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Engine swap for 1.8
Posted: Tue Oct 25, 2022 2:10 am
by LarryK
Hello,
What's a widely available engine that can replace a 1.8 in a Marina currently with auto? It's a North American model, if that matters.
Re: Engine swap for 1.8
Posted: Tue Oct 25, 2022 11:28 pm
by locost_bryan
Doubt if there's anything widely available in North America, that would be a simple installation. In the UK, I would suggest a Rover O-series, or the later 16v M-series or T-series. The Borg Warner 35 auto can handle the extra power, where they would kill the manual gearbox.
What are you wanting to achieve - better parts availability, more power? How much fabrication work would you want to do?
If you want to retain the auto, then the BW35 was used in a lot of compact cars in the US, you could possibly find a combo that would allow you to use the existing driveshaft and gearbox mounts. Rover 3500 used it iirc.
A Mazda MX5 engine and gearbox might be a relatively straightforward swap - compact, plentiful, not too powerful.
A Range Rover Discovery V8 and ZF auto will also fit without too much work, see
here.
Re: Engine swap for 1.8
Posted: Wed Oct 26, 2022 1:53 am
by LarryK
Mainly looking for reliability, not necessarily looking to keep the auto. I think I saw something somewhere about using an MX5, so I'll see what my mechanic has to say about that. Cheers.
Re: Engine swap for 1.8
Posted: Thu Oct 27, 2022 2:19 am
by locost_bryan
Another option is a Suzuki Jimny/Samurai 1300 engine and gearbox. Early engines have the advantage of being carb not efi, so no need to add an extra fuel line and swirl pot.
Pictures and measurements
here, from a 16v installation into a Sprite (8v shares same block).
Re: Engine swap for 1.8
Posted: Thu Oct 27, 2022 8:40 pm
by JoshWard
Surely introducing a more sophisticated engine into a vehicle that was not designed to house it is likely to decrease reliability? The B series is a very simple and rugged unit. Even when they're are completely worn out they'll still run!
Re: Engine swap for 1.8
Posted: Sun Nov 06, 2022 12:19 am
by Kilroy
Most Marina 1800's used the BW65 auto, which is totally bullet-proof on small bore engines.
The fact that these engines feature a long stroke means that they are quite effective even with only a 3-speed auto.
I chose to elicit more horsepower from the 1800 - multiple choices of overbores available thanks to MGB enthusiasts - and the auto will handle them without flinching.
My current 1903cc B series engine and BW65 auto are currently enjoying their 4th body, having outlived 3 previous.
I suspect total mileage on running gear around 300km as of now .

Re: Engine swap for 1.8
Posted: Sun Nov 06, 2022 10:13 am
by MarinaCoupe
Hey Kilroy - long time no see! Mk1 Marinas like Larry’s will have had the BW35 auto box as standard, just as robust as the later BW65. I think the changeover date was 1976
Re: Engine swap for 1.8
Posted: Sun Nov 13, 2022 10:36 pm
by Kilroy
Great.
Always more to learn.
Thanks Chris.
I wonder if the BW45 could be used, it worked so well in the Hillman Hunter and I am sure most small bore 4 cylinder engines would prefer the 4-speed.
Re: Engine swap for 1.8
Posted: Mon Nov 14, 2022 7:28 am
by MarinaCoupe
I’m sure it would, however in the UK they are like the proverbial Rocking Horse Poo!
I did some research on the BW45, in the UK it was only used on Hillman (Chrysler) cars, not sure if any European cars used them. If anyone has one, they have a 4 speed automatic box in their hands. No over driven top which remains as 1:1, but of course it has the advantage of closer gear ratios than the BW35 & BW65 3 speed gearboxes.
Re: Engine swap for 1.8
Posted: Wed Dec 07, 2022 6:08 pm
by stoterstangen 90
Volvo? Maybe the bw55 or the AW 70/71