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Cost of helicoil/time-sert for stripped head bolts


RSL

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What would be a fair and market-based cost to repair a stripped head bolt or two, including all parts and labor?

 

In other words, what bottom line, out-the-door charges at a competent shop with an experienced BMW oilhead mechanic?

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Joe Frickin' Friday
What would be a fair and market-based cost to repair a stripped head bolt or two, including all parts and labor?

 

In other words, what bottom line, out-the-door charges at a competent shop with an experienced BMW oilhead mechanic?

 

If you're talking about a head stud, they'll probably get you for an hour or two of labor, at maybe $80 per hour. The cost of the Helicoil is nada, maybe a couple bucks.

 

If you're talking about a valve cover bolt, they ought to be able to knock that out in a half hour or forty five minutes, depending on whether you have valve cover guards in place, and whether there's tupperware in the way of removing those guards (is this an 1100/1150RT?).

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if you are in Atlanta, GA area, we have a tech day on Nov 4, and I have all the tools, kits etc for repairing the valve cover threads. Just let me know and I will bring my kit

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What would be a fair and market-based cost to repair a stripped head bolt or two, including all parts and labor?

 

In other words, what bottom line, out-the-door charges at a competent shop with an experienced BMW oilhead mechanic?

 

RSL, there is really no way to know without knowing exactly where you are located.. Even then it depends on the repair difficulty & what has to be removed to obtain access to the area for the thread repair..

 

 

Things that will effect the price (cost) of repair is how precise you want the repair done & who in particular is doing the job..

 

If the head is already removed & the area has good access & you just take it to a repair shop & have a kid drill the old threads out & stuff in a Heil-Coil it won’t cost too darn much..

 

On the other hand if you want a perfectly straight thread install, that takes a drilling fixture & probably a qualified machinist & that will cost quite a bit more money..

 

Twisty

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If you're talking about a head stud, they'll probably get you for an hour or two of labor, at maybe $80 per hour. The cost of the Helicoil is nada, maybe a couple bucks.
But if he means that the studs have stripped the case, it's certainly take longer than two hours... frown.gif

 

Pat

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The stripped thread is in the aluminum block. It is the hole that holds the lower front cylinder head stud. The stud would not take the 20 NM + 90 degrees + 90 degrees torque. So, the stud stripped its hole threads an came out with ~1/2" of aluminum clogging the end of its thread grip, leaving the upper ~1/2" of thread clean. (The stud had not been properly/fully seated, so only half of its threads were engaged into the block--that's why the stud pulled aluminum from the block.)

 

Presumably the cylinder head must be removed to properly access and tap the hole in the block to install the new Helicoil or Time-Sert.

 

So, what would be a reasonable bottom line shop cost to fix this? Presumably it would entail a Time-Sert or Helicoi for the stripped block thread, plus a new headgasket, oil change, valve adjustment/end play adjustment, labor, etc..

 

And, is it OK to install 2 short Helicoils end-to-end in the hole, rather than one long one?

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Longer heli-coils are readily available. 2 diameters long is a standard length, 20mm long for a 10mm helicoil for instance. IMHO, it would be a waste of time and effort to try to properly install 2 of the shorter length inserts in the same hole. Two diameters is plenty of engagement.

 

all the best,

 

Mike

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Longer heli-coils are readily available. 2 diameters long is a standard length, 20mm long for a 10mm helicoil for instance. IMHO, it would be a waste of time and effort to try to properly install 2 of the shorter length inserts in the same hole. Two diameters is plenty of engagement.
Two diameters IS NOT enough engagement. A good friend of mine found out the hard way by only installing one standard length heli-coil for his repair. It lasted until he tried to re-torque the heads after re-assembly & break-in. The FULL length of the threaded part of the stud must be engaged in the block or else the heli-coil will strip out of the block. My friend used two heli-coils (easily installed) and has had no problems since. The bike has about 187,000 miles now.

 

Also, the jug must come off for coil installation. At least one of the stud holes is also an oil passage (I don't remember which). You wouldn't want chips in the oil system, even if you could manage the drilling, tapping & coil installation procedure with the jug still on. Sorry I can't give any repair estimate. This was a home repair...

 

Pat

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To diameters is enough engagement. I've been doing this for over 20 years, and consulting the engineering standards often enough to know this. You say he installed a standard length insert - WHICH standard length insert? Standard length can be 1 diameter, 1.5 diameters, or 2 diameters. On occasion the install can cause early failure, if not done properly. I own a machine, and stock and install inserts....... both helicoil and time-serts

 

all the best,

 

Mike smirk.gif

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To diameters is enough engagement. I've been doing this for over 20 years, and consulting the engineering standards often enough to know this. You say he installed a standard length insert - WHICH standard length insert? Standard length can be 1 diameter, 1.5 diameters, or 2 diameters. On occasion the install can cause early failure, if not done properly. I own a machine, and stock and install inserts....... both helicoil and time-serts

 

all the best,

 

Mike smirk.gif

 

He claims to have installed back-to-back Helicoil inserts to match the grip length on the lower end of the 10mm cylinder head stud. The threaded grip length on that ~10" stud is ~24-28 mm. I had specified Time-Serts per BMW repair manual, per advice of two local automotive machinists, per advice on this forum, and per advice of the service manager at the nearest BMW motorcycle dealership, which is 90 miles away. Rather than get the requested Time-Sert of proper and specified length, this mechanic installed back-to-back Helicoil inserts. He then tried to charge me $15 each for these Helicoils, which are sold in local car parts stores for ~$1 each, retail. Without my prior knowledge or consent, he also says he installed a total of 6 other Helicoils on my bike, after having stripped a torx bolt which should not even have been touched in conjunction with the approved job, which was fixing the stripped case thread that holds the ~10" long stud. Sound fair to you?

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The strength of the repair is more than adequate, assuming he kept the drilled hole straight and to size. There's really not a significant difference of strength between the time-sert and the heli-coil. They both use the same size tap, which means the installation will have the same size tapped hole, right? (if you read the time-sert website, they do note that an "STI" or standard threaded insert type tap is used) It's nice that he fixed other stuff, I guess - but I'm not sure why, based on your comment. (I'm not sure what if any nuance I'm reading here, since this is typed, etc). There's a very (really very) slight loss of strength between 2 shorter inserts and 1 long insert, but not enough to worry about. If it was my bike, I'd be happy - again assuming the hole prep was done properly. That's really the most important part of the install. The inserts can be replaced.

 

Labor would be the highest part of the job. When I do things like this, I've charged a price per hole, which is pretty standard in this sort of thing. If the install/setup is more difficult or risky, the price can go up. If it's a normal shop, I've seen prices of $10 to $50 per hole, depending on circimstances. If several of the same size are installed, the price sometimes goes down. If it's a fellow/brother cyclist, the price is often "pass it on." In aerospace, it's sometimes standard practice to install inserts in aluminum parts that will see higher stress, or active use.

 

all the best,

 

Mike

 

P.S. in my above post I meant to say I own a machine shop, not a machine dopeslap.gif

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Thanks, EagleMike, for your insights and suggestions.

 

As a machine shop owner, what is your professional opinion about a machinist (sole proprietor of his own shop) who does extra and unrelated work that was not agreed on, then tries to nearly quadruple the bill?

 

Such work may or may not be desirable, but damn sure was not contracted for. Why should the customer pay for anything he did not request and/or even know of until after the fact?

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If I was in your shoes, I'd be kind of cranky about it. In fact, I've been there, just not with heli-coils. eek.gif If your discussions with him didn't address this potential issue prior to the work, IMHO he should have called you and given you options and costs.

 

all the best,

 

Mike

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