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This reminds me of my 1977 VW Scirocco and it's self destroying differential.
To save a little money they left off the circle clips on either end of a shaft, and so eventually it rubbed through the aluminum housing, letting the oil leak out.
I didn't think Porsche did the same type of cost cutting, or maybe it was just a materials selection mistake?
This reminds me of my 1977 VW Scirocco and it's self destroying differential.
To save a little money they left off the circle clips on either end of a shaft, and so eventually it rubbed through the aluminum housing, letting the oil leak out.
I didn't think Porsche did the same type of cost cutting, or maybe it was just a materials selection mistake?
Hello GT4 owners (especially the one’s who bought their car to take it to the track). I want to make this more clear and specific regarding these bolt replacements. First, all the pictures and information above speaks for it self, especially the pics & info from BGB who started this thread. I have known John Tecce since early 2009, he did this as a favor to me as I contacted him directly. I wanted his shop to do the job but they are 3 weeks behind and 1k miles away. So he agreed to supply me with the hardware to have my local and trusted mechanic do the swap. And so I could get back on the track with a whole lot less stress. My car was driven hard for 7k (track) of it’s first 20k miles and then I bought it. I have put another 5k miles on the car with about 600 of that on the track. This seemed like a no brainer and John agreed. His shop is the best place to get this done, bar none. My independent mechanic said he hopes he never has to do it again, “total pita” were his words with the engine in the car. If you have questions or concerns regarding your GT4, I highly recommend you call John or Wray at BGB. Thank you.
I'd like to play the role of devil's advocate so we can flush this out thoroughly.
As i understand it, the cam adjuster comes as a part with the bolts pre-installed from the factory, and the factory says to its field techs "don't replace the bolts, replace the entire assembly". And this cam adjuster is an aluminum part with aluminum seats for the stock aluminum bolts torqued in the factory only. So, if a Porsche tech can't even replace the stock boats aluminum bolts in the field, why is it a good idea to replace them in the field with steal bolts?
And I admit, I know very little about the engineering involved.
And, did not the Panamera suffer a similar problem? And, what is Porsche's fix for that?
I'd like to play the role of devil's advocate so we can flush this out thoroughly.
As i understand it, the cam adjuster comes as a part with the bolts pre-installed from the factory, and the factory says to its field techs "don't replace the bolts, replace the entire assembly". And this cam adjuster is an aluminum part with aluminum seats for the stock aluminum bolts torqued in the factory only. So, if a Porsche tech can't even replace the stock boats aluminum bolts in the field, why is it a good idea to replace them in the field with steal bolts?
And I admit, I know very little about the engineering involved.
And, did not the Panamera suffer a similar problem? And, what is Porsche's fix for that?
I've been through the same thought process - ok yet we make the bolts stronger - but then what is the next thing in the linkage that would break instead of these and what is the impact of that?
Well at least the bolt head(s) would not be in-jested may the adjuster itself breaks... but I don't know what that would look like.
Ref Panamera - yes - it also has been a fault on both these and Cayenne. I spoke to my specialist in the UK about this issue, and they have seen numbers of both of these cars and they also think that this is a good thing preventive thing to do.
Based on what I've seen in this thread, and read in other older RL threads about similar failures like the one that started this thread (there was at least 1 GT4 the cam adjuster bolts failed on fairly early on after GT4s were on the street), I'm making the proposition these failures are more so due to the OEM bolts coming loose and allowing "hammering" back-n-forth on the aluminum bolts causing them to fail. As RobC4sX51 posted, "one of the bolts was a couple turns loose" when his mechanic was doing the bolt replacement.
Just a theory at this point, that's why I referred to it as a proposition.
Same thing happened with the BMW s54 motors. Solution was upgraded bolts and loctite. In this case I wonder if it could be enough to simply loctite the OEM bolts but I suppose if you're in there anyway, might as well go steel....
Just a follow up as I was at Road America last weekend with my GT4. The car was spectacular and I felt total confidence in pushing it hard which I did. 3rd gear down shifts in many of the corners there is a must, even 2nd gear in Canada corner (now called MAGA corner btw) as you climb out of the lowest spot of the track (almost 200’ from the highest spot). So for me this was an expense that gave me some peace of mind. The pictures are a PPI DME and my DME after last weekend. You can see the car has 116 range 4 over revs from the original owner. None so far by me and I plan to keep it that way EVEN with the new steel bolts. The engine has nearly 3000 more hours on it since the last range 4. I have put just over 2200 hours on the car since I purchased it which also means it had nearly 800 hours since the last range 4 was put on it before I purchased this awesome track machine.
My car is in with my specialist getting 718 Intake system, Filters, Custom headers and tune, and we've decided to just get this done also. I didn't really want to drop the engine - but hopefully means that once it goes back in, it won't come out again for a failure.... only for a 4.5!
Do you think it's possible to diagnose this type of failure through the cam position sensor hole with a boroscope?
My 7800 mile GT4 went into limp mode and threw a bunch of bank 1 misfire and cam position sensor codes. Would not restart and had to be towed. There's now a loud clicking noise when cranking which I fear may be in the valvetrain.
05-11-2020, 07:37 AM
