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Discussion Starter #1 (Edited)
OK, so it's been established that I'm PlaneCrazy. And I have been thinking...

1. How different is the 2.9l OM602 from the OM617? I might be able to use the latter's fuel pump, but what about its cam shaft? This would be the cheapest performance mod I've ever done to my engine. Otherwise I'd have to risk profiling my cam shaft to have the OM602's timing... (65 kW/170 Nm to 74 kW/190 Nm without a turbo!). Intake and exhaust manifolds are not compatible, though. Maybe OM602 has a higher injection pressure? Some of the OM602-powered Sprinters had pure mechanical injection here - no "electricks", straight swop. What about the injectors themselves?

2. Maybe I could use the OM602's flywheel and damper too? I don't believe I can use the OM602's engine mount on OM617, or vice versa, not that I'd want to. (I have seen some W123s running the 290GD engine, but it just looks wrong. Goes like a train, though. I still wouldn't do that.) But the flywheel and damper for OM602 are more readily available than for OM617, here in Scrapyard Republic. I mean South Africa. I hypothesise that the flywheel will bolt straight onto OM617's crank shaft, but if there is sufficient difference in the harmonic response and inertia, I could snap the crank shaft right at the rear main bearing. (And, to really break the bank, how's about a dual mass flywheel?:D)
 

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Seems like a lot of fun but why not just do a 602 engine swap and then have the 5 speed 'box?

And with the reliability issues of a dual mass flywheels why would you choose to have one unless you're thinking of it being necessary for a DSG?
 

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Ok, yes, you are crazy... :D

But seriously now... Why do all that? Why not just drop in an OM602? Surely that would give u all the performance increases u need?
 

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Discussion Starter #6
Seems like a lot of fun but why not just do a 602 engine swap and then have the 5 speed 'box?
No thanks, I already mentioned that it doesn't look right. And there are other issues.

The dual-mass thing was sarcasm...
 

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Just in case you're being serious - direct shift gearbox

Direct-Shift Gearbox - Wikipedia, the free encyclopedia

I've been keeping an eye on the second hand prices for these things to see if a W123 mod could ever get close to being in budget. I think it would be quite a cool addition... it could even make the car better on fuel according to the blurb...
Pardon my ignorance, is that in my 1998 VW jetta TDI?
1.9L 66*kW (90*PS) I4 TDI (1Z/AHU)
 

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Discussion Starter #8
Just in case you're being serious - direct shift gearbox

I've been keeping an eye on the second hand prices for these things to see if a W123 mod could ever get close to being in budget. I think it would be quite a cool addition... it could even make the car better on fuel according to the blurb...
Why not just slap a 722.6 or a 7-G auto onto a 230E? Or a 2.9L OM602? Or a OM642 3.0L V6 turbodiesel?

Say "No" to auto's trying to be manual-ish, and "No" to manuals trying to be auto-ish!:mad::mad::mad: If you love driving, get a proper manual; if you hate driving, or can't drive, get a chauffeur!
 

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Why not just slap a 722.6 or a 7-G auto onto a 230E? Or a 2.9L OM602? Or a OM642 3.0L V6 turbodiesel?

Say "No" to auto's trying to be manual-ish, and "No" to manuals trying to be auto-ish!:mad::mad::mad: If you love driving, get a proper manual; if you hate driving, or can't drive, get a chauffeur!
I disagree with everything except the driver! There's no fun driving in this country anymore even at 5AM I can expect to sit in traffic. There's no such thing as the "freedom of the open road" here. The sooner computers take over the better! At least I'll still have fun fixing 'em.
 

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Discussion Starter #11
There's no fun driving in this country anymore even at 5AM I can expect to sit in traffic. There's no such thing as the "freedom of the open road" here.
Come visit South Africa sometime!:thumbsup: I'll take you on the roads less occupied.
 

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Come visit South Africa sometime!:thumbsup: I'll take you on the roads less occupied.
Well in principle I could just drive down and see you - now that would be a trip!
 

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Discussion Starter #13
How different is the 2.9l OM602 from the OM617? I might be able to use the latter's fuel pump, but what about its cam shaft? This would be the cheapest performance mod I've ever done to my engine. Otherwise I'd have to risk profiling my cam shaft to have the OM602's timing... (65 kW/170 Nm to 74 kW/190 Nm without a turbo!)
What is the possibility of finding a blank cam shaft for OM617? Or will I have to make a cam from scratch?
 

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What is the possibility of finding a blank cam shaft for OM617? Or will I have to make a cam from scratch?
I think you need to get in touch with a shop that specializes in this sort of stuff - I've only ever heard mention of blanks being for sale - no real evidence that they are actually available...


...what are your "from scratch" plans ideas?
 

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Discussion Starter #15
Take a 4130 chrome-moly solid round bar or something, and make the cam from that. A lot more expensive than starting with a blank might be, considering the waste material, the time etc.
 

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Take a 4130 chrome-moly solid round bar or something, and make the cam from that. A lot more expensive than starting with a blank might be, considering the waste material, the time etc.
Aren't most cams formed by some form of forging? I would have thought you'd want some nice grain flow around those lobes particularly at the root. You don't want shear forces winning the day - that could be expensive.

From the little I know about hardening - I'd be seeking advice on how to harden a chrome-moly alloy steel. That is almost certainly is a job for a professional. My understanding is that the insides of a cam shaft should be strong an yet resilient to shock whilst having hard surfaces on the outside.

It will be interesting to see what you come up with.
 

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Discussion Starter #17
Aren't most cams formed by some form of forging? I would have thought you'd want some nice grain flow around those lobes particularly at the root. You don't want shear forces winning the day - that could be expensive.
The blanks may be forged, but the profiles are always machined - it's the only way to ensure precise geometry and timing. The cam shaft may the be induction hardened or nitrocarburized on the cam surface, leaving the core tough and resilient.

4130 is aircraft-grade steel with excellent case-hardening qualities as well as incredible annealed (i.e. unhardened, untempered) mechanical properties. It is also rediculously expensive. It does machine easier than SSAB - Domex 550 W, which has similar mechanical properties but is a bitch to machine, IIRC. Then again it is possible that neither of these are available in large diameter solid round bars...

From the little I know about hardening - I'd be seeking advice on how to harden a chrome-moly alloy steel. That is almost certainly is a job for a professional. My understanding is that the insides of a cam shaft should be strong an yet resilient to shock whilst having hard surfaces on the outside.
That's the perk of working for a sailplane manufacturer - we employ said professionals! And next year, as part of my practical workshop training, I get to play along with them:D
 

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The blanks may be forged, but the profiles are always machined - it's the only way to ensure precise geometry and timing. The cam shaft may the be induction hardened or nitrocarburized on the cam surface, leaving the core tough and resilient.

4130 is aircraft-grade steel with excellent case-hardening qualities as well as incredible annealed (i.e. unhardened, untempered) mechanical properties. It is also rediculously expensive. It does machine easier than SSAB - Domex 550 W, which has similar mechanical properties but is a bitch to machine, IIRC. Then again it is possible that neither of these are available in large diameter solid round bars...



That's the perk of working for a sailplane manufacturer - we employ said professionals! And next year, as part of my practical workshop training, I get to play along with them:D
Wow well you are most certainly in the right place to make your own cam then.

I'm staying tuned!

Not that it will probably help that much but I have made some measurements of my non turbo cam here

OM617 (non turbo) cam profile specs, piston height specs etc - Page 2 - PeachParts Mercedes ShopForum

Yes I got a bit bored last year...
 
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