Milky oil

[alldodge]

Push rods normally change when lifters do

 

[Lou C]

wonder if the lifters have a different pn?

 

[SeaRayboater95]

I’m wondering why there’s like .010” difference in length? GM did so many odd things like mixing SAE & metric fittings it’s not surprising. I guess try to get the ones for the head you bought measure what you have & compare. Adjustment of preload might make up any difference. A machine shop guy or engine builder should know.

I went and measured the rods from the donor motor and they were .004 longer. That is likely wear and not an issue?

 

[alldodge]

I went and measured the rods from the donor motor and they were .004 longer. That is likely wear and not an issue?

no worries

 

[Lou C]

There's quite a bit of leeway in the hydraulic lifter preload adjustment, way more than the differences you are seeing. This is one reason why I prefer it to the non-adjustable set up they went to in the Vortecs.
Might also look inside the rocker arms and see how much wear there is in the pocket that the pushrod fits into.

 

[Lou C]

OK just because I am curious I looked at the merc catalog at Marineengine where I get all of my OMC Cobra parts.
They break the Pre Vortec down into several year ranges
I compared yours 93-95 to the next one back in time (92-93) and basically all these parts are the same part numbers:
pushrods
lifters
rocker arms
rocker stud
btw, it is obscene what Merc charges for what are standard GM parts that they don't even MAKE!
not sure if this is the be all and end all, there are other parts sites as well.

 

[Scott06]

I went and measured the rods from the donor motor and they were .004 longer. That is likely wear and not an issue?

Prob not wear just manufacturing tolerances. When you set preload on lifters normal you are compressing the lifter i Think .030-.050” so no issues as AD said.

 

[SeaRayboater95]

Prob not wear just manufacturing tolerances. When you set preload on lifters normal you are compressing the lifter i Think .030-.050” so no issues as AD said.

I believe these are just torque to 20 ft/lbs, unless I'm missing something. No adjustment. That's how I read the shop manual.

 

[Lou C]

Nope that spec is the newer net lash (non adjustable) style. You have the older classic adjustable style. There's a whole procedure that you have to follow to get it right.

 

[Lou C]

If you can't find a good resource, I can find the pages in my OMC shop manual that explains how to do it and post up a pic.
Suggestion:
take a marker and mark each valve retainer with a cylinder # and I for intake or E for exhaust. It makes it much easier to not make mistakes.