3VZ-E Rebuild Tips
#1
3VZ-E Rebuild Tips
Hey guys, currently I am in the middle of a tear down on my 94, I couldn't get compression of my #1 cylinder and I found a burnt exhaust valve. Was hoping I would get away with replacing the one valve. What are the signs of a bad head I should be looking for! Also does anybody know if the bolt holding the timing pulley on my camshaft is right or left hand thread, she's pretty tight. Any other tips or tricks are greatly appreciated!!
#2
Registered User
i would have it checked out for warpage, and evaluated for valve seat viability. at this point, you need the one valve, but knowing if the heads are worth rebuilding is key. it should be cleaned real good and checked for warpage. it would be a good idea to re-ring and put new bearings in, but that is your call.... i've known burned cylinders to go forever, but that's a gamble. if you can afford it, might as well drop the head off (because the one burned valve will need the new replacement to be properly seated) dropping the pan, hone, re-ring, and bearings will only ensure you are not wasting on your investment.
#3
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You can check for warp yourself; the procedure is in manual. But as AKHeathen says, you probably should have the valve seat reground, so you might as well have a shop do all 6 valves, pressure test the head, and check for warp. it's not cheap, but it will never be cheaper than when you have the head off.
I (personally) wouldn't bother re-ringing unless I saw something on the cylinder wall that I didn't like. When you re-ring, you "should" check the size and shape of the cylinders, and then you might need to re-bore .... It's just a matter of knowing when to stop, and with a 22 year-old truck you might want to just get a few years out of it.
The cam-shaft bolts are right-hand threads, but they will be very tight. There is a "special" tool to hold the crank pulley, but I don't recommend it for a bunch of reasons. Instead, try this: https://www.yotatech.com/forums/f116...l#post52283495
I (personally) wouldn't bother re-ringing unless I saw something on the cylinder wall that I didn't like. When you re-ring, you "should" check the size and shape of the cylinders, and then you might need to re-bore .... It's just a matter of knowing when to stop, and with a 22 year-old truck you might want to just get a few years out of it.
The cam-shaft bolts are right-hand threads, but they will be very tight. There is a "special" tool to hold the crank pulley, but I don't recommend it for a bunch of reasons. Instead, try this: https://www.yotatech.com/forums/f116...l#post52283495
#4
Thanks for your help boys, the head is off and heading to the repair shop. A couple more questions for ya!
Is there any reason to retorque the head bolts or any other bolts for that matter, beyond the first installation?
Anybody have any preference in gaskets? I have the board type and could not get my hands on the steel type, would they be sufficient?
Should I be applying any sealent to gaskets or hoses/vacuum lines as I reinstall them?
Thanks for your help! This site is wicked!
Is there any reason to retorque the head bolts or any other bolts for that matter, beyond the first installation?
Anybody have any preference in gaskets? I have the board type and could not get my hands on the steel type, would they be sufficient?
Should I be applying any sealent to gaskets or hoses/vacuum lines as I reinstall them?
Thanks for your help! This site is wicked!
#5
Registered User
on other engines, especially small engines, it's good to retorque the head bolts after a few heat cycles, but i'm sure you can understand what this entails for most vehicles, and would mostly be a precautionary measure, so make sure it's done precisely the first time. as for an old head, perhaps you can put a torque wrench to the bolts to check them, but they should be locked in place and require more than the spec torque to even bust them loose, then any corrosion/oxidization, etc would probably be less clamping pressure that it originally had if you crack them loose then retorque. i'm partial to copper and mlm gaskets where i might have the head off a few times, or on a decked block/milled head, for any number of reasons i deem fit, but for purposes like yours, regular graphite composite gaskets work great and fill any gaps/imperfections better. biggest thing is put a strait edge on it and check for any warpage, etc, then clean the bolts/bolt holes real good with chases as thread condition will greatly effect clamping pressure in relation to torque. also, make sure the bolt holes are cleared out real good. you don't want to hydrolock them when you put the bolts in. torque as per spec, then go over it a second time final torque.
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