Cam rotation resistance

88911coupe · 09-16-2008, 07:27 AM

I tried to ask this on the end of another thread but thought I'd just ask it in it's own thread for clarity. I've done a search and can't find an answer so here's the question. Is there some way to convey or quantify the resistance you should feel when a cam is installed and the tower is torqued down. In my case it's for an '88 3.2 but I assume the question applies to all models. Both cams spin quite freely when inserted into the unattached cam towers but after torquing the drag on the right one is noticable but "seems" okay...
The left side was pretty tight but after some fiddling with the torque sequence it has freed up substantially but still more sticky than the right. Is ithe resistance supposed to be about the same as if untorqued and just sitting in the cam tower? I can rotate both of them but it takes using my index finger wrapped around it as compared to being able to spin in with my fingertips when just in the tower, untorqued. I realize this may be hard to convey since it's by "feel" but I'm trying to decide if I need to tear the heads down or not.
TIA

Henry Schmidt · Henry Schmidt's Garage

The parts you are working with have been torqued, heat cycled many times, and retorqued. It would be normal to expect some level of inconsistency. That said, I would think that if the cams can be turned sans tools, that is to say, "by hand" you will be fine.

There is a level a high quality that we all strive to achieve but perfection is the level achieved in fantasy only. It's your fantasy, make it as perfect as you wish.

88911coupe · 09-16-2008, 08:07 AM

Thanks Henry...you've answered my question and it helps tremendously when those with your experience answer our questions. We all have areas we are comfortable in and areas we need some hand holding and sanity checks.
Both cams can definitely be turned by hand so I'm going to move ahead with the project.
Thanks again,

Henry Schmidt · Henry Schmidt's Garage

You are welcome.
As for hand holding: I'm ok with a little hand holding but long walks on a moon lit beach will require some gender appropriate follow-up

88911coupe · 09-16-2008, 08:56 AM

spinning off topic here....

Henry Schmidt · Henry Schmidt's Garage

Life is way too short to avoid obvious comic relief when it presents itself. Laghter keeps us younger and I need all the help I can get.

88911coupe · 09-16-2008, 04:24 PM

OK...figured out a way to quantify the situation. I just put the cam bolt in the end of the cam and rotated it with a torque wrench. Obviously not very scientific but at least it's something. It barely registerd to the 1st dash which on my wrench is about 2 foot pounds. I'm assuming this is low enough to proceed but if anyone has other opinions I'd love to hear them before I get too far along.
TIA

WERK I · WERK I's Garage

If you used moly to lube the cam journals, there is gong to be a lot of drag. If it's coated with light motor oil, it should turn pretty easy with your hand with no noticeable drag in a 360 degree rotation. How's that?

88911coupe · 09-16-2008, 06:38 PM

Only WD 40 and I can certainly feel noticable drag, although it is pretty consistant throughout the 360 degrees. But to be honest, I can feel some noticable drag when it sitting in the cam tower untorqued. I guess it time to take it apart again.

WERK I · WERK I's Garage

Buck,
Check for nicks on the exterior portions of the journal in the cam tower. One tiny nick on one journal can cause the drag your mentioning. It is quite easy to hit a tower journal with the cam when your removing it.
Are there any grooves (rings) on the cam journals?

88911coupe · 09-16-2008, 08:30 PM

Dave, thanks for the suggestions. The journals are very clean as we the inside surfaces of the cam tower. I guess now I'm back to trying to determine what is an acceptable amount of drag.

WERK I · WERK I's Garage

I guess the last question would be; Are you measuring the drag with the spacers, sprocket and nut attached to the cam? Sometimes the journals may be worn in to a "sweet spot". You don't have to torque the nut down on the cam....such sufficient tightness that the slack is taken out of the spacers. If it turns by hand 360 degrees without no binding anywhere in that scenario, you are good to go.

88911coupe · 09-17-2008, 07:19 AM

Dave, all I attached was the large bolt that goes into the end of the cam and the large washer type thing that goes on the end of the cam. I Only put the washer on to keep the bolt from bottoming out in the hole but I don't suppose it was atually necessary. Then I put the torque wrench on the bolt and rotated the cam. As I mentioned above, it was barely registering to the first dash which seems to indicate the torque needed to rotate the cam is under 2 lbs. My concern is comments to the effect that there should be "no noticable resistance" On my cams there are not any areas that are substantially more resistant that others throughout the 360 degrees. My problem is I don't have any reference as to what's considered acceptable for the basic reistance. I may just go ahead and remove the tower, clean off the 574 then assemble and torque it to spec to see if possibly I got the sealant too thick at some spot.
Thanks

Henry Schmidt · Henry Schmidt's Garage

So far you have two peaple telling you that "if you can turn it by hand, you're ok." You have said it turns all the way around , "by hand". Why are you still struggling with this issue?

88911coupe · 09-17-2008, 11:15 AM

Point taken...moving ahead tonight. Thanks and sorry for making this into a bigger issue that it probably should have been.