SMOG DELETE: Question?!

[thefaculty]

Hi everyone

I am in the middle of a smog delete/ heater backdate on my '79SC and, having pulled the remaining brackets, my newbie question is: What do I need to do to these left over bolts?

I'm assuming they need to be tightened properly but now that the brackets are removed I either need spacers or new bolts. Or can I just leave them off (probably a very dumb question).

Oh and the spider web lines have not yet been removed from the headers. This will happen when I go SSIs but that won't be for a few months so do I need to cap the valve there or will it do any harm just leaving it as is?

Thanks once again in advance for any quick advice you'd be willing to offer!!

cheers
Dan

[MARISOL78sc]

Here is the link to the plugs you require from our HOST!
https://www.pelicanparts.com/cgi-bin/ksearch/pel_search_2016.cgi?command=DWsearch&description=PEL-BRC-02

[thefaculty]

Thanks Paul! The plugs are for the headers once the remaining lines are removed right? Or are they for my issue above which is the bolts that held the original bracket in place?

[MARISOL78sc]

They are for to plug the air injector ports when spider is removed. Here is an answer to the stud problem:
You can make spacers out of pieces of metal tube or install the correct length studs. The correct studs are BM6x42 (6mm x 42 mm long); Porsche Part no.: 900.061.092.02. If you elect to go the spacer tube approach put a washer on the front and back of the tube so the tube doesn't "dig" into the soft magnesium or aluminum chain case cover and so the nut has adequate surface to bear upon. You can make a stud out of 8.8 (numbers are formed on head) grade 6mm hex head cap screws (saw off the head and dress up saw cut with a file) if you can find them with enough thread length. Remove the old studs by "double nuting" the end or by using a stud collet. Install the new studs with red loctite on the portion of the threads that screw into the chain case. Do not be tempted to just install screws in place of the studs as everytime the screw is removed/tightened in future the threads in the soft magnesium or aluminum are worked and they'll wear out or fail. Save your air pump parts as you or a future owner may need them someday and they will be hard to replace.

[thefaculty]

Thanks again Paul! Quick update - for anyone looking for these this part number is no longer available. You'll need: 900.061.092.02 - which is not available via our host and hence teh only reason I am posting a link to where you can find them: Porsche Porsche 911 1974-1977 Screw BM 6X42 (2 suggested),…

(I hate living in Canada at times like this were shipping is twice the cost of these studs!! I couldn't;t find them anywhere here!)

[juanbenae]

remove the studs and use proper sized and length allen bolts. simple as that cause the spacers look like shat.

also the plugs will go into the heads, not the headers. use lots of heat when remove the spider manifold. they are a nightmare if in rusty, frozen condition.

[Bob Kontak]

Originally Posted by juanbenae

remove the studs and use proper sized and length allen bolts. simple as that cause the spacers look like shat.

also the plugs will go into the heads, not the headers. use lots of heat when remove the spider manifold. they are a nightmare if in rusty, frozen condition.

Listen to this guy.

[thefaculty]

Replacement BM6-42 bolts arrived - does anyone know the torque specs on these?

[Targalid]

These are small bolts going into aluminum. I used 15 ft/lb as I recall when I replaced mine and nothing stripped. You could probably get away with less torque since the only function of the bolts at this point is to seal the chain case. I backed out the long studs with the double nut technique.

[thefaculty]

Originally Posted by Targalid

These are small bolts going into aluminum. I used 15 ft/lb as I recall when I replaced mine and nothing stripped. You could probably get away with less torque since the only function of the bolts at this point is to seal the chain case. I backed out the long studs with the double nut technique.

Thanks!! Did you use any loctite?

[Jameel]

Just did this to a '79. I ended up using studs because I read that bolts, after repeated installation, could ruin the threads in the soft aluminum chain housing. I'm pretty sure I just bought some proper grade bolts with enough length, cut the heads off, threaded that end (since the plating was removed in the cutting) into the housing with a little blue loctite and used Al washers and nylocks as on the rest of the studs holding the cover on. I removed the stud from the bottom hole entirely, as it's only purpose is to hold the smog pump on, its a blind hole and doesn't go through the cover.

[thefaculty]

Originally Posted by MARISOL78sc

The correct studs are BM6x42 (6mm x 42 mm long); Porsche Part no.: 900.061.092.02.

Well I can confirm that the part above is NOT the correct bolt to replace these studs so back to the drawing board on that solution. If anyone has the correct part number or bolts I would need that would be a huge help!

cheers
Dan

[Jameel]

So my '83 cover has the same hole layout as the '79, even though my '83 has Carrera tensioners. So I looked at the PET for the 84-89 and it looks like part #4 is the stud you're looking for. I can tell you for sure its not a 6mm. I put 8mm in the '79.

Pelican sells the stud.
https://www.pelicanparts.com/More_Info/99906205202.htm?pn=999-062-052-02-OEM

[Jameel]

Found a couple pics of the 79. Did this just a few months ago. Looks like I did use the threaded portion of a correct yellow zinc graded bolt and not a factory stud (since I don't see the unthreaded center section as in the stud available from our host). Hope this helps. I wouldn't hesitate to do this again if you don't want to wait for parts to ship. I bought the bolts at the local FLAPS, who carries a good selection of 8.8 yellow zinc fasteners.

[juanbenae]

Originally Posted by Jameel

I ended up using studs because I read that bolts, after repeated installation, could ruin the threads in the soft aluminum chain housing.

hogwash! how often are they really going to be removed?

I would consider anti seize on the plugs into the heads as they are also steel going into aluminum with high heat exposure.

no lock tight!