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Watching my TB job go farther south..

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Old 05-30-2018, 06:04 PM
  #31  
GregBBRD
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Originally Posted by Rob Edwards
I know you trust this shop and i'm sure their patience is thin after the loctite mess but if they're not willing to use the proper tool to time the cams, have them put a timing belt on, get it close to the marks and get it out of there. It'll run acceptably if not optimally, and you can 32V'r it on your own time at your own pace later.
If the cam timing was close before the water pump seized and the belt stretched, it would be extremely similar with a new belt (once it is broken in), as long as they don't loosen the cam gears, right?
Old 05-30-2018, 08:12 PM
  #32  
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Originally Posted by GregBBRD
If the cam timing was close before the water pump seized and the belt stretched, it would be extremely similar with a new belt (once it is broken in), as long as they don't loosen the cam gears, right?

Thats what I have been hoping for as well, as as "hey we dont like this" as they...I guess rightfully have been so far (But they stop when you say 'Greg Brown Did This')...but they hvae said nothing about it going back together, so that is what likely happened. Maybe ill get there tomorrow to pick it up. It'll be a half day adventure to do that.
Old 05-30-2018, 09:24 PM
  #33  
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Originally Posted by GregBBRD
Is the friction on the surface area is a good thing?
Certainly we need friction. Otherwise screw-in fasteners don't work. We need enough friction force due to the bolt stretch on the threads and the friction against fastener head to keep the bolt from backing-out due to vibration and thermal expansion/contraction cycles.

The question is if the static friction of the machine screws is so in-excess of this needed friction such that the head is always close to being stripped-out when it's broken loose.

Both screw types have a (in the manual) recommended torque consistent with their shaft diameter. We know that that torque in other applications is sufficient even with the minimal head surface of a hex-head bolt. The machine screws have about 3 times the 'head' surface area as the button head screws. In first semester physics we learn that friction force is independent of area and thus it shouldn't make a difference. However, in more-advanced classes we learn that real-world surfaces are not perfectly flat and thus surface area along with the deformation of the surfaces due to force do make a difference. (Otherwise we'd all be running around on skinny tires like in the 1910s...)

What does all this mean? Nothing. Unless someone is willing to do some testing. I'll do that when I install the ATI damper on my '91. I'll report back in about 7 years when it needs the next belt.

In the meantime I'll follow the directions and use my Stahlwille torque wrench to make sure the specified torque is never exceeded.
Old 06-01-2018, 05:54 PM
  #34  
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Wel...conclusion is that its cheaper to do it yourself. But the challenges the shop ran into, Id still be working on it 2wks later.

Pictures of the bolts and pump that was removed are here: (link to flickr)

www.flickr.com/photos/28804666@N08/shares/8fT2H8

The six countersunk bolts, would not unglue themselves until they used a bull nosed burr, to grind sideways on the heads until it was very thin on one side, and then hit it with a chisel and hammer, then the loctite broke free around the diameter of the head where it was thin and could deform easier..and they all came out by hand once the loctite let go.

There is no evidence of distortion of the allen holes, and they appear to have used the correct bit. They didnt sound unfamiliar with the ATI, but initially preferred "A new stock unit" in place of this..more on that later.*

The three button head screws, same fate, two came out with a chisel, and also show no evidence of stripping/distortion by poor initial removal attempts, and one had to be nearly ground flat..no head left at all, before it would let go.

My OVERALL question is this...loctite says to use it at the tip of the bolt, or where a nut engages if on a through hole. I cannot find a reference on using loctite under the head of a bolt, and not directly on the threads. Im curious is that isn's just making it way too difficult, because the design use is directly on threads. And on M10 black oxide bolts (these, basically) the non torqued down breakaway (http://www.holdit.com.au/standards-t...-methods-specs) for Loctite 242 (http://www.loctiteproducts.com/tds/T_LKR_BLUE_tds.pdf) is only listed as 71 to 168 lb·in. Not a lot. Add in the fastener torque on top of that too, at least. I tried to get photos of the Loctite there, and it shows up in the photos as a dark blue area..hard to see, but way easier with eyes than camera.

Using this under the heads of the button head, and on the countersunk mating surfaces AND threads...seems like it would greatly complicate removal by adding adhesion on a much greater surface area -and- at a much longer torque/lever arm. And that Loctite calls out black oxide bolts as 3x 'harder' to remove than plain hardware, made us wonder if it really all adds up to how loctite was used. Theres also the (my, but who knows) theory that antiseize also lubricates and that a dry 20FtLbs is something "more" when you lubricate the fastener...maybe it doesn't, maybe it does..but the shop showed me -3- 3/8" breaker bar heads broken trying to remove these.

Hi Tec...was possibly the cleanest and most professional shop I have had to use, and that was welcoming when I picked the car up. It's owned by a Norcal928 regular, and when I went there, there were 3 other 928s in the lot (clean ones) and all manner of other older Porsche metal.

*Onto the ATI Damper...they all noted that this was 'the smoothest 928 we have ever driven', and we had a chat about the ATI unit. We debated back and forth about 'new' OEM dampers, and that a 'new' one is 30yrs old, and is it really a new quality damping product..and just possibly, is 30yrs enough time to advance the engineering of a third party product?

They agreed that it must have had a lot to do with it, and were very impressed by Greg's use of this.
Old 06-02-2018, 05:07 AM
  #35  
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Nice to see it all ended well. Those button head allens are the work of the devil. We used to use them screwed into an insert on the wheels of the race car to prevent the tire coming past the mounting in case of a failure. Can't tell you how many looked like your pics even though they were not all that tight. Hack sawed a slot for a chisl just like yours.

Wonder if using torx drive allens would help in the removal process? Seems the torx bits would have more to grab on to, unlike the butter soft allens-
anyway samples here :
https://www.mcmaster.com/#torx-machine-screws/=1d3tjvr

https://www.mcmaster.com/#torx-machine-screws/=1d3tr3q

Last edited by Jim Devine; 06-02-2018 at 04:12 PM.
Old 06-02-2018, 07:02 PM
  #36  
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Originally Posted by Jim Devine
Nice to see it all ended well. Those button head allens are the work of the devil. We used to use them screwed into an insert on the wheels of the race car to prevent the tire coming past the mounting in case of a failure. Can't tell you how many looked like your pics even though they were not all that tight. Hack sawed a slot for a chisl just like yours.

Wonder if using torx drive allens would help in the removal process? Seems the torx bits would have more to grab on to, unlike the butter soft allens-
anyway samples here :
https://www.mcmaster.com/#torx-machine-screws/=1d3tjvr

https://www.mcmaster.com/#torx-machine-screws/=1d3tr3q

You missed it...the allens didnt strip. 3/8" tools broke.
Old 06-02-2018, 09:07 PM
  #37  
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Originally Posted by Speedtoys
Wel...conclusion is that its cheaper to do it yourself. But the challenges the shop ran into, Id still be working on it 2wks later.

Pictures of the bolts and pump that was removed are here: (link to flickr)

www.flickr.com/photos/28804666@N08/shares/8fT2H8

The six countersunk bolts, would not unglue themselves until they used a bull nosed burr, to grind sideways on the heads until it was very thin on one side, and then hit it with a chisel and hammer, then the loctite broke free around the diameter of the head where it was thin and could deform easier..and they all came out by hand once the loctite let go.

There is no evidence of distortion of the allen holes, and they appear to have used the correct bit. They didnt sound unfamiliar with the ATI, but initially preferred "A new stock unit" in place of this..more on that later.*

The three button head screws, same fate, two came out with a chisel, and also show no evidence of stripping/distortion by poor initial removal attempts, and one had to be nearly ground flat..no head left at all, before it would let go.

My OVERALL question is this...loctite says to use it at the tip of the bolt, or where a nut engages if on a through hole. I cannot find a reference on using loctite under the head of a bolt, and not directly on the threads. Im curious is that isn's just making it way too difficult, because the design use is directly on threads. And on M10 black oxide bolts (these, basically) the non torqued down breakaway (http://www.holdit.com.au/standards-t...-methods-specs) for Loctite 242 (http://www.loctiteproducts.com/tds/T_LKR_BLUE_tds.pdf) is only listed as 71 to 168 lb·in. Not a lot. Add in the fastener torque on top of that too, at least. I tried to get photos of the Loctite there, and it shows up in the photos as a dark blue area..hard to see, but way easier with eyes than camera.

Using this under the heads of the button head, and on the countersunk mating surfaces AND threads...seems like it would greatly complicate removal by adding adhesion on a much greater surface area -and- at a much longer torque/lever arm. And that Loctite calls out black oxide bolts as 3x 'harder' to remove than plain hardware, made us wonder if it really all adds up to how loctite was used. Theres also the (my, but who knows) theory that antiseize also lubricates and that a dry 20FtLbs is something "more" when you lubricate the fastener...maybe it doesn't, maybe it does..but the shop showed me -3- 3/8" breaker bar heads broken trying to remove these.

Hi Tec...was possibly the cleanest and most professional shop I have had to use, and that was welcoming when I picked the car up. It's owned by a Norcal928 regular, and when I went there, there were 3 other 928s in the lot (clean ones) and all manner of other older Porsche metal.

*Onto the ATI Damper...they all noted that this was 'the smoothest 928 we have ever driven', and we had a chat about the ATI unit. We debated back and forth about 'new' OEM dampers, and that a 'new' one is 30yrs old, and is it really a new quality damping product..and just possibly, is 30yrs enough time to advance the engineering of a third party product?

They agreed that it must have had a lot to do with it, and were very impressed by Greg's use of this.
The threads appear that they have gold never seize on them, not Locktite. When we use Locktite, we always put it inside the female threads, so it can't be wiped off the male threads and end up between the damper and the adapter, much less under the head.

I've never had a countersunk screw not come out because the tool broke....the internal allen always seems to round out long before the tool breaks.

I'll switch over to Torx bolts and review the installation/tightening procedure with the guys.
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Old 06-02-2018, 10:14 PM
  #38  
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Just a point to be made:

I'm a proponent of factory water pumps......big proponent. It's my belief that if no one in the aftermarket or no rebuilder had ever built or touched a 928 water pump, and the only thing available had been the "expensive" factory water pump, the 928 community, as a whole, would be hundreds of thousands of dollars ahead!

I've NEVER had to warranty or replace a low mileage factory water pump. I've NEVER even had to go in and replace a factory water pump before the belt was due to be changed!

On the contrary, I've replaced so many low mileage Laso, rebuilt, Geba pumps that I couldn't even begin to tell how many....literally hundreds and hundreds. If I'm redoing a timing belt job at 5-1,000 miles (super common), I will preemptively remove the "****" aftermarket/rebuilt water pump and install a factory pump, so the owner won't have to do this job again, in the near future!

The water pump that seized in this thread is a Laso....and by the looks of it, it hasn't been on this car for anywhere near 60,000+ miles. How much do you suppose it cost to replace this water pump?????
I can guarantee you that it cost more than the difference in cost between a Laso pump and a factory pump....a couple of times over!

And by the box it is sitting on, it appears that another Laso was installed....
What is that saying? Doing the same thing over and over again, expecting a different result, is the definition of insanity?

Choose wisely, people.

Install a factory water pump and forget about it!
Old 06-02-2018, 10:38 PM
  #39  
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"it appears that another Laso was installed.."

Its the one I got from you, here:

https://rennlist.com/forums/928-foru...95-models.html
https://rennlist.com/forums/928-foru...l#post13019492
Old 06-03-2018, 05:44 PM
  #40  
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Originally Posted by Speedtoys
"it appears that another Laso was installed.."

Its the one I got from you, here:

https://rennlist.com/forums/928-foru...95-models.html
https://rennlist.com/forums/928-foru...l#post13019492

Me also; I read the same thread linked above in Feb of 2016, and bought that nice looking Laso. I feel dirty.
Old 06-03-2018, 10:36 PM
  #41  
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Originally Posted by SteveG
Me also; I read the same thread linked above in Feb of 2016, and bought that nice looking Laso. I feel dirty.
I still stock and sell them, today.

No matter how great the factory pumps are, some people can't rationalize the price....and I completely understand, when a water pump costs 1/4 of the entire value of someone's car.

While the failure rate of a Laso is much higher than a factory pump, it is certainly not anywhere near 5%, which apparently is good enough odds, for many people.

Am I going to put one in a 20K rebuilt engine????

Not hardly.

And the newest "iteration" of the Laso pump has a plastic impeller, so if it does fail, at least the block will not be damaged.

I "draw the line" with the Geba pumps. Going back to a metal impeller, is crazy....even on a $5,000 car#

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Old 06-03-2018, 11:05 PM
  #42  
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I just replaced a factory 944 pump that had ~3K miles on it that had failed. It was installed by TRE so I know it was done right.

Anyway, the point is any of them can fail or last for a long time, (my 81 928's pump was original to the car with 160K miles and was still fine)

The factory one just happens to be the most reliable. At 3X the cost of the Laso last I looked it better be.
Old 06-03-2018, 11:23 PM
  #43  
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Well..I felt that if Greg's gonna run a sale on something, I dont have to think a lot about it...and I shouldn't have to.

Apparently I should have thought a lot about it.
Old 06-04-2018, 11:36 AM
  #44  
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Default Laso

I guess it's this statement that bothers me now:

Some people (including me) think that any one of those choices are bad...some far worse than another.
.

Price is almost always a factor when we make decisions.

More grist for the mill --

Erkka/Vilheur posted this in Sept 2016: https://rennlist.com/forums/928-foru...-models-5.html I believe it is the Laso that this vendor (Rose Passion) is selling -- priced at 283 Euros. Current exchange rate works out to about $325. I'm guessing $435 is about par as a markup. Hmmmm. "Wheels within wheels" is a 60s phrase to describe complicated forces at work, many variables. Guess I'll just take a shower.

Last edited by SteveG; 06-04-2018 at 12:17 PM.
Old 06-04-2018, 01:53 PM
  #45  
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I've been extremely vocal about aftermarket/Laso pumps....you guys would have to live in caves to not know I encourage people to use factory pumps, because of the higher failure rates of the non-factory pumps.

However, when Laso quit making the '87-'95 pumps, that left people with extremely poor alternatives, besides the factory pumps. Metal impellers and cheap Chinese bearings are not remotely a good choice.

A couple of machine operations can convert an early Laso to a '87-'95 version (it takes time and thus costs money to modify them....thus the price has to be higher....duh.)

All I did was provide people with an alternative.....
which I still do, to this day!

Not every 928 owner is going to buy a $1100 retail pump and a ~$450 Laso that fits us a hell of a better thing than a metal impeller or a inferior Chinese bearing.


There's a tremendous amount of humor in this thread....Jeff is bitching about a shop not knowing how/not having the ability to remove a high friction countersunk screw, yet not bitching about replacing an almost new looking Laso pump.

I, as other people did, assumed that the internal Allen had rounded out on this hardware, which is what normally occurs when people don't know how to get this style hardware out.

To drill or grind out perfectly good Allen Bolts is really sad...but certainly nothing I can cure or is with-in my control. Supplying these people with Torx hardware would not have solved their issue....short of me flying up there and having a "shop training exercise", their entire problem is beyond my control.

Bitching because the shop one picks to do a job doesn't have the proper tools/the proper knowledge to remove a piece of hardware has absolutely nothing to do with me or the quality of my product!

And Jeff....if they like the stock damper better...have them try to order one.

That statement, alone, shows what they know about 928's.....the stock damper has been NLA, for many years!


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