Ticking noise caused by worn valve tips?.

[turquise1]

Originally Posted by andrewwynn

Loud tick in valve train world is 0.004". If you could feel the difference it would sound like marbles were being shot around in the valve train.

Isn't the tick caused by the space between the cam lobe - lifter or lifter - valve tip (some valve tips are hammered and flattened which is a sign of a bad lifter?)? So wouldn't that number have to be bigger to cause that much noise?


I have two new lifters. I will compare their measurements to older ones to see if there is a big difference..


Thanks,


Ozzie

[turquise1]

Originally Posted by turquise1

Isn't the tick caused by the space between the cam lobe - lifter or lifter - valve tip (some valve tips are hammered and flattened which is a sign of a bad lifter?)? So wouldn't that number have to be bigger to cause that much noise?

I have two new lifters. I will compare their measurements to older ones to see if there is a big difference..

Thanks,

Ozzie

So, I did some quick comparison of old vs. new lifters. I emptied the oil out of them first and the new one has .5 - .6 mm more piston extension compared to old one. That number seems to get worse when the lifter is full of oil and the piston becomes a lot less responsive to compression. Looks like the piston spring became shorter on the old one. I have seen the same issue on several lifters.


Take a look at the photos..


Thanks,


Ozzie

[Purplefade]

Ozzie, AW is right, I wasn’t thinking about the cams being out and you wouldn’t want to time it just to turn it over by hand and have things out of sync, that could be disastrous.

The bummer is that you don’t have a way to test the lifter recovery, my guess is that the compression struck isn’t the problem, it’s the refill or when the spring goes to lift the valve that the lifter may not be recovering fast enough.

Maybe Andrew has an idea on how to test that. At the moment I’m stumped. Lifter fills, lobe depresses it, and moves on to release pressure and depress again but the lifter (potentially) hasn’t recovered from its last compression stroke - of that makes sense.

(Did I read that you had replaced some or all of the lofters though? And I wouldn’t guess that minor of a difference would cause a “slap” issue or the guys on here with 300k would, I’d imagine, be seeing this issue more.)


Sent from my iPhone using Xoutpost.com

[80stech]

The only thing taking up the valve lash is the spring. Older designs used oil pressure as well but that leads to lifters pumping up at high rip-ems, so if spring is not extending the plunger fully it becomes a problem.

[andrewwynn]

Unless: the problem is the opposite. We are all thinking there is slop. Maybe a lifter is too tall and causing a tiny "knock" that sounds like a tap because of the relative size.

Since my m54 taps when the oil is cold =thick I'm assuming it's lifters that aren't quite full but it could be dry cam lobes before they get sprayed by the overhead oil channels.

[80stech]

Oil is what locks the piston into position to open the valve, the spring adjusts the lash.

[turquise1]

Originally Posted by andrewwynn

Unless: the problem is the opposite. We are all thinking there is slop. Maybe a lifter is too tall and causing a tiny "knock" that sounds like a tap because of the relative size.

Since my m54 taps when the oil is cold =thick I'm assuming it's lifters that aren't quite full but it could be dry cam lobes before they get sprayed by the overhead oil channels.

My guess at this point is the old lifters (one or many) are not fully expanding (or not recovering) after compression. There is no new lifter in there yet. Some are the originals and some are picked up from another X5 and rebuilt. By rebuilding I mean, just disassemble and do a good clean up. I did not change any parts in them. What I saw again when I disassembled some today was their small piston springs were shortened a little by use which may explain them not recovering quick or expanding enough and causing the tick. When I compress them by hand, I can definitely tell the new one has more strength..

I am going to check all the lifters tomorrow but I am leaning towards replacing all the lifters (can find them (INAs) for $15 - 20 each) and air pressuring the oil passages for final clean up..


Thanks,


Ozzie

[tartilla]

From the photos of the valve stem damage, it appears to be more of impact wound, vs constant contact.

Are you going to just lap in a new valve?

There is merit to a rocker follower system. You can even get better ramp rates with multiplied leverage. Easy lash setting.

Roller options.

At least the lifters are massive, enabling some good hydraulic cam ramp rates.

[turquise1]

Originally Posted by tartilla

From the photos of the valve stem damage, it appears to be more of impact wound, vs constant contact.

Are you going to just lap in a new valve?

There is merit to a rocker follower system. You can even get better ramp rates with multiplied leverage. Easy lash setting.

Roller options.

At least the lifters are massive, enabling some good hydraulic cam ramp rates.

Yep, no rockers on M62. I think they have them on the next version N62. I think I am just going to replace the lifters at this point and see what happens. It's very tempting right now to replace the head. I'd try that if I could find a new one but it's risky to replace it with another used one (I see some used ones on eBay for $200 or so) which may cause similar issues quickly.



Thanks,


Ozzie

[tartilla]

A head that is in spec, with clear galleries should be ok.

I bought 2 heads of ebay 12 years ago...for $200. Buddy didn't want to ship them. Had to make a claim. They eventually came.

But I would not hesitate to use a used head. New lifters are not a bad idea, certainly with your short spring issue. How is the break in with the new lifters on the old Cam?

Modern oils don't really account for non-roller cams as they once did. Is the cam lobe getting wiped out an issue on the M62?