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Noisy valves- what to do
https://slantsix.org/forum/viewtopic.php?t=42357		 Page 1 of 2
Author:  Reed [ Fri Oct 22, 2010 3:51 pm ]
Post subject:  Noisy valves- what to do
About a year ago, I installed a custom reground cam in my brother's 225. The cam core was a 1964 225 stock camshaft. I had it reground to the Erson RV 10 profile by delta camshaft here in Tacoma. At the same time I replaced the cam, I replaced the lifters with lifters that had also been reground/resurfaced. Not new lifters, but used reground lifters.

Ever since installing the cam the valves have made lots of noise. I have tried two different cylinder heads, three different rocker arm assemblies, and valve lash settings from .008 to .020 on both intake and exhaust and this valve noise just won't go away. The lash is currently set at .012 intake and exhaust.

The cam was installed with lots of cam break in lube on the lobes and on the bottoms of the lifters. I followed the break in procedure of running it at 1500 RPM for 20 minutes and changing the oil and filter, running it for 500 miles and changing the oil and filter, and then regular oil changes after that. I started with straight 30 weight oil, then switched to 5w-30 oil after the second oil change.

What the hey? The motor runs fine, has plenty of power, and doesn't act like the lobes or lifters are worn. I am getting oil flow out the tips of the rocker arms, but the valves are just really noisy. If I tighten the lash up, the motor starts missing and the lifter noise doesn't go away. Before the cam swap the motor was the usual quiet slant-six lifter noise we all know and love.

Should I try a different weight oil? Synthetic? Are reground cams and/or lifter just noisy and/or a bad idea?

:? :shrug:
Author:  hellion_locdogg [ Fri Oct 22, 2010 4:38 pm ]
Post subject: 
Valve springs?
Author:  Doc [ Fri Oct 22, 2010 4:45 pm ]
Post subject: 
Are all the pushrods spinning?
I sounds like Delta reground that cam using a hydraulic lobe profile. (master)
You would have to use a dial indicater and degree wheel, to check the lash ramp geometry, to know for sure.
DD
Author:  Reed [ Fri Oct 22, 2010 5:11 pm ]
Post subject: 
The head is rebuilt and the valve springs *should* be within spec, but I guess I should check. I'll check for spinning pushrods too. I sure hope it isn't that the cam was ground with a hydraulic profile. Argh. I'll have to get hold of the van for a weekend so I can put a dial indicator on the cam and watch for valve events.

If it is a regrind mistake, I guess I can save the cam for the hydraulic motor I will be building for my brother's Duster...

Thanks for the help.
Author:  Reed [ Sat Oct 23, 2010 8:56 am ]
Post subject: 
On the other hand, if the cam is a hydraulic cam profile, I could just swap in new hydraulic lifters, hydraulic pushrods, and hydraulic rocker arms and see if it quiets down, right? :?

How do I tell if it is a hydraulic cam profile? If I put a dial indicator on it, what characteristics am I looking for to determine if it is a hydraulic cam? Thanks.
Author:  Aggressive Ted [ Sat Oct 23, 2010 10:35 am ]
Post subject: 
Reed,

On the RV10 cam Delta Cams ground for me was on my original cam from the 74 motor. It was noisy at first with thicker break in oil but running 0-30W Mobil 1 really quieted it down. The thicker the oil the noisier it gets. I even notice a difference between 0-30W and 5-30W. I am use to a fairly quiet motor. The stock 79 SL6 I am running now is the same noise level as my 74 "torque and mileage build" motor. If I run 10-30W Rotella or Valvoline it makes more noise than 0-30W Mobil 1. I have run the valves at the stock setting .010 and .020 and have tried Doc's suggestion for more torque at .012 and .022. Not a lot of difference in noise.

My good 74 motor is on a motor stand at the moment waiting for some upgrades. HD oil pump, double roller chain, Engine Builder valves, crank scrapper, and the four barrel Weiand intake manifold. I want to be able to run it hard at the track testing the one barrel, two and and 4 barrel Holley carbs against each other.

Let me know what you find out on the lobe events.
Author:  Reed [ Sat Oct 23, 2010 11:36 am ]
Post subject: 
Hmmmm. I'll try running 0W-30 Mobil 1. I really don't want to tear this motor apart AGAIN. If the lighter weight oil doesn't quiet it down I will dig out the dial gauge and degree wheel and spend a day mapping valve events.

What would make these cams be so noisy? Stock cams are quiet no matter what type of oil is put in the motor, so why are these any different? Is it a function of the lobe profile? :? I much prefer a quiet and smooth running motor. I hate unnecessary noise and vibrations.
Author:  DusterIdiot [ Sat Oct 23, 2010 1:04 pm ]
Post subject:  Yep...
Quote:
Is it a function of the lobe profile?
Yes it's the ramp profile and how it loads and unloads the lifter...chevy profiles for chrysler grinds can do this since they were set up for a different lifter diameter...

-D.Idiot
Author:  Reed [ Sat Oct 23, 2010 2:18 pm ]
Post subject: 
Ahhhh. Thanks! I'll try the 0W-30 and see how that works. If that fixes the problem I will be a happy man.
Author:  Aggressive Ted [ Sat Oct 23, 2010 7:10 pm ]
Post subject: 
Reed,

It may take a few days to a week or so to work through, but after two weeks I re-gaped the valves and the noise settled down. It also did wonders for the stock 79 engine I have in the car now.
Author:  Reed [ Sat Oct 23, 2010 7:14 pm ]
Post subject: 
Will do, thanks.
Author:  Doc [ Mon Oct 25, 2010 9:17 am ]
Post subject: 
The lead-in ramp or "lash ramp" is very different between a mechanical and a hydro cam.
A mechanical cam's lash ramp is slow and easy, it can cover many degrees of rotation in order to produce a small amount of lift.
A hydraulic cams "lead-in" ramp is opposite, it transitions into the lobe's flank as fast as possible, in order to quickly compress the oil pocket, inside the lifter.
DD
Author:  Reed [ Mon Oct 25, 2010 10:48 am ]
Post subject: 
Thanks Doc! That makes sense. I have been searching online for a decent and easy to understand difference between the mechanical and hydraulic cam profiles, and came up empty. Your answer was concise and easily understood. I love this site.

I won't have my hand on the motor again until November 10, but I will do an oil change then report back what happens. If the motor quiets down, great. If not, then it is cam profiling time. :x
Author:  Doc [ Mon Oct 25, 2010 11:19 am ]
Post subject: 
If it is a hydro lobe profile running with solid lifters, all you can do is run the lash as tight as possible, with-out misfire...
The last one of these I ran into ran pretty well when lashed at .006 intake and .008 exhaust.
DD
Author:  Reed [ Mon Oct 25, 2010 11:33 am ]
Post subject: 
Thanks. If it does turn out I have a hydraulic profile, I am thinking I will just go all the way and swap over to hydraulic lifters, pushrods, and rocker arms.
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