| Author |
Message |
busman78
Samba Member
Joined: August 17, 2004
Posts: 4524
Location: Oklahoma City, OK
|
 Posted: Tue Dec 12, 2017 11:12 am Post subject: Re: Engle cam forging issues - W-120 |
 |
|
| I use a small sharpening stone, fine grit, little oil, breaks the edge with ease. |
|
| Back to top |
|
 |
jason
Samba Member
Joined: August 07, 2002
Posts: 3444
Location: Garage
|
| Posted: Tue Dec 12, 2017 11:53 am Post subject: Re: Engle cam forging issues - W-120 |
|
|
| Little sanding drum on a Dremel works great and fast. Don’t be suprised if all their cams are like that one. |
|
| Back to top |
|
|
SuperOldSchool
Samba Member
Joined: August 15, 2009
Posts: 59
Location: Chicagoland
|
| Posted: Tue Dec 12, 2017 2:15 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
Thanks all!
I did send it back for a little cleaner one.
I’ll try the Dremel approach to clean up the new one.
SOS |
|
| Back to top |
|
|
KROC
Samba Member
Joined: February 20, 2006
Posts: 359
Location: Vancouver B.C.
|
| Posted: Tue Dec 12, 2017 2:39 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
I don't understand the need to dress the edge of a cam lobe, the lifter is convex it should not be touching the outside edge. Unless of coarse your lifter bores are toast, or the lifter is worn out into a cup shape.
Most of the domestic cams like Crane etc, do not bevel the edges
37 years of building these things and have never "dressed" a cam lobe.....
Have had a few cams go flat over the years but it was due to Lifter/Cam Rockwell issues...
Anyways would love to hear the rational behind this. Perhaps I can be convinced to spend even more time on these builds 
Thanks |
|
| Back to top |
|
|
UK Luke 72
Samba Member
Joined: September 07, 2011
Posts: 2867
Location: Little Britain
|
|
| Back to top |
|
|
jason
Samba Member
Joined: August 07, 2002
Posts: 3444
Location: Garage
|
| Posted: Tue Dec 12, 2017 4:16 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
| Probably not needed but if I can cut myself on it I will knock it down. |
|
| Back to top |
|
|
mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
|
| Posted: Tue Dec 12, 2017 4:21 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
| UK Luke 72 wrote: |
| VW did it. |
along with the lobes being TAPERED. and different lifters are tapered difterently...convexed?? now thats vexing Im at a loss for words..... the quickers eazesy way Ive found doing it is a 1" wide belt sander, extreamly eazy&fast to do. much more reliable than a diegrinder/dremmol. v8 cams can be a booger, wilh 4x as many lobes and so close togeather. these vw cams are so eazy to do.
rock well issues......well those edges and especialy the ones like on that op's pic will probably be harder due to being so thin and they can eazely dig innto the lifter..so yes rockwell issues..knock off the rock...hard edges and no place to scar the lifter and start the eating prosess.
also Ive never seen a used lobe that didnt show sines of the lifter wear on the edge of the lobes...how does it show sines the lifter was contacting the lobe all the way to the edges.... because it does contact it there. the lobe and lifters are tapered so they make contact across the face of the lobe and lifter.if they were not the lifter would just contact at it's highest point in the center and...dig a ditch. |
|
| Back to top |
|
|
midtravelmidengine
Samba Member
Joined: August 06, 2009
Posts: 861
Location: Riverside, Ca
|
| Posted: Tue Dec 12, 2017 4:43 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
| KROC wrote: |
Have had a few cams go flat over the years but it was due to Lifter/Cam Rockwell issues...
|
Or were they ?  
hahahah just messing 
_________________
| modok wrote: |
| And I know you don't know because if you did you would know the reason for my knowing you didn't. |
| youngnstudly wrote: |
I just wasn't sure if I should recommend the 1/3 race cam, the 1/2 race cam, or the 5/8 race cam instead...guess it depends on how much of the race he wants to lead???
|
|
|
| Back to top |
|
|
modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
|
| Posted: Tue Dec 12, 2017 6:01 pm Post subject: Re: Engle cam forging issues - W-120 |
|
|
| KROC wrote: |
| I don't understand the need to dress the edge of a cam lobe, the lifter is convex it should not be touching the outside edge. |
Good question. It is for two reasons.
On the nose of the cam, it will eventually wear such that it will have contact all the way to the edge. So if that were the only reason, then you;d just do around the nose, and in this case, to correct the location of the lobe (which does matter), it would only be necessary to correct around the nose, as the rest of the cam the lifter will never touch the edge until it's worn so bad it's dead anyhow.
Any time you have a machining operation on a part that has sharp corners, it probably will generate a small burr at the edge. It could be a casting, a gear, a crank, really any part. Even a valve. These days 90% of the time in industry there is a subsequent operation to remove the sharp edges, blasting, vibratory polish, tumbling.....ect. If there isn't then you do it by hand.
Why bother??
Besides cutting your hands to ribbons, it is also likely these small burrs could fall off and get in to he moving parts. Cams are not terribly hard, but are chock full of chromium carbide and iron carbide. You don't want any of that in the oil.
Also a good idea to polish up the thrust bearing faces on these cams. Another thing the cam grinder SHOULD have done but they don't. |
|
| Back to top |
|
|
FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4278
Location: deepest, darkest Switzerland
|
| Posted: Wed Dec 13, 2017 2:20 am Post subject: Re: Engle cam forging issues - W-120 |
|
|
I seem to remember reading someplace (here?) that the hardening process comes in from the outsides, to a certain depth, so, where two surfaces meet (the edges of cam), the hardening process has done a double job, coming in from one side and the other, so the edge is very hard, harder than the cam surface.
 |
|
| Back to top |
|
|
mark tucker
Samba Member
Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
|
| Posted: Wed Dec 13, 2017 10:21 am Post subject: Re: Engle cam forging issues - W-120 |
|
|
some cams are vibritory polished now for supperior serface,and some electro polished or a combo of both.I think it's comp thats doing it and getting a lot better cam in the end. also dragzine has a new artickle from erson that sheds a little light on hardening and grinding the cam in the correct position.I kinda doubt that these cams we get are indexed worth a shite,thats not the cam guys fault it's the guys that are prosessing the blanks and adding the holes&pump slot witch is what is the index to locat the cam for grinding. a few degrees this way or that way and....havva look and see if this link works.
http://www.dragzine.com/features/pri-coverage/pri-...e-grinding .
no I aint no link wizard, if it dont work oh well. cut &paste, just dont eat the glue. |
|
| Back to top |
|
|
nsracing
Samba Member
Joined: November 16, 2003
Posts: 9481
Location: NOVA
|
| Posted: Sun Dec 17, 2017 4:02 am Post subject: Re: Engle cam forging issues - W-120 |
|
|
I did them like this when I had my grinder here in VA...
|
|
| Back to top |
|
|
|
