We just replaced the right side head gasket on a Stock 94 Z28 LT1. Start it up and it runs, but we see no oil coming up through the push rods/rocker arms. Pulled the other valve cover and no oil flow there either except for maybe a slight dribble on a couple of rockers. The car's oil pressure gauge reads around 50 PSI when it is running. We plan to pick up an external oil pressure test gauge to verify this. We don't know if this started before the head gasket change or after.

If we did not adjust the preload correctly could it be loosing oil between the rods and lifters? We followed shbox'es guidance at http://shbox.com/1/4th_gen_tech2.html#adjust_valves for this. The feel of them seems comparable to the ones on the right side of the motor that we haven't touched. When we took the rods out we used compressed air to blow them out and verified that were clean inside. We just pulled one out again and there was some oil in it... but obviously it was not making it all the way up.

We did not prime the oil pump... but I didn't think that was necessary for just a head gasket change. Should we have done this?

We have only had it running a minute or two at a time at low rpm and only a handful times since the head gasket change. We've also poured a little extra oil over the rocker arms a couple times to keep things lubricated. Does the bottom half of the engine rely on oil flow down from the top to be lubricated properly? We don't want to make things worse while we diagnose it.

We would welcome any advice on what to look for. This is our first time going this far into an engine... so even ideas that may seem too obvious to suggest are welcome.


Thanks

 

have you held a pushrod up to a light and see if you can see through the hole.. you might need to give them a good cleaning, especially if the oil changes have been neglected..

 

Yes, when we took them out we blew compressed air through them to get all the old oil out and then were able to see light through them.

Thanks

 

Depending on how long the engine has set, it can take a while to get oil up through the pushrods (people often have this situation with a new engine). With the relatively low RPMs it can take several minutes or more. Oil should eventually flow.

 

What Rob said. It takes a little while to get oil up through the pushrods. It took about 10 minutes for me to see oil through the pushrods when I was priming my last motor. Did you use good amounts of lube on all your top end parts?

 

Yes, we used engine assembly lube on the pushrod ends, rocker arm ***** and valve stem ends.

Looks like we need to let it run a little longer... I just get very nervous when I don't see oil flowing. Hopefully we can try it a little later today and see what happens. Is it better to just let it idle until the oil flows or give it a few more RPMs to get it flowing faster?

Thanks for the help!

 

I'd say keep it under 1500 RPMs.

 

It took a little over 5 minutes before we could see the oil flowing. It wasn't squirting out like I was originally expecting... but it was running down off each of the rocker arms.

Thank you to everyone for your help!