652cc Engine Swap

[motomallett]

Hi all you technically minded club members I would like your advice on uprating the engine of my PAC 3 Wheeler.
At the present it is propelled by a 602cc engine with twin choke solex, high compression pistons and lightened flywheel.
We have done several thousand miles in the car, to France and to rallies, and it has gone very well. I have now acquired a 652 Visa engine and wondered if it would be worth the swap. I have read that the 652 would give me more torque but no more top speed.
Also I understand that the 652 is more reliable that the 602, is this correct as reliability is the main criteria.I will be mating it to the 602cc gearbox which i am aware of the nesassary mods needed.Would appreciate all your experienced views before i take the plunge. I would like to wish all club members a Merry Christmas and a Happy New Year and hope to meet up in 2015 regards Roger

[hutchii]

Roger,
I'm sure the previous owner of your PAC told you that the 602 engine used to be supercharged. Went like stink too, even with his home built caravan on the back. When I heard that he was selling, I also heard that he was intending removing the blower. What a shame!
I'm sorry but I can't give any advice re the 652 engine, except to say that IF it's more reliable than a maintained 602, it's one special engine!
As I think most owners of our cars will tell you, the 602 is almost indestructible assuming you do the necessary maintenance on time or sooner. If you want some more go, see if you can get a copy of "It's not a Mouse but a Lion" by John Nash, and carry out at least some of the suggested mods. Also have a read of the various tuning sites on the net. Some say that the lightened flywheel influences how well the cars goes up hills! Too light and they run out of steam.
Ian

[Mendip.Wursel]

I have a Lomax 223 and I considered upgrading my engine to 650cc but too many people kept telling me that cooling could be a problem and that the car could be less reliability, so I stuck with the 600cc engine (assuming you do not have the 2CV fan at the front of the engine).

[Boggy]

Hi Roger
I have done a few conversions to 652cc, if you can find a Citroen LNA gearbox then the conversion is very easy, if not then you will need an adapter to hold the ignition sensors.
If you need any info or pictures ( I am doing one now for a Dyane ) pm me or send me an email
Cheers
Boggy

[Claus]

Hello,
I did this conversion some times and there are 2 principle ways:

Using original ignition, you first need a adaptor ("bridge") to hold the 2 sensors in position. This adaptor will be fitted between engine and bellhouse.
You have also to drill two holes in the bellhouse where the sensors go through.
The adaptor is about 5 mm thick, means that now the clutch will be 5 mm "farer" away from the clutch realease bearing. This could become a problem
in adjustment of the pedal......
~ 60.- € and some work

Using the 123 ignition
Using this ignition (in front of the engine) you need a adaptor fitted to the camshaft..
I have a pictured assambly guide on my homepage (german only, but you will understand by pics..)
http://burtonkitcar.de.tl/Umbau-Visa-auf-1_2_3.htm
The next problem is the flywheel of the Visa engine, because it is thicker than the 2CV flywhheel, so you have to mill it ......
~300.- € + milling the flywheel

The simplest way is to use a pair of new piston & cylinder, you have to change nothing nor to remove the engine....
http://www.burton2cvparts.com/big-bore- ... -5988.html
~320.- €

And there is may way, but very special:
http://burtonkitcar.de.tl/Forum-und-Ver ... -Motor.htm
~ 400.- €

Anyway, if you have any additional question feel free to mail me
dreiradclaus@web.de

Regards
Claus

[John Sobey]

Hi, I have done this swop with the adapter bracket etc. If you are interested and not too far away probably best to visit, have a chat and see my car....do please pm me to arrange, I am in Gloucestershire.

[motomallett]

Many thanks to you all for the info received.I have now acquired the book Its Not a Mouse but a Lion, worth every penny.John would like very much to meet up and have a look at your engine conversion. My email is frenchmalletts@hotmail.com if you could send me a contact number so we can arrange a day to suit you. Once again many thanks guys for all your help. regards Roger

[notsmartcar]

I've fitted many 652 now but not recently the best flywheel/clutch set up I found was the diaphragm clutch .. The sensor bracket which I know works is the one from le patron (others may work of course)..if you have the original bell housing for the sensors that is much better and can be cut to suit in stead of buying an adapter ... You can keep the visa clutch,flywheel and ring gear so you can use the visa starter motor . your gear box ends up spaced 5mm (may be a little more if the rotating parts touch)away from your engine.. Give the clutch pedal more clearance to save straining the cable .. I found all the ecu I used were interchangeable with the VA1 giving a quicker ignition advance curve than the VA4. But either are fine. I never had troubles with sensors or ecu s. The vacuum sensor is Very important and must be fitted .. The visa starter spigots in to the gearbox with 2set screws as normal but you will have to ease 3mm off the top of the starter as sometimes the mesh of the teeth may be too tight .. Fantastic engine and runs cooler than a 602. Enjoy . If I were doing it again and didn't have sensors or ECU. I would use the 1 2 spark system that people are raving about

[motomallett]

Hi Notsmartcar, thanks very much for the info about the engine swap. I would like to have your contact number as I am a novice regarding these Citroen engines and hopefully would like to seek your advice from time to time. My email address appears in my last post. As we are both in the South West region we might be close enough to meet up should you choose to make contact. Regards Roger.

[Meharidude]

I use a 652 in the Mehari, and installed according to a philosophy of using as many 2CV parts as possible and without mutilating any of the existing components in the car. Maybe not the cheapest way, but the least hacky way.

Premise:
In case the engine, gearbox, starter, ignition or clutch breaks down it should be easy to repair or replace using off the shelf 2CV parts, as 2CV parts are easier and cheaper to find at 2CV meetings and at 2CV shops.

Flywheel modification, diaphragm clutch type:
Flywheel removed, starter ringgear pressed off. The flywheel is mounted in a lathe, and the shoulder or flange that the ring rests on, is then "moved" 6mm towards the engine, through turning, naturally still keeping the the original diameter of the flywheel. Starter ring from a 2cv is then fitted (heat using oven or blow torch, then it slips on to the flywheel). Fit flywheel, you might want to press or hammer the ignition lug further in, 5-7mm would do, to clear the bell housing. Now everything is in the right place, no reason to resort to clutch hacks. 2CV starter can easily pull the 652.
Advantages: Unaltered clutch, unaltered starter, and input shaft is in full contact with the support bearing, 2CV starter is still used. A 2cv engine can easily replace a broken down Visa unit, without modification.

Ignition:
An adapter is fitted at the end of camshaft, running a 123 og DG 2cv ignition, use a 2cv fanpulley, as it clears the ignition box.
Advantage: In case the ignition breaks down, another 123 or DG is a straight fit, and you can use the more common black 2CV coil, no mutilation of bellhousing, (any 2cv box will now fit without problems), no brackets needed. No need to find room for a blackbox.

Carburettor:
If running an induction feed from fan, connect the black hose from fuel bowl to rubber elbow between carb and airfilter. If running a special carb or filter, leave the hose open, or remove it leaving the fuel bowl vent open. Various vacuum hoses, block them all if running a special filter, the very front one, used by the vacuum switch, can be used for a vacuum gauge or 123evo, otherwise block it.

thats basically all you need to do.