Lon Ross
Member
Hi, this is for all who have solid lift cam Toyota's and have valve adjustments recommended for your truck. 1st. let me say I have 45+ years in the automotive industry and have been a mechanic, restoration specialist, professional racing motor builder and shop owner over those years.
I have read many post about Toyota valves and adjusting them. Here is the truth and the fiction on them. If your Toyota has adjustable valves, they NEED to be checked / adjusted from time to time. The same is true if you have a timing chain instead of a belt, it NEEDS checked! The chain most likely won't need replaced unless it has been abused by poor oil changing intervals or high RPM use, but checking it is easy when adjusting your valves. You don't need to remove it and measure it as recommended IMO, just make sure there is NO play in the chain and the plastic runners are all in tact.
Now on to the valves. If you have a Toyota that lets you adjust the valves by turning a adjusting screw, good for you. Many have shims that need measured and replaced with the correct tolerance shim for the current motor ware.
I have read that the exhaust valves will burn due to the incorrect adjustment because they don't contact the head long enough to cool if out of adjustment, WRONG. As a man who ported and polished many racing heads and built many high performance motors, this is wrong. The reason your exhaust valves not only have much more liberal specs then the intake valves, is due to the abuse they under go ALL the time. They run MUCH hotter due to the hot exhaust passing over them constantly. This causes a lot more ware at the seats as well as more stretching of the valve stem from the heat.
So if you check your valve lash, don't be surprised if your intake valves are still in speck and your exhaust is getting close to a burnt valve!!! That is expensive and easy to avoid if you check / adjust your valves every 40k or so. Good luck with you trucks, I hope this helps
I have read many post about Toyota valves and adjusting them. Here is the truth and the fiction on them. If your Toyota has adjustable valves, they NEED to be checked / adjusted from time to time. The same is true if you have a timing chain instead of a belt, it NEEDS checked! The chain most likely won't need replaced unless it has been abused by poor oil changing intervals or high RPM use, but checking it is easy when adjusting your valves. You don't need to remove it and measure it as recommended IMO, just make sure there is NO play in the chain and the plastic runners are all in tact.
Now on to the valves. If you have a Toyota that lets you adjust the valves by turning a adjusting screw, good for you. Many have shims that need measured and replaced with the correct tolerance shim for the current motor ware.
I have read that the exhaust valves will burn due to the incorrect adjustment because they don't contact the head long enough to cool if out of adjustment, WRONG. As a man who ported and polished many racing heads and built many high performance motors, this is wrong. The reason your exhaust valves not only have much more liberal specs then the intake valves, is due to the abuse they under go ALL the time. They run MUCH hotter due to the hot exhaust passing over them constantly. This causes a lot more ware at the seats as well as more stretching of the valve stem from the heat.
So if you check your valve lash, don't be surprised if your intake valves are still in speck and your exhaust is getting close to a burnt valve!!! That is expensive and easy to avoid if you check / adjust your valves every 40k or so. Good luck with you trucks, I hope this helps