miles of this bike and one of its lifters were pitted

I didn't mean to imply that this problem only occurs in Monolever bikes. From what I've seen, there's a higher incident of it happening in them.

wecm31 · Nov 14, 2011

EBEEBY said:
Just curious, what does the pushrod end look like ?

Push rod end was fine, the cup perfect with the little drain hole in the middle.
Ditto the pushrod itself.

I can't see the connection between the valve and the lifter, given the cylinder wall itself looks perfect, cross hatching still visible with no scoring at all. The chunky bits that broke off the valve must have gone out the exhaust, they didn't slide down the cylinder.

AntonLargiader · Nov 15, 2011

wecm31 said:
Bike was running fine....no noise that I could tell...

Same here. Bike came in for a tune-up and new gaskets. I rode a warm-up on it and didn't notice anything wrong.

I just remembered I do have pics of the parts:

http://www.largiader.com/oneyear/day102.jpg

mikegates · Nov 15, 2011

All four of my lifters were pitted like my post. Cam was fine.

wecm31 · Nov 15, 2011

Anton...thanks for the picture. I can see the left side exh cam lobe is badly pitted, mine are perfect in comparision, especially the second lobe (one mated to my worst lifter). Confidence in my cam builds...

As for the suggestion of Isamemon to remove the engine... I don't plan to change the cam or timing chain as of now, perhaps the chain in a few years. I am hesitant to do too much at once, too many variables for my skill level.

Otherwise, I am glowing in the luck of having purchased a Princess Auto (US readers insert HF) lift this fall. It is a godsend, makes working on the bike so much easier. Pulling the engine wouldn't make things that much easier at this point, I can do the rear seal and oil pump in the frame.

88bmwjeff · Nov 15, 2011

wecm31,
While I do not have any first hand knowledge or experience here, I've heard/read several well experienced individuals indicate that they have only replaced the cam followers/tappets and have had no ill effects. I would not worry that you have to automatically replace the cam shaft just because the tappets are f***'d up. Now determining whether or not the CAM is in good condition or not, that I cannot help you with.

Chipped Valve & Pitted Lifter

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