Looking for proper spec/profile for 617 turbo cam:

I have a 1985 w123 with strange power issue, more so in the lower speed range in the morning but always under powered.

Engine was rebuilt around 70 - 80K ago in 2000 by PO and has had a string of owners since with me around 6th or 7th. Compression is good and even (380 or better as i recall), i replaced injector nozzles and calibrated, new filters and tank screen, even swapped in a re-calibrated pump. Car will go 80+ MPH on the highway but suffers from poor mileage - 19 MPG combined or less. Prior to the IP swap the engine had more shake from 900 - 1400 rpm then it would smooth out a bit but never quite right, always seemed a little off.

The car is VERY slow to start in the morning at 40 degrees going up a medium grade hill - slow enough where i could walk/jog faster - my 116 with 160K does not suffer from whatever ails the 123. The only thing i feel could be the problem is the camshaft - maybe they used a poorly reground cam (#11). Last time i adjusted the valves - currently over due - the lobe(s) were worm unevenly to the point i got different results at the front or back of one or more cam lobes. As i recall 2 lobes were pitted on the face. Engine is not properly balanced, not too bad, but could be better with a little shake, its more the sound it makes or rather doesn't make, very mushy sounding and un-diesel like. Someone used the term "beeswax" and that fits.

I just read an article from a cam shop in Canada Camshaft Tech Tips - Colt Cams and they explained how cams were reground, correcting the shape of the lobe peak to establish original profile or custom per clients request. This got me thinking that for whatever reason the original engine was rebuilt - 85 123's had problems with the trap oxidizers where the trap and often turbo were replaced (heard stories of carbon from clogged up trap braking loose and damaging turbo blades causing engine damage, etc), run low on oil...whatever, maybe the cam was replaced or messed up. The engine is not original and who knows what was done.

thanks

chris

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1985 300D, 250k
1980 300SD, 180K

If it was Me I would look into getting Camshaft in good condition and the Bearing Towers at the Junk Yard.

Perhaps one of our Members has the Same and would be willing to sell it.

What type of condition are the Rocker Arms in? If not so good I would also get those.

2 other issues. What type of Degrees do you show when you line up the Camshaft Drive Gear and Bearing Tower timing marks.
I have read where people have done rebuilds and not replaced the Timing Chain or used that cheap Beck Arnley one (made in Japan).

Off Subject but when my Car was slow on the bottom end it was that the Linkages were not adjusted correctly.

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84 300D, 82 Volvo 244Gl Diesel

Diesel911 - Timing chain stretch: I did the cam tower mark line-up about 10k miles ago and i had 2 - 3 degrees. I did it twice to verify.

Beyond the pitting and measuring a difference at the lobe during valve adjustment, i don't believe i am qualified to make a judgement on the other components unless you can specify some type of test or measurement.

I do have digital calipers so if i know what a good cam spec's are i could compare to what i have and see it there is a measurement way out of whack.

Junk yard diving: Happy to go and dig around but might be difficult to assess quality or wear with my limited knowledge. Given i find a good candidate car how many miles will a cam hold its edge or "shape"

Towers and rocker arms - Again, sorry for my lack of knowledge but how would i assess wear or viability?

thanks

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1985 300D, 250k
1980 300SD, 180K

If you are weary of a junkyard cam, you can send it or your cam (provided it has enough meat on it) to Geoff Bardal at Colt Cams and he'll regrind it for you. He can also make you a performance grind if you like.

Here is some information of camshaft profiles from forum member Army.

http://www.peachparts.com/shopforum/diesel-discussion/290268-om617-non-turbo-cam-profile-specs-piston-height-specs-etc.html



.

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1983 123.133 California
- GreaseCar Veg System

Yep - the turbo cam has a higher lift so it will have a bit more of a pointy egg shape to it than the camshaft profile I measured.

If you look in the FSM chapter 05-215 in the non turbo and turbo sections you can see when the valves should open and close before or after TDC or BDC.

You can also see from that chapter that the camshafts are stamped on their back ends with identification numbers. If you are shopping for a camshaft in a scrap yard you might want to know what you are getting. For example for the turbo engine cam codes 00 and 08 were only used in the older 617.950 engine - you probably want a 05 camshaft - but you need to check that.

You might also find that since the FSM was translated / written there is a newer cam code for the turbo engine version available. There is a newer version for the non turbo that's not mentioned in the FSM...

To check for new cam codes you'll need to get onto to EPC (www.startekinfo.com)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Sounds alot like the bad ALDA I had. Car would barely move when floored in the cold. I removed it and the problem went away.

DeliveryValve - I have looked over Army's posting and gained a little knowledge also had a quick look at Colt Cams site but without a spec to measure current cam i think its shooting in the dark to send them mine.

Army - I do have the FSM and checked EPC for cam code, p/n is A 617 051 11 01. I currently have cam #11, FSM shows turbo cams with additional lift for intake at 10.0mm and 10.4 mm for exhaust. Would still be nice to ave the actual profile, especially the height of the lobe.

aaa - Morning slowness could be caused by what your describing - not sure if i had this prior to IP replacement - but still there is an underlying problem.

thanks for all the input,

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1985 300D, 250k
1980 300SD, 180K

Camshaft Measurements are most often done witha Dial Indicator and a Degree Wheel.
I do not know if the Crank Damper Degree marks with any sort of Timing Chain Stretch would be good enough for that.
Do the degree marks even go all the way around the Crank Dmper.

If you get a Camshaft from the same Engine Model a Visual Check should be enough. As you have noted with your own Camshaft you can actually see the issures it has.

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84 300D, 82 Volvo 244Gl Diesel

No the degree marks don't go all the round - also you've got chain stretch to contend with - and then the crank spins twice for each whole revolution on the camshaft so the error at the crank could be bigger.

I opted to use the teeth on the "camshaft cog" - it was all that I had. Like you say a degree wheel would be ideal... but it's a bit out of my budget at the moment. I was a bit bored when I made the measurements => looking for a bit of geek fun!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Send me a camshaft and I'll measure it!

Turbo camshafts are as common as rocking horse sh** over here.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Army - Thanks for the offer but the shipping costs would kill the deal

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1985 300D, 250k
1980 300SD, 180K

Yeah tell me about it - shipping costs can suck. However, if you know someone who has access to company discounts the costs can come down by huge amounts.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

How you come to this conclusion is a bit beyond the pale as I see it.

The camshaft lets air into the cylinder and exhaust out of the cylinder. That's it. If the camshaft is ground improperly, you might get insufficient air and the engine will smoke if it gets sufficient fuel.

Since it's not smoking (presumably), the camshaft is not the problem.

Since the engine has suffered all kinds of abuse from previous "mechanics", the question begs whether any of them ever set IP timing. Your symptoms are classic for retarded IP timing if the vehicle won't get up and go.

The other possibility is low fuel due to an ALDA that has not been adjusted in decades or the failure of the boost to get to the ALDA.

Have you checked boost pressure at the ALDA or checked boost pressure anywhere on the engine?

Brian - Thanks for your input. Maybe i should have stated i am not a mechanic but have FSM's and use these forums either by posing questions or reading other's post to resolve the issues at hand.

Check IP timing - so with 70K on a rebuilt engine do i still set at 24 degrees and check?

Smoke - Well it's not billowing smoke out the back, but has a more at startup and less as it warms up which i assume is due to more complete burn with increasing engine temp.

This is the order of tasks from when i bought the car:
* Replace all filters, tank screen and fuel hoses
* Change all fluids (engine, coolant, trans, diff, brake)
* Adjust valves and adjust timing - indy shop did this the first time - unable to resolve engine shake
* Install new engine mounts and both engine shocks
* Pop test injectors, replaced nozzles and calibrated by local shop
* Clean banjo bolt and line both sides of switch on firewall
* Adjust ALDA (original IP) in small increments of 1/4 turn - black plastic top cut-off previously, adjustment slot broken on side but turn-able with pliers did not make any noticeable change.
* Found another 85 IP, had local Bosch shop calibrate (not rebuild) installed by old-school mechanic whom i assume would have also set the timing - maybe he forgot or pump moved prior to tightening the nuts. Mistakes happen.

The replacement IP smoothing out the engine shake that was most noticeable between 900 - 1400 rpm but may have introduced other issues as when fall/winter set in i noticed the reduced power at startup. Also at this point the 123 was not my daily driver. I had bought a 116 1980 300SD - with the thought of driving one and working on the other....

Also i have noticed the center exhaust resonator is leaking due to rust holes or broken weld where i can place my hand over the tailpipe and completely stop any exhaust from passing through muffler. Obviously this needs attention probably first as it could restrict flow and add to my problems. Still the engine sounds mushy - non-diesel like.

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1985 300D, 250k
1980 300SD, 180K

You check it.

My suspicion is that it won't be anywhere near 24 BTDC.


You also check for boost at the ALDA. Do you have 12 psi under maximum load above 2800 rpm?