TheSamba.com :: View topic - mahle vs KS cam bearings end play variations-Opinions needed

Wed Sep 09, 2009 4:23 am

miniman82 wrote: Jake Raby wrote: Remember, you haven't built a TIV engine yet.

Doesn't matter, they both use the same exact cam bearing setup. Matter of fact, I'm using T1 double thrust bearings in mine. It's not my first shindig.
Thats because the thrust bearings are the same!! (except if you double thrust, then the tang has to be removed from the TI bearing) Two of the other cam bearings have a different width and their tang locations are not correct for the TIV engine.

The TI responds the same to settling of the bearings before the end play is measured. The fact is when material is removed to set cam end play prior to settling of the bearings you'll generally be out of spec before the engine ever sees the first 100 miles.

If you didn't know that, then perhaps you haven't had enough "shindigs" yet.. Don't worry, it all comes with time... Check back around engine #800 and we'll compare notes. :-)

Not trying to be a dick here fellas, just trying to stimulate thought that may save you from the same harsh learning curve that we experienced.

Maybe I need to illustrate this with video.
BTW_ I have cam thrust bearings made that are 2X as resilient to wear as the mahle and KS units, called "Extreme" bearings. These have the toughest thrust surfaces available as they were developed with my roller camshaft program to endure the rigors of 100K+ miles of service with a roller profile and heavy dual springs.

Wed Sep 09, 2009 6:33 am

Jake - the next engine we build, we will use one of those sets. I've noticed that T4 wear cam bearings and lifter lobes more than T1, especially with heavier springs.

Wed Sep 09, 2009 6:50 am

I sanded mine not only to give the correct clearance, but clearance, period. The bearing was too wide for the journal. I like Jake's idea, but even that wasn't practical for a cam that won't even fit in the bearing.

Wed Sep 09, 2009 7:05 am

When I face the situation of bearings being toot ight for assembly at all I generally remove the absolute least amount of material possible, then settle the bearings.

After that the clearance is generally spot on.

My next DVD will go over these procedures.

Wed Sep 09, 2009 12:47 pm

Jake Raby wrote: miniman82 wrote: Jake Raby wrote: Remember, you haven't built a TIV engine yet.

Doesn't matter, they both use the same exact cam bearing setup. Matter of fact, I'm using T1 double thrust bearings in mine. It's not my first shindig.
Thats because the thrust bearings are the same!! (except if you double thrust, then the tang has to be removed from the TI bearing) Two of the other cam bearings have a different width and their tang locations are not correct for the TIV engine.

Or do like I did, and file a spot for the tang to sit in right into the case. Only takes about 10 minutes with a hand file, super simple. Truth be told though, I only did it because I had a set of T1 cam bearings in the garage, and didn't want to wait for T4 stuff to show up through the mail.

Quote: when material is removed to set cam end play prior to settling of the bearings, you'll generally be out of spec before the engine ever sees the first 100 miles. If you didn't know that, then perhaps you haven't had enough "shindigs" yet..

You're making assumptions...
I never said I don't seat the bearings. :wink:
I do it with main and rod bearings as well, before using plastigage.

Like Sigurd, I've had bearing sets that would go onto that cam at all unless they were first wet sanded a little bit. It's also a good idea to lightly sand that sometimes sharp outer edge of the thrust surface of the cam, so the bearing doesn't get hung up on it. I sometimes see blanks that leave much to be desired in finish work.

A lot of this doesn't really apply much to me though, since I use straight cut gears in T1 engines. The T4 will matter though, it has stock gears.

Wed Sep 09, 2009 12:50 pm

I never make an assumption, thats the first turn off on the road to failure..

Looks like we are on the same page, happy building.

Wed Sep 09, 2009 11:53 pm

SGKent wrote:
Sanding a soft material like a bearing can be problematic. The soft material picks up the loose abrasives and it then becomes a cutting stone. What would be better is to use a babbit knife or even a pocket knife with a flat blade to gently scrape them until they fit.
Scraping stock cam bearings is about the dumbest thing I've heard in months. You'll never get a true flat surface.

If you were so worried about sanding the bearings, just throw the cam in the lathe and cut the flange wider.

Thu Sep 10, 2009 5:38 am

Bruce wrote: SGKent wrote:
Sanding a soft material like a bearing can be problematic. The soft material picks up the loose abrasives and it then becomes a cutting stone. What would be better is to use a babbit knife or even a pocket knife with a flat blade to gently scrape them until they fit.
Scraping stock cam bearings is about the dumbest thing I've heard in months. You'll never get a true flat surface.

If you were so worried about sanding the bearings, just throw the cam in the lathe and cut the flange wider.

My thoughts exactly, if you need to remove material in a precise manner, why not used a machine designed to remove material in a precise manner? Only slight problem I can think of is clamping down a soft part as a bearing in a secure fashion.

Thu Sep 10, 2009 8:39 am

My idea to machine the thrust would be to put the bearing in the case (or a fixture which simulated the clamping load of the case), then put the case/fixture in a mill with a cutting head and take material off that way. If you ask me though, it's a lot of work for nothing, seeing as how you can get the correct endplay by wet sanding. I mean really, it takes what, maybe 10 minutes to get it right with some fine grit, or a few HOURS the other way? :roll:

Thu Sep 10, 2009 9:16 am

ya'll are making this way too difficult.

Thu Sep 10, 2009 12:24 pm

Jake Raby wrote: ya'll are making this way too difficult.

I'm used to Marines saying stuff like that to a squid like me, but I think it has more to do with Marines being simple. :lol:

Thu Sep 10, 2009 12:36 pm

Quote: but I think it has more to do with Marines being simple.
And effective..

Thu Sep 10, 2009 2:23 pm

miniman82 wrote: My idea to machine the thrust would be to put the bearing in the case (or a fixture which simulated the clamping load of the case), then put the case/fixture in a mill with a cutting head and take material off that way. If you ask me though, it's a lot of work for nothing, seeing as how you can get the correct endplay by wet sanding. I mean really, it takes what, maybe 10 minutes to get it right with some fine grit, or a few HOURS the other way? :roll:

Never said it was the perfect way, but what a couple extra hours to a guy that worries about embedding aluminum oxide in the cam bearings? :D

Thu Sep 10, 2009 2:25 pm

The finest whetrock with honing oil keeps that from occurring..
Then hone it with a piece of leather... Just like glass.

Thu Sep 10, 2009 9:16 pm

how to tailor fit a bearing with a babbitt knife:

http://books.google.com/books?id=5jNS4NubpR4C&...mp;f=false

Fri Sep 11, 2009 5:18 pm

Google Books wrote: Scraping bearings is an obscure, but useful technique for removing bearing high spots.

It's a method for removing high sopts, not correcting clearance according to your link. :wink:

Mon Dec 05, 2011 2:32 pm

Resurrecting an old thread to ask a completely neophyte question: I've been told that non-magnetic gray gook buildup on the oil filter screen is an indication of severe bearing wear. I'm just curious to know what material bearings are made of if they are metallic but not magnetic. Be gentle and thank you! :D

Mon Dec 05, 2011 3:02 pm

79SuperVert wrote: Resurrecting an old thread to ask a completely neophyte question: I've been told that non-magnetic gray gook buildup on the oil filter screen is an indication of severe bearing wear. I'm just curious to know what material bearings are made of if they are metallic but not magnetic. Be gentle and thank you! :D

old bearing are steel backed lead. New bearings are aluminum backed

Mon Dec 05, 2011 6:24 pm

yes, bearings are most often made form babbit(tin/lead), bronze, or aluminum

None of these are magnetic

Mon Dec 05, 2011 7:09 pm

Thank you!