car will not stay running after cc306 install!
03-22-2011, 10:22 AM
#21
From the looks of both posts I would say you have the cam timing wrong and the valves too tight and also a problem with the reluctor/pick up.You need to take it apart and start over.Show us pics of the timing gear marks at TDC if you can.Also get rid of that chain and get yourself a ZZ4 set up.It is all the LT4 parts minus the cam gear,no water pump drive.Available at your local dealer
03-22-2011, 10:56 AM
#22
Staging Lane
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When we set the cam timing we had the cam at 6 oclock and crank at 12 oclock with #1 TDC. should it have been #6 at TDC instead? Does the cam dow have to be at the 3 oclock position to set timing??
03-22-2011, 02:40 PM
#25
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Not sure what you mean by "all the way down." What it reads like is the lock or set screw is deep inside the adjusting nut. If that is the case then the rocker/trunion is upside down. The flat surface on the trunion should be facing up so the adjusting nut seats true.
I don't think it's your rockers, however. Especially since the car ran before you loaded a new tune. If it were me I'd try to get another PCM installed to see if it will fire up.
I am interested in knowing why that way is wrong as well. Especially since that method has been around since the beginning of time.
I don't think it's your rockers, however. Especially since the car ran before you loaded a new tune. If it were me I'd try to get another PCM installed to see if it will fire up.
I am interested in knowing why that way is wrong as well. Especially since that method has been around since the beginning of time.
03-23-2011, 04:31 PM
#26
03-23-2011, 09:47 PM
#28
I do one cylinder at a time with the engine cold. I rotate the cam until both lifters are on the base of the cam, bring the rocker to zero lash, and on 3/8" studs I set preload at one full turn. This is the factory preload for GM lifters. It has worked well in my junk. I like the GM racing hydraulics better than the stock ones. I do it this way because all eight cylinders are set almost exactly the same.
Last edited by GIZMO; 03-24-2011 at 08:54 AM.
03-24-2011, 08:56 AM
#31
GIZMO I have never been able to adjust them like that and not float the valves.Even when at 1/4 turn.Used to set them that way then went to dyno and had horrible float.Puled car off,re set the valves running and picked up 35 rwhp. OP is this thing sorted out yet? Curious to know what you had found?
03-24-2011, 09:30 AM
#32
I have always done it the way I described. The factory spec. is one turn. There are millions of stock GM roller lifters riding around this country that are adjusted that way. There are also a ton of lifter adjustment, cam change fail threads in this section. One thing that almost all of them have in common is the 1/4 turn adjustment. The second is high mile used lifters on a new cam.
03-24-2011, 10:31 AM
#33
I do one cylinder at a time with the engine cold. I rotate the cam until both lifters are on the base of the cam, bring the rocker to zero lash, and on 3/8" studs I set preload at one full turn. This is the factory preload for GM lifters. It has worked well in my junk. I like the GM racing hydraulics better than the stock ones. I do it this way because all eight cylinders are set almost exactly the same.
The preload is likely round about the same if not better while running...becuz you are treating each valve individually making up for any micro differences in between. When u take out the slack to make it stop rattling its probably about 1/2 turn....then the additional 1/4 or half would equal your full turn. (but who is actually closer to dead on? and running the lifter at its full pump?) The guy with the engine running.
The problems you speak of with ppl not adjusting correctly are probably morons who read wrong....and combined BOTH methods and slung a full turn after no more tapping.....so u cant blame the method for that.
It's messy and not for porcelain skins......but its worked best for me.
03-24-2011, 10:35 AM
#34
I do one cylinder at a time with the engine cold. I rotate the cam until both lifters are on the base of the cam, bring the rocker to zero lash, and on 3/8" studs I set preload at one full turn. This is the factory preload for GM lifters. It has worked well in my junk. I like the GM racing hydraulics better than the stock ones. I do it this way because all eight cylinders are set almost exactly the same.
03-24-2011, 01:42 PM
#37
Ahh ok very interesting.. Have you seen any advantage to a car running 1.6 rollers and doing a full turn instead of a 1/4.. I'd be very interested to see.. I have always adjust my valves the way you described when the engine is out of the car.. Sadly i can never seem to get it right when the motor is in the car.. :/
03-24-2011, 02:06 PM
#38
Village Troll
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If doing one cylinder at a time it is best to use EOIC. That way you are guaranteed to be on the base circle of the cam when making your adjustments. I agree it's crap to try and position both valves closed on the same cylinder when trying to adjust. I've always adjusted GM stock hydraulic lifters a 1/2 turn past lash whether it was with the engine running or not with great results. I have adjusted Comp lifters .008 past zero lash with a GM847 cam and it worked flawlessly. It doesn't matter if lifters are adjusted a full turn or a 1/4 turn as long as the valve train can handle the cam that is being run. Many many many people have been doing this for the last billion years since the SBC has been around...
03-24-2011, 02:23 PM
#39
I have heard this, but I built a motor recently, and forgot to put the reluctor in. The car would NOT run without holding the gas. It threw 2 codes for the CPS. I tore the front of the motor back apart, installed the reluctor, did not change anything else. The motor fired up and ran great on the first try after getting it back together with the reluctor.
03-25-2011, 09:04 AM
#40
I'll add one last thing to this debate.
The only item that the LT1 and LS1 share is the lifter. How are all those LS1's getting by with a non adjustable rocker? Could it be that the lifters were designed to run at a fixed amount of preload?
For the record, I learned to adjust hydraulics by the "old school rattle method" on a 1969 GTO that I street raced a little when I was a teenager. So I do have a tiny bit of experience with that too.
The only item that the LT1 and LS1 share is the lifter. How are all those LS1's getting by with a non adjustable rocker? Could it be that the lifters were designed to run at a fixed amount of preload?
For the record, I learned to adjust hydraulics by the "old school rattle method" on a 1969 GTO that I street raced a little when I was a teenager. So I do have a tiny bit of experience with that too.