intake plenum cross thread issue on 95z34
 

While doing a tune up on my z34 which included replacing upper intake plenum, egr plenum, spark plugs and wire, cleaning throttle body, iac sensor. I seemed to have cross threaded the port where one of the longer 10mm studs where the top throttle body braket attaches to intake is. I noticed this while I was tightening to torque specs.(30lb/ft) that the damn stud never got tighter it just spun. I backed out stud to find a nice shinny corkscrew of aluminum on the stud threads. The question I have is what are my options with tap and die, do I need to take down uim again to do this or can I use the existitng pilot port as a guide? Could I just use something like jb weld(I know this is the half ass way)? Any suggestions are appreciated, thanks.

ideas that come to mind... thread locker? could help or could be very bad...

go to autozone and get a heli-coil to redo the threads will have everything you need. yes you will need to take the UIM off. i always used some anti seize on my intake bolts just to make sure they wouldnt bind and strip... just like on the plugs. im always over cautious with the al pieces... as my LIM bolt stripped before... it seems that the first 1/2" of threads on the bolt were thicker so i ended up using about 1/2" of washers to space the bolt out and i was able to Tq it down. worked out well.

Thanks for the advice, any Tips or tricks on doing job quicker? took me a couple hours to remove components attached to uim(first time doing this job on my own, well second time now).

on my DOHC i used two upper intake gaskets and RTV'd them to each side so the lower intake would have a gasket and the upper would have a gasket... so when i would need to pull it they would just come right apart. but on your 95 you can access the plugs without needed to pull the plenum... so this might not be as important to you.

most of my tricks wouldn't work on your car... i tuned out my ERG and EVAP systems and completely removed them. this makes pulling the upper intake so much faster... it was just the 7 bolts that go from the upper to the lower and it was off... not even the coil pack had bolts to the UIM. without a tuner i wouldn't recommend doing anything with the egr though...

in the future to do plugs and wires you can remove the front dog bone and put the car in neutral and let it rock back... the engine tilts forward and you gain room to work on the back plugs.

Sweet, should have researched a little more. would you recomend rtv ing my plenum to the lower side and running a bead on the top half before bolting back together? Also since I got the top off should I go ahead and look at valve cover gaskets, spark plug tubes etc. or anything else I should look at replace? This car was sitting for 5+years with bad tranny. I replaced tranny, fuel tank, fuel pump assembly, brakes, tires, iac, tstat(180*) coolwnt flush, egr gasket/carb cleaned egr. This car has been idleing rough and in cool damp mornings idles high and stalls multiple times until I give light throttle and warms up. You seem to be a bank of knowledge and I appreciate the help.

did you replace the Lower intake manifold gaskets?? those are the ones that are the real problem with the car. with fresh gaskets and a cleaned surface there is no need for RTV on these engines.

when pulling the lower intake drain some coolant out so that there wont be a lot spilled... ours dont open up to a lifter valley like the 3800's where oil and coolant mix, but still better to keep coolant out of the heads. with the lower intake removed look at the heads where the coolant comes in. if there is a lot of build up then clean it out a bit.

also with the lower removed look pretty much under where the TB would sit. under the rear head you will see a metal plug in the block. this is the dreaded Oil pump drive shaft cover. these have a cheep rubber Oring that always fails. to properly remove it you need to pull the rear head. the easy repair that people try is RTV.. this rarely holds longer then 3-6 months. what i did is to lift is as high as i could clean it and then use "QuickSteel" epoxi. pack it in and then push the plug back in. its doubtful anyone will ever rebuild one of these engines and if they do a swift hit of a hammer will knock it loose... but the epoxi fix lasted the 5 years until my engine died a quiet death at 225,000 miles.

for more information on this engine the best site is really 60degreev6.com they what moved on to the 3100/3400 engines and even the 3.5 engines now but they still have the most information and help for it.

Looks like I am going to go ahead and do the lim gaskets while I'm tearing everything down. Thanks for the info and the link to 60degreev6, lots of god info there. Thanks again and I will keep everyone posted on my progress

lower intake gaskets complete!
 

So I finished up today, new gaskets, new o rings for fuel injectors, checked oil distributor plug and did the helicoil for the uim. Was nervous when drilling out the threads and tapping new threads, but they worked, oh and I used some washers to even out the gap created by the helicoil insert. Started the car up and she runs beautifully now, no more crazy idle issues, no more service engine light. Feels great. Thanks to all here who have helped walk me through this.