hydraulic lifter wear

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DirtT
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hydraulic lifter wear

Post by DirtT » Sun Sep 09, 2018 9:06 am

Hi everybody-

first post here (or anywhere). I love this site though.

I recently did my 1st rebuild on a 2.0 type IV engine for my 1981 Vanagon. Did the standard cam run in for 20 minutes and have put about 1000 miles on the rebuild. Had the rotating mass balanced, rod ends rebushed, new bearings, pistons, cylinders (mahle), heads, pretty much the works. Runs well in my opinion except... if I let the engine idle at startup I hear what sounds like a very faint tap that goes away after about 3-5 minutes. Dropped the engine and pulled the oil pump to check for loose cam thrust and possible scoring on the cam gear bolts (new webcam, stock hydraulic grind). Checked flywheel endplay and tightened it up from .0045" to .003". No visible wear on the cam bolts and with the rocker arms off cant get the cam to jump at all axially - this is with rotating the cam back and forth by turning the big nut on the crank snout and also tapping it a bit with a rubber mallot. Runout on the gear face is around .002". Pulled the lifters and they all look fine in my opinion except for one - there is a slight divot spanning the face of the lifter. Can barely feel the indentation with my finger. Could this be the source of the problem? Cam lobes look good from what I could tell by looking through the lifter bores and rotating the cam.

Anyway I put the engine back in and have since put a few hundred more miles on it with no issues but that tap after startup is still there. Pulled the suspect lifter and its neighbor to get some photos. The suspect lifter is on #3 intake. At this point I'm thinking I should call up webcam and see if they will sell me a single lifter and see what happens. I wanted to get some other eyes on this though and seek some informed opinions. Should I just run the lifter as-is or replace it and see if that settles down the tap?

CHTs rarely get above 400 with a DD gauge on #3 plug. Typical temps are 370-380 at cruising speed (55-60 mph).

Here are a couple of pics of the lifters:
IMG_0949.JPG
#3 intake and #3 exhaust(for comparison). Intake has the divot.
I would sincerely welcome thoughts/comments...the path gets dark sometimes when you don't have knowledgeable folks nearby to help out.
Attachments
IMG_0944.JPG
#3 intake.

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Amskeptic
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Re: hydraulic lifter wear

Post by Amskeptic » Sun Sep 09, 2018 9:32 am

DirtT wrote:
Sun Sep 09, 2018 9:06 am
Hi
if I let the engine idle at startup I hear what sounds like a very faint tap that goes away after about 3-5 minutes.
I would sincerely welcome thoughts/comments...the path gets dark sometimes when you don't have knowledgeable folks nearby to help out.


Your reaction thus far has the hallmark of over-attentive anxiety disorder.

I am at a disadvantage here as far as not being able to define "very faint tap", but in my universe, these engines do all kinds of not faint taps at all times. Let's exacerbate your anxiety.
Could it be the oil pump drive tangs clattering on the cam slot when the oil is still cool?
Could we have a minor exhaust leak that tack-tack-tacks until the engine warms up and arrives at operating clamping force?
Could it be a wrist pin knocking?
Could it be perfectly harmless piston slap that occurs only when cold when the pistons are still new?

New lifters should still be convex across the bottoms, and yes, there will be a visually noticeable center because the lifter does rotate in normal operation, but it should not be tactile. If the bottom of the lifter has raised or sharp edges, then a slight trough on the way to a raised center point, then it is indeed going south. If it is an intake, there is a lot of interaction with the opposing pair lifter across the now-suspect cam lobe. You will need to think carefully of whether or not it is worth performing such invasive surgery. I would not do so at this time, but I would alert my vendor right away of the mileage and symptoms and ask them for feedback. Then I would keep an eagle eye on changes in the valve adjustments. IF your preload diminishes, i.e. your 1 1/2 is only a 3/4 before you find the "0" point, then you have a developing problem. Remember that a new engine should be adding to the preload number slightly, as parts bed in.

Too many possibilities here. Your best bet is to re-torque the exhaust system nuts, and intake manifold nuts while we are at it, keep clean oil in it, adjust the lifters to 2 turns if you are at 1 1/2, or 1 1/2 if you are at 2, and . . . .
Drive.
Colin
BobD - 1978 Bus . . . . . . . . . . . 111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 108,000 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

DirtT
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Re: hydraulic lifter wear

Post by DirtT » Sun Sep 09, 2018 11:53 am

Hey thanks for your advice Colin. Ill pull the opposing lifter when I tighten down the exchanger on the 1/2 side. Already tightened up the 3/4 exchanger. Plan to put in another lifter maybe and then keep on driving. I probably do suffer from O.A.A.D.

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Amskeptic
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Re: hydraulic lifter wear

Post by Amskeptic » Sun Sep 09, 2018 3:33 pm

DirtT wrote:
Sun Sep 09, 2018 11:53 am
Hey thanks for your advice Colin. Ill pull the opposing lifter when I tighten down the exchanger on the 1/2 side. Already tightened up the 3/4 exchanger. Plan to put in another lifter maybe and then keep on driving. I probably do suffer from O.A.A.D.

Don't do it until you answer the question posed above. Does the #3 intake lifter bottom have tactile center or sharp edges with a trough between the center and the edge? Have subsequent adjustments shown wear or recession?

viewtopic.php?f=46&t=11408


How do I say this . . . ?
SETTLE DOWN.
Colin :blackeye:
BobD - 1978 Bus . . . . . . . . . . . 111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 108,000 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

DirtT
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Re: hydraulic lifter wear

Post by DirtT » Mon Sep 10, 2018 4:43 pm

Hi Colin-

The best way I can explain it is that the lifter bottom has a linear feature on it that spans almost all the way across. I can feel a very slight indentation that is in the center of the linear feature, which is also in the center of the lifter bottom. It is not raised. The wear toward the edges is not tactile at this point. There is also a normal looking rotational wear pattern that is either overprinted on or wearing coincidentally with the linear feature...cant quite decide which. I have only done one adjustment at this point - from 1.5 to 2 turns in not long after I broke in the cam and ran the engine for a couple hundred miles or so. At the time of the adjustment it was pretty much 1.5 turns out on all the screws.

I noticed that the "noisy lifter" post has a photo of a similar wear pattern toward the end of the post viewtopic.php?f=46&t=6295&start=30.

Imagine a more subdued version of that kind of wear on only one lifter with evidence of rotation as well.

Hey I'm settled.

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Amskeptic
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Re: hydraulic lifter wear

Post by Amskeptic » Mon Sep 10, 2018 8:14 pm

DirtT wrote:
Mon Sep 10, 2018 4:43 pm
Hi Colin-

The best way I can explain it is that the lifter bottom has a linear feature on it that spans almost all the way across. I can feel a very slight indentation that is in the center of the linear feature, which is also in the center of the lifter bottom. It is not raised. The wear toward the edges is not tactile at this point. There is also a normal looking rotational wear pattern that is either overprinted on or wearing coincidentally with the linear feature...cant quite decide which. I have only done one adjustment at this point - from 1.5 to 2 turns in not long after I broke in the cam and ran the engine for a couple hundred miles or so. At the time of the adjustment it was pretty much 1.5 turns out on all the screws.

I noticed that the "noisy lifter" post has a photo of a similar wear pattern toward the end of the post viewtopic.php?f=46&t=6295&start=30.

Imagine a more subdued version of that kind of wear on only one lifter with evidence of rotation as well.

Hey I'm settled.

So drive already . . .

Image
BobD - 1978 Bus . . . . . . . . . . . 111,155 miles
Chloe - 1970 bus . . . . . . . . . . . 206,820 miles
Naranja - 1977 Westfalia . . . . . 108,000 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,885 miles

DirtT
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Re: hydraulic lifter wear

Post by DirtT » Tue Sep 11, 2018 6:23 pm

Will do and will keep an eye on the adjustments. Thank you for your perspective and advice.

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