valve seal replacement

[lostinbama2x]

Hello all.

I just wanted to get some feedback on this topic from anyone who might have done this or had it done before. Heres my thinking behind wanting to replace the valve seals. When my camper sits for a few days and i start it up im getting some oil smoke for the first couple of minutes and then it clears up. If i drive it regularly for a few days i dont see the smoke. There is'nt any smoke while driving, even when motor is pulling hard and im not seeing a drop in oil level , so i dont believe its a ring or blow by problem. I did also notice oil residue on the two rear exhaust ports while changing the manifold.

I have been doing some reading and from what i understand a leaking valve seal can cause a loss in compression. This loss in compression will make the engine difficult to start,- mine is hard to start when cold. This leak in what is supposed to be a closed system will also cause misfire during accelleration, -mine has an obvious miss and shake to the motor when reving from idle.

I understand that my symptoms can come from any number of other causes but with the oil burning i figured i would put the valve seals at the top of my list.I will also replace valve cover gaskets and of course have valves adjusted at the same time.

If anyone has had there seals replaced and noticed changes in engine performance i would like to hear about it. Thanks.

[mycomitan]

Your miss on acceleration could be Oxygen sensor, or throttle position sensor. or dirty injectors.

Edited October 16, 2007 by mycomitan

[WME]

Doing the valve seals with the head on the engine is ALMOST impossible. The camshaft mounting bolts are the head bolts. Removing them means that if you use air pressure to hold up the valves when you replace the seal you can blow the head lose

So ya'all be careful

[Geysergazers]

Actually, it is even worse than that. Simply loosening the Head Bolts requires that the Head Gasket then be replaced...Valve Seal replacement on a 22R engine will require Head Removal.

Leaking Valve Seals cannot cause Compression Loss. In the old days they could cause loss of Engine Intake Vacuum . Air can enter the intake tract through a VERY WORN Intake Valve Guide and Valve Seal, but you aren't seeing that in a Toyota 22R engine.

In 170,000Mi of driving these Toyota Motorhomes, I have always noticed a bit of smoke with a cold startup following several days of rest. If your Oil Consumption is not excessive and Engine Compression is above 128PSI, I would not tear down an otherwise healthy Toyota engine for this.

An engine miss off-idle (no load-just revving the engine?) is caused by the EGR Valve opening and admitting inert gas back into the Intake Tract. This is normal operation (the State Emissions Test Computer even cautions the Tech when testing 22RE fuel injected engines to hold Fast Idle for 2Min so the EGR operation can stabilize before testing.

To adress Hard Starting, Folks here will need to know if this is a 22RC carburetor) or a 22RE (electronic fuel injection) Engine??

Lew

[lostinbama2x]

Thanks for the replys. Good to hear from some experienced folks. I would never have thought that valve seal replacement could be so involved. Im used to older american vehicles. Sorry for not giving a little more vehicle info on this post. My camper is a 1986 22re. Yes, the miss is reving engine off idle with no load. After reading some thoughts here i think my next best move might be a compression check. Also, what would one consider to be a bit of smoke, or how long will it smoke before clearing up? I think today i will just get in the rig and drive it a while as i have not done much driving since i got it. Thanks.

Edited October 17, 2007 by lostinbama2x

[mycomitan]

A compression check will not fix your miss, when I had this we pulled the injectors and had a professional lab clean them, You will know its the injectors if when you start the engine and it runs good then after a minute or two it starts missing.

[Geysergazers]

A Compression Test will tell general Engine condition. In this case it will also rule out Burnt Valves, which can cause Hard starting (cold) and a miss off idle. Probably not the problem though, with a 22R Engine.

A miss off-idle still sounds like normal 22RE EGR Valve "hunting". lostinbama2x, if you hold the engine at a steady fast idle for at least a minute, does it then smooth out?? If so, it is normal. If not, or if this miss only happens for a couple seconds when you pull the Throttle open, keep looking.

Hard starting (cold), I think of the Cold Start Injector or maybe Fuel Pressure bleeding off (fuel pressure needs to hold while the engine is shut off). I am assuming Spark Plugs and Ignition parts are OK?

Lew

[lostinbama2x]

Took camper for about 50 miles yesterday. On the hiway at 50 to 60 motor performs well. After returning home warm motor still a little slow starting. decided to take a look at throttle body today. removed cleaned and tested throttle position sensor.If im testing properly it seems resistance values are lower than stated in service book (Bently manual).Also, it looks as if someone has adjusted throttle stop screw. I figure this may have been done to compensate for failing TPS or some other worn component ive yet to find.Will have someone double check TPS before i invest the $80 for a new one.

Lew, to answer your questions. no it doesnt smooth out after a minute. Pulled plugs and they as well as the wires look to be new. After i get TPS figured out and throttle body installed i figure i'll take a look at cold start injector and fuel regulator.I also want to do the compression test. Ive seen the kits to do compression test in parts store. Dont know much about it. Is it a difficult procedure? Thanks, Bama.

[WME]

Some folks with out a manual to check, think the throttle stop screw is the idle speed screw. It will screw things up if used that way.

So set it right and adjust idle speed with the correct screw.

[Geysergazers]

...I also want to do the compression test. Ive seen the kits to do compression test in parts store. Dont know much about it. Is it a difficult procedure? Thanks, Bama.

Bama, doing a Compression test is simple. Just make sure you purchase a Tester which screws into the spark plug hole and which has a built in check valve to hold the pressure for you to read at your convenience (i.e. after you crawl out of the Driver's Seat and stick your head under the Hood).

1) Don't Forget to Disconnect the Coil High Tension Wire (either at the Coil or at the Distributor).

2) Pull the Spark Plugs.

3) Block the Throttle Wide Open.

4) Screw the Compression Tester into a Spark Plug Hole.

5) Turn the Ignition Key to "Start" and crank several revolutions.

6) Observe and Record the Pressure indicated on the Gauge.

7) Repeat for the other three Cylinders.

8) Unblock the Throttle, reinstall Plugs and the Coil Wire.

All four readings should be within about 5Psi of each other. I say "about" because you will know it if you have a problem. Low pressure on one or two cylinders and you may be looking at burnt valves. No reading should be below 128Psi. Toyota's new engine spec for 22RE is 170Psi. You would like to see around 160Psi, indicating an engine with tip-top Piston/Ring/Cylinder Wall condition.

As always, YMMV

Lew

Edited October 20, 2007 by Geysergazers