need some advice

[static]

Hi, posting this here since it relates to 24v motor somewhat

last night i looked at the bolts that fasten the mounting arms to the block and what do i see: 5-grade imperial bolts... (compliments of the mechanic who did my swap)

I know most of you will frown when i say that my swap was performed by a mechanic and not by myself, but i was a big noob when it was performed and i still don't have a proper equipment/place

Anyway... here are my choices, what would you recommend i do:

1. Keep using the SAE bolts as they probably messed the block threads and if i put the proper ones in, it'll move teh threads the opposite way and weaken them even more

2. Put in (with a bit of force of course) the newly bought 10.9 M8x26 that should have been there in the first place. Rationale here is that wrong grade5 threads being weak hopefully didn't mess up the block threads too much

3. tap/chase the block threads with a tap before putting the M8's (which will undercut threads a bit)

4. drill and tap to, say, M10

5. helicoil


ultimately, i'd like to avoid paying too much $$ and/or put too much work into it. But i need it to be sturdy and safe (track/autox duty)

[Mike B.]

Drill/tap or helicoil. I would expect your threads to be shot and these options will give you a clean slate.

[Jason89i]

Drill/tap or helicoil. I would expect your threads to be shot and these options will give you a clean slate.

agreed. not a fun chore, but the right way to do it. cheers, jason

[E30_fiend]

I'd say drill and tap. This way you will not only be doing the safer thing but it will also be the strongest. Yet to find a higher grade bolt though. Grade 5 and 6 break all the time in my shop. And actually in the regulations and spec book on the sweeper trucks I work on, its against regulation to use anything but a grade 8 bolt anywhere on the truck.

So when you fyill and tap, try to make sure that you find a high grade bolt because this area of the block sees a lot stress.

Good luck, I hope everything goes well.


E30Fiend

[golde30]

why dont you try the oem bolts first, and try to torque them to spec, if they strip, then you will have to go the above route, but if they get tight, then yer gravy... i would probably go though the threads real quick with the tap to clean it out first too.

[static]

Thanks guys. I am gonna tap them as few people suggested and use the proper bolts. I figure that 4 on each side @ required 20lb/ft it'll hold well enough even if 50% of thread strength is gone

then i'll fix it the right way when i pull engine or something

[2002maniac]

just chase the M8 threads. It should be fine.

[btec116]

Helicoil it. Do it properly! You'll never have to think about it again.
C'mon, these are the bolts HOLDING your engine in the car. Running the original size tap over damaged threads is not cool.

[craz azn]

I'm kinda surprised sort of to some degree to hear about this Alex. Thats a pretty hack thing of them to do to your swap. Hope you resolve it well.

[BigD]

I'm kinda surprised sort of to some degree to hear about this Alex. Thats a pretty hack thing of them to do to your swap. Hope you resolve it well.

Why assume they did it? First of all, why would they even touch the motor mount arms? That, together with the fact that it's a BMW only shop and has no reason to have imperial hardware around, it's pretty low to bash them for this behind their back.

[static]

Noone is bashing anyone here. This thread was conceived to get an advice on how to fix this, not how i am mad about it or such (even though i obviously am).
Thus i kindly ask to please remove any negativity direct or indirect from my thread. Thank you very much.

Before judging me, check your assumptions first: Swap was performed in his old shop and at the time was shared with another mechanic who did lots of imperial stuff, i.e american cars (i know cause i used to hang around there a lot)

I am not an idiot to make such statements without any backup or checking my assumptions first.
The engine arms were bought separately from a different person (Bruno, and he himself dropped them off at mechanic's) and given to the mechanic.
Besides, EVEN IF the arms were on the engine (which wasn't the case, which is why i was asked to get a set of arms separately) and it was someone else who used the wrong bolts, it is still the mechanics duty to check the fastening quality and the fasteners used (the marks on the bolt heads are pretty damn clear) in such an important place. Let me put it this way - if the motor disconnects from the body and causes an accident/damage, who will be held responsible for the wrong fasteners used?

Mistakes do also happen, but all 8 bolts ain't no mistake.

In addition, if i were to make a stink about it and try to ruin his rep, you know i would post all about it on the local forum. I chose not to do this because of the past friendship.

If anyone feels like talking to me further about it, please contact me by the PM (otherwise can it and move on). Publicly voiced judgements full of false assumptions like the above example is the root of all evil on internet forums.

Alex

[craz azn]

Why assume they did it? First of all, why would they even touch the motor mount arms? That, together with the fact that it's a BMW only shop and has no reason to have imperial hardware around, it's pretty low to bash them for this behind their back.

^^ Dude, I have no ideas what it takes to do a 24v swap. Never looked into it. So I wouldn't know that you dont have to take the motor mounts off (if thats what your implying)... Why wouldn't they have replaced the bolts then? I'm sure they would have looked it over... I guess the real question is to ask Alex where did he get the engine from? maybe the PO did it? but even then, why?

Why shouldn't they have imperial stuff?... For example... PTG Racing who ran the e36/46s BMWs back in the day... they worked on BMWs too (obviously)... you would think they would use Metric hardware.... GUESS WHAT? half the car was imperial (whatever work they did to the car) and the untouched stuff was Metric. Not that hard to see IMO. I don't think its a bash at all. Its just an opinion.

[static]

^^ see the response above

[craz azn]

Sorry Alex, I just don't want BigD (and others) to come off with the impression that I'm badmouthing anyone. It was just my opinion on the single fact at hand ONLY. If BigD still has a problem with that, PM me.

Alex, I would just try run a tap through it and see what happens (as was pointed out earlier in the thread)... If not, I think it would be tricky to drill and Heli-coil it in the car, hard to get it straight, etc...

[BigD]

If BigD still has a problem

My problem is putting down a great guy and a master mechanic for something so stupid. If you expect him to check every bolt on every part he's going to put into your car, you don't think the money he charges for the swap should be more like 5x higher? I'm not saying you badmouthed him directly but jumping on the bandwagon without the other side having even presented their case is not cool. That's just me though. Maybe your dad strips down every car he works on to check the type and grade of every bolt (or he knows by smell - which I admit, knowing his work, is possible) but other people make some (normally) safe assumptions. What's next, expecting him to xray all of the internals for stress cracks? It can be done, but not for like a grand.

Whatever though, sounds like there's more to it than initially stated but I still don't believe he would have done this and without hearing his side, which we probably won't, I don't want fellow E30ers (esp those from the GTA) taking this as gospel. If nothing else, a man of his integrity would have fixed this without a peep if it was brought to his attention before the internet.