Valve Job on 3.0 v6

[docweathers]

I have a 90 Winne 3.0 V6 auto with 74k. Just before I bought it at 62k it burnt a valve on the right bank. The prior owner did a valve job on the right. Now, 12k later I have a burnt valve on the left bank. It burns no oil. Compression test is about 150 on all cyliners except the bad one, which is 25 lbs. It still has quite a bit of power but runs a little rough at idle. I am being told by my mechanic that the extra compression created by a valve job risks damaging the lower end, such as throwing a rod. They are recommending a rebuilt engine instead. Almost half a century ago I was a car mechanic. I did valve jobs all the time with no problems with the lower end. I am told that modern engines are different, but they look the same to me. What is the reality here? Can I do a valve job safely or are the telling me the truth?

Also, it is my conjecture that the fuel injection running lean is causing it to burn valves. It that accurate and what needs to be done to the FI to solve this? If not, what else could be causing it to burn valves

Thanks Larry

[jim]

Larry

I am a mechanic with 40yrs experience, the last 20 with Toyota. I also have a 90 winnie with 3l engine. I would tell you to get away from that so called mechanic as fast as

possible. On older north american engines if you did valve job on high mileage engine they would sometimes burn alot of oil after but these toyota engines are good for

many miles and dont normally have ring problems. Go ahead and have a valve job done and be sure the person knows how to adjust the valves properly as they are a

shim type. Go to someone who does alot of toyotas, may cost more but will be worth it.

I just returned from holidays with mine. Drove just over 6000 miles and averaged 19.5 mpg (this is on canadian gallon which is bigger than american).

Hope this helps

Jim

[docweathers]

Thanks, That makes a lot of sense. What do you think could be causing it to burn valves?

Larry

[WME]

It would burn the valves if no body was setting the clearance. On a lot of Toys the valve clearance DECREASES with mileage.

SO after awhile you leave a valve open and in about 50 mi the seat is burnt.

Never heard of blowing out a lower end with to much compression after a valve job. BUT I have had a older mid mileage Toyota 22re go from 2500 mi per qt of oil to 700mi to the qt after a valve job and a HP cam. A ring job solved that and its now 5000mi+ on a qt of oil.

[docweathers]

Thanks... that is helpful. Larry

[jim]

Thanks... that is helpful. Larry

Larry

I agree that problem could have been poor valve adjust, thats why I say get someone who knows these engines well to do the work. You say you have good compression on the

other cylinders and if you are using very little oil now it should not change much. Only if you have a poorly maintained engine (few oil changes) should you have any problem.

My 3vz in my 22ft 1990 motorhome has about 120k miles on it and on the trip of 6000 miles I mentioned above it used only 1 quart of oil, so if yours has been good I wouldnt

worry, Ive done lots of valve jobs on these engines over the years. If it was running so lean to burn a valve you should have power/driveabiliy problems, I have frankly never

seen such a problem on one of these engines , not to say it couldnt happen but unlikely.

Happy motorhoming!

Jim