FYI for people using heads with bent valves

[ToughTalon]

I thought I would post this for people because I hear about a lot of people using heads that have previously had bent valves. I should have made the title of the thread "FYI for people re-using heads with bent valves". I recently re-built and did a mild port job on a head that had bent valves.

Much to my suprise the bent valves cracked 5 of the 16 valve guides. I have been wrenching on DSMs for years and this was a new one to me, so for noobs and not-so-noobs always keep the valve guides in mind if you bend valves or re-use a head that had bent valves. I doubt the vavle guide would break but its still scary to think about.

I didnt post a pic with this because after the head was cleaned and I removed the valves, the cracked valve guides were obvious.

 

[nuclearr]

You do know if you bend a valve you are suppose to change the guides. Thats why I have 3 head laying around waiting to be rebuild. I would NEVER conceder slapping in some new valves and call it a day.

 

[whe3ls]

my head thats sitting at the machinist waiting for me. it bend all 8 intake and all 8 intake valve guides were cracked and replaced, all the vavles were ground along with the seats. also replaced all the seat seals too

 

[BogusSVO]

Its rather common, bend the valve Crack the guide, I see it all the time.

http://www.dsmtuners.com/forums/newbie-forum/341218-how-change-valve-guides-4g63t-head.html

 

[ToughTalon]

It was news to me, have you guys ever seen a valve guide break appart, or a chunck break off and get sucked into the engine??

 

[BogusSVO]

It was news to me, have you guys ever seen a valve guide break appart, or a chunck break off and get sucked into the engine??

I have replaced many of the guides that were missing chunks out of them, I seldom see the short block, but the chunks have to go someplace.

 

[ToughTalon]

Well great, my efforts to go to college for a second degree and build my car are not working well right now.

I was going to re-use a head with cracked valve guides, in hind-sight I think I would be an idiot to run the engine with those in there.

While I have your attention, do I need to have the head and block decked to use a MLS head gasket or is simply a clean surface ok? Thanks

 

[kottyking]

Yes, you need a mirror like finish for a proper seal.

 

[BogusSVO]

here you go....
it should look like this...

http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html