I've got a 70 camaro with a 350 that the previous owner installed a hot cam. The valve train has been pretty noisy so I decided to adjust it after finding out that it could be done.
I tried 2 different processes that ended up leaving the valve train noiser that before I started.
I don't know if high lift cams effect standard valve adjustment but I am wondering that because the 2 procedure didn't work. The first one involved getting Cyl 1 where the intake just closed and then going to 6 and adjusting the intake to where pushrod stops spinning and then 1/4 turn. Then folling through a specifice order of the rest of the intakes and then the exhuasts. After 1 then 8 and so forth.
The second finding TDC on each cylinder and adjusting both valves.
After neither one worked, out of frustration I went ahead had my son turn the engine a little bit a time and feel for any loose valves and tighted them to snug and then quarter turn and then kept checking and rechecking. My thinking was that if there was any play that it had to be sitting on the flat part of the cam. Car is quiet now but not running all that good. Did I mess up bad or is it possible that I just need to adjust my timing now?

I know this is alot but really baffled.

Rapid is this a mechanical cam, hyd or roller? There are two different procedures for adjusting based on that answer. Mech cams will have the lash rec by the manufacturer. Hyd cams the procedure is the the same regardless of size. I have no experience with roller so I can't help there.

At this point I'd suggest you go ahead and do a hot lash with the motor running and slobbering oil all over the place. It sounds like you've gotten yourself a little lost in which way and how to adjust the proload, so ideling and getting the lifters pumped back up is probably the easiest. Just a FYI, I bet you have a Comp Extreme grind in the motor and valve train noise is just a way of life with those cams.

I assume it is a hydraulic. Standard rocker arms with no adjustments.

Adjusting Hydraulic Lifters for Proper Preload

In order to adjust the preload, the lifter must be properly located on the base circle or "Heel" of the lobe.

At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.

1. Remove the valve covers, and pick a cylinder that you are going to set the preload on.

2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)

3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)

4. Now lift up and down on the rocker arm at the valve stem while slowly tightening the adjusting nut. When you just get to where it does not have any more gap to lift off the valve stem you are at "Zero Lash". Turn the adjusting nut down one half to three-quarters of a turn from that point. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

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My Cars (http://www.camcojb.com)

Billet taillights for 69 Camaros (http://www.marquezdesign.com)

[This message has been edited by camcojb (edited March 14, 2005).]

[This message has been edited by camcojb (edited March 14, 2005).]

Thanks for the replies. I may either try a running hot adjust. I have a friend who has oil restricters or the last procedure posted. I can assume if still not good after that that my valve train is probably worn out.

<font face="Arial,Verdana" size="2">Originally posted by RapidRoy:
I assume it is a hydraulic. Standard rocker arms with no adjustments. </font>


I would suggest finding out what tappet style cam you actually have before "trying" anything.
Rich

Yea, I agree with Rich here. You NEED to be sure it's not a mechanical cam before messing around with a hot lash. You can't assume anything when it deals with the valve train. Bad things happen.

in the haynes manuals it says to do the tdc #1, #6 ect ect .. get the up and down play out of the pushrod and do a another full turn on the rocker nut.. you said you only did 1/4 turn.. that might be some of the problem possibly...

i might be able to scan in the page and email it to you if you wanted me to...

i've done it the way it says in the manual on 3 diffrent engines.. and no problems...

[This message has been edited by 1981coupe400ci (edited March 14, 2005).]

camcojb has it just right! Other methods are outdated for todays cams!

The best way I've found is to do running mates,eg. when #1 rocks I adjust #6,when #8 rocks I do #5 and so on.
I have never readjusted my valves during the season,just check once in awhile.I also don't use the allen key to tighten the lock,I snug it just before where I want my lash to be then take out the last little bit while tighten the lock.
Jody's way works fine and is a bit less confusing but once you get use to the way I do it,it's quick and simple.

Thanks for all the help! Right now the engine is running terrible and was thinking becuase it is quiet that I could do a hot running adjust. A friend of mine has the rocker oil blockers so it shouldn't be too messy. The procedure I found has me going from one lifter to the next and loosening until it rattles and then tighten until it is quiet and then an addtional 1/2 turn. This with the engine warm. Should I go ahead or maybe do what camcojb has suggested.

[This message has been edited by RapidRoy (edited March 15, 2005).]

before you do that, be SURE you've got hydraulic lifters in there, don't just assume (you know what happens when you assume http://www.nastyz28.com/ubb/wink.gif ). If you do anything that involves tightening the rocker past zero preload and the lifters are mechanical, then you WILL kill the camshaft.

If it's hydraulic then so you don't get oil spurting all over I'd get a old valve cover and drill holes where the nuts are using a hole saw, then while the engine is running you can put your socket on the nut and turn counterclockwise until the chatter begins and then turn 3/4 clockwise taking 1/4 turns at a time and waiting for 10 sec. If you have solids then use http://ca.geocities.com/mlvd@rogers.com/images/doc_adjusting_solid_lifters.jpg

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Mark D
1970 Z28
http://http://ca.geocities.com/mlvd@rogers.com/ (http://ca.geocities.com/mlvd@rogers.com/)
WTB: 70 SS396 Chevelle 4-spd, flapper hood car, no rag tops, 1-2 owner car.

Roy,
When you say "hot cam" do you mean that generically or are you referring to the GM LTI Hot Cam? My buddy has a Hot Cam in his 350 and yes it is a little noisy even when properly adjusted. Same with the XE series by Comp as Marv stated.

I am talking generically. Don't know what kind of cam other than it is very lopey. BTW, sounds great with my American Thunder exhaust.