Rear trailing arms... 2.2 vs. 1.6

[Waldo]

Hi,

I have worked on the drive shafts for my HDI conversion today...

Seems like I have very limited space between my gearbox and trailing arm.

I know that the trailing arms on the 2.2 are different from my 1.6... the rear wheels are 20mm further apart, and depending on how my project works, the 10mm might be exactly what I'm looking for!

Does anyone have more information about the difference between the 1.6 and 2.2, mainly in regards to the trailing arms but also in general?
A picture of the two different trailing arms would be spot on 

Also, if you would happen to have a set of trailing arms for a 2.2 I know someone who could be interested in buying 

[Anders Dinsen]

On the gearbox side, the 5th gear housing is only some 5 mm from the trailing arm on the 2.2. On the engine side, it's primarily the oil pan that is sitting close. So the wider arms are certainly necessary on the 2.2. I'm pretty sure Matra didn't plan to have different trailing arms for the two cars, but the 2.2 had a difficult start as it wasn't the engine of choice initially. The original idea was to use the shorter Douvrin 4 cylinder engine which later showed up in the Espace, and I think that could have easily slideed in between the suspension components of the 1.6.

The chassis mount points for the trialing arms are identical on the 1.6 and the 2.2. The differences in the two chassis types are elsewhere, and are minor. So I don't think you would have any problem fitting 2.2 arms on your 1.6 chassis, but you would have to upgrade the brake discs to 2.2 as the calipers are fitted further out from the hub on the 2.2 to accomodate the larger discs. Strut and anti roll bar fixings could also have been used.

Is your power pack really that wide?

- Anders

[Waldo]

Hi Anders,

Thanks for the info...

Yes I'm more than close on the gearbox side... 5th gear is actually above the trailing arm, and I think the arm might hit the gearbox when the spring is compressed...

I will take a few pictures tomorrow.

I have found a breakers yard in Germany that are supposed to have a 2.2 sitting around.
Asking price: 600 Euro... Anyone needs any other parts (engine, gearbox etc.)
Though the trailing arms should be in a bad condition, but I guess a bit of welding can fix most things 

[Anders Dinsen]

I have found a breakers yard in Germany that are supposed to have a 2.2 sitting around.
Asking price: 600 Euro... Anyone needs any other parts (engine, gearbox etc.)

Count me in! I'm ready to split transport corsts too of course.

Though the trailing arms should be in a bad condition, but I guess a bit of welding can fix most things 

They usually are the first part to rust away on our dear cars. I have heard a few examples of people who have welded their arms   with good results, but it isn't legal to do it. So it has to be done so it isn't noticed in MoT.

[Bart_Maztra]

When i was doing the 1.9 conversion, i had the same problem. The end cap of the gearbox was above the treiling arm. I "fixed" it by raising the engine as high as possible, because i couldn't move the engine more to the right. 

If you can fix it by using 2.2 arms, do it. It's the best option.

Which hdi engine are you using?  Pictures? Pictures? Pictures? Pictures?

[Waldo]

Hi,

Well I could maybe move the engine another 10mm to the right, but I would like to have just a little space on both sides...
The 2.2 trailing arms should be an easy fix to my problem.

Gearbox is allready sitting as high as possible (or nearly), also I will have problems with the angle of the left drive shaft is the gearbox is much higher...

Another thing... Can someone tell my the "correct" ride height at the rear?
I measured the two cars I got, from ground to the arch of the fender I have 645mm on my Yellow 1.6.
I believe this is slightly lowered, but looks rather nice, so I'm aiming for this height on my HDI (I'm installing adjustable Spax suspension).
At moment it's sitting at 680mm, but it will get somewhat heavier (no windscreen, doors, rear window aso) though it won't get even close to the 645mm no matter how heavy it get's...

Pictures later today 

[Bart_Maztra]

Gearbox is allready sitting as high as possible (or nearly), also I will have problems with the angle of the left drive shaft is the gearbox is much higher...

I had exactly the same problem with the trailingarm and gearbox. I placed the engine as high as possible, with the result that the driveshaft joints making a too big angle. Going around the corner i could hear and feel the joint being on (beyond) its limit of angle. i had to lower the engine to solve this, but then i had the problem that the trailing arm sometimes hit the gearbox.



Also the new rubber gaiter only last for 2 years.



The only way to do it right is to place the engine in such way that the driveshafts are as straight as possible. That means placing the engine lower as it is now. If you are not doing that, you will regret it every time you go around the corner.  So first make sure the driveshaft is straight, second make sure the trailing arm cannot touch the gearbox. I know one guy solved this by grinding a piece of the endcap of the gearbox and welded a new plate in to close it.

Have a look at the pictures on the 1900 section of my website
http://www.maztra.nl/C1900_inb.html

Pictures? Pictures? Pictures? Pictures?

[Waldo]

Hi Bart,

Yes I'm aware of the issues you have mentioned...
The drive shaft is going to be very close to horizontal when I have the mentioned ride height of 645mm (ground to arch of the rear wheel fender).

I'm going to have a problem with the gearbox/trailing arm clearance.
Looked into modifying the gearbox today, but there is pretty much nothing to gain by cutting and welding the gearbox cover!

I'm going to move the engine 5mm to the right and are searching for 2.2 trailing arms 

A few pictures I made today with a borrowed camera:


Engine installed temporary 


Custom exhaust system (custom manifold, stainless flex pipe, HDI cat and Volvo backbox) 


Lower engine mount


Limited space on the gearbox side 


Maybe a little to close 
Though nothing a bit of welding can't fix I'm sure, but don't tell anyone 


Maybe the engine could get 5mm closer on the right hand side... as they say a gap is a gap 


Custom exhaust manifold... and yes my welding skills are getting better every day!


Anyone ever considered what their petrol tank looks like from the inside 


Engine out for roughly the 37th time... and probably another 22 to go 
Looking to modify the gearbox cover to gain clearance, but it's closer than tight allready 


Any donation for a digital camera would be highly appreciated 

[Bart_Maztra]

Mmmm, HDI in murena, i like it

Some comments:
Your driveshafts are much straighter than i thought it would be. It seems ok to me.
The engine can be moved more to the right by cutting a piece of the "table" onwhich the right enginemount is sitting. That is a common thing to do when placing an other engine. See picture.
Is the lower engine mount strong enough? It looks like it can flex forward/backward.




Don't bring back the camera and keep the photo's coming!

[Waldo]

Hi Bart,

Yes I also believe the drive shaft angle is fine, but still concerned about the trailing arm.

I know that I could make more room by cutting the engine mount on the chassis, but that's been my goal not to modify the chassis all the way along...
I wan't a conversion that can be taken back to orig., not that I will but I like it that way and also that will give me less problems at MOT I believe...

Modifying items like engine, gearbox and bolt on items like engine mounts, trailing arms, exhaust etc. are fine 

The lower engine mount is plenty strong I should think. From an engineering point of view that is.
It's only designed to take forces in one direction (holding the engine against rotation / torque)... not sure what you think is to weak, but it's very strong indeed made of 40mm pipe with 5mm wall thickness, also rather short.

[Anders Dinsen]

The lower engine mount is plenty strong I should think. From an engineering point of view that is.
It's only designed to take forces in one direction (holding the engine against rotation / torque)... not sure what you think is to weak, but it's very strong indeed made of 40mm pipe with 5mm wall thickness, also rather short.

I agree, your construction looks very sturdy, perhaps even too sturdy as you may end up deforming the chassis on the high torque levels you are aiming for. I wouldn't worry initially, though, but I think you should take some precise measurements of the chassis, so you can detect deformations before they become serious. The problem is that the vertical bar carrying the engine mount will be subject to torsional forces with your engine, instead of forces that are "straight on" as it was designed to take.

[Oskar]

I think you should do a similar mounting on the gearboxside to outeven the torsionforce on the lower enginemount.

[Waldo]

I have another torsionbar attached to the cylinderhead that's fixed to the front of the engine bay... Unfortunately it's not in the pictures, but it's attached approx. in the middle of the engine bay.

To be honest I'm not that worried about the forces going to the chassis... The car seems pretty strong, but I guess only time will tell how >300Nm of torque affects the chassis 

If it breaks you might see a HDI engine installation kit in the "for sale" section...

[Oskar]

how do the manage to fit a alfa v6engine in a 1.6 and what kind of gearbox?

[michaltalbot]

Oh my god! Diesel engine in Matra Murena  Phillipe Guedon is turning upside down in his grave