99 Taco Exahust Valve Replacement -- Wisdom Needed
04-04-2014, 08:04 AM
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99 Taco Exahust Valve Replacement -- Wisdom Needed
Greetings friends,
I've got a 99 Taco with 223K miles, 2.7L which I bought knowing she'd need some TLC. I intend to use her as a work truck so was not looking to go overboard on costs.
The exhaust manifold has a crack and as expected cyl 4 has a burnt ex valve; C1: 130 psi, C2: 128 psi, C3:119 psi, C4: 44 psi.
A leak down test confirmed air was escaping the exhaust system. I also poured some oil into the Cyl4 to verify that it wasn't a ring, no change in compression.
Now to fix her
I have examined all the options from new rebuilt engine to a remaned head to doing the valves myself. I think I've decided to do the valves myself as I believe it will be the least expensive, which seems obvious 
. Planning on doing Cyl 4 and maybe Cyl 3 but should I just do them all?
Ye who have experience replacing exhaust valves, how did it go? What did you do? I am planning on lapping the new valves as I don't really have access to grinding equipment, etc. I have followed @zlathim 's advice on this thread: https://www.yotatech.com/forums/f2/1...valves-140030/
Thoughts on how to proceed, wisdom to share? I am going to tear down the head this weekend before ordering parts to get a good look at the valves.
Thanks in advance for the advice.
I've got a 99 Taco with 223K miles, 2.7L which I bought knowing she'd need some TLC. I intend to use her as a work truck so was not looking to go overboard on costs.
The exhaust manifold has a crack and as expected cyl 4 has a burnt ex valve; C1: 130 psi, C2: 128 psi, C3:119 psi, C4: 44 psi.
A leak down test confirmed air was escaping the exhaust system. I also poured some oil into the Cyl4 to verify that it wasn't a ring, no change in compression.Now to fix her
I have examined all the options from new rebuilt engine to a remaned head to doing the valves myself. I think I've decided to do the valves myself as I believe it will be the least expensive, which seems obvious . Planning on doing Cyl 4 and maybe Cyl 3 but should I just do them all?Ye who have experience replacing exhaust valves, how did it go? What did you do? I am planning on lapping the new valves as I don't really have access to grinding equipment, etc. I have followed @zlathim 's advice on this thread: https://www.yotatech.com/forums/f2/1...valves-140030/
Thoughts on how to proceed, wisdom to share? I am going to tear down the head this weekend before ordering parts to get a good look at the valves.
Thanks in advance for the advice.
04-04-2014, 09:43 PM
#2
Registered User
That compression seems pretty low all around. I don't know what the 3rz is supposed to be but the 5vze is a little over 200psi from the factory. You might see if that can come up at all before tearing into the head. Here is one thread that might help. If not maybe a new or remaned head is in order.
04-05-2014, 03:44 AM
#3
Contributing Member
The low compression is most likely the tester used, a long hose will cause much lower readings.
replace all the valves at once while you are in there. They are cheap, the hard part is the install. Since you will have the head off anyways doing them all is not much harder then 1. The hardest part is usually the shimming once you get it down.
I would also get the head off before you buy too many parts, make sure everything else is in good enough shape to reuse before you commit to this.
replace all the valves at once while you are in there. They are cheap, the hard part is the install. Since you will have the head off anyways doing them all is not much harder then 1. The hardest part is usually the shimming once you get it down.
I would also get the head off before you buy too many parts, make sure everything else is in good enough shape to reuse before you commit to this.
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