Series Overdrive Options

Less than it sounds like!

Haynes BoL quotes maximum power at 4250 rpm which a rough calculation from gear ratios and tyre sizes puts somewhere around 65mph on an LWB.

I've had the Lightweight up to 60mph, once. That's on 6.5 rims, so I think my calculation is near enough. Unloaded, I'd expect the engine to reach 5000rpm, which would be around the 70mph limit on my wheels.

But what's the official red-line on the engine?

High ratio diffs?. You should be able to get a pair for less than £100 i should think (I think thats what paddocks sell em for)

Dunno, but on my 2.6 6-pot it's limited at 4750. I can't find any official information on a rev limit for the 4-pot. I can deduce that the limit would have been about 5250-5500. I'd say than on a 30 year old engine an upper limit of 4500-5000 would be a good idea.

Alex

If memory serves - 4 cyl 2.25's are 4250, and 6 cyl are 4750 - those extra 500 rpm make real difference to the 6 cyl engine - I loved mine to bits and have always regretted selling it.

Both my 109 and first 88in would go perfectly happily at 65-70 on the motorway, plus about 10 mph with overdrive. The 6 cyl would do 85 for long stretches with overdrive - great fun!!

Richard

I'm not keen on the idea of high ratio diff because of their impact on the off-road ability. That weedy 2.25 need all the gearing it can get at times.

When do they become 6 cylinder engines?

It was an option on Station Wagons, and other 109's, from around 1967 to 1985, though it was largely surplanted by the V8 from about 1980 in the Stage 1. Lovely engine, and wrongly much maligned, masses of low down torque, sub 1500 RPM, but very thirsty - 15 to 18 to the gallon!

Richard

How do you tell one from another?

One has a 6 cylinder enginge while the other has a 4 pot installed ;-)

Raoul

Very funny - can you tell just by looking at them - are there any visual differences?

we had a 1969 2.6 6 cyl 109. lovely and smooth and sounded like a baby V8.

calculation

IMHO no, just the Stage 1 can be easily distinguished from the 4 and 6 cylinder models. The latter ones look identical.

Raoul

The distributor and spark plugs would be a dead giveaway. Manifolds, too, even if the ports in the head are paired.

From the outside - the only obvious clue is that the 6 cyl exhaust comes out into the wheel arch, otherwise its lift the bonnet and count the spark plug leads.

Richard

The six is externally identical to the four, but is easily recognised by looking in the cab - the gear lever comes out of the floor about four inches further back. The bulkhead is different but this is less obvious. The six has the front of the engine in the same place as the four, but the engine is longer so the bulkhead needs to be different and the gearbox is further back. JD

Hmm. I've had mine without the rev limiter on it, and it revved up to

You can have my 2.6 lump when I'm finished with it. I'll only need a complete rebuild, welding to the head and you'll have to shear the head bolts to strip it in the first place.

I love it to bit tho, the extra 2 cylinder make soooo much difference. I'd rather drive a six pot anything over a 4-pot.

Alex

The bulkhead is indeed very different. I went to have a set of sound mats fitted, and the bloke had to make me a custom set on the spot. The engine is about 4-6 inches further back, which means the gearbox x-member is in a different place, and the proshafts on a 109 2.6 are unique.

Alex

I beg to object, my 2.6 exhaust exits at the rear nearside corner. About 2" inside the bodywork, which means my number plate is covered in black smuts (oh what a shame - photograph that you bastards)

I think the exhaust position depends on which tank you have fitted, the rear tank exits at the rear, while under-seat exits like a SWB.

Also, you could have the option of an underseat second tank on the 2.6

Alex