Should I replace just the burnt exhaust valves?

.. I have 3 cylinders with low compression.

Yadda yadda, I got the head off and tested the valves and i have a few exhaust valves that leak bad. See vid here https://youtu.be/aQji8LHWoiI

It's like a oval shaped compared to its sister exhaust valve... you can see the lip in the pic when I put them end to end. ... and in the side by side pic the height difference is visible too

Is it common to just replace them all at the same time? Or should I replace the 3 that are obviously not round?

 

I'm no expert in heads, but I would take it to a head shop and let them look. With my burnt valve they just replaced the one, surfaced the head, put in new valve seals, and set all the shims.

@Speedytech7 might have some input too.

 

Looks like a double post

 

My opinion. You’re already in there and have the head off. Do them all.

 

Why’d you post the same thing twice?

 

inspect valves if any others show signs of abnormal wear, otherwise no need to replace

 

sorry.. i cant figure out how to delete one of them.. the "other" one has more pictures tho: https://www.tacomaworld.com/threads/should-i-replace-just-the-burnt-exhaust-valves.702243/

 

sorry, my internet went out and now i cant figure out how to delete one. the other one has more pictures actually : https://www.tacomaworld.com/threads/should-i-replace-just-the-burnt-exhaust-valves.702243/

 

So maybe another opinion sort of question... but how concerned should I be about getting OEM valves in there? I was thinking of buying a set from yotashop and bringing it to the machine shop for them to install... I assume they would put after market ones in, but I dunno if that's fine or not.

OEM exhaust valves are 25$ each for this 2.7L 3rz head

 

I replaced my head with one from kingcylinderheads.com
Been happy with mine and still going strong. Comes shimmed already and upper valve train already all assembled

 

The head shop I went to gave me no reason to replace valves that weren't burnt. Runs fine. As long as they're the right shape, they do their job.

Come to think of it, replacing all the valves may add to your labor cost considerably.

 

Not really, they need to take out all the valves and grind them anyway. Actually, it would be a bit less labor, because the new valves won't need grinding/machining.

 

if it were me I would determine why this needs to be done. If it was due to a valve adjustment isuse is one thing if it was due to high mileage, that is something else. If the seats are worn because of high mileage then a valve job is needed if it is due to lack of adjustment and the seats arent damaged the low budget way is new valves lapped in.

 

I just had a head completely redone for 625.00 . You don’t want to tear it apart again

 

well, before i took the head off i checked valve clearances, and all exhaust but one was 0.000" .. the odd one was 0.006", still not in spec which is 0.010 to 0.014. So ya, with that in mind, im thinking ill just do all exhaust valves to be safe.. i was thinking maybe they are all "burnt" and maybe leak some anyway under higher pressure, but just the 3 that i marked with a X are the really bad ones that leak with a simple water test.

anyway im going to have the machine shop resurface it anyway, so i think i will just let them handle the valves.. i do believe some of the exhaust valve seats might need some work, but the intakes seats look perfect.. ie. i can see the 3 angle cut clearly. the exhaust seats look a little more smooth. Off to the shop it goes next week.

Now on to tackle the timing chain