where has my acceleration gone

V

vin-kohler

Member
Hi, gentlemen.

My previous thread was from Aug.17 till Aug. 25 2012 and concerned "engine failing when hot". (2000TC)
Considering quite a few additional items that had to be fixed vs. my creaky joints I entrusted the Lady to a highly recommended expert. (Unfornunately his workshop is 160 miles to go to.)
Friday last the car was ready to be picked up. (No joke!)
He says he fixed: Compression, valve clearance, spark plugs, carb tuning. And he installed a 'Powersparc' electronic ignition (red arm!) and coil.
On my way home the drama unfolded. On level parts of the autobahn I kept my usual 85 mph, however the acceleration is terrrible and inclines that I know well had to be done in a gear lower than before (manual gearbox). Engine start and idle are satisfactory. The fuel figure which was normally well above 28 mpg went to 23 mpg.
Upon my mail he recommended I should advance the static timing from 6º to 12º. Should THAT really be the answer against a DRAMATIC loss of power ??
I havn't got around to do any tinkering yet, I only checked that the line to the vacuum advance is connected, didn't do the sucking check though. My next thought was fuel starvation. But then I would expect a more sudden powerloss, yet the car rather feels like beeing grossly underpowered.

Your suggestions are appreciated
Vin Kohler

EDIT: One thing that puzzles me much: The MOT which was done 3 days before the car was returned to me says:
CO allowed 3.00 %, CO measured 0.004 %. Is that not peculiar ?
 
You may not be in a position to do it, (hence why you had to get someone else to do all the work for you) but I would say check everything again starting from the very beginning, paying particular attention to all of the things that your "highly recommended expert" has done.
I'd say 12 degrees BTDC would be far too advanced.
 
Just a thought (maybe totally wrong!), the list of repairs would mean the camshaft has been removed.

I'm wondering if the camshaft timing has somehow been wrongly set/lost. :?:
 
A above, the problem could be one or more of a number of things. Some things that spring to mind:-

1. From the symptoms you describe, I would always suspect ignition/timing problems first. You could check to see what type of spark plugs he fitted and that gaps are set correctly (0.025 inches).

2. Can you find out the make & model of electronic ignition and coil fitted - to make sure they are the correct type for you car?

3. Do you have a strobe lamp to check the timing - I believe 6 degrees BTDC at 650rpm is correct on a 2000TC? If you can attach a timing light and rev the engine, this should confirm that the advance system is basically working.

4. You could check the valve clearances as they may not have been set up correctly?

I would check all the basic valve and ignition timing is OK before looking at the carb's. The problem could be poorly balance carbs which you could check by listening to them with the air filter removed using a piece of hose to get a rough indication of balance.

Apart from the loss of power and increased fuel consumption, is there any other symptoms, like pinking (knocking) when you try to accelerate?
 
SUCCESS
I'll walk along your posts.

Harvey, yes indeed, my trust in experts has vaporised and reluctantly I remembered that 35 years ago I quite successfully attended to my 2000TC.
So I did what I had intended to avoid: Got my tools in the ready.
I started on the easiest and most suspected item - the ignition.
And there it was: Ignition timing 1º AFTER TDC.
Changed it to 6º before TDC.
With a strobe light assured that the centrifugal advance was operative.
Assumed that the vacuum advance is ok as the distributer is a new
'D7-Powerspark 25D Electronic Distributor'.
Inspected the spark plugs: # 1+2 sooty, # 3+4 gray.
Leaned front carby.
Adjusted idle rpm.
Went for a 20 mile drive.

I'm inclined to say that when accelerating the g-forces were considerable.

That covers or eliminates the points made by Dave and IVY. And fortunately also that horrible suggestion by Darth.

Next will be to acquire a second Colortune to work on the carby setup. When that is done or fails I call again.

And as yesterday was my 74th lets have a little puzzle:
An oldtimer climbs a 1-mile slope with 15 mph. Then a 1-mile downhill grade lies ahead. How fast must he go to cover these 2 miles with an average speed of 30 mph?

Enjoy the weekend and thank you for your compassion.

Vin Kohler
 
I'm glad that you got the car sorted, and am REALLY glad my theory was wrong. :D


vin-kohler said:
And as yesterday was my 74th lets have a little puzzle:
An oldtimer climbs a 1-mile slope with 15 mph. Then a 1-mile downhill grade lies ahead. How fast must he go to cover these 2 miles with an average speed of 30 mph?
Click to expand...

The old timer does the 1 mile climb in (1/15) of an hour, which is 4 minutes by my reckoning.

To cover the 2 miles @ an average of 30mph would require him to cover the 2 miles in (2/30) hours, but 2/30 hours = 1/15 hours = 4 minutes... but that's the time taken for him to do the first mile, therefore he'd have to do the last mile in zero seconds (i.e cover the last mile at infinite speed)

In other words, it's an impossibility; he can't physically do it!
 
And as yesterday was my 74th lets have a little puzzle:
An oldtimer climbs a 1-mile slope with 15 mph. Then a 1-mile downhill grade lies ahead. How fast must he go to cover these 2 miles with an average speed of 30 mph?
Click to expand...

I don't think the distances matter - it's only the speed:-

Average Speed = (S1 + S2)/2
We know Average Speed = 30mph & S1 = 15mph.
S2 is the speed on the downhill part of the journey.
So,
30 = (15 + S2)/2
15 + S2 = 60
S2 = 60 - 15
S2 = 45mph :?:

Glad you have made some progress with your car Vin and hope setting up the carb's does the trick.
 
Sorry, IVY, but I fully agree with Darth's solution. To cover these 2 miles with an average speed of 30 mph takes 4 min. But these 4 min have already been used up during the climb. There is no time left. Only an instantaneous teleportation can now help.

Vin
 
JVY said:
I don't think the distances matter - it's only the speed:-

Average Speed = (S1 + S2)/2
We know Average Speed = 30mph & S1 = 15mph.
S2 is the speed on the downhill part of the journey.
So,
30 = (15 + S2)/2
15 + S2 = 60
S2 = 60 - 15
S2 = 45mph :?:
Click to expand...

Just for academic interest: Let's assume the man actually does 45mph on the way down.

Therefore he takes (1/45) of an hour which is (4/3) minutes (i.e. 1 minute 20 seconds) to cover the last mile

The whole 2 miles is covered in (4 + 4/3) minutes = (16/3) minutes

So, the average speed would be 2 miles in (16/3) minutes, or [2/(16/3)] miles per minute, which becomes a more aesthetically pleasing (3/8) miles per minute, or ([3/8] x 60) miles per hour = 22.5mph

Travelling down the last mile @ 45mph results in an average speed of 22.5mph
 
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