57 replies to this topic

[Earwax]

Well covered above, also consider the valve lash.  if the lash operated the lifters on the steep cam lobe slope instead of the gradual ramp then that would tend to eat at things.   I know reground cams are usually heat treated after, and don't doubt that this occurred, but I have a suspicion that some old cams and new regrinds somehow make a softer cam... ( Don't want to get into any depth of hardening argument here!!!!!  :)  but more of an observation for others to comment on.)

Note: What i am getting at is a small percentage of regrinds end up with accelerated wear/damage without many other reasonable explanations.

[mini-geek]

Can 1.5 rockers contribute to these issues?

[Spider]

Can 1.5 rockers contribute to these issues?

 

I would say no. What I see is in general terms, poor quality. The 1.5 Rockers may bring this to a head sooner, but I can't see them being a cause.

[Wim Fournier]

Well, 1.5 rockers compared to 1.3 (std) rockers means 16% more pressure between the cam lobes and followers. It ads up.

[CPC]

I'm just using standard rockers..

And yes I'm planning to change the cam, maybe try the mini spares evolution cam..

Thanks for the info guys

[mini13]

I would look at AC Dodds Cams, or the Russel engineering cams available via Keith Calver, certainly the Russels ones have a much less pointy "nose" so are less prone to wear, I belive this is true of AC Dodds too.

 

as mentioned the cam should rotate the follower, as well as checking the follower radius and cam taper are present, its worth checking the cam end float, as really you son't want the cap flapping pack and forwards a load intead of turning the followers.

 

also as mentioned, correct oil is important, must have the zddp and be in the region of 1500ppm, apparently the level can be overdone which causes issues elswhere, so dont be tempted to load up oil with a load of zddp cam break in lube to up the content.

[Spider]

..... have a much less pointy "nose" so are less prone to wear,

 

I've heard that before actually and sorry, but I disagree on that. There's only ever (or should only ever) 'line' contact between the lobe and the follower. So being 'pointy' or not shouldn't have a bearing on wear.

 

For what it's worth, I wouldn't touch a Russell Cam.

Edited by Moke Spider, 07 September 2016 - 08:41 AM.

[imaparana]

 

..... have a much less pointy "nose" so are less prone to wear,

 

I've heard that before actually and sorry, but I disagree on that. There's only ever (or should only ever) 'line' contact between the lobe and the follower. So being 'pointy' or not shouldn't have a bearing on wear.

 

For what it's worth, I wouldn't touch a Russell Cam.

 

whys that?

[mini13]

Well ok, fair point it is to all intents and purposes only a line contact, but it really does seem that the nose profile has an effect on wear, and also for that matter general scale of the came lobe, ie the base circle it originates from, perhaps the nose profile is having an effect on the oil wedge?

[mini13]

another point worth raising, also is it seems that the transverse varients suffer more with more cam wear generally ( and follower pitting), and I have noticed it tends to be on cyls 3&4,

 

I suspect that its due to debris in the oil being thrown up by the gearbox,

Edited by mini13, 07 September 2016 - 02:27 PM.

[Orange-Phantom]

There are plenty of people out there who suggest upping the ZDDP content of the oil for break in purposes specifically for the cam, with the best A Series tuner out there David Vizard being one of them.

 

http://www.oilextreme.com/breakin.html

 

http://www.hotrod.co...break-in-guide/

 

http://johnmaherraci...lifters-part-1/

 

http://www.crankshaf...tips_and_tricks

[MIGLIACARS]

I would really lean more to a poor quality followers,   I had this issue when I stripped an engine built by MBE.  engine had only done about 4 hours running. Under investigation the followers were cheap and nasty. Since, I now build my engines with MED followers and so far they have been good on inspection on the rebuilds.

I have always used good quality oils.

 

Last week I was messing around making something. and used an old genuine cam follower, I tried drilling the end with various drills to no avail, even in the lathe with a center drill they would not drill, I ended up using a tungsten lathe tool to make the hole and even this wasnt easy,   just goes to show how hard they are ment to be!!!!

[Spider]

Last week I was messing around making something. and used an old genuine cam follower, I tried drilling the end with various drills to no avail, even in the lathe with a center drill they would not drill, I ended up using a tungsten lathe tool to make the hole and even this wasnt easy,   just goes to show how hard they are ment to be!!!!

 

They were around 62 - 64 Rc, so quite hard.  If you ever need to drill anything like that again, try an Artu brand drill bit, be sure to follow their instructions, they need moderate to high speed and a fair amount of pressure, but once they get a little heat in to them, they go through stuff like this like the proverbial hot knife though butter.

[MIGLIACARS]

 

Last week I was messing around making something. and used an old genuine cam follower, I tried drilling the end with various drills to no avail, even in the lathe with a center drill they would not drill, I ended up using a tungsten lathe tool to make the hole and even this wasnt easy,   just goes to show how hard they are ment to be!!!!

 

They were around 62 - 64 Rc, so quite hard.  If you ever need to drill anything like that again, try an Artu brand drill bit, be sure to follow their instructions, they need moderate to high speed and a fair amount of pressure, but once they get a little heat in to them, they go through stuff like this like the proverbial hot knife though butter.

 

cheers dude

[MIGLIACARS]

 

 

Last week I was messing around making something. and used an old genuine cam follower, I tried drilling the end with various drills to no avail, even in the lathe with a center drill they would not drill, I ended up using a tungsten lathe tool to make the hole and even this wasnt easy,   just goes to show how hard they are ment to be!!!!

 

They were around 62 - 64 Rc, so quite hard.  If you ever need to drill anything like that again, try an Artu brand drill bit, be sure to follow their instructions, they need moderate to high speed and a fair amount of pressure, but once they get a little heat in to them, they go through stuff like this like the proverbial hot knife though butter.

 

cheers dude

 

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