Fitting a Chev 2.5 engine to a Series Land-Rover

Why?

The Chev 2.5 engine is fairly close to the Land-Rover 2.25 engine in power output, size and weight. So why go to the trouble of replacing the stock, extremely tough LR engine with something else?

Cost: Rebuilding a Land-Rover engine can be extremely expensive. My Land-Rover is a 1959 model, in other words a Series II (and not a Series IIA). When Land-Rover introduced the IIA, they also introduced the 2 1/4 diesel engine. At the same time, they upgraded the 2 1/4 petrol engine to use the bigger block and crank, effectively orphaning the early 2 1/4. As the early 2 1/4 was only produced for two years, 1959 and 1960, bearings are extremely hard to obtain, and the water pump casings are also scarce (The water pump guts are the same as SIIA).
Size: The very popular (In South Africa) Chev 4.1 6 cylinder conversion requires either a 6 cylinder bulkhead or some serious modifications to the 4 cylinder bulkhead, as well as moving the radiator forward. The Chev 2.5 fits in the same space as the LR 2.25. It is also lighter than the 2 1/4 -- the 2 1/4 weighs almost as much as the Chev 4.1.

Performance: The Chev 2.5 has somewhere around 25% more power and torque (depending on who you choose to believe, I've heard 120HP (90kW) quoted for the stock 2.5, and 145HP (108kW) for the marine version). (Note: I'll believe this when I see it :-) The torque, however, is developed at somewhat higher revs (not ideal for off-roading). (See "Performance" at the bottom of the page)

Power Torque Source

Land-Rover 2.25 52kW@4000rpm 163Nm@2000rpm TeriAnn's page

Land-Rover 2.25 52kW(nett)@4250rpm
70bhp(nett)@4250rpm 168Nm@2500rpm
124ft-lbs@2500rpm Lindsay Porter/Official LR figures

Land-Rover 2.5 62kW@4000rpm 181Nm@2000rpm TeriAnn's page

Chev 2.5 (1962-1970) 90HP(nett)@4000rpm
(67kW(nett)@4000rpm) 152ft-lbs@2400rpm
(205Nm@2400rpm) Scott's Nova Resource Site
Using TeriAnn's conversions.

Chev 2.5 (1973-1978)
(SA Auto Data Digest) 88kW(SAE)@4600rpm 220Nm@3200rpm Auto Data Digest

Spares could be a problem in the heart of darkest Africa. I've heard that Land-Rover 2.25 spares are plentiful throughout Africa, but I don't know about spares for the Chev. OTOH, one can always find a replacement Land-Rover engine if the Chev engine is beyond repair.
Originality: See my philosophy on the subject. Or, to quote a guru:

One word of caution, if you do an engine swap, don't talk about it at meets and keep
your bonnet down, least the PC (politically correct) police come after you.
-- TeriAnn Wakeman, 1996-06-30.
Other advantages: The Chev has hydraulic tappets, timing gears (no chain), five main bearings (most LR 2.25 engines have three) and oil seals designed by Americans (The British never could get the oil to stay in... :-)
(Later: OK, OK, I eat my words. See the bottom of this page, under "Problems")

	Power	Torque	Source
Land-Rover 2.25	52kW@4000rpm	163Nm@2000rpm	TeriAnn's page
Land-Rover 2.25	52kW(nett)@4250rpm 70bhp(nett)@4250rpm	168Nm@2500rpm 124ft-lbs@2500rpm	Lindsay Porter/Official LR figures
Land-Rover 2.5	62kW@4000rpm	181Nm@2000rpm	TeriAnn's page
Chev 2.5 (1962-1970)	90HP(nett)@4000rpm (67kW(nett)@4000rpm)	152ft-lbs@2400rpm (205Nm@2400rpm)	Scott's Nova Resource Site Using TeriAnn's conversions.
Chev 2.5 (1973-1978) (SA Auto Data Digest)	88kW(SAE)@4600rpm	220Nm@3200rpm	Auto Data Digest

Different "Chev 2.5" Engines

I found that there's some confusion about the Chev 2.5 and the "Iron Duke", which are completely different engines. I also found, the hard way, that there are various flavours of the Chev 2.5 engine, with different seals, different compression ratios, and probably a few differences that I have yet to find. So, here's my attempt at The Definitive Chev 2.5 Page.

Overhaul

If you're interested in the nitty gritty of the overhaul, go here. Summary: it cost me R5733.08 + (my) labour, in 2000. Worth it, I think.

2002-11-14: I'm overhauling another engine. Parts are about 50% more expensive.

Fitting the Chev 2.5

OK, so I was under the impression that it would be a fairly easy drop-in replacement. Well, it's fairly easy, compared to some conversions I have seen, but not quite trivial.

Modification to the chassis

The oil filter and the righthand side engine mount outrigger are in the same place. I suppose I could have fitted a remote oil filter, but I decided to cut off the mount and to have a new mount manufactured and welded to the rear of the existing mount.

Engine mounts

I had two plates made up to adapt the Land-Rover engine mounts to the Chev engine. The first ones were of 3mm steel plate, these bent during the Y2K trip, so I made new ones using 10mm steel (overkill? Indeed!).

You also need four 3/8" dia studs, about 2" long, with UNC thread on the one side and UNF on the other. Locktite these into the block, and fit the plates using hi-tensile nuts and lock washers.

Interference between adaptor plate and chassis

When I first started the engine there was an incredible vibration. Eventually traced it to the adaptor plate hitting the chassis. Fixed the problem with an angle grinder, took off a fairly large piece of the adaptor plate.

Clutch spacer

Important! I used an old but good clutch plate I had lying around. All was fine. I had to fit a new clutch in Messina (Read the Y2K writeup for details) and then a problem surfaced. You need a 12mm spacer between the release bearing and the pressure plate. At least, I think 12mm is the right size, it works for me for now.

Running in, how NOT to do it

As always, I finished working on the Land-Rover at 13:00, and we left to go on the Y2K tour at 15:00, with less than 100kms on the brand new engine. Not recommended. At all.

Performance.

The engine behaved really well, some teething problems, but we travelled a lot faster than we would have done with the stock 2 1/4. I must admit, I really missed the 2 1/4's low down torque in the thick sand at Tsodillo Hills in Botswana, but OTOH we were able to leave Ai-Ais the morning and reach Bellville (about 800km) just after sunset the same day, something my 2 1/4 would not have been capable of.

Problems.

When I started this project, I was under the impression that the Chev 2.5 had a "proper" elastomeric rear crank seal, and not a rope seal like the 2 1/4. Well, the block I rebuilt takes a rope seal. But the gasket kit comes with both types, which tells me that there was a design change somewhere along the way. I checked the other block I have and yes, it takes the elastomeric seal.
The engine leaked, nay, pissed, oil out the back since day one. After we got back from the Y2K tour, I pulled the engine and got Peter Burgers, who has done this job a few times before, to help me replace the seal. Result? Still pisses oil like crazy.
So I figured out that just maybe I ended up with a rope-seal block and an elastomeric-seal crankshaft. So I rebuild another engine, and I must say, it leaks less oil. As a matter of fact, it looks as if the oil is *not* leaking from the rear seal at all (touch wood).
The engine pinged under load with low octane fuel. Did you know that there's a low and a high compression head for the Chev 2.5? Neither did I. Engine #2 has the low-compression head and I'm very impressed with the engine.
The engine mounts shifted during the Y2K trip, with the engine sitting about 3cm lower (at the front pulley) than when I installed it. See note on 10mm engine mounts above.
Not really a problem per se, but the Chev sump holds very little oil (about 3.5 liters, compared to 8 or so for the 2 1/4). I had a bigger sump welded up, which takes about 6 liters.

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(This page last modified 2005-04-29)