Rods in the 93 3.1

Hi All,

what is the best or worst that would happen if the connecting rods are put back in wrong?

there are 2 lengths - the book says the exhausts are longer than the intake, but they also say the intake has an orange valve seat, but this rod is longer than the one that is from the blue valve seat...

I was careful about taking them out, and putting them back, but I may have not remembered which side I started, etc

will the worst that will happen, be that I bend the rods? or will it ruin the valves/rocker arm/cam? - I plan on listening VERY carefully when I first try to start it... but my guess is something bad will happen within seconds if they got installed wrong?

Thanks to all that reply
:lol2:

You mean the pushrods, correct. If you mix them up, you bend a valve when it starts.

You will need to determine the sizes of the push rods.

Some are:
6.389" for exhaust
6.042" for intakes

Or

6.074" for exhaust
5.746" for intake

In any case, make sure the longer push rods are used on the exhaust and the shorter push rods are used for the intakes.

Hi,

I saw that too, when I went to order them - why would they list 2 sizes for the same year, and same engine? is there a way to tell by the VIN which size that engine has?

Yes, I meant the pushrods... I thought that all that happens is that rod gets bent, but I guess it makes sense that they might/could bend the valves, since a longer than usual rod would extend the rocker too far, causing the valve to bend

how can you tell from the top, which valve is which? - are the exhaust valves different somehow?

We reused the same rods that we took out, so I know they are the correct set for this engine - I'm just a wee bit nervous about this now, and wondered if just pulling the valve cover, I'd be able to check, etc

Can they be switched if need be, without taking the intake back off?

Thanks

Left side cylinder head (front of car) radiator side, from front of engine, looking from passenger fender.
Valve arrangement:
E,I,I,E,I,E

Right head (fire wall side) from front of engine,
Valve arrangement:
E,I,E,I,I,E

Basically looking at valves, valve closest to exhaust manifold port is the exhaust valve and they are generally the valve closest to the outside of the head.
You should not need to pull intake manifold off to replace push rods.
Confused yet?

Wow! - Thanks so much! - this is exactly what I was hoping for! - so, you are 100% sure this is for the older style 3.1 right? (the one that has the coil packs in the front, under the exhaust manifold, not on the top rear of the engine, like the 94 or 1995 versions...

Just want to triple check here, before I pull the valve covers and do this. This is the 3.1 that has the larger one piece valley gasket for the intake, and not the newer style that was prone to all those intake problems...

do the valve covers need to be torqued when I put them back on? I know that the rocker arms do, correct? what was that spec again?

Thanks so much - now at least i don't have to guess, and ruin something.

as a side note - all the local mechanics kept telling me it was the intake gasket, but it ended up being a bad head gasket - (#4 to be exact) - they look like the gaskets were defective from GM, since the one in question was already oblong when they put it in, because you can see the shape of it on the head, and the head was never apart prior... so it could have been failing for a long time, and you can see the tears and crack, etc...

the new fel-pros looked so much better, so I hope it runs great again...

Also, last question - firing order on this older 3.1...

The engine is 2 -4 - 6 in the front of car, left to right, and 1 - 3 -5 in back at firewall, left to right, correct?

the coils are: 1,3 - 4,6 - 2,5 ?? left to right?

Thanks so much!:biggrin:

Whoa! Never trust any one 100%. I'm giving you the best information available to me, but I'm quite confident that the info I shared with you is correct.
Like I said before, Follow the valves closest to the exhaust ports to confirm this arrangement.
I believe the valve covers should be torqued to 89 inch lbs. or 10 newton meters

Fair enough :-)

but, as I recall, I think the valves are all in a straight line... maybe is very subtle, but that is a very helpful hint, and will check them all again...

at least its good that they are only 2 sizes :-)


How about the firing order? any chance you have that?

Thanks,

1993
3.1 liter V-6 VIN "T"

http://z.about.com/d/autorepair/1/0/W/3/41894193.gif

1993 Chevrolet Lumina
3.1 liter V-6 VIN "T"

http://z.about.com/d/autorepair/1/0/5/g/92770412.gif