ENGINE GURUS: Need advice with diagnosis of excessive valvetrain noise(!)...

[bob86gn]

Thanks 8sec. Looking forward to Cecil. The 20 to 30 minutes makes me feel a heck of a lot better. The car has only run about 5 minutes so I will start it and let it run. Hopefully, they will work themselves out.

 

[bob86gn]

Well. I ran it for a half an hour and it seems like the drivers side is pretty quiet however the passenger side is making noise. It did not get any better nor did it get any worse. Looks like the valve covers come off again. Seeing as the drivers side is quiet I assume it is not a psuhrod length issue. Tough to tell which ones with a steth, but it sounds like 2 and 4 are louder than 6.

Any thoughts?

 

[J Banning]

Thanks for the info Bill. I'm headed to the garage here in a few minutes to test the car out after the work I did on the grounds.

What you said about Comp Cams lifters not liking much preload is interesting. I did a search and found a couple other people saying the same thing. What do you recommend for preload? How much less than .030?

Thanks,
-Banning.

P.S. I'm interesting in seeing the new toy of yours at Cecil. You put a 3.8 in that Banshee?

 

[Intercooler]

Originally posted by J Banning
Thanks for the info Bill. I'm headed to the garage here in a few minutes to test the car out after the work I did on the grounds.

What you said about Comp Cams lifters not liking much preload is interesting. I did a search and found a couple other people saying the same thing. What do you recommend for preload? How much less than .030?

Thanks,
-Banning.

P.S. I'm interesting in seeing the new toy of yours at Cecil. You put a 3.8 in that Banshee?

C:Shim up the shafts to .000-.010 or use adj. rockers (adj pushrods are JUNK imho)
Good luck!
Bill

 

[Intercooler]

Originally posted by bob86gn
Seeing as the drivers side is quiet I assume it is not a psuhrod length issue.
Any thoughts?

I wouldn't assume anything. Did you check preload?

 

[J Banning]

Well, all the work I've done the past couple of nights on my grounds wasn't worth a sh!t. Took the car out earlier and it's still doing the EXACT same thing.

Next stop... rechecking lifter preload!!!

I'm having soooo much fun

-Banning.

 

[Jeff]

I have Comp lifters in my '76 Chevy 454, and in a friends' '67 Pontiac 400. They just seem to be noisy with Xtreme Energy Cams....I dunno, just thought I'd mention it. I've been meaning to call them and see what's up...
Jeff

 

[REDS HOT AIR]

i guess i'll answer your pm here..

eight second is on the money with 0 preload on comp lifters...they plain suck

pm crazy gn on here and see how much rpm he gained by putting sealed power lifters in it over the comps.

IMO: if you are going to run zero lash and have the noise you might as well run a solid lift cam.

i've said all along something is holding your mph back and you may just find a few mph in a lifter swap. and if you really want some high gear pull swap out cam and lifters to a 204-214 and hold on when you click into high gear..

 

[J Banning]

Thanks Red. I've got a Comp Cams pushrod length checker coming from Summit Racing. Should be here tomorrow.

We'll see what happens.

-Banning.

 

[J Banning]

1) What can I use as shims?

2) Do I need to check EVERY pushrod, or is it safe to test a couple and then apply the same shim to every one?

3) Is there any chance that I'd be reducing the integrity of the rocker shaft and/or bolts by using shims? I plan to take the motor to 5600-5700 RPM.

4) Should I still use the recommended torque specs on the rocker shaft bolts?


Thanks,
-Banning.

 

[Intercooler]

Originally posted by J Banning
1) What can I use as shims?

2) Do I need to check EVERY pushrod, or is it safe to test a couple and then apply the same shim to every one?

3) Is there any chance that I'd be reducing the integrity of the rocker shaft and/or bolts by using shims? I plan to take the motor to 5600-5700 RPM.

4) Should I still use the recommended torque specs on the rocker shaft bolts?


Thanks,
-Banning.

1. Shims. I can get you what you need but you have to poke your own holes
2. Check several. They should all be the same or damn close.
3. No.
4. Yes.


Let me know ASAP. I can get the stainless steel shim stock from work on Monday if you let me know what thikness cures your problem and puts you at 0-.010" preload. The shim kit I have can be bought at Grainger for $75.00.

 

[bob86gn]

I think I found my problem as well. There is zero preload on a couple of the rockers, others are within spec. Pretty weird that two next to each other can be at different levels. It may answer Banning's question. You have to check them all.

I guess I need some adjustable rocker arms. Looks like I'll be ordering some stuff for overnight on Monday. If I make it to Cecil is will be a miracle!!

 

[J Banning]

Preliminary results show that...
1) I had stock length pushrods in the motor.
2) My lifter preload was between .050 - .060.

Since the Comp Cams lifters are supposed to have little to no preload, perhaps this is the cause of my 5000+ RPM stutter (valve float)? I'm headed out now to see if I can find any metal stock to use as shims. Will post results later tonight.

-Banning.

 

[J Banning]

P.S.
That Comp Cams pushrod length checker is a pain in the ass. It's not long enough... the adjuster is too far down in the head to get your fingers on. Every time you need to adjust it out (to get to the point of zero lash) you have to take the rocker arm shaft off and pull it out, then set it back in, then put the shaft back on.

-Banning.

 

[bob86gn]

I am not sure what you are going to shim? Are you going to shim the rocker shaft off of the pedestals?

Also, I have to relieve one of my pedestals since it is rubbing on the exhaust of #2.

 

[Intercooler]

Originally posted by bob86gn
I am not sure what you are going to shim? Are you going to shim the rocker shaft off of the pedestals?

Also, I have to relieve one of my pedestals since it is rubbing on the exhaust of #2.

You just place the shims under the shaft at the mounting points where the bolts go.

 

[REDS HOT AIR]

Originally posted by J Banning
Preliminary results show that...
1) I had stock length pushrods in the motor.
2) My lifter preload was between .050 - .060.

Since the Comp Cams lifters are supposed to have little to no preload, perhaps this is the cause of my 5000+ RPM stutter (valve float)? I'm headed out now to see if I can find any metal stock to use as shims. Will post results later tonight.

-Banning.

or change to sealed power lifters....whichever you find easier

im running stock pushrods with single steel shim gasket which dropped the heads .042 and i still dont have a rpm problem bounces off the 6200 rev limiter easily.

 

[J Banning]

I got everything buttoned up and made a couple test runs tonight. I don't see any signs of my previous problem. I made two runs amnually shifting at about 5600 and both times the engine pulled clean to the shiftpoint. I'm totally pumped and can't wait to do some more testing tomorrow!!

Woohooo!!!!!!

-Banning.

 

[EightSecV6]

Glad to see things are working out, once you get the preload right (.000-.010) they will make more power than the cheapies as they stay pumped up at the top of the RPM range.
Bill

 

[REDS HOT AIR]

Originally posted by EightSecV6
Glad to see things are working out, once you get the preload right (.000-.010) they will make more power than the cheapies as they stay pumped up at the top of the RPM range.
Bill

which are you saying stay pumped up???