Raising the engine to get at exhaust bolts

[bcredliner]

Stiffening or skid plate are slang descriptive names we use but reinforcement plate is the accurate name.

There is no torque modification that will result in meeting proper torque specs.

The counter is always everybody does it. There is never an "expert" that quantifies the risk or lack of. True believer is used as a 'slam' of sorts, that one does whatever BMW states. The alternative is just because a lot of people reuse them it doesn't mean that is the correct decision. It seems means it is a guess that all BMW dealers reuse the bolts.

If the bolts cost $.50 each there would be no logic in reusing them again. It's all about the price that results in a rationalized decision.

As a potential safety issue I think it important to consider both sides and make an informed decision, that's the reason I post the other point of view each time this comes up.

[crystalworks]

Originally Posted by bcredliner

Stiffening or skid plate are slang descriptive names we use but reinforcement plate is the accurate name...

... As a potential safety issue I think it important to consider both sides and make an informed decision, that's the reason I post the other point of view each time this comes up.

Since we are moving this debate from the thread its based in... even though I know you like for a thread to stay exactly on topic... your position would have much more weight if you could show a single case where reusing the bolts resulted in a safety issue/concern.

The community has shown tens of instances of no issues, and many more if you take their word that dealers/indies/etc reuse the bolts. I have personally seen them reused at an indy I worked at at least a few dozen times. Mine have been on and off now a half dozen times. And will be off again in the near future.

BMW recommends refreshing most, if not all fasteners on the suspension when working on them... does everyone do that too? Of course not, and those bolts are not $10 each.

[andrewwynn]

I will have a very helpful case study soon. When I replaced my stiffening plate a while back I used less than grade 8 bolts and definitely not torqued to spec. I just used a good during strong yank on a breaker bar.

The only problem that could be expected if the bolts aren't doing their job is that the plate will slide sideways during a body twist situation.

As I'm well known for tight parallel parking shortcut of driving straight in over the curb about a foot and back onto the road my car gets a very significant "ditch witch" twist test regularly. I need to remove the plate soon to track down an oil leak and will take close looks at all the six mounting points and let everybody know if there is any sign of movement of the stiffening plate.

If there is or isn't the question can soundly be answered.

The primary job of the bolts during normal operations (not a wheel off the ground off-road operations which I'm also no stranger to), is to hold the anti sway bar down.

The sway bar doesn't need half the strength of the bolts used for this job: implication is that the only reason they are overkill bolts is to prevent side slip and that's pretty clear by the name of the part or holds: stiffening plate. It stiffens by preventing the subframe from twisting out of square. (Think of it like a giant "X" under the engine to keep the front left and back right of the engine bay the same distance as the front right and back left. Rather than a couple 1" thick steel bars BMW choose to use a 5mm thick aluminum plate that coincidentally blocks road hazards from the engine, noise and catches drips from messing up people's garage floors (until the foam is saturated and that's usually a second owner problem).

The math I'm sure worked out to "holy shit that's a lot of sideways force" so when they added on the typical 200% to 300% safety factor it landed where it did.

As far as a safety concern by the time you get to where one of these bolts fail there will be 8 things far more risky to your well being and more than likely the bolt failing would improve your chance of survival by decreasing the forces required to crumple the engine bay and reduce the g-forces transferred to the cabin.

[Oldmactech]

Was never my intention to let loose a can of worms. I will say if I remove the plate it’ll just get put back the way it came off. I always thought the skid plate was the plastic plate under the front of the engine.

[Fifty150hs]

"PS: Bentley can "suckit" on single use bolt on the stiffening plate. You can absolutely reuse they are not head bolt"

Please. Let's not restart this old argument.

[andrewwynn]

Argument is new to me. Actually as mentioned above I'm quite open to figure out that you really need more force but off my experiment determines that my stiffen plate needs more clamping force, rather than thow away stretchy bolts I will upgrade to a size up and do some math to figure out an equivalent clamping force without getting to yield

[bcredliner]

[QUOTE=andrewwynn;1151376]I will have a very helpful case study soon. When I replaced my stiffening plate a while back I used less than grade 8 bolts and definitely not torqued to spec. I just used a good during strong yank on a breaker bar.

The only problem that could be expected if the bolts aren't doing their job is that the plate will slide sideways during a body twist situation.

As I'm well known for tight parallel parking shortcut of driving straight in over the curb about a foot and back onto the road my car gets a very significant "ditch witch" twist test regularly. I need to remove the plate soon to track down an oil leak and will take close looks at all the six mounting points and let everybody know if there is any sign of movement of the stiffening plate.

If there is or isn't the question can soundly be answered.

The primary job of the bolts during normal operations (not a wheel off the ground off-road operations which I'm also no stranger to), is to hold the anti sway bar down.

The sway bar doesn't need half the strength of the bolts used for this job: implication is that the only reason they are overkill bolts is to prevent side slip and that's pretty clear by the name of the part or holds: stiffening plate. It stiffens by preventing the subframe from twisting out of square. (Think of it like a giant "X" under the engine to keep the front left and back right of the engine bay the same distance as the front right and back left. Rather than a couple 1" thick steel bars BMW choose to use a 5mm thick aluminum plate that coincidentally blocks road hazards from the engine, noise and catches drips from messing up people's garage floors (until the foam is saturated and that's usually a second owner problem).

The math I'm sure worked out to "holy shit that's a lot of sideways force" so when they added on the typical 200% to 300% safety factor it landed where it did.

As far as a safety concern by the time you get to where one of these bolts fail there will be 8 things far more risky to your well being and more than likely the bolt failing would improve your chance of survival by decreasing the forces required to crumple the engine bay and reduce the g-forces transferred t

I am not qualified to take a position either way. My bet is you aren't either. All we should do here is offer our opinion and/or advice. Any anecdotal input or experiments we can offer would be, at best, logical rather than standardized industry testing. We can state there are 8 things far more risky to our wellbeing, that it is the typical 200-300% safety factor, sway bar doesn't need half the strength. That reusing them is safer than replacing them. And primary function is holding down the sway bar (would love to hear your basis for that one)--just our layman opinions. FYI- the reinforcement plate on a 2002 4.6 is not 5mm thick.

As far as exactly on topic, that was about the what did you do to your E53 today thread. I thought some members were not aware that the thread is not intended to be used to ask about how to fix a problem, show pictures of what you had for dinner, etc. The only reason is that the majority of members follow that thread and receive post alerts. I think it is a great thread and would not like to see members op out because of so much WAY off topic posts. It's like this irritating debate where some op out or post things like please stop, don't do this again.

[Oldmactech]

Will a 3/8 swivel head socket wrench give me enough torque to break the exhaust manifold nuts loose?

[crystalworks]

Originally Posted by Oldmactech

Will a 3/8 swivel head socket wrench give me enough torque to break the exhaust manifold nuts loose?

At the head or at the collector? 3/8 is definitely possible with good access. But in-situ things could get a little more hairy between u-joints and/or extensions. 1/2 makes things much easier usually.

[Oldmactech]

At the head. 11mm I believe. Haven’t started yet.
Tried a1/2 in at the collector, no joy yet. Used copious amounts of PB blaster on those 15mm. Probably try a breaker bar or even a nut cutter if I doesn’t give up.