RenntechE55

Like the title says what would be the repercussions if a 6.3L mercedes bolt went into a 55K motor? The 6.3L bolt is noticeably longer and .05mm wider in diameter according to a micrometer. Thanks

LZH

Well if would have never happened at the factory as the 63 bolts didn't exist during 55k producton.
So, are you saying that an engine builder did this ? And, what exact bolt are you talking about ?? Rod bolt ??

Yacht Master

I get the feeling I know what the next post will be.

M-bENZ

lol

RenntechE55

No I bought the car with a stage I RENNtech on it. In the picture the bolt on the left is a 6.3L crank bolt and on the right is a 55k crank bolt , when the RENNtech pulley was installed at Dyno-Comp by the previous owner they used a 6.3L bolt. So did it stretch my crank? and could this be the reason the 55K crank bolt kept popping out? thanks

Hammer Down

Do you mean "went into the motor" as in the bolt is physically in the motor? or do you mean it was bolted in the place of the 55k bolt?

RenntechE55

no just the 6.3L bolt in to the crank in place of the 55k bolt.

shardul

iTrader: (1)

quick question did you get your car fixed

RenntechE55

no not yet , Jerry told me to send the pulley back and he will send a different one so pulley era will be out of the question. But I did find out today that the crank bolt that came off my car along with the RENNtech pulley was a 6.3L crank bolt. I called Dyno-Comp and they said they reuse the the factory bolt on the car so it could'nt have been them who put it in. Not saying the 6.3L crank bolt caused it, I would just like to know why it was in there and why 2 other 55K bolts popped out so fast and a 6.3L bolt stayed in for so long.

shardul

iTrader: (1)

so dyno-comp installed your pulley that became loose and came off?

RenntechE55

Yes, I didnt do it but the guy before me said he got all of his cars tuned there and he had the stage I done there. But I spoke with the owner of Dyno-comp and he assured me that when they did the install that they removed the old crank and put the RENNtech one on with the same bolt so it could'nt have been them.

komp55

As the facts come out now, this just goes from bad to worse. You CANNOT reuse the crank bolt because it's a stretch to torque bolt. The MB WIS is very clear on this. Did no one learn anything went Jangy went through this with James a while back?

If the crank bolt is reused, it's simply a BAD INSTALL.

hooleyboy

The work on this car at Dyno-Comp was done in 2006. when a standard renntech pulley is sent to us from Renntech they only send the pulley. The stock crank bolt on the car is reused. the 6.3l was not out in 2006. Making it impossible to get a 6.3 crank bolt.

Dyno-Comp has never pulled a 6.3 pulley. In fact Dyno-Comp has never had to replace a crank bolt on any 55AMG or 36AMG. When the crank bolt comes off and the new pulley is installed the old crank bolt is put back in.

It the guy you bought the car from messed with the car after the fact. then who knows what bolt the guy used. So the point is.. Dyno-Comp did the install of the Renntech pulley and the had never worked on the crank or had to re-pull the pulley after the Renntech pulley was installed. Please feel free to come by and check out or database of customer invoices.

I'm guessing the Renntech pulley gave 3+ years of working service and the problem only arose when the new 180mm pulley was installed independently.

Honestly I don't even know if a 63 crank bolt will fit on a 55.

I understand your frustration, but please note: in 2006 when this pulley was installed the 63 wasn't even out. I can check with my parts guy at Schumacher Mercedes, where we get our MBZ parts from and check the service records on the car to see if they did any crank work on the car.

hooleyboy

I had my crank pulley pulled by the dealer twice and both times they reused my stock bolt.

Renntech reuses the stock bolt, AMS reuses the stock bolt, Mercedes reuses the stock bolt, and I'm sure other tuners reuse the stock bolt.

why didn't the reused bolt fail during the 3+ years of service with the renntech pulley? Why havent a number of members cars have bolt failures after reusing the stock bolt?

EDIT: there is debate on the reuse of the stock bolt. Im not a mechanic and dont do install work. I just race and come up with crazy ideas. From what my eyes have seen and what the dealer has done to my car. I've never personally seen the bolt fail on the number of pulley i've seen installed. strangely enough I've seen some pulleys come in to the shop that have failed, None on a MBZ though. Well except for a CLK430 that had the rubber damper missing from the stock pulley.

RenntechE55

Ya I talk to Richard about it and he said the same thing you did about the same bolt coming off and going right back on , so it Wasnt Dyno-comp thats not what I'm trying to say. I know for sure that a 63 crank will go into a 55K crank , thats what I pulled out. I was just looking through a folder that the previous owner gave to me of service and maintenance records I found the Stage 1 was installed on 8/10/06 and its been fine ever since I have had it, so should I just try and get another 63 crank bolt and use that? since it held the RENNtech pulley in for how ever long that bolt was in there?? Thank you everyone for your help , Im not trying to play the blame game or point finger I'm just trying to figure out how to fix my car with out dropping it off at the dealership and paying $14,000

hooleyboy

I would say bring it on by and see if we can help ya. If the key and crank gear are the only things needing replacing. its not the most expensive thing in the world. Its just kind of a pain to get at as the timing case has to come off.
Im sending you a PM.

RenntechE55

Ok thanks

BlownV8

The 55 kompressor engine is still being built by Mercedes. I wouldn't think it would be that far of a stretch to have an engine builder pull the wrong bolt or have the wrong bolt given to him.

stevebez

Sounds like the slightly larger 63 bolt has stretched the internal threads of the crank making it a very week fit for the 55k bolt. The 63 bolt may not be a stretch version either - or not to the same degree - so that could also require different torque levels too.

I just don't understand why one would fit a 6.3L bolt on a 55K motor? To me thats a far worse install than using the old 55K bolt.

Again only my 2c.....

MRAMG1

Okay, the engineer in me has to point out two facts from the picture:

1. The 6.3 bolt being longer may bottom out, hence NEVER holding the damper correctly.

2. The 6.3 bolt has a longer shank, aka the part with no threads, this to could cause the bolt to never fully tighten, aka the shank makes contact with the crank first.

Either one of these issues could EASILY cause a wobbly damper, loose damper, or fatal error if you catch my drift.

Good luck, as I beleive we all know where this is going.



PS: The bolt, either one, would NEVER be able to strecth the crank as some have implied.

komp55

I'm not a professional mechanic either, but when doing stuff on my cars, I follow a variation of the advice given to me by my fifth grade teacher: "When all else fails, read the directions." Now as an older person, I shortcut that advice and actually read the directions first.

Here's a portion of the official MB WIS procedure on doing a R&R of the crank pulley:




Personally, I do not think there is any debate on the "reuse" issue. The crank bolt is a stretch to torque bolt, and once it's stretched, it cannot be reused and torqued correctly. Will it bolt back in? Yes. Will it be correctly torqued? No.

JustPete

^^^

Looks pretty clear to me.

Whenever I've done work on motors, with any high torque bolts that meet a lot of stress. The rule has always been to replace with new.

Andy0331

When I had my car tuned, I was given the old crank pulley & bolt after the install. It appears some guys do it at least.

RenntechE55

well like hooleyboy said the 63 bolt held up for almost 3 years so its not like thats the problem.

komp55

Okay, let me make sure I've got this straight -

1. The bolt was NOT replaced as specified by MB workshop procedures;

2. Somehow you later end up with the wrong part (bolt) installed in your car;

3. Whatever bolt was installed wasn't torqued down correctly in two steps; and

3. Now you're wondering why the crank bolt backed out and probably ruined your crankshaft.

We all feel your pain, but back when you first posted about your Ferrari mechanic not being able to find the tensioner release for the accessory drive belt, many on this Board advised you to take your car to a mechanic that was competent and familiar with MBs. That didn't happen and it's only gotten worse from there. I hope whoever messed up your latest install accepts their responsibility and pays for the damage they've caused. GL getting it repaired and back on the road.