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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21519 Location: Oklahoma City
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Posted: Tue Jan 16, 2018 2:11 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle |
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The one size fits all....."0" number cam gears...are not in themselves a problem....as long as the lash is not excessive and the bolt flange area is milled flat.
I have used numerous or them with 0 issues. However....you need to measure lash at a teetb to make sure they are concentric.....and you need to measure runnout...and you need to rotate the gear on a cam with the crank in the case to check for tight spots.
If all of that checks out and your cam thrust face is polished smooth....there is no way it will wear out the thrust flange on the cam bearing. But again.....using a double thrust cam bearing set....is good insurance. Ray |
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hazetguy Samba Member
Joined: April 06, 2001 Posts: 10773 Location: iT StiNgeD iTseLf tO dEAd
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Posted: Tue Jan 16, 2018 2:23 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle |
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have a read through this thread: https://www.thesamba.com/vw/forum/viewtopic.php?t=692236 _________________ thebucket: I invested in hoodride, now DBD won't return my call?
hazetguy: invested?
thebucket: Yeah Haze, its where people put money into a company in hopes of a return on their money |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 537 Location: Talbott, TN
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Posted: Tue Jan 16, 2018 6:28 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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Split the case and got the cam and bearings out. Clearance on the thrust face is .024", way out of spec, but I can't see that there is any unusual wear on the bearing or the cam, so either I got a bearing that was too small, or the cam was ground too wide on the thrust surfaces. Does anybody have measurements for a new set of cam bearings. My current cam bearing is 1.080" at the thrust faces, the width on the cam is 1.104", giving the .024" clearance. I'd like to put this thing back together with double thrust bearings (it currently has a single), can cam bearings be ordered in oversized widths?
Thanks for sharing that post with the Jake Raby comments, Hazetguy. He described the knocking at idle sound, from axial cam movement as if he'd seen it a hundred times Well, I'm going to confirm he's right. |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 537 Location: Talbott, TN
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Posted: Tue Jan 16, 2018 6:45 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle |
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SGKent wrote: |
So we chalk this up to a cam gear.... can't ya hear me knocking.[/youtube] |
Just to be clear, the cam gear is NOT the problem
The problem is excessive clearance on the camshaft thrust bearing.
In this case, the cam gear is firmly attached to the shaft, with no runout and no tight spots, no loose bolts, and no bolt heads too tall. The aftermarket cam gear only came in "standard" pitch line, but it must be right for my crankshaft gear, because I can't measure any backlash in the gears.
After 50,000 miles of run-in, the wear pattern on the cam gear teeth looks almost non-existent. It rolls smoothly, and won't back the cam out of the bearings when turning in backwards rotation, so I'd have to say the cam gear is good to go.
Just have to get the cam bearing clearance sorted now.... |
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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Tue Jan 16, 2018 9:12 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle |
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69BahamaYellow wrote: |
SGKent wrote: |
So we chalk this up to a cam gear.... can't ya hear me knocking.[/youtube] |
Just to be clear, the cam gear is NOT the problem
The problem is excessive clearance on the camshaft thrust bearing.
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Get another set of cam bearings and check the thrust clearance. The last bum set I had was .011" thrust clearance out of the box (some cheap brazilian junk).
Kolbenschmidt replacements had .0018" thrust clearance. _________________ www.itinerant-air-cooled.com |
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Hoody Samba Member
Joined: November 28, 2007 Posts: 1948
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Posted: Thu Jan 18, 2018 9:37 am Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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It amazes me that people think the Brazilian aluminum cam gears cause issues. Raby used these in every type 4 motor that he built and never had issues with them. Reusing a magnesium cam gear to build a new engine is just a recipe for disaster. |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 537 Location: Talbott, TN
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Posted: Thu Jan 18, 2018 10:46 am Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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I can see why the aftermarket cam gears cause problems if you don't bolt them to the shaft properly (with the correct low profile bolts and cutting lock washers) and they loosen up over time.
Aftermarket quality control of the gears is always a concern, but the aluminum one I got from Webcam seems to be pretty good. backlash is less than .001" all the way around, and same goes for run out. The gear looks almost brand new after 50,000 miles of running.
Since I was mating an aftermarket cam gear to the OEM crankshaft gear, I didn't have a choice on pitchline variance. At the time, "Standard" is all they offered, and I got lucky the fit was right with my engine case, giving the proper backlash between 0 to .002".
What makes me feel like an idiot is trying to figure out if I put the cam in my engine and forgot to check for excessive clearance at the thrust bearing, or if it just wore itself down the the .024" clearance I have now. I can't find any dimensions for either cam or bearings anywhere (not in the Bently manual, Haynes manual, or web), so there's no way to know if the aftermarket cam I purchased from Webcam is too wide at the thrust surfaces, or if the cam bearings are too thin. I ended up posting a separate thread to see if anybody knows the dim's on cam bearings, since none of my local suppliers stock them, and none of the web vendors can physically put their hands on them to measure; all they know is the dim's on the shipping box |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50351
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Posted: Thu Jan 18, 2018 11:03 am Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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69BahamaYellow wrote: |
I can see why the aftermarket cam gears cause problems if you don't bolt them to the shaft properly (with the correct low profile bolts and cutting lock washers) and they loosen up over time.
Aftermarket quality control of the gears is always a concern, but the aluminum one I got from Webcam seems to be pretty good. backlash is less than .001" all the way around, and same goes for run out. The gear looks almost brand new after 50,000 miles of running.
Since I was mating an aftermarket cam gear to the OEM crankshaft gear, I didn't have a choice on pitchline variance. At the time, "Standard" is all they offered, and I got lucky the fit was right with my engine case, giving the proper backlash between 0 to .002".
What makes me feel like an idiot is trying to figure out if I put the cam in my engine and forgot to check for excessive clearance at the thrust bearing, or if it just wore itself down the the .024" clearance I have now. I can't find any dimensions for either cam or bearings anywhere (not in the Bently manual, Haynes manual, or web), so there's no way to know if the aftermarket cam I purchased from Webcam is too wide at the thrust surfaces, or if the cam bearings are too thin. I ended up posting a separate thread to see if anybody knows the dim's on cam bearings, since none of my local suppliers stock them, and none of the web vendors can physically put their hands on them to measure; all they know is the dim's on the shipping box |
I know that I have had cam thrust bearings that were too tight to fit the cam, so the opposite would not be unexpected either. |
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scubaseas Samba Member
Joined: May 24, 2013 Posts: 442 Location: ME & Texas, in a Bus or on a boat somewhere
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Posted: Thu Jan 18, 2018 11:43 am Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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Quote: |
What makes me feel like an idiot is trying to figure out if I put the cam in my engine and forgot to check for excessive clearance at the thrust bearing, or if it just wore itself down the the .024" clearance I have now. |
Maybe Web has that dimension if you call them?
Did you polish the thrust faces of the new cam? The last two Web cams I got were pretty rough when they were new. Both cams needed to be polished on the thrust faces. Maybe that's what chewed up the bearing? I doubt the gear is an issue given what you describe.
Thanks for sharing what you found. Nice documentation and fast work. Real nice looking bus too. _________________ Al
08/1970 T2a Westphalia owned since 1980
ASE Master certification. 50 years pushing a wrench
Retired |
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Hoody Samba Member
Joined: November 28, 2007 Posts: 1948
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Posted: Thu Jan 18, 2018 11:45 am Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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My advice would be to locate some nos steel backed KS and double thrust the cam bearing. If you can not locate them which isn’t easy supposedly Glyco still steel backs their cam bearings. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Thu Jan 18, 2018 2:15 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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You know, I come here to help and get flamed. It was the Brazilian gear. I could measure the deviation in it and the replacement. Like an idiot I used it anyway because it seemed the thing to do. The bearing was within the correct lash. What happens is that the runout moves the cam back and forth which ruins the thrust surfaces on the bearing. The problem went away with a stock aluminum gear. I bought up every junk cam the came up for sale here for a couple years el cheapo, collected a full set of like new aluminum German gears in almost each number.
But I am glad the OP argued with me because when I asked him what the number it was to send him a factory ALUMINUM gear to help the situation, which is no longer going to be offered. Geeeez.
Bob - WTF mentioned magnesium? I didn't. All mine are aluminum ones in outstanding shape and they have already been milled and threaded for a new cam. No they aren't for sale.
And everyone else, including Colin. When the gear has any runout it runs the cam back and forth hammering the thrust bearing. Road Warrior did it to you Colin - want me to find the thread you posted about it?
Maybe I measured the lash and endplay wrong? Used the wrong tools? failed to bolt the gear on right? What do you think?
_________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21519 Location: Oklahoma City
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Posted: Thu Jan 18, 2018 2:51 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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SGKent wrote: |
You know, I come here to help and get flamed. It was the Brazilian gear. I could measure the deviation in it and the replacement. Like an idiot I used it anyway because it seemed the thing to do. The bearing was within the correct lash. What happens is that the runout moves the cam back and forth which ruins the thrust surfaces on the bearing. The problem went away with a stock aluminum gear. I bought up every junk cam the came up for sale here for a couple years el cheapo, collected a full set of like new aluminum German gears in almost each number.
But I am glad the OP argued with me because when I asked him what the number it was to send him a factory ALUMINUM gear to help the situation, which is no longer going to be offered. Geeeez.
Bob - WTF mentioned magnesium? I didn't. All mine are aluminum ones in outstanding shape and they have already been milled and threaded for a new cam. No they aren't for sale.
And everyone else, including Colin. When the gear has any runout it runs the cam back and forth hammering the thrust bearing. Road Warrior did it to you Colin - want me to find the thread you posted about it?
Maybe I measured the lash and endplay wrong? Used the wrong tools? failed to bolt the gear on right? What do you think?
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Nope...you are right...which is why I noted earlier that you have to measure everything...lash between gears, radial runnout at each tooth, axial runnout for helicoptering and flatness. And then you have to run it slowly through several 360* rotations in mesh...to make sure you have no teeth flanks that are out of spec making tight spots or really loose spots
However....you really should do this with all cam gears.
My point earlier was that its not always and automatically the new Brazilian gear that is bad.
I have only found one out of the dozen I have used that had any issues. While I realize that...not building that many engines myself....one out of 12 is 8.3% having defects....and if my sample is exemplary of all Brazilian type 4 cams....then that is not great. But one out of 12 to me...and fixable....is still quite good for parts these days...so it may as well be a Brazilian to 1 odds....get it?....Brazilian to 1!!!...been waiting years to use that one! ..cough...cough. Ok.
The one defective gear I found was slightly out of round measuring at the tips of the teeth outer circumference....so it made a slight tight spot when rotated.
Yes....the teeth opposite were slightly undersized but the looser spot they made in the gear mesh were so close to spec it did not matter...so I dye marked the tips of the high teeth and simply buffed them with a sanding block and the problem was gone.
But...had I left that tight spot in there...it would have made for an oscillating cam that ate cam bearings....so your point about the quality of the Brazilian or aftermarket gears is well taken.
But when they are good...they are quite good. You just have to inspect them carefully. Ray |
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lil-jinx Samba Member
Joined: August 14, 2013 Posts: 1109 Location: New Brunswick,Canada
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Posted: Thu Jan 18, 2018 3:47 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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69BahamaYellow wrote: |
, giving the proper backlash between 0 to .002 |
I would think that 0 backlash could be a problem,It would become tight when it heated up.and .000 could be minus .00?. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes. |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12727 Location: on a bike ride somewhere
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Posted: Thu Jan 18, 2018 5:13 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - POSSIBLY SOLVED |
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lil-jinx wrote: |
69BahamaYellow wrote: |
, giving the proper backlash between 0 to .002 |
I would think that 0 backlash could be a problem,It would become tight when it heated up.and .000 could be minus .00?. |
The late Bob Hoover talked about how the lash actually expands or doesn’t change, since the gear expands but so does the case. I have no actual experience in measuring hot engines here, but I DID set my old backlash to loose zero and that cam spun the bearing in the case so....
Robbie _________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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69BahamaYellow Samba Member
Joined: April 22, 2011 Posts: 537 Location: Talbott, TN
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Posted: Thu Jan 18, 2018 5:57 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - PROBABLY SOLVED |
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SGKent wrote: |
You know, I come here to help and get flamed. It was the Brazilian gear. I could measure the deviation in it and the replacement. |
Sorry, man, I meant no offence pointing out that my problem was not the gear, but I'm glad you explained what was happening in your case. I can see how run out would beat the cam back and forth on the thrust bearing and wear it out.
That ain't what happened to me, though. I checked my gear with a dial indicator, just like you did, and it's all good, so mine was either a bad bearing or a bad cam. Well today, I'm happy to say I got in touch with Web Cam, and they gave me the thrust surface width spec (1.110"); in other words, that's the width that all of their type 4 cams leave the factory at. Wait a minute.... Mine measures 1.104"; how can that be? Well on closer inspection, I think somebody let my cam out of the factory without the final finish grind on the thrust surfaces. What I thought was a normal looking surface finish really looks like babbit material smeared into the rough steel surface of the thrust facing.
So now I'm thinking the clearance was right initially, or at least close, since I don't remember checking, and the rough surface of the cam just ate the bearing over the last 50,000 miles. So new Kolbenschmidt bearings are now on order, and once I get a measurement on those, I'm going to grind/polish the cam to meet Webcam's 1.110" spec.
Man, this has been great info, though, so THANK YOU to everyone who has contributed. I'm going to refresh the rest of the engine, while it's out, but I'll update a new video, once I get it back together. |
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Hoody Samba Member
Joined: November 28, 2007 Posts: 1948
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Posted: Thu Jan 18, 2018 8:08 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - PROBABLY SOLVED |
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Steve I was not saying that YOU used magnesium cam gears. But since the Brazilian aluminum one is the one available and that’s what has been available for a long time that is what everyone uses. Many people however try to reuse their magnesium cam gear which is a disaster waiting to happen. I was not flaming you and simply stating facts. |
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lil-jinx Samba Member
Joined: August 14, 2013 Posts: 1109 Location: New Brunswick,Canada
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Hoody Samba Member
Joined: November 28, 2007 Posts: 1948
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Posted: Thu Jan 18, 2018 10:55 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - PROBABLY SOLVED |
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Why don’t you just return the cam and lifters and get a new one? They should stand behind it if it left the factory subpar. |
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mike77777 Samba Member
Joined: May 13, 2009 Posts: 119 Location: portland or
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Posted: Thu Jan 18, 2018 11:12 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - PROBABLY SOLVED |
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Good discussion, I will be re camming a 77 2.0 liter soon. Has anyone had good results with the straight cut cam/crank gears? Seems like the lack of thrust of the gears would eliminate one possible difficulty. _________________ patience and putty |
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mike77777 Samba Member
Joined: May 13, 2009 Posts: 119 Location: portland or
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Posted: Thu Jan 18, 2018 11:18 pm Post subject: Re: Type 4 Engine Knocking Noise at Idle - PROBABLY SOLVED |
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I have heard of using two sets of bearings to "double thrust' the one journal. Does any modification of the thrust bearings need to be done if attempting this? Thinking of oil getting all the way around both of the thrust faces. Thanks, mike _________________ patience and putty |
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