What is the best way to determine if you have bent valves from a timing chain beak?

22re 1986 Toyota 4-runner

 

Most guys that I know in that situation find it easiest just to put a new chain/belt on it and if it runs great if it doesn't theres your answer.

 

I've already pulled & replaced chain, but still had no compression. Pulled the head, #1 exaughst valve was broke. #1 & # 4 intakes do not completely seal. I do not have a valve gridner, so I'm trying to determine the easiest way to tell if the leaking valves need replaced or if I can just lap them?

 

Im not expert but I would have to say that if your valve isn't seating then its obviously bent. Sounds like its time for a valve job.

 

Oh yeah did you do a compression check on each cylinder or??? That would give you an idea of which valves arent seating properly

 

before you go and just do a valve job, pull the pistons! you will most likely need to replace these, since it hit a hardend piece of metal. i am willing to bet that your valves cracked your pistons. that kind of contact is usually catostophic, especially if you broke one valve and bent others. i think you are looking at a total rebuild.

 

Wow, that sounds a bit messy.
Well, if you have the head off, then do a leak test on each valve by first coating the combustion chamber side of the head with talcum powder. Then test by pouring isopropyl alcohol into each intake and exhaust port. If the talcum gets wet that valve needs work. Then pull any bad valves and first check if they are bent. If they are bent, get a new one, you cannot fix a bent valve. To check if they are bent use a clean piece of glass (of resonable thickness, say 0.25 inches) and roll the valve stem across the glass. Again if you see any daylight between the stem and the glass, replace it. Glass is super flat to any imperfections will be very obvious. If the stem appears flat then all the valve probably needs is a good lapping. It is pretty easy to do and just use the fine grit only (I find coarse too agressive) and be patient to get it right. When you think you have done a good job then do a leak test and check your work. If it leaks you need to continue lapping.
Some good advice....if you did bend a valve in a cylinder, then look for damage on the piston too. Wouldn't want to do all that valve work only to have a piston give way later.

 

Thanks for the input. I'll give these suggestions a try. I was talking to one of the guys here @ work & he suggested just rolling the valve accross a flat surface. If you see wobble, you know it's bent. I tested this theory during my lunch period & the first one I checked passed the bent test, but when I looked at the location where the valve seals to the seat, it was obvious it needs some lapping. I'll give it a try, & I will inspect the pistons too.

Thanks everyone.

 

When mine broke, I found a nice little "smile" in the top of one of the pistons. Wasn't very big and the valve may have been ok, but I replaced it anyway.

 

If it bent them right after you replaced the timing chain and the the engine never started and you only had the chain off one tooth. Pull the head and if the pistons look ok and it dosent have a ton of miles on it you can put new guides, valves, seated with lapping compound.Then turn the head upside down and poor gas into each chamber and see if it dosent leak out.If it dosent . Consider yourself lucky and put it back on.It happened to a friend of mine.He ran it for another 80,000 miles before selling it.Good luck.Merry Christmas

 

Don't use gas to check, very dangerous.
Better to use another liquid (mineral spirits, rubbing alcohol, etc)

 

Sorry. I forgot some people smoke. Please dont use it unless your out doors,Rubbing alcohol burns as good as gas.Just put some wd40 or something that will not evaporate to quick . If it will hold it for 10 minutes its propbably ok.I forget sometimes that I dont know how much experience othere people have working around cars.The internet takes away that aspect. I guess I have been around the block a few times.Please be careful.Your house is worth more than an old truck.Even if it is a toyota. For those who dont have one a fire extinguisher makes a geat gift.Merry Christmas to all of you and thanks for all the help and ideas.

 

Even with my bad luck.. If you have screwed up valves, send the head out to be re-done. It will cost you about $250 and it is done.. It is hard to lap in newer engines due to harder metals. Pretty much all the shops recut the valves. Also the valve has a 3 angle cut oon it that may be muted by the "lapping" method.

Also, from what I have come across. I would almost say to install new valves. I am unsure if the 22r's are as bad as my 3.0 has been, but it sure seems like you can not take too much off the valves. If you have even a question, just repllace all valves. Heck, there are only 8 of them!

 

I hope you totally destroyed the motor. Now after the repairs are complete you'll have a 262 or 350 chevy motor in there, RIGHT?

 

I was very lucky when my timing chain, no bent valves. I have good compression but after everything was put back together the "ticking" is a little more noticeable.

 

Only if the 350 says toyota on it.