SSIs on 1985 - Crossover and Tapping the Case?
 

I havent dealt with this particular combination of engine/exhaust before and would appreciate some responses;

THis is a 1985 911 carrera motor with a set of SSI's I had laying around. This engine case has stand-offs cast but is not tapped for the SSI exhaust support tab. First question is whether it is common practice to drill and tap the later case here?


http://forums.pelicanparts.com/uploa...1706146673.jpg
http://forums.pelicanparts.com/uploa...1706146673.jpg
http://forums.pelicanparts.com/uploa...1706146673.jpg
http://forums.pelicanparts.com/uploa...1706146673.jpg


Second question is to confirm the right oil crossover line for this combination. I had ordered a stock version but find it fouls the 4-5-6 side SSI heat chamber. I have the stock one installed there, when I remove it the SSI fits correctly but again there is a standoff for the SSI tab but it isnt drilled and tapped.

Is this the right crossover?

https://www.pelicanparts.com/More_Info/ERMP0180000.htm?pn=ERMP-0180000&bc=c&SVSVSI=0582


Thanks!

Drill and tap is normal. You often have to tweek the return line to fit right, normal.

It looks like what I have, so It should work. I can't see from the pic where it interferes with the SSI. Possible it got tweaked a bit in shipment? Be sure to fit the SSI correctly and snugly to make sure it interferes. It seems to me the last time I rebuilt my engine, I had to do that, and then it fit correctly, but when it was a little loose, I had some rubbing. If it interferes only a little, use a special clearancing tool to open up the space.* There is a tab on the pipe that screws to the oil cooler. Make sure ti lines up too.

Yes, drill and tap the mounting bosses on the case to support the SSI sheet metal tab. Install the exhaust system on the SSI's so that you have everything in final alignment before you drill the holes (that also ensures your exhaust system aligns with the SSIs--some do not align well). You do not want to put stress on the tab on the SSI, otherwise with vibration, heating, and cooling cycles, it can fatigue and crack. Bend it slightly if necessary and use spacers to get it to fit without stress.

* a hammer. ;)

I didn't bother with the drill/tap. Been on for 16 years and 40k miles. No issues.

Seems to be holding up fine unconnected, do these rattle otherwise ?

The OEM HEs aren't held in place by teeny tabs bolted to the case(!).

Don't know. Ive always screwed these down. I figure SSI put those tabs on the exchangers for a good reason.

Thanks guys, very helpful!

How deep, 10mm? There's enough meat there?

I had a hole on one side for my '82 so I bolted it there and just put a high temp rubber pad between the SSI and the case on the other side. Same thing where the oil line passes by the shroud on the other side, high temp rubber jammed in to prevent any potential rattling.

10mm or thereabouts. Use a short bolt and a bottoming tap. Just looks more finished with the tabs bolted up.