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Author Topic: Dan's 1.6 repairs  (Read 6949 times)
Grapes
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« Reply #75 on: July 19, 2021, 05:00:10 pm »

Simon doesn't have them, I checked. I might make something at some point.
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Grapes
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« Reply #76 on: July 20, 2021, 08:26:01 pm »

OK, new strange thing popped up today... My speedometer needle is jumping up and down and sometimes stops working. Any tips what I should look for?
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Anders Dinsen
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« Reply #77 on: July 21, 2021, 07:12:22 am »

OK, new strange thing popped up today... My speedometer needle is jumping up and down and sometimes stops working. Any tips what I should look for?

I'd check the speedometer cable. It goes from the speedometer to the left front wheel through the front compartment. The cable could be broken, if so most likely around the place where it is attached to the wheel hub. Inspect it carefully. The attachment to the speedometer itself can be checked by reaching up with your hand behind the instrument cluster from below. It might have undone itself from the speedometer. If so, push it gently onto the speedometer until the cable latches onto the speedometer.

/Anders
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1982 Talbot Matra Murena 2.2 prep 142
2001 Renault Matra Grand Espace "The Race" V6 24v
2017 BMW i3 "Charged Professional" 94Ah
Grapes
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« Reply #78 on: July 21, 2021, 11:12:59 am »

I have been messing with the cables of the radio and its one big mess behind the dash so it wouldn't surprise me if I accidentally dislodged it. Fingers crossed 🤞
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Grapes
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« Reply #79 on: July 22, 2021, 05:18:18 pm »

So I finally got around to doing a compression test and it's looking pretty grim I guess? it's more less 8 kilo Pascal across all cylinders with 1 cylinder maybe around 8.5 and first one from the rights may be around 7.9. It's really hard to read out kilopascals on the compression tester that I had.
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JL
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« Reply #80 on: July 22, 2021, 07:31:20 pm »

Are you sure that you are reading kilopascal, 1kpa = 0.145psi? If were Bar then 8bar = 112psi - not great but at least the readings are reasonably even and the engine would run.
Cheers
John
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Grapes
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« Reply #81 on: July 22, 2021, 09:01:37 pm »

In psi I think it was about 120 for the good ones and 110 for the worse one. Could that be correct?

Two of the spark plugs were pretty black as well and replaced all of them and I'm going to check again in about a week to see if it gets black again.

On top of that the rubber seals that are around the spark plugs that I assume prevent dirt from falling through are completely eroded so will need replacement as well.

But yeah the engine runs, probably far from optimal though.
« Last Edit: July 22, 2021, 09:08:13 pm by Grapes » Logged
Anders Dinsen
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« Reply #82 on: July 22, 2021, 10:39:46 pm »

I'd like to see a photo of the spark plugs. It is normal for the plugs to turn black over time on carburetted engines. We have gotten so used to fuel injected engines with O2 sensors that we expect plugs to stay the same colour through their life.

Also, I find it odd that you get more or less the same reading for the compression test on all four cylinders. Are you sure your meter is good?

/Anders
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1982 Talbot Matra Murena 2.2 prep 142
2001 Renault Matra Grand Espace "The Race" V6 24v
2017 BMW i3 "Charged Professional" 94Ah
JL
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« Reply #83 on: July 23, 2021, 08:03:44 am »

When you are taking the compression readings have you taken all of the plugs out of the head and is the battery good enough to crank the engine over at a decent speed?
Cheers
John
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Grapes
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« Reply #84 on: July 23, 2021, 12:10:14 pm »

Two plugs where the regular "black" and two where covered in sooth Wink Will make the picture later.
I wasn't sure how to do the compression test so I did the following steps:
1. Warmed up the engine.
2. disconnected the main lead to the distributor.
3. disconnected the plug on the first cylinder to the right
4. took the plug out
5. attached the meter
6. cranked until the needle stopped moving
7. put a new plug in
8. put the lead back on (I didn't want to mess up the order so I did them one at a time)
9. repeat steps 3 to 8 working my way right to left.

I threw out the broken rings from 3 of the 4 plug holes since they where well... broken...
It did surprise and slightly relief me that the reading across all cylinders are roughly the same. The one on the right is definitely worse than the one on the left and the two in the middle where more or less equal to each other. I written it down as (right to left) 7.9   8.0   8.2  and  8.4
The meter was fine according to my friend who used it on his bike previously. It wasn't one of the most high tech ones though. They all seem to come from the same Chinese factory... Mine was broken unfortunately :/

@John
I did not take all plugs out at once (I wasn't sure that was needed and didn't want to risk putting them back in the wrong hole)
I'm not sure if the battery is good enough to crank the engine over at a decent speed. I haven't driven this car much since I got it last summer and it has been in repairs since Septembre or something. I figured if it starts and doesn't drain the battery if I don't drive it for a week or two by itself it should be fine.
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JL
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« Reply #85 on: July 23, 2021, 02:15:08 pm »

To get a better idea of the compression, remove all of the plugs before you spin the engine over and have the carburettor fully open and no choke - this should give you better readings.
Cheers
John
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Grapes
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« Reply #86 on: August 05, 2021, 04:54:34 pm »

Unfortunately I haven't had a chance to test the compression yet with the new instruction where I'm supposed to remove all the plugs yet.
However in the mean time there's another issue I'd like to start giving some attention.
I recently noticed my car hangs ever so slightly towards the driver's side (it's almost like the 40 years of carrying just the driver on one side have caused this).
I never really noticed this myself until someone pointed it out. Another thing I noticed is that it's drifting slightly off to the drivers side as well and I wonder if it might be related. If so I guess I need to fix the hang first before I fix the alignment. I already checked with a local shop but they told me they can't align it because the computer doesn't know the car (frustratingly enough I did notice several older cars like the Renault Dauphine in the list) so I also wonder how I'm going to fix that  Huh
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Grapes
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« Reply #87 on: August 06, 2021, 09:52:52 am »

Just had a bit of Googling around and I wonder if the only solution is to use the old school play with measuring tape and pieces of string... Or will it be possible to give the right dimensions to a shop so they can put that into the computer to perform the alignment?
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GP
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« Reply #88 on: August 06, 2021, 10:45:33 pm »

Err there is not that much a Computer can do to help you with alignment on a standard Murena really.....
Only thing you can easily adjust is the "Toe in and Toe out" of the front wheels with the track rods. Never been near a computer for this myself, most tyre fitting shops in the U.K. have a portable alignment gauge that they do this with.  
The other item on the front that is adjustable is the "Camber" which you adjust by adding or removing the "Camber Shims" between the upper suspension arm bracket assembly. Castor is fixed.
There is absolutely nothing that can be adjusted on the rear of the car except tyre pressure!
As for the front ride height, this can easily be taken up and down by the nut on the end of the lever which goes to the spline on the end of the Torsion bar part of the front suspension. Measure this with a Tape Measure from the ground to the lower edge of the front wing above the wheel and make adjustments accordingly.
The rear ride height on a standard Murena is non-adjustable. If you want to adjust the rear ride height you would have to invest in new Coil Over Shock Absorbers with Adjustable Spring Platforms.
I suspect though that you just have worn dampers front and rear and that the rear springs have all sunk with age?
You would replace both sides of the car for this as standard practice.
Cheers, Graham

P.S. Read this from Roy's Website:-

http://www.matraclub.org.uk/files/Susp_Strg.pdf
« Last Edit: August 06, 2021, 10:56:17 pm by GP » Logged
roy4matra
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« Reply #89 on: August 07, 2021, 03:47:06 pm »

Err there is not that much a Computer can do to help you with alignment on a standard Murena really.....
Only thing you can easily adjust is the "Toe in and Toe out" of the front wheels with the track rods. Never been near a computer for this myself, most tyre fitting shops in the U.K. have a portable alignment gauge that they do this with.  
The other item on the front that is adjustable is the "Camber" which you adjust by adding or removing the "Camber Shims" between the upper suspension arm bracket assembly. Castor is fixed.

Actually that is not true Graham.  The castor can be adjusted too, because if you take out or add more shims to the front or rear top wishbone fastening then it will move the top ball joint forwards or backwards and therefore adjust the castor angle!  Actually it is not just the number of shims, since there are three different thicknesses of shims, so it it the total thickness that is important.  You must take out (or add) the same thickness of shims at the front and back fastening of the top wishbone if you want to adjust the camber and not disturb the castor.

Quote
There is absolutely nothing that can be adjusted on the rear of the car except tyre pressure!

Correct, but the rear tracking should always be checked because if something is bent or worn it could be incorrect.
 
Quote
As for the front ride height, this can easily be taken up and down by the nut on the end of the lever which goes to the spline on the end of the Torsion bar part of the front suspension. Measure this with a Tape Measure from the ground to the lower edge of the front wing above the wheel and make adjustments accordingly.

Correct the front ride height can be adjusted up or down normally... but in this case I'm very much doubtful he will ever get anything satisfactory, as I've already explained to him owing to the wheel and tyres that have been fitted previously.  So that you can see the problem, these are what are fitted to his 1.6 Murena:

Front: 205/45ZR16 tyres on 7.5Jx16 wheels
Rear:  225/40ZR16 tyres on 9.0Jx16 wheels

These may look good cosmetically, put they are really too big for a Murena, particularly a 1.6 which doesn't have as much power or cornering potential, and I wouldn't want to drive or corner fast on them without a lot of careful testing, as they have altered the carefully designed Matra set up outside the correct parameters.

Now I did a calculation on these and the front is riding 16mm higher than the rear!  So the car has a 'nose up' stance which is bad for aerodynamics as well as upsetting all the carefully designed suspension set up done by Matra Automobiles to produce a superb handling car.

His front tyres will raise the front ride height compared to the original Murena 1.6 175/70HR13 tyres by 8 mm.  They would also be much closer to the front wheel arch and therefore there will be a more limited amount you can lower the front on the torsion bar setting.  Since the wheels are 7.5" wide, which are strictly a little too wide for 205 width tyres, I suspect the offset is incorrect with more to the outside also altering the contact patch centre of the tyres and again generally upsetting the way the car was designed.

His rear tyres will lower the rear ride height compared to the original Murena 1.6 195/70HR13 tyres by 8 mm.  Again the wheels are much too wide for those 225 width tyres, and certainly the offset must be incorrect otherwise the inside edges would foul the semi-trailing arms.  The front tyres could have been put on 6.5" and the rear tyres on 7" wide rims.  The greater offset will put a torque twist on the bearings and therefore the hubs and semi-trailing arms, as the contact patch is again outside of the original design spec.

Quote
The rear ride height on a standard Murena is non-adjustable. If you want to adjust the rear ride height you would have to invest in new Coil Over Shock Absorbers with Adjustable Spring Platforms.
I suspect though that you just have worn dampers front and rear and that the rear springs have all sunk with age?
You would replace both sides of the car for this as standard practice.
Cheers, Graham

P.S. Read the article from Roy's Website (as stated in my posting)

To sum up, I'm sorry but you simply can't truly diagnose any faults with this cars suspension with those inappropriate wheels and tyres!  Ideally you would put a set of original wheels and tyres on it first, whether that is the 70 profiles on 13" steel wheels or the 60 profile tyres on the 14" alloys, but if you use a set of alloys with 60 profile tyres, then you need to lower the front torsion bar setting to allow for the fact that even those 195/60HR14  rear tyres lowered the rear ride height and produced an incorrect front to rear ride height, which Matra forgot to allow for!  This is all explained in my article, where I strongly recommend using 55 profile 14" tyres on the front to bring the ride heights back to the original design specification.

A final point is that the Murena appears to have been designed to suit French roads with their, at times, heavily cambered surfaces.  In the U.K. where we drive on the left and any road camber is the opposite of French roads, I found when my car was brand new, that it would drift slowly into the kerb if you didn't pay attention to keep it straight.  So working in the trade with access to all the right equipment, I double checked all the suspension was correctly set as per the design spec.  It was, so I live with that slight drift.  However, whenever I took the car to France, which I have done now on various occasions, I found that the car tracks perfectly straight and I can take my hands off the wheel, even at 130 kph, and it runs perfectly straight!

Roy
P.S. as for the garage that can't do any checks because 'the computer doesn't know the car', that just proves how pathetic some mechanics and their understanding is now - if a computer can't tell them, then they have no idea!  Rubbish!  Even if I didn't have the actual spec. for any vehicle, I could still check it out fully, see what readings I got, and know if it was about right or something was patently wrong.
« Last Edit: August 10, 2021, 12:33:31 am by roy4matra » Logged

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