Advice on a rebuilt 617a please
 

Hello from the UK,

I have only just found this forum but the wealth of information has had me reading for hours!
I have not (yet) found the information I am looking for and hope someone will be able to advise.

Recently I have had the 617a in my G-wagen completely rebuilt, this did not go without a hitch though.
Engine came back and was fitted to the car, it was then found the timing was way out. Pump off and back the rebuilers. Pump back on and it wont idle at all, pump off etc... new governor fitted. This pump was alledgely overhauled..
Now the car is back at the rebuilders with a leaking injector (proper leak!)

Now to my question: the engine seems very low on power, in fact if the turbo isnt up and spooling it will hardly move at all. It has now done all of 200 miles since the rebuild including 2 days of offroading.
Having read up on the ALDA adjustment I got excited at the prospect of my g accelerating.
However, should the ALDA need adjusting on a rebuilt engine or am I looking at other problems which the rebuilders should adress while it is there?
There is zero smoke even going uphill in the 2.5 tonne G

One interesting event happened 50 miles after the rebuid, I was gently chugging along at 55mph which is about 2500 revs when the engine suddenly held back, an huge cloud of grey smoke belched from the exhaust, car then surged forward and seemed to be fine since?
Related?

I do thank you for reading this far and look forward to your opinions.
This engine is very rare in the UK (less than 10 I would imagine) so it is hard to get info over here.

Thank you and regards

G.

It can. How was it performing prior to the rebuild? If it was doing the same thing then it does sould like an ALDA issue. BUT I would be VERY concerned if an engine came back to me from rebuild and the timing was WAY out:eek:.

Welcome to the forum!
 

Your description sounds like there might not be any boost getting to the alda. I would check the line that goes from the back of the intake manifold to the overboost switch and from there to the alda for connections and/or obstructions.

Are you getting good power after the turbo spools up to about 2K rpms?

How about an underhood picture? I thought right hand drive G's couldn't be turbo'd due to the steering mechanism being in the way.
Does it have new fuel filters installed?

good advice. it also could be cracked.

tom w

Thank you for the replies, much appreciated!

I have attached some pictures of the engine in situ, sorry about the mud:D

I can't really compare performance before and after rebuild because the original engine I had put in turned out to be very worn, hence the rebuild.

All filters have been replaced at the rebuild, 200 miles ago.

Once the turbo has spooled up it is ok, but sooo slow to get there

I will check the ALDA line but would imagine that would be new or am I hoping for too much.
I noticed that I haven't got the overboostprotection valve, is that a problem?

Whilst looking at it today I also noticed that the wastgate(?) where it bolts onto the manifold has a metal plate fitted between the wastgate and manifold blanking it off??

Putting this engine in a Righthanddrive hasn't been a problem, see pics.

Oh, it will now not switch off anymore:mad:

I am not mechanically inclined at all (being a simple country veterinarian) but would like to learn as much as possible so that the rebuild company can't just tell me anything!

should they be able to check if the alda is working correctly and that the engine is making the power it should?
What questions should I ask them?

And lastly, why would you be VERY worried if they got the IP-timing wrong?? Thats got me worried now.

Thanks again for all your time

Best regards

G.

I took this to mean that the boost signal is getting to the injection pump without any issues.

That is the egr valve. Don't worry about the plate at that location.

In your second pic note the black plastic round cap. Take a pair of dykes and cut the metal from around the plastic cap and remove it along with the cap. This is your ALDA adjustment. Loosen the locknut that you will see around the adjustment screw and turn the screw in 1/2 turn. Lock the lock nut back down and test drive the vehicle. Continue doing this until you get more improved acceleration off the line. Only adjust it about 1/2 turn at a time. I'm going to assume that your wastegate (at the turbo) is operative. You do not have the overboost protection SO when making adjustment to the ALDA I would try to have a boost gauge hooked up to either make sure the wastegate is operative OR that you are not exceeding 13 psi of boost pressure.

If they did not know or take the time to figure out how to properly set the IP timing then I wonder what else they did that was not "by the book" - i.e., measuring/replacing head bolts, connecting rod bolts, and clearance between the pistons and sleeves, etc....

Thank you for your detailed reply.
I see where you are coming from with the 'worried part' I am also worried now. I am now in negotiation with the rebuilders for an extended warranty on this engine as I only do about 2000 miles a year if that.

I will certainly do the ALDA adjustment as per your instructions, or more precisely: have it done by a trusted mechanic.

Would you recommend having the overboost protection fitted and if so where could I cource one from. The turbo has been rebuilt as well to be on the safe side:rolleyes: as has the gearbox/radiator/oilcooler/starter/alternator............

The rebuild shop is picking the G up tomorrow as I flatly refused to drive it to them with a leaking injector. To say I have lost confidence in them would be putting it mildly and these guys are the TOP Mercedes rebuilders in the UK.

I suppose what I am really looking for is more low down torque which is usefull offroad.

Thanks again

G.

Just a quick update on the rebuilt 617a in my G-wagen, it is now back at home and is a completely different car, it now feels like a rocket!:D

They changed the faulty injector, took the pump of YET again and it turned out that the maximul fuel adjustment (?) wasn't set up right.
It now smoothly picks up power and when the turbo comes in, yihaaa
Just a shame my clutch has now decided it can't be doing with all this power and slips a bit when the turbo kicks in, which is odd as it is the right clutch for this engine:confused:

Thanks again for all your help and advice

best regards

G.

Thanks for the follow up.

What are you fishing for in that pic with the guy laying on the hood?

Aah yes, the winch controls are mounted on the winch itself and we were trying to get it out of freespool and into gear. Managed that and then the winchrope snapped:eek:

G.

OK, getting fedup with this now:mad:

Yes, car goes like a rocket now, brilliant BUT it is so difficult to start now!
Could this be something to do with the IP-adjustments carried out by the rebuilders? I have to turn the coldstart knob on the dash right up to maximum and play with the gaspedal just to get it started and ticking over, after a few minutes it idles fine if a bit smokey which it never was before. Then it revs up on its own till I turn the coldstart knob down again

Temperature here in the UK about 7 degrees C

Glowplugs are new (or so they tell me:confused: )
Where to look first?

All advice greatfully recieved

Thank you for your time

Regards

G.

With a cold start knob, I'm not exactly sure how it is set up. Is this like a manual idle adjustment for colder weather?

Some suspicions I can think of is glow plug system or the rack dampner screw adjustment. Are you allowing it to go through a complete glow cycle until you hear the relay trip? If you pull the plug from the relay, you can check the resistance of the glow plugs to ground with a meter and they should be about 1 ohm. Also physically check the 80 amp metal strip fuse inside the relay housing. (Sometimes it can "look" good but end up having a hairline crack.) For the rack dampner screw, unscrew it about 1/2 to a full turn and see if there is any improvement. (Screw with a locknut, located on the firewall end of the injection pump.)