Another engine question...pushrod engine experience please [Archive] - Forum


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05-21-2004, 05:32 PM
On our 3400s, which pushrod is longer? Exhaust or intake?

Also....let me ask a hypothetical question:

Let's pretend that in the course of replacing a LIM gasket, the pushrods were put in the wrong order, meaning exhaust pushrod into intake rocker. Would this result in the following conditions:

1. A little more ticking at startup, though not constant after the car warms up.

2. o2 sensor going berserk.

3. Evap system throwing codes.

4. Crappy the area of two tenths at the track....hypothetically of course.

Is it reasonable to think that in this strictly hypothetical situation that the exhaust valve isn't closing all the way, thus loss of compression, and unburned fuel spewing through the cat to the poor rear o2 sensor causing bad cat and evap/emissions codes?

Just a question for a uh..."friend"....of course. :banghead

05-22-2004, 01:20 PM

05-22-2004, 01:43 PM

So you didnt notice when I dropped my gum into your engine...

05-22-2004, 01:51 PM
hehe, almost as good of a ****-up thread as my gas tank lol

05-22-2004, 01:59 PM
The exhaust pushrods are longer by about 1/4". And in regards to your 4 questions, the answers are very likely/yes to all.

05-22-2004, 06:35 PM
Hey. no flames if im out to lunch, just say politely 'hey, you're out to lunch :)'

IANAEG (I am not an engine guru (in fact, far from it) :), new acronym of the day) but based on mfuller indicating that the exhaust pushrods are longer, I would expect the engine to misfire since youve essentially caused the intake valves to be open longer during an intake stroke and the exhaust valves to not be open long enough on the exhaust stroke. If I'm right on this, then hooking up a tech2 scanner or something of the like to the car should tell you real quick if you have misfiring problems.

Also, since I've never pulled apart the engine I really dont know, but wouldnt shoving longer pushrods in the thing damage the lobes on the camshaft? EDIT: or the valve lifters / springs, since they're being pushed up further than designed?

05-23-2004, 11:43 AM
hehe, almost as good of a ****-up thread as my gas tank lol

Almost. lol

The thing is, it runs fine. It's just that in 3 trips to the track this year I've been running slow. I feel as I'm driving around, that there's something missing. No noticeable misfires. Maybe a little rough at startup.

I'm just trying to figure out what it COULD be. And it occured to me that when HO Driver and I were doing my LIM gaskets...I took the rods out and set them in one order, but then he picked them up in a different order. So we decided which goes where based on the fact that I had just lossened the rockers enough to get the rods out, so the longer rods wouldn't fit into the smaller space. So it's still possible that this isn't my problem. I'm just trying to figure out what's hurting me so bad this year, and the result from this seems to cover just about all the problems/signs I'm having.

05-23-2004, 12:08 PM
Yeah if you ****ed up the pushrod order you would bend the valves, the problems your listed would be the least of your conserns, you might have the torque on the rockers no set right

05-23-2004, 12:12 PM
, you might have the torque on the rockers no set right

Nah, I know I did those right. I had all the correct torque specs with me. Unless they loosen themselves after a while. Something's not right. I just can't figure out what it could be.

05-23-2004, 12:15 PM
Check you pms dave

05-23-2004, 08:40 PM
Sidenote - could loose rocker arms cause the same problems I mentioned above?

05-23-2004, 08:44 PM
Nah, thats what was goin on for me before grudge match. definetly not it.

05-24-2004, 03:23 AM
Nah, thats what was goin on for me before grudge match. definetly not it.

What's that? You had the symptoms I had or you had a loose rocker arm?