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16 Videos on Bore Scoring! - Really Jake Raby?


Peter M
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I knew Jake Raby likes the sound of his own voice but this is ridiculous! 

16 videos and  3 hours on this topic and I suspect he still doesn't get to the root cause if any of his earlier IMS presentations are an indication.

Sure I acknowledge he's done (or lucked on?) some good stuff like the IMS Solution and has probably pulled down more 996/Early 997 engines than anyone but I worry if he can't describe the problem and solution in one video, does he really know? 

Anyway, some more stuff for you early water cooled guys to fret over I guess~

https://www.youtube.com/channel/UCvIKNFbE_iWnpFFh9qy9ZvA

through to:

 

 

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Yes, I don't like the fear mongering that seems to be inherent in their marketing.  For example, if you don't use Driven oil and use their targeted (TM, patent pending no doubt) oil analysis bullshit you're going to regret it type tone (Yes, I've only made it to Part 3A where we meet some oil expert with a wacky name who looks like a meth head trying to tell us that 0.000008% is "significant".  Sorry I may have got the number of zeros mixed up but it was a lot and all on the right hand side of the decimal point.)

At this point I've wandered off looking for some facts on iron piston coatings and found the US Mahle Motorsport "tech" talks good.  Even found out how to say "Mahhlee" correctly!

Also, why's do you guys call this "bore scoring" when it's really piston galling from what I can see? 

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3 hours ago, Peter M said:

Also, why's do you guys call this "bore scoring" when it's really piston galling from what I can see? 

Because piston galling (as I remember it) isn't really the whole story. The piston skirt "coating" whether it's metallic (iron in the early engines) or plastic is a lot softer than the Alusil coating on M96 bores. So it should not scrape the bores as deeply as shown in the vids. Raby may be a self serving businessman but he (and Barry Hart @ Hartech in the UK) have been trying to interpret this problem for 10-15 years...…..

Bore scoring  and ovality is far more prevalent in the UK and USA on 3.4 Caymans, 3.6 / 3.8 M96 /97 engines than here in Australia - why is a conundrum.... 

Personally, I would never buy an ex UK car with one of these engines. 

 

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2 hours ago, dan_189 said:

….we should be thankful for resources like this.

Yes, I am thankful but expect more rigour from someone who is trying to sell me something.

He has certainly done some good stuff and the IMS solution is an example of this.

I would expect anyone who is "waging war on bore scoring" to have a clearer idea on why occurs in the first place, rather than some wishy washy explanation that it could happen for various reasons and the only sure way to rectify it is to join the queue, wait possibly a year and have him install Nikasil'ed wet liners and new pistons.

When he discovered that the bores of the 3.8 had just started to score in the stroke range of the oil control rings but the pistons had not lost their ferrosan costings, you could hear his excitement in his discovery.  But to my dismay he didn't spend any video time investigating the cause even though he had wasted time previously on some pretty banal chat in the earlier videos.  Surely that was worth a detailed inspection of the oil rings and some measurements?

Also some more chat about why No.6 seems to be the most common victim would have been good.

I certainly learn a few things:

  • Bore galling does not effect the early Boxsters with cast pistons.  (He didn't elaborate why which I thought was odd unlike his lengthly explanations about the Mezger's.)
  • Didn't know the second ring on M96 & 97 engines are pinned like a 2 Stroke engine primarily to minimise likelihood of smokey startups
  • Opened my eyes to the possible contribution of oil dilution from leaking injectors (I still think of 996's as modern cars but he is right that the early ones have injectors that are 24 years old now.)
  • Austausch stamping on replacement blocks

Some of what he said made me cringe:

  • "Special oil that doesn't soak up the bad stuff"
  • High Si and Al in the UOA is a sure sign of bore scoring.  (It actually could also mean your air filter is ineffective.)
  • The fuel discussion

Surely galling can only occur if the ferrosan coating is lost.  How can that coating be damaged?  Too tight piston/cylinder clearance is some running situations that seem to be strongly related to extreme cold ambience conditions?  Damage intitiated from the oil control rings? That would be a surprise given how little tension they generally have.

I admit he has mellowed and not as fear mongering as he used to be.

I appreciated his comment in the "preventative" video: "...there is only so much you can do.."

 

This is an example of how I think a tech video should be and very relevant to the above :

 

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