PSA - More Garbage Parts, this time Bosch

[Jonny042]

Cross post from my build thread, but I'm posting here as a PSA, plus would like to collect any wisdom from others if possible:

Well, add Bosch to the list......

The 2.7RS space cam (new from Bosch in 2017) has a Brinell hardness of 119.8 (Many thanks to Brookieslayer for the hardness testing). To put that in perspective that's less than what you'd expect from untreated mild steel. It didn't even register on the Rockwell C scale, and read 0.0.



Of course we tested a used original part, made in the good old days.... it tested to 30.3 on the Rockwell Scale and is appropriately hardened:



There is a visible ridge at the edge of the wear area on the 2.7RS space cam, and who knows what else is going on. I need to look for a pic from before I installed it.



The original one which probably has 100,000 miles on it:



So.... yeah. A lot of things are starting to make sense, including the fact that it seemed like the harder I tried to get the MFI to work well, the worse it got.

Today was day two of working with the 911T space cam and I feel like I'm making good progress. Although I'm back where I started A YEAR AGO!!!!!

[jpnovak]

That sucks...

[slow&rusty]

Wow...

[thsupernge]

A lot of Bosch is now made in China which I'm sure everyone knows. Certainly not the quality we were all used to seeing from them.

[jpnovak]

I guess once you get the replacement ground to your engine you should harden the surface.

[jjeffries]

Not diminishing the disgracefulness of Bosch selling this rather half-baked part, can it now be hardened through some metalurgical process, or is it simply made of duff metal?

John

[Jeff Higgins]

Are these surface hardened or through hardened? If they are the former, is there any reason they might harden the flyweight bearing surface differently than the stylus bearing surface? If it is through hardened, we would expect both surfaces to be the same hardness. You are, in the photos, measuring hardness on two different surfaces. Granted, this is a reach, but just looking for an explanation as to why these two surfaces might have different hardnesses.

[Jonny042]

Originally Posted by Jeff Higgins

Are these surface hardened or through hardened? If they are the former, is there any reason they might harden the flyweight bearing surface differently than the stylus bearing surface? If it is through hardened, we would expect both surfaces to be the same hardness. You are, in the photos, measuring hardness on two different surfaces. Granted, this is a reach, but just looking for an explanation as to why these two surfaces might have different hardnesses.

Good eye! - the pictures do show that, but we actually took readings immediately adjacent to the "map" area for this reason, in all a half dozen spots all around the various surfaces. All with exactly the same results.

The used 911T cam is uniformly hard throughout, and the new 2.7RS cam is consistently soft everywhere.

That ridge you see on the right side of the stylus map is a good 3 or 4 thousandths, it's hard to get an idea of where else on the cam is worn, and by how much, from use.

I do know that the AFR became more and more "jumpy" on the data logs for no apparent reason over time, and I seemingly went nowhere with the tuning. Even more frustrating was the fact that I couldn't get back to where I started by putting the settings back to my initial settings!!!!!

[Jonny042]

Originally Posted by jjeffries

Not diminishing the disgracefulness of Bosch selling this rather half-baked part, can it now be hardened through some metalurgical process, or is it simply made of duff metal?

John

I'm afraid it's been wrecked from use. Had I known I would have had it hardened before I started using it.

[Jonny042]

Originally Posted by jpnovak

I guess once you get the replacement ground to your engine you should harden the surface.

I think the 911T part would be hardened to a sufficient depth that the minor amount I may need to take off (maybe .005" at most) won't break through the hardening.

I'm not really up on my metallurgy, but google tells me that to achieve that sort of hardness it would have to be some sort of cast steel or tool steel, ground to profile, then hardened. Or possibly some sort of abrasion resistant steel but not sure how they would machine the profile into it.

I've ordered some diamond impregnated polishing burrs to see if I can slowly and accurately remove material once I decide where and how much....

[jjeffries]

Originally Posted by Jonny042

I'm afraid it's been wrecked from use. Had I known I would have had it hardened before I started using it.

Yes, apologies, now I see/understand that.

Ugh.

And I’m sure it was not inexpensive...

John

[Jonny042]

Originally Posted by jjeffries

Yes, apologies, now I see/understand that.

Ugh.

And I’m sure it was not inexpensive...

John

No worries!!!

Last I heard they were around $750.00. I bought direct from a European distributor but it wasn't much less from what I recall.

[smadsen]

Anyone remember the Brazilian Bosch coils from 10 years ago. Paid big money for a "original" Bosch replacement coil for the old SC. They all had a life of 2 weeks to two months. Every distributor in north America had a pallet of that crap they had to sell through.

Another example of a great name being monetized by new ownership for momentary gain.

[john walker's workshop]

Just returned a SR68X starter that the bendix didn't retract after cranking.

[Jonny042]

Originally Posted by smadsen

Anyone remember the Brazilian Bosch coils from 10 years ago. Paid big money for a "original" Bosch replacement coil for the old SC. They all had a life of 2 weeks to two months. Every distributor in north America had a pallet of that crap they had to sell through.

Another example of a great name being monetized by new ownership for momentary gain.

Let me guess - no return on electrical parts??

[Jonny042]

Originally Posted by john walker's workshop

Just returned a SR68X starter that the bendix didn't retract after cranking.

Let me guess - no way you can charge your client for the time wasted??

[75 911s]

Jonny, any of the old Mercedes space cams fall into RS territory? I wonder what Gus says on the subject.

[Jonny042]

Originally Posted by 75 911s

Jonny, any of the old Mercedes space cams fall into RS territory? I wonder what Gus says on the subject.

I try not to bother people if I'm not a customer..... and since I do my own pump rebuilds and built my own test rig, I'm definitely not.

Maybe I'll give him a call one day.

[75 911s]

Originally Posted by Jonny042

I try not to bother people if I'm not a customer..... and since I do my own pump rebuilds and built my own test rig, I'm definitely not.

Maybe I'll give him a call one day.

I "bother" everyone. Many times I become a customer because of that first phone call. I've spoken to Gus, and I've spoken with Mark Jung. I've also referred countless people to these Porsche specialty shops, even if I haven't personally used them. Some of these shops are backlogged years afaik so they aren't hurting for work, and they probably would enjoy talking with someone who actually knows MFI pumps inside and out like you do. You might be a customer if he has a good original RS space cam, which he probably does.

Thankfully we have Michael Burgess' MFI DIY guide too. I just feel like with a such a specialty subject, so much knowledge will be lost if we don't try to reach out and build relationships with some of these masters. I get not wanting to use them for their proprietary knowledge, but you still need to get a sense of who they are, the timelines it takes to do the specialty work, and how much it will cost.

I had forgotten you put MFI on your project. Your car is one of the best DIY builds on here. I wonder if webcams could make a billet version of the RS spacecam?

[Brookieslayer]

Originally Posted by Jonny042

I think the 911T part would be hardened to a sufficient depth that the minor amount I may need to take off (maybe .005" at most) won't break through the hardening.

I'm not really up on my metallurgy, but google tells me that to achieve that sort of hardness it would have to be some sort of cast steel or tool steel, ground to profile, then hardened. Or possibly some sort of abrasion resistant steel but not sure how they would machine the profile into it.

I've ordered some diamond impregnated polishing burrs to see if I can slowly and accurately remove material once I decide where and how much....

The material could also be some 4140 ( or other German chromium / molybdenum steel) that is heat treated correctly. It can reach a maximum of RC 56 or slightly higher, so 30 is easily attainable. The tempering after also makes it very tough too as it re-aligns the carbon atoms more uniformly in the material.

The 2.7 spacecam was likely not even made out of the correct material based on our measurements. If the material is wrong, you cannot get the final hardness anywhere near correct... there are some hardening surface treatments, but I think they would be difficult to apply in this case.

Your case hardening is likely .060" to .125" thick as a minimum, so no issue with the small amount of material you will remove.

just my .02