valvetrain question
 

i cant find my miss and have tried everthing and everbody i know...my next option is going to be to put my stock cam back in, my question is can i put my stock cam back in with 1.6rr crane 10308, and hardened pushrods(stock)
and not ahve any problems for an hour or 2
thanks
daniel

Re: valvetrain question
 

I don't see why not, your just going to get a tiny bit of more lift outa the stock cam.

Sorry to hear about ur problems, stupid question but did u replace all plugs and wires?

Re: valvetrain question
 

plugs wires coil gm distributor fuel pump moved injectors pulled intake changed gaskets changed egr gaskets changed maf both ac delco o2 map censor compression test re adjusted rockers...and so on...still cant figure out why my back cylinder on each side is almost 300 degrees colder than the 6 front ones

im gettin :mad: and :confused: makes me wanna :cry:

Re: valvetrain question
 

Pull the fuel rail off and crank the motor, check to see that all 8 injectors are spraying a nice cone shape. If that checks out, and they already have compression, it is something sprak related.

Pull those two plug wires, stick a spare plug into the connector and have someone start it. If its getting spark to both cylinders, and its getting fuel, then double check it for compression. Also, did you replace it with a GM opti or an afternarket distributor? I WOULD NOT swap cams.

Is it making any kind of noise? Perhaps the lifters collapsed? And the valves wont open fully? I would try and make sure there is no ticking coming from the valves on those cylidners.

Check the antifreeze, pull the cap off the radiator and start it. If it blows water up out, thats a bad head gasket 99% of the time.

Thats weird that its the back cylinders

Re: valvetrain question
 

Are you getting a misfire code through the PCM? Got a link to a post showing some history on this problem? If not give us the run down.

Re: valvetrain question
 

What are the chances that the valves are floating? What springs are you running?

Re: valvetrain question
 

What are the datails of the miss? Is it happening at idle, only under load, at high RPMs, or just all the time?

To test the injectors, you could swap injector 6 with 8 and 5 with 7 and see if the issue moves to cyls 5 and 7.

If you're getting spark, and it's not a fuel problem, I agree with a previous poster and would start looking at headgasket. Did you do a compression check yet?

Thomas.

Re: valvetrain question
 

Why would you put the old one back in. Don't you know how to check the one that's in there now to see if it's the problem?

In addition, you claim to have done a compression test. Don't you understand what the results were?

Re: valvetrain question
 

ok ill try to answer yall...i was just sayin that because im sooooo frustrated with this whole ordeal...and the stock cam i can listen to easily and find somebody that can work on it and know for sure...

i have swapped injectors from those cylinders...7-1 and 8-2 and they still miss....so its no fuel related...
the opti is brand new GM opti, new plug wires and spark plugs...when i removed them they looked brown from the back cylinders but i switched them from front to back and the miss is still in the bac cylinders
i did a compression test by a gauge in the spark plug hole and crank over...they were at 190 psi for cylinders 1,3 and 7(the one with the miss)...i dont believe its a head gasket things were prepped very well...and its on both back cylinders...no coolant droppage and no oil consumption no smoking at all...
no codes present
all of this testing and so on is at idle...but it does it throughout the rpm range...i hear NO valve ticking...the rockers have been re adjusted
for valvetrain info its a cc306...hardened pushrods...1.6 pro mag rr...and gmpp guideplates...and crane 10308 springs...
the bottom end has about 15k on a complete rebuild and ran fine before cam..
the intake gaskets we thought were leaking due to discolor on the top of them on the back 2 cylinders each side so i replaced them and siliconed them...
fpr does not leak though the vacume line...fuel pressure is low(37 or so at idle) but i believe this to be due to the miss
does this in closed and open loop...cold or hot(more violent when cold)
cant tell if there is any vacume leaks...and mechanics say we cant really test it due to the cam changing the intke vacume...
anythign else please respond ANY IDEAS!!!

Re: valvetrain question
 

I know you said you readjusted the valves, but what are the chances that you just have the valves cranked down too tight and there is blow by when its running? How far past zero lash did you go?

I think I would try and get the fuel pressure up. I mean, I highly doubt that is it. But it is a existing problem. And the more things you narrow down, the easier its going to be.

Just because you switched injectors doesnt mean it is not a fuel problem. Pull the rail and crank it. Make sure all 8 are spraying a nice cone. Or use Noid lights ... Its possible something in your harness is shorting out and cutting fuel/dumping into the back two cylinders from improper pulse width, or lack of it. I really would be looking to the fuel injectors if you know its getting spark.

And pull those two wires off, stick a plug in them, and crank it. Make sure its a nice strong spark. I know you replaced all that stuff, but really, just make sure. It takes 3 seconds to disconnect a plug wire, jam a old plug in it, and get someone to crank the motor.

And it only takes 20 minutes to take the fuel rail off with all 8 injectors on it, and crank it to make sure their all spraying.

I really think your problem is going to be fuel related. And I think your mechanics play with themselves. There is no reason for you to have to put the stock cam back in. If they cant figure it out, take it to another garage, or performance shop that can.

Re: valvetrain question
 

ok ill try the injectors out the the intake and look at them...although i would think if one of them is not spraying good that the miss would follow that injector.
and im not sure it is fuel problem it occasionally smells rich...so i think its sprak just dont know where! its def not opti or plugs and not my 1 month old msd coil...i think wires possibly so im goana try some switching wires today and see if i can get wire from cyl 5 to go to 7 and vice versa, i think that heat and the length of my wires might not be lettin a good spark get back there...they are o'reiley stock replacement
ill look at the spark with an extra plug and see how good it looks...
and my mechanic is good but just isnt sure what all the reading should be with a cam in it...but hes been beside me the whole way tryin to help...
for shops around here im kinda lost every1 does lsx motors now and no1 even has datalogging capabilities or dyno tune nothin with 250 miles that i know of!:cry:
goana back off the valves today til they click and se if the cylinders pick up
ill let yall know later
thanks