Best Way To Clean Engine Block Threads

[sioux90]

Hi,

I am replacing my exhaust manifold/catalytic converter in 2003 Lancer ES.



I want to replace the engine block threads and nuts (all are significantly rusted). For nuts, I will just get some regular anodized nuts. I was told, changing the threads isn't very easy. So I hope I can at least renew/clean them. Can anyone suggest the best way to do it?

Perhaps, a metal wire brush on a drill?

Or maybe a thread restoration kit like this? http://tinyurl.com/d2kfeva

Thanks for any help.

[shorod]

Welcome to the forum!

When you talk about the "threads" I believe you are actually referring to the exhaust manifold studs, correct? Yeah, it can be tough in some cases to get the studs out without breaking them. And of course other times the studs will spin out when trying to remove the nut. If you are concerned with actually removing them, then a wire brush on a drill would likely work, but you'll want to plug up the exhaust ports so you don't get all that debris in to the ports and possibly in to the cylinders. My personal preference would be to use a die (such as what's in the thread restorer kit) and chase the threads. It may be worth double nutting a few of the studs though once the manifold is removed to see if you can back the studs out relatively easily, then replace them. I'm not sure you'd want to go with anodized though as there may be a galvanic reaction between the manifold and anodized nuts. I don't know metallurgy well enough to proper address that risk though. I would probably just go with OEM studs and nuts and be sure to use anti-seize when reassembling.

-Rod

[sioux90]

You are right, not sure why I wrote treads instead of studs. Thanks for the info!

[shadows]

shorod- is correct
you are meaning remove the exhaust manifold stud nuts- cleaning up the studs-

there is and has never been a reason to remove those studs- nuts act like the stud is the problem- is not so- it's corosion on threads
easily cured- run a thread chaser

if you feel such studd is bad- install 2 nuts and back out the stud

most have no common scense on rust/heat/results on an external stud and nut- 9 times out of 10- you can resuse everything

[vgames33]

Don't go through the trouble to pull them all out. You're more likely to break something than to do any good. Clean up whatever comes out and use some anti-seize on everything. A tap and die kit can clean everything up a bit and make assembly easier. I'm going to guess those are M10 x 1.5 based on the picture.

If you insist on replacing the studs, be prepared to use heat to get them out of the head. I highly suggest soaking everything in PB blaster or some other penetrant for a few days prior to removal to minimize the risk of broken studs (which is no fun at all to fix). Don't forget to hit where the pipe connects to the converter as well. Those tend to get very badly corroded over the years.

[shadows]

Originally Posted by vgames33

Don't go through the trouble to pull them all out. You're more likely to break something than to do any good. Clean up whatever comes out and use some anti-seize on everything. A tap and die kit can clean everything up a bit and make assembly easier. I'm going to guess those are M10 x 1.5 based on the picture.

If you insist on replacing the studs, be prepared to use heat to get them out of the head. I highly suggest soaking everything in PB blaster or some other penetrant for a few days prior to removal to minimize the risk of broken studs (which is no fun at all to fix). Don't forget to hit where the pipe connects to the converter as well. Those tend to get very badly corroded over the years.

ahhh- bet you've built an engine or two in your day
always cracked me up- replace this replace that- I've heard- while nothing but nut heads- spout off that this or that should be changed-

still chuckling- 30 some years- I figure engine guys know a joker or two that is lurking- spouting off to be heard- we have a couple of goof balls here- we who know- roll over with laughter

carry on-