Posted this in the wrong section-AGAIN. Don't know what's wrong with me.

3VZE Valve Troubles? What are some symptoms of "Tight Valves" on a 3VZE?

I have taken my p/u to a knowledgeable mechanic in my opinion and he thinks this may be the cause of my problems.

Problems:
Erratic Idle. A skip and shake of the engine without any real pattern too it. I also notice inconsistent exhaust at idle. I went to the back and put my hand in front of it. You get a larger "puff" once in a while without a real pattern either.

Also, a skip at erratic times when driving. Floor it through the gears, no symptoms. Drive normally under partial throttle and you get the skip now and again. Most noticeable at the low rpms/higher gears.

Plugs, Wires, Igniter, Distributor seem to be fine.

Thanks for any input.

ThePlumber.

 

I've noticed the skip/shake "puff" your talking about with mine. It gets better when I back-off on my ignition timing, I run mine way further advanced than stock. Around 22-23 degrees BTDC vs. the stock 10 degrees BTDC. But, I haven't noticed it happening at higher rpms, just below say 1500-1800 or so.

I think your mechanic might be on to something with the inadequate valve clearance diagnosis though. 2 of my exhaust valves were a little too tight from wear/age/lack of adjustment at the time. I'm actually in the middle of a full rebuild right now though, and I've already finished taking care of all the valves. The intakes got miked/lapped/reinstalled/adjusted to spec, the exhausts I replaced/installed/adjusted along with removing/replacing/installing their seats. It might make a difference, but I ain't through puttin' her back together yet. We'll see...

Checking the valve clearance is easy, just not the consequential upper engine disassembly required to do so I'm afraid. But, it's the only way to get that measurement and be sure whether or not the clearances are an issue.

 

I don't see how valves would get TIGHTER with age....???

 

Sounded kooky to me too. But I did find this thread where a couple of the posts talk about it.

http://www.toyotanation.com/forum/ar.../t-261891.html

ThePlumber.

 

They do though, usually....

Over time the valve face flattens/pounds/wears itself down causing the valve itself to be pulled further up towards the camshaft to reach the seat. Thus raising the cam follower(valve lifter) and decreasing the amount of clearance between the adjustment shim and the camshaft base circle.

Similar wear occurs to the valve seat, just slightly less quickly. Being as the seat is made of a harder steel than the valve. This wear, over time, also contributes to the problem by decreasing valve clearance even further. Because the worn down seat face is then a little farther away from the valve face. So then, the valve must travel up that bit more before hitting the seat. Thus raising the cam follower(valve lifter)...