Checking cam wipe?

[siteunseen]

Dykem dye on the rockers contact pads first, let them dry.  Grease the cam lobes.  Do one rocker at a time.  Should I put any grease on the painted rocker pad or leave them dry for the centering wipe check?  

[madkaw]

I don't see why you need to grease if it is spotlessly clean!

[cbuczesk]

I didn't grease mine and I applied the dye to all the rockers at once.

 

Chuck

[siteunseen]

Thank you for confirming what i was thinking. I over reacted a bit, anxious I guess. So far it's easy, just slow. Luckily I have 8 .175 lash pads and I had to use one so far. I think it maybe too thick but it brought the wipe closer to the valve side than the pivot end of the arm. Still not perfect but much better.

I'm doing the easy ones first and using a spare rocker arm and a big screwdriver to compress the springs.

[Zed Head]

Just to add to your concern - in a discussion about wiping cam lobes (the bad wiping, like destroying) one of the engine builders described damaging the lobes just from turning the engine by hand.  He could see things starting.  Best to keep things over-lubed with the zinc additive lubes.  Pressures at the rocker arm - cam lobe interface are still high, even at low speed.  The old safe/sorry conundrum.

[siteunseen]

I've been doing one then removing it. I turn the toe of the lobe 2 times over the pad. The dye barely comes that way, if I put moly lube it wouldn't I don't think.

[240260280z]

lightly oil the cam and just use a permanent marker on the ends of the rocker pad.  You just need to see where the wipe starts and stops.

 

You can use softer springs or just one spring for just this procedure if wear is too worrying.... then when the wipes are good put the regular springs in.

 

You can check the wipe pattern in this sequence:

 

1. Oil/assembly lube all rockers and cam lobes.

2. Back off rocker pivot bolt all the way down for all rockers

3. Start with  cylinder 1 Exhaust Rocker... Turn cam so that the lobe is up.

4. Set the hot lash...yup...hot.

5. Wipe oil off just the ends of the rocker pad.

6. Cover the ends of the rocker pad with marker.

7. rotate cam and watch it wipe

8. Verify what you observed by inspecting what was wiped off (marker remaining)

9 Repeat 11 more times

Edited September 18, 2015 by Blue

[madkaw]

I guess when I considered an answer I should have remembered that I was using light springs, so wear wasn't a concern. My machinist just used permanent marker with light springs. Probably with full on springs a little lube wod be good.

[siteunseen]

lightly oil the cam and just use a permanent marker on the ends of the rocker pad.  You just need to see where the wipe starts and stops.

 

You can use softer springs or just one spring for just this procedure if wear is too worrying.... then when the wipes are good put the regular springs in.

 

You can check the wipe pattern in this sequence:

 

1. Oil/assembly lube all rockers and cam lobes.

2. Back off rocker pivot bolt all the way down for all rockers

3. Start with  cylinder 1 Exhaust Rocker... Turn cam so that the lobe is up.

4. Set the hot lash...yup...hot.

5. Wipe oil off just the ends of the rocker pad.

6. Cover the ends of the rocker pad with marker.

7. rotate cam and watch it wipe

8. Verify what you observed by inspecting what was wiped off (marker remaining)

9 Repeat 11 more times

Hot??? I've read cold, a few times.

I'm lucky this is my hobby. I've learned something I've never taken time to practice, patience.

[240260280z]

Assemble cold lash before you start the car but the cam will be wiped hot so you should replicate it when setting lash pad height. Maybe I am wrong on this but I am assuming that reproducing the hot lash is correct and more accurate.

[siteunseen]

Okay, that makes sense. Before I crank it and run it 2,000rpm for 20 or 30 minutes I should set them on HOT specs. They are a little wider, great thinking.

Thanks a million, again!

[siteunseen]

What to do?  Tom Monroe says do the run in set at the cold specs, then after you shut it off set to hot.  I have a Schneider cam kit that I'll be using someday,    , and the cam card says set the valves to cold specs too.

 

It'll be awhile before I crank it so I'll read up and see what others are doing.

 

I'm going to continue checking the wipe with them set at .10 and .08.