If I replace the valve guide/stem (never sure what to call them) seals on my 305 without pulling the heads (using compressed air to hold the valves up during the procedure), will I need to adjust the valves afterwards? My gut tells me no, since I'm not disassembling the head, I won't need to adjust lash. But, this is the first time I've worked on valves or replaced valve seals and want to double check.

This started as a valve cover gasket replacement project. After removing the alternator, disassembling half of the AIR system and moving misc heater hoses and wiring harnesses out of the way, I was able to remove the covers. I want to make this effort more meaningful than just replacing the old cork valve cover gaskets (leaking). The car smokes on startup but doesn't appear to burn oil otherwise so I'm guessing it's just the valve guide seals and figured I'd do it while I've got everything apart--and it's snowing outside.

Thanks for any help!

 

You will have to adjust the valves afterward since you are pretty much disassembling the heads and removing the valve springs. Adjusting the valves isn't really a big deal though. Hope this helps.

 

You can replace valve seals alone.

 

I had my valve seals replaced in November for a startup smoking issue using the compressed air method and my mechanic mentioned that he did do a lash adjustment. BTW my smoking issue was resolved.

 

Did you valve it right?

 

Exactly that. You'll have to set the valve lash after replacing the valve guide seals. It'll be necessary to remove all of the valve train hardware to access the seals.
Reassembly means adjusting the lash too.
PS. I'd skip the cork gaskets and go for the FelPro blue silicone gaskets. I've found them to be much better.

 

Thanks for the replies. I now realize that my question was a bit 'junior'. I've since completed the valve seal replacement, and last week I took a few hours to read up and watch videos of how to adjust valves on SBC's before putting everything back together. Pretty simple once I took some time to study it.

I'm pretty happy to say that I think I nailed the valve adjustment on the first try. I used the method of finding TDC #1 and adjusting the intake and exhaust valves on the 4 cylinders that can be done in that position. Then, one clockwise rotation to TDC #6, and adjusted the intake and exhaust valves on the other 4 cylinders. It was literally the easiest part of the whole job.

With everything back together, the car runs and sounds great. No noise, and I don't think the valves are too tight either. I literally obsessed over the feeling of each one, then completed the half-turn of the rocker arm nut to seat everything. Stock 305 with hydraulic lifters, easy as cake.

I did use a set of Felpro rigid-core rubber valve cover gaskets on re-assembly...man did those baked-on original cork gaskets slow me down trying to get everything cleaned up and all that old baked on stuff scraped off!

I'm still waiting for something to explode, or to find out I've destroyed my engine somehow...

...and with the new Felpro positive style seals on the valve stems, I haven't seen a blue puff of smoke at startup. Mission accomplished!