wopfe

Hi, i was wondering if anybody knows the use of this (untapped) boss on my '79 euro engine block. Run into it when replacing my waterpump and tensioner. Discussed it already with some wise 928 men who are not sure. I am just curious if this is just a certain serie of engines ('79's)?

PorKen

I think it is a vestigal bolt hole for a pre-production tensioner.




It is shown drilled and tapped in the WSM and PET.

Note lack of ribbing under tensioner which were used 83- for tensioner oil passages.




I always wondered what the small extension was for as neither the tensioner nor the cover rest on it.

PorKen

Probably only present 78-79 4.5L. I bet the casting was changed when the 4.7L 'S' engines were developed for '80.


Here is another odd feature on 4.5L heads left over from development which disappears on 4.7L heads. There is a square opening (red line) for an exhaust crossover for a carb'ed intake manifold. (If you pour water in there it will boil.)

wopfe

Well Ken, thats it then i guess Sounds like a very reasonable explanation. I was just wondering if anybody else ever run into this boss and had another idea.

Thanks again!

PorKen

I was going to post about it too, in the hope that someone had a better theory, but you beat me to it.