Engine swap

[Perkins]

Hi All,
A new twist on a perennial question. I have decided to take our beloved R4 GTL off the road for a major overhaul. This will include all new brakes, a bit of welding, a respray and a new engine and possibly an LPG conversion.

Living here in France, I've currently got the choice of a 1976 R5 GTL 1300 engine @ 42hp or a later 1984 R5 GTL 1100 engine @ 45hp The 1300 is a long drive away, the 1100 is close by.

I would have thought the 1300 would produce more torque, but according to the figures it doesn't ! My question is, has anybody had the experience of driving an R4 with both options and if so which is the better bet. As far as I can see the 1100 is the same engine as I already have, but with a bigger carb. I would imagine the dizzy is not the Femsa unit, but apparently according to earlier strings the cam on both R4 and R5 was the same. I can't believe a carb only will give 30% more power in the same engine.

So which to choose 1100 or 1300 ? Is the 1300 better and worth the extra hassle ?

Thanks for any help,

Perkins

 

[montenegro]

hi, I put a 1300ts motor in a R4 it gives around 56 bhp but, it did drink the petrol if you put your foot down ! as the engines you have a choice of are the same bhp then the one with the less mileage would be the choice...

 

[Perkins]

Hi Montenegro,
I notice you are in Brittany too - whereabouts are you ?
Did the R5 engine make a big difference in performance and was it worth the trouble to change it ?
As I'm considering LPG I don't mind loosing a bit of MPG !! what sort of MPG were you getting from yours ?
Thanks,
Perkins

 

[barnfind]

hi
I have quite a bit of LPG experience on modern cars, having run two Subaru Legacies almost entirely on LPG for several years.

Anyone thinking of using LPG might find the following of interest:

You need some petrol capacity since the car needs to start up on petrol and in the UK, if you are driving long distances, you may find filling stations with LPG a little thin on the ground in some areas and you will need a petrol reserve. This means two tanks, the LPG tank usually in an estate type car, being fitted in place of the spare wheel. If you want to carry a spare this means reduced boot space, not too much of an issue with a car with small wheels, but still a potential complication if you need to carry a load.

Valve seat recession is an issue on many cars. Modern cars like the Subaru sometimes use a system like the Vialle system which delivers the LPG under pressure as a liquid and therefore cools the valve seats sufficiently to remove the worst of the erosion. Nevertheless even with this in place, the Subaru service regime required valve clearances to be checked every 12k. It would be prudent to have a system which injects an upper cylinder lubricant (called flash lube) into the gas flow, since this theoretically, removes that risk.

My last Subaru, on petrol, averaged 28mpg. On LPG that dropped by about 3mpg. That was with modern fuel injection, so expect a bigger drop with a simple carburettor based system. There was no appreciable performance drop when driving on LPG, although my son always expressed the view that the power delivery was smoother on LPG. Again, you may not find this to be the case on a less sophisticated R4 conversion.

Obviously the main attraction is that LPG in the UK is only about 60% of the cost of unleaded. But do your sums carefully. Even at current fuel prices, this conversion is still something that can take a long time to recoup the cost of, unless you are a high mileage driver and you are in a position to make regular use of the cheaper fuel. You may also find that any reduced performance is irksome on something like an R4.

 

[Perkins]

Hi Barnfind,

Thanks for the information. LPG here is about half the price of petrol and I have worked out even with a big margin for overclaims of efficiency etc, that the cost of the kit and fitting etc can be recouped in 12 months, given the mileage our R4 does.
I was looking at the Flashlube kits too as I know vale seat regression can be a problem on R4s. EDF used an LPG system on the R4 vans over here, and they were I believe fitted with special valve seats and an uprated valve material to protect the heads. I'm working on the basis, that if I burn the valves, I can find a new head easily enough and the Flashlube should at least give at an element of protection !!

The drop in performance with a carb engine, was also the reason for considering the 1300 GTL engine, as the current engine in our R4 is actually in very good order. I just thought the extra capacity would offset the LPG performance drop - and and R4 isn't exactly the best car for entering the fray on French roundabouts !!!

Your experience seems to confirm some of my thoughts, which is comforting.

Perkins

 

[Steve Hennessey]

If the R5 Mk1 1100cc engine come with ancillaries - especially the IF32 Zenith carb then go for it - the carb gives it quite an increase in performance.

 

[Charliemouse]

Pretty sure you can't fit an LPG kit and get through a CT...

 

[Azazello]

I drive my r4 on lpg from a year ago, at the beginning with a 956 engine coupled with a 163 gearbox. First times it was quite slow, but once I got used to it the difference was undetectable. The car drives smoother, and I eliminated all problems related with carburettor and rust in my fuel tank.
Consumption increase was from 15 km/l to 12 km/l.
After some months my head gasket blowed away, I do not know if it was lpg fault or because of the long journey to Thenay or just because the engine was 225000 km old.
I had the engine rebuilt to 1108 standard (as Angel said me was possible), but with harder valves and valve seats, still coupled with 163 gearbox.
So performances increased, but even consuption: now around 11 km/l.
I am going to buy a 354-146 gearbox... found online, just have to arrange the courier to bring it to me...

 

[Perkins]

Hi Charliemouse,
A few people have raised the question about the CT. Tinleytech in Cambridge assure me several people have managed it in France and are going to put me in touch with a guy who managed it with a DIY installation. I would imagine it is going to involve an 'expertise' inspection and a lot of gallic shrugging, slating english stuff, shelling out a few hundred euros and gaining a photocopy of the magic piece of paper. Probably far more difficult than the conversion itself. I'll keep you posted !!

Perkins