Drilling and tapping end plates for engine mounting bolts

[MikeLMR]

Having a bit of a session planning my engine mountings at lunch and I reckon we have a solution (may pan out when I can look at the engine in the car ... or not)

But I would like to add some additional tappings to the engine in the areas circled at either end (original mounting bolts also highlighted) ... I\'m not interested in the why we are tapping them part I\'m interested in the is this technically OK, I\'m 99.9% sure there are no oilways in these sections and I\'m certain they will take the loads as I\'m also fairly sure that the 20B and the renesis (and the cosmo 13b?) use very similar places for engine mounting pickups.

Like I said not interested in the why do it like ... just CAN we do it like that ? I guess we will find out if no one knows :Giggle

[stuart wizy]

hi mike
the areas u circled are a little close to the drilled hole going through the plates for main bolt which goes through rotor housings and plates.
Cast iron is very brittle and could crack if you try and hold 80kgs plus in these areas which are close to the edge of the bottom of the plate.

[MikeLMR]

they would not be the only mounting points, we are proposing to drill all the cast iron housings out to M8 + a thread insert on the sump flange, then pick up on the two standard engine mounting points highlighted on the centre plate as well as 3 of the sump holes. Then the engine cradle would pickup on the standard side mounting  on the passenger side as well as the lower studs near the front of the engine and a couple of bell housing bolts at the rear. Thinking about it ... might not bother drilling them at all.  The engine should be well enough supported using the existing points we have to pickup on.

Like I said I\'ve not sat down and played with the real life solid model yet so I don\'t know if it will work.

If you look at a 20B or a 13B RE I\'m certain they pickup on those points as standard ... as does the renesis. Suppose the housings will be a little different in those areas though ?

[MikeLMR]

it certainly looks stronger than the front housing mount I have from a 12a(cantilevered off an aluminium front cover)

(btw on the photo below someone has measured the wall thickness for drilling and tapping where they are marked on the card ... it is a 12a front plate IIRC)

[MikeLMR]

OK, these are for inspiration (found them after we discussed the idea ) .. think of it seperate from the sump, made out of small steel box section and picking up on some of the bolts down the side of the engine too and you will have what I am thinking of. Gutted I\'d not seen this before or i\'d of made myself and intergral engine mounting with my sump plate :Giggle  ... I don\'t wish to make another sump hence the ideas

[MikeLMR]

20B engine mounting photo

[MikeLMR]

just me rattling on with more ideas again ... are the end plates cast iron or cast steel ?

*edit* they are cast iron

[mattmaclennan]

there are significant differences in the plates between 13B/T *REW *RE/20B regards mounting points. You can\'t just smack a mount on the plate. Why am I telling you... you know that! If you had a 12A front cover and a TII centre plate and a REW/RE rear plate then you\'d be on to a winner... what\'s this going in? I like those sump/cradles!

[MikeLMR]

it\'s going in the 323 ... but not in the usual place so not a lot of the conventional bits fit.  

and no, I don\'t know if all the engine plates are significantly different, obviously on the outside they have extra tappings but are they much different behind those areas to support it or is there enough meat on a standard casting to take some load.  I\'ve not had the chance to handle many rotary parts ... the limit is the S4 13B I have now and a s3 12a I pulled to bits ... oh and photos on the net.

I\'m confident we can pull off an engine cradle, we are using all but one of the factory mounting points (because its now in the middle of the sump) all the other points are in addition + the load is shared better because the mountings will all be linked.

Why are we doing it like that ? why not, we can\'t TIG weld the front cover (no TIG welder) we can\'t be @rsed to make another custom sump (been there made on of those ... now bored of that) and a 12a front cover does not just bolt up to a S4 13b (why does no one mention that anywhere I\'ve seen it mentioned?)