Rough running after R&R heads

[mjsrun]

I suspect others who have replaced head gaskets/valve grind may have encountered my problem or similar.
After setting the valve lash several times and still getting the same results of having an engine that runs lousy I ask myself what I could have done wrong in the reinstallation of gaskets, distributor, wires or other important items.
I checked the TDC with the distributor and the rotor is between #'s 1 and #8 such as the manual discribes. The exact location which I removed the distributor.
After checking the timing it appears that there is about 55-60 degrees of advance in the marks before the marks line up at approx 6-10 deg's.
I really don't know how this could happen as there is a pin under the base of the distributor that keeps it aligned up to 180deg and a mistake is literally not possible unless I am actually 180 deg off. The distributor will not go down fully if I don't align the pin at the base of the distributor. Almost a given when removing the distributor.
I checked the wires to see if one of them is mislocated and they are correct.

Any thoughts you pros might have would be appreciated

 

[Mike Zarnock]

Mark,
No offence, but, if you have never done this before, you have no business doing it. There are so many variables that could possibly be the problem.
To start, look at the bottom of your distributor where the gear is. There is a pin. This pin goes into a slot that drives the oil pump. It is turned by the camshaft with that gear. All you have to do there to get the rotor to line up is to take a long screwdriver and turn the slot one why or the other.
Your rotor should be pointing right at the # 1 electrode of the distributor cap when the harmonic balancer is at TDC (top dead center).
That is the place to start.
Then check for intake leaks while it is running. Squirt some WD40 by the intake runners one at a time to see if it gets sucked it. Then go to the carb base and do the same. If the idle goes up and down, it is a vacuum leak.
If it is skipping, check the wires, make sure they are in the right order. The firing order should be stamped on the intake manifold.
18436572?
Like I said, there are many things that can go wrong. Take it from a guy who has had them all happen at one time or another over the past 35 years of wrenching.
Mike

PS. You may also have even tightened a valve too tight to start with and it is staying open a little. Check those too before starting the motor. Make sure you do one cylinder at a time when each cylinder is at it's own TDC so both valves are at a closed position.

 

[mjsrun]

Mike,
I will check make the corrections to the distributor setting and get it corrected to #1 cylinder as it should be. I wasn't aware of turning the oil pump slot. Might be just what I need to do to get the line up corrected.
Thanks,

 

[Mike Zarnock]

Mike,
I will check make the corrections to the distributor setting and get it corrected to #1 cylinder as it should be. I wasn't aware of turning the oil pump slot. Might be just what I need to do to get the line up corrected.
Thanks,

Yup, that might just be it. The smallest thing will mess it up. Keep us posted and Good Luck!

 

[RWDsmoke]

If it runs at all you can't be too far off. If the plug wires are on correctly and the timing is set at around 6* before TDC (don't forget to disconnect the EST wire to disable the advance while setting the timing) then you probably have a vacuum leak. You'll figure it out, just look at it as a great learning experience.

 

[Mart]

Mark,
No offence, but, if you have never done this before, you have no business doing it.

Then check for intake leaks while it is running. Squirt some WD40 by the intake runners one at a time to see if it gets sucked it. Then go to the carb base and do the same. If the idle goes up and down, it is a vacuum leak.

No Offence Mike But,

No Business doing it ?????? why not it's his car, and if no one ever played with thier vette's there would be alot of Rich mechanics and poor drivers.

BTW, It's going to be really hard to spray WD40 into the Carb base, there is no carb on a 90' it's a TB Mike. Maybe you should rethink the "no business doing it"

Just playin with ya,
Mart

 

[Mike Zarnock]

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No Offence Mike But,

No Business doing it ?????? why not it's his car, and if no one ever played with thier vette's there would be alot of Rich mechanics and poor drivers.

BTW, It's going to be really hard to spray WD40 into the Carb base, there is no carb on a 90' it's a TB Mike. Maybe you should rethink the "no business doing it"

Just playin with ya,
Mart

Definitely my mistake there. I was thinking it had a throttle body. I thought it was older for some reason. Anyway, it's been a while since I've lifted the bonnet on one of them baby's.
I just don't want the poor guy to get into more trouble that he can afford. It must be the Dad in me talking there. I have two boys 23 & 12 that I keep fixing the things THEY fixed, if ya know what I mean? And I have to admit, I did the same when I first started too, but they were Impala's and Nova's, not Corvettes. LOL

 

[mjsrun]

Mike,
Not a problem about messing around with my vette. I am an novice, but know that I can do the work. I would prefer to have the local Corvette shop do my repairs, but I had the head gasket replace several years ago for the sum of around $1,500. That is the real issue here AND that is without a valve grind. Shows how labor has gotten extravagant in itself.
I didn't realize that the job itself of pulling the heads is a really big job. Now I know how and could do it again with less grief and fewer battle scars.
I have pulled several heads on my Ford's. There are many more wires on the Vette as well as emissions items that I really am disgusted with. My distributor was a tooth off, I corrected the setting and will write back when I crank it up. Suspect this was my major problem. Has to be since there is nothing else that could be a holdup unless it was a vacuum leak around the intake runners. Basically, I was looking for little things that the experts know that might help me to complete my job with less reinventing of the wheel.
Thanks guys!!

 

[GeorgeT]

Interesting comment: "If you've never done this before, you have no business doing it". If so, how will this work ever get done since, at some point, everyone has "never done this before". There has to be a first time for everything and working on your own car is a great place to start.

 

[Mike Zarnock]

Yes, places are really getting the big bucks for labor these days and what you get are guys that just read a manual. I myself, don't do much work on my own `vette or even my Blazer these days. There are way too many things under the hood and you usually need a computer to find the problem with whatever computer is in the car too. LOL
That's why I still like the older cars and motors, they're basic and you could always track down the problem. Give me a carb and a set of points any day....
Glad you got some experience on this one. Who knows, maybe you'll be the guy giving the advice next time.
Best of luck and let us all know what you find. I know I can use a little updating myself.

 

[Edmond]

Interesting comment: "If you've never done this before, you have no business doing it". If so, how will this work ever get done since, at some point, everyone has "never done this before". There has to be a first time for everything and working on your own car is a great place to start.

That was exactly my thinking.

But I think if you haven't done it before, try to get someone who has done it before and see if they can work with you. That's what I usually do. Having someone there who has been there and done that feels much better than doing it yourself for the first time.