Hi all,
I've been lurking around this forum for quiet a while, but not posted before.
I have a Caterham live axle BEC with a R1 power unit. One of only two or three around that I'm aware of.
It's very nimble and agile, weighing in at just 380kg, and I love it !
I do around 6,000 miles / year in the car, and find that engines only last a couple of years before starting to use oil and breathe heavily from the
crankcase.
I'm considering updating from a carbed 4XV / 5JJ engine to a newer generation R1 unit, since finding "good" low milage 5JJs is getting
more difficult.
I've recently bought one ( 4XV ) from flea-bay, and after all the work swapping over, find that it has the common problem of 2nd gear jumping out
under load.
I suppose I could re-build the recently removed engine ( the gearbox was fine ), but once opening the crankcase it could be a money pit and I really
don't have the time / facilities / tools / patience / skills to do it.
The 5PW injected engine is basically the same lump, and would still run with a wet sump ( with baffle plate ) using the same sub-frame / chassis
mounting points, and would be the most straightforward swap, though I'd probably need a bonnet cut out for the airbox, as well as sorting out the
electrics.
Easier still, would be to put a 5JJ head on a 5PW block and run it on carbs. Is this possible? Is the 5PW more robust than the 4XV? ( especially 2nd
gear )
Would there be much difficulty in fitting a cross plane " big bang" engine? Does it fit in the same space? Can they run a wet sump in a
BEC?
The car's mostly used on the road, with the occasional track day, and I'm wondering how much improvement ( different driving characteristics
) there would be with the newer variant engines.
Any advice gratefully received.
Thanks,
Ivaan
Hi
Be interested in the answers to a few of those questions myself for future reference!
Only Big Bang car I've seen is a mk indy,and the air box is massive!
https://m.youtube.com/watch?v=1ZtWyB2XdYM
I know some of the newer bike engines run complicated air boxes/second sets of injectors etc,so I don't think you can just bang on a foam filter!
380 kg????
Isn't the 5vy one of the better options as there cheap and very reliable?
No brainer really, simply fit a 5VY.
5VY is a pure injection unit, easy to fit, easy to wire. Virtually indestructible.
Gearbox issues are there, the dogs are made from chocolate, but you do have to be pretty brutal (or not brutal enough) to wear them away too quickly.
However, replacements are easy to fit. No dry sump needed, simply add a baffle plate. Oil cooling is essential, not for you on the road, but fit some
slicks and go racing and you'll need an external cooler. Standard rods are OK, they're crack split bottom ends, an individual fit, but they
won't survive if the engine is heavily tuned.
Perhaps the best sounding 1 litre out there.
Drawbacks... it's not up there, power wise, with the more recent competition. Torque and mid-range is pretty dismal, you need to keep it on the
boil all the time. It does eject it's oil (you need a return breather tank).
I wouldn't fit the 4c8 and certainly not the 'big bang' lump.
I like the 5VY idea... Can the mid range be improved with a Power Commander ECU?
From what I can see, it has similar mounting points to the 5JJ, so alterations to the cradle and hopefully the prop should be minimal.
I need to measure and compare side by side.
Any recommended sourses? Malcolm from Yorkshire Engines has helped me in the past.
On the other option, can a 5PW engine be fitted with a 5JJ head and run on carbs? I have a ported head available, and appreciated the extra horses on
the old engine. I also quiet like the carb charateristics and induction noise ( foam filter )
Cheers,
Ivaan
I'm getting just over 170 bhp from my 5vy with a pc3 and torque and midrange is great
4xv gears are not hard to replace. A bike engine specialist will do it for you for not much cash. If the 4xv lump is in, I'd get the gearbox sorted on that one.
I have thought of stripping / rebuild of the engine I've just taken out myself. There's quiet a good set of guidance vids on utube. But
it's the hours and hours of labour stripping, inspecting, re-building, regrinding valves etc, to get back to where I started.
I think the 5VY is the way to go. Project for the winter.
In the meantime, the old lump is going back in tomorrow.
quote:
Originally posted by Ivaan7
I have thought of stripping / rebuild of the engine ... it's the hours and hours of labour stripping, inspecting, re-building, regrinding valves etc,