Fellow V6 owners,

Rebuilt a junk yard motor and had a constant #2 Misfire since fire up, see pictures
Tried everything, plugs, spark plugs, ICM, injector....(had extras from a motor rebuild)

Well it was the compression...go figure.
Come to find out my son extremely over tightened the rocker bolts (trying to help while I was at work).
Loosened the bolts on #2 and viola 160psi on #2.
Retighten to spec 132 in lb plus 90degs....zero compression. loosen again and torque to 132...zero compression.
Extremely loose and compression is back.

What is my solution?
A new valve train? Rockers/pushrods/lifters?
Heads and valves were serviced by a rebuttable engine shop, valve job, decked and checked for cracks.

I am hearing significant lifter tap. (did I answer my own question?)

Thanks!

Misfire #2

Fuel Trims

Timing

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Everything looks correct...any help would begrateful

 

When you say it was rebuilt was there any machine work done to the heads or block? If they decked the head and you are using a thin head gasket then this would make sense. You have two options, you would need to get an adjustable set of push rods and do testing to get the new lengths figured out. Then order new push rods. Option 2 is if you find out how much was decked off the head and then find a thicker gasket of that much then you could use your stock push rods.


I would never recommend this but I would be tempted to shim the rocker. You would have to understand where to put the shim and how to cut it so it did not interfere. I would also use hardened shim stock. I would start around .010"-.015" thick. Remeber things are going to change length when they are hot so you have to allow for some of that.

Something I do not like. The hydraulic part of the lifter is designed to take up for variation in valve train components. Machine shops know this and they know the safe limits on how far they can go when cutting a head or a deck. If they need to even get close to that limit you would think they would give you a heads up and a recommend head gasket.

 

They cleaned the heads and did a valve job, didnt tell how much they decked.

I didnt bleed the lifters prior to installing them, they are used...and it has major lifter lifterpkus it is only the #2 cylinder. Maybe those lifters were locked with oil.

When i get back later this week ill bleed them before looking at a head gasket.

 

Fixed the compression issue with lifter bleeding. Motor seized again ... pulling soon. Can i use a fwd upper intake on these?


Its on a new motor i have

 

no to tall and I believe they point the wrong direction

 

Thanks, i saw your other post as well