kevinkal

I've some questions and would appreciate good advice on how to procede with servicing my 3VZ-E cylinder heads.

While doing my headgasket, I decided to inspect the valves and put in new oil seals. Well.. it was a good thing. Although all the intake valves and their seats look very good, all the exhaust valves and seats need work.

Here's what I've found:
The exhaust valve seats are worn down and pitted. The exhaust valves are pitted around their contact area. The valve to seat contact ring thickness is on the order of 0.080", which is above the factory service manual (FSM) stated max tolerance. I've measured all valve stem and margin thicknesses and they are within FSM tolerance. I cannot measure the valve guide ID, as I don't have a tool to do that.

The cams look good.. the #6 exahust cam lobe was polished all around(even where is should have had clearance), suggesting that it was putting light pressure on the exhaust valve during the compression stroke. (The valve is not burnt though.) I plan to reshim both heads to FSM specifications.

For both heads, the intake, exhaust and headgasket surfaces are very flat (well below FSR spec), so they should not require any resurfacing.

With that, here's what I think is needed to overhaul the heads:
1. recut exhaust seats or replace them
2. grind exhaust valves
3. new valve guide oil seals
4. check valve clearance and reshim as needed

Does that sound right?

Thanks for any thoughts/advice with this.

Kevin

TNRabbit

If you're having work done, you should have ALL the valve seats redone. Do a complete valve job. That's what I just had done.

TNRabbit

You realize if you only do the valves, you're going to start burning more oil unless you do the bottom end as well....?

SEAIRESCUE

Yo,
Exactly what I found on my 3.0. If you got time and a few bucks, get stainless exhaust valves from Enginebuilder out of Washington State (advertises on Ebay). Otherwise grind them all. Do not cut the head if its flat. I generally resurface head with a long body file and some wet sand paper just to rought it up for better sealing. There are some new metal head gaskets on the market that are rumored to be the best to date. Do some research on 3.0 head gaskets. I suggest adding 0.002 additional clearance to the exhaust valves since they are prone to expanding more in the rear cylinders. I put on the older graphite gaskets dry and so far, so good. Good luck, that engine is a real Witch to work on and be careful where you plum those lines under the intake.

TNRabbit

Don't forget to check both idler pulleys; now's a good time to replace them if need be. Also don't forget to replace the knock sensor wire. did you get a gasket set from engnbldr.com?

kevinkal

TNRabbit, I wish I had the time/energy to pull the engine.. but I just don't. Thus, I hope the block is able to handle a little more compression. I've run Mobil 1 since the truck was new and changed it regularly. I dont know how good the main bearings or rings are.. but the cylinder walls still have stock hone marks with no worn spots.
As for the pulleys.. I actually put on new ider pulleys and tensioner about 5k miles ago.. they're basically brand new factory parts. I didn't do any head gasket research. I just bought a toyota factory gasket kit.. A bit pricey, I must say. =[

Seairescue, its good to hear someone else found the same thing. I like your idea re. 0.002 extra for the exhaust. I assume you're referring to the shim selection. I've been eyeballing those shiney new valves. Hmm. I hope to find a machine shop open tomorrow so I can talk with them to see about grinding potential for the old valves.

I'll try to find a picture hosting site.. and post some all too familiar 3.0 pics.. but with lots of cooling system rust! =[

TNRabbit

www.photobucket.com
www.putfile.com
Two good hosting sites that won't spam you to death.

kevinkal

Here's some pictures that show what my valves and seats look like after 211K. All intake looked good. All exhaust need work. See pics below:

TNRabbit, thanks for the hosting site suggestions. I tried putfile.com, but they were hosed and I could not upload after registering. I found that google had some sort of hosting .. so I'm trying that.

TNRabbit

Holy Schnikes! I've never seen such a mess!

Aren't the valve supposed to have a 3-angle grind??

kevinkal

Yes the valves should be 30/45/60 degrees. There's almost no 30 degree segment left on the exhaust seats, perhaps 0.010" left.