Another engine swap advice thread...

Discuss mechanical problems here.
Neil MG
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Another engine swap advice thread...

Postby Neil MG » Tue Feb 08, 2011 10:14 am

I have a lovely, very original 1956 series II 2 door. Everything works perfectly, but with 68,000 on the clock, the engine is getting a little tired and it still has its unmodified head. So time for a rebuild....

Ok, I guess this has probably been done to death...but, I plan to change my 803cc block and head with a 948 or 1098. I will also change to a 948 gearbox, but keep the same gear stick arrangement (from the old box).

So my question relates to the fact that I would like to keep everything looking absolutely standard. That means transferring all ancillaries from the old engine to the replacement. So what issues are there?

First, I realise that the filter/carburettor/manifold is not optimised for performance! but what kind of restriction will that represent to the increase of power/torque from the larger engines?

Are both these blocks interchangeable regarding flywheel/clutch/backplate etc?

Any other differences; oil filter mounting?

Would greatly appreciate help and advice before I purchase a replacement engine. ( I already have a gearbox)

Thanks,

Neil
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Tue Feb 08, 2011 11:35 am

If you stay with a 948 engine (and don't bother/worry about 'unleaded' - it's not necessary) then it will work well enough with your original 803 bit's and pieces. The oil filter is always going to be different - there really is no way around that. You could fit a remote filter - but that's just going to be extra expense, and even more obvious! Used with a 948 box (gear change extension swaps straight over) it will be an easy bolt-in conversion. You will have a little more power - and to get the best from it you may in time want to consider changing the final drive ratio to the 4.55 which was standard with the 948 engine.
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mike.perry
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Re: Another engine swap advice thread...

Postby mike.perry » Tue Feb 08, 2011 11:37 am

John Evans does 803 gear changes onto 1098 boxes, he could advise on 948/803 boxes. P 50 Minor Matters.
You could replace the 803 H1 carb with the early 948 H2 carb
You will need to change the diff for a 4.55 ratio and the speedo for a 1504 TPM
The oil filter will be the give away, the 948 has a proper external filter not the rubbish by pass filter on the 803, otherwise no problems
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bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Tue Feb 08, 2011 11:42 am

The H2 carb won't fit on the H1 manifold - so it will all start to look different if you swap these parts. In fact - it will look just like a 948!!
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Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Tue Feb 08, 2011 12:13 pm

Thanks, I'm happy with the rear axle and the 948 box ratios, I am not trying to create a motorway cruiser. I would just like a little more torque to cope with these Cumbrian hills! With the original set up I can't cope in top and it's a long way down to third!

And yes exactly! I don't want it to look like a 948! I wondered if I could somehow adapt the oil filter attachment?
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

rayofleamington
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Re: Another engine swap advice thread...

Postby rayofleamington » Tue Feb 08, 2011 1:34 pm

Anything is possible with enough time and effort / expense.
However the 948 oil filter is superior, and the bypass filter on your early a-series could be one of the reasons it wears so much. I've never put the two next to each other but I've wondered what it would take to make the 948 filter 'look' more like the SII version.

On the flip side - there are very few SII's remaining in original condition with original running gear...
A cheap Minor 1000 would come with all the bits you want, fitted as standard.

What you do is up to you as it's your car ( I'm not taking any moral highground as I've had quite a few SIIs and they all came fitted with 1100 or 1275s.. )
Ray. MMOC#47368. Forum moderator.

Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block :(

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Tue Feb 08, 2011 4:13 pm

I think it would be possible to bore out the 803 to take 948 pistons - and fit a 948 crank - you would need 948 conrods and pistons of course..... But it would be a '948' in an 803 block!
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chrisryder
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Re: Another engine swap advice thread...

Postby chrisryder » Tue Feb 08, 2011 5:42 pm

bmcecosse wrote:But it would be a '948' in an 803 block!
that would be a slighty bigger sheep in sheeps clothing! :lol: i imagine the 803 head would be a bit restrictive. guessing a 948 head would go on the 803 block?

my dads SII has 1098 running gear. ok to the trained eye, you can tell, but he's still retained the massive oil bath air filter on the top. i think it must be an 803 carb for that to fit, but i could be wrong. it was done before i was 5, so i wasn't paying much attention, and it's in winter storage now so i can't check or take any pics any time soon!

Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Tue Feb 08, 2011 7:24 pm

Ray, you are right, it's a shame to alter one of the few remaining original cars, this one even has its original carpets and is still on crossply tyres (albeit new ones). It has obviously lived its life in garages as it has not only escaped the tin worm, but also the hands of the "improver". The only add on is windscreen washers and they were most likely fitted when the car was new. I want to keep the car standard, but I also want to drive it. I use it almost daily in the good weather for all my short journeys and when not being driven it is kept in a dehumidified storage facility. So I want the change to be invisible, but I will also keep all the original parts as part of the history.

My understanding is that the 803 is not really suitable for over-boring and also has a particularly weak crankshaft, in short, not an engine that can be tuned.

Chris, that's my plan!
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

mike.perry
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Re: Another engine swap advice thread...

Postby mike.perry » Tue Feb 08, 2011 8:17 pm

Is it possible to treat the crank to harden it? Then maybe the 803 would take a bit of tuning.
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chrisryder
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Re: Another engine swap advice thread...

Postby chrisryder » Tue Feb 08, 2011 8:47 pm

BMC mentioned fitting a 948 crank too. providing the main journal diameters are the same i can't see why it wouldn't fit.

Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Tue Feb 08, 2011 9:13 pm

OK here is the latest:

Went to pick up the (948) gearbox and by chance the guy had a complete 1098 engine - so I got that too.

On closer examination at home I can see the engine number begins 10V/189E/H. Does that mean it is a post 1970 Morris 1000 van high compression engine?

The engine turns over very smoothly and looks like it hasn't run since being rebuilt. The guy selling it didn't know anything about it except he got it some time ago in the condition it is in now. I will strip it down anyway. Interestingly, judging from the intake ports the cylinder head has been "flowed". I don't know if that will adversely affect my project, but it might not match the manifold? The inlet ports have been polished and measure 30mm diameter at the manifold mounting surface.

So does anyone know what will happen if I try to swap blocks and heads or do I just suck it and see?
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Tue Feb 08, 2011 10:57 pm

You can use the 1098 engine - but it will be hopelessly strangled by the 803 carb - it will need the later H2 carb - and it really wants an H4 carb ! You are now moving well away from the 'original' look. The 948 gearbox won't last long with a 1098 going through it..... and swapping the pudding stirrer gear lever onto a 1098 box is much more difficult -where it is a simple swap of tail-section on an 803/948 swap. The 1098 head is a much better head anyway.....it's actually NOT a great idea to 'polish' the ports... And yes - don't attempt to improve the power of an 803 - but I do believe the 948 crank can be fitted - and I don't see why it won't bore out to take 948 pistons. It was just a suggestion - to get the ideas flowing!! I suggest an engine swap is the way to go and just grin and bear the oil filter........ The 803 can always be reconditioned and dropped back in any time you want to go back to the original spec.
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Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Wed Feb 09, 2011 11:40 am

Really appreciate the feedback!

I think you are right in pretty much everything you say! My real question is how much? How much will the 1 1/8" carb. restrict the engine, enough not to destroy the gearbox? Actually the car is only used for pottering about and not so many miles (I have another half dozen cars) I just thought that rather than rebuild the engine I would try and add just a little more torque. If I had fallen on a 948 instead of the 1098 I would have taken that.

My understanding from David Vizard's book is that the 948 was a different casting and it is not a straightforward job to bore out the 803?

I know it's a strange question, a straight 948 engine and box swap or even 1098 engine and box swap is simple, but I really want the car to look standard, hence the restriction with using the original carb. I can see I am going to have to be creative and that's no problem. I just wondered if anyone has done anything similar?

I don't want the car to be concours, but I do want it to look excellent original. Incidentally I have an MGA 1600 that has boxes full of concours trophies (from its previous owner) including Benson and Hedges Masterclass - all those with an (invisible) 1800 MGB engine fitted!

So, my latest thoughts are to rebuild the 948 gearbox, seems ok so hopefully no big cost there. To strip the 1098 engine and if it is ok then just fit as is and see what happens. Maybe using the standard 1098 oil filter system initially. If everything works well I will then try to modify to a more original look. If it doesn't work for me then I will look at rebuilding the 803 engine with whatever internal improvement I can make.

Are there any issues with the 803 flywheel/clutch on the 1098? or can the 1098 clutch be used with the 948 gearbox?
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Wed Feb 09, 2011 4:53 pm

For a straight swap - use the 803 flywheel and backplate on the 1098 engine. And swap the tail assembly from the 803 gearbox onto the 948 gearbox - it should just be a bolt on job. Use the H1 carb/manifold etc - and see how it goes. It will be fine - roughly equivalent of say 3/4 throttle on a normal 1098 engine - but then most Minor folks never floor the throttle anyway! And with the low final drive in that car - it will climb mountains - and frankly should be ubber fuel efficient too.
No one in their right minds would bore out the 803 engine - but you do want more power and an original look - so I only suggest a possible way to do it.... Yes the Wizard is right - it is a different casting with that different (and let's face it pretty hopeless) bypass oil filter arrangement. But I think it would work! The 803 crank is rightly described as a piece of bent wire - so hardening it is unlikely to help much. The filter situation could be covered by frequent oil changes - say every 2000 miles - which for you could be a number of years! The MGA sounds great - hard to get at that engine to check if it is MGB based!
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Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Wed Feb 09, 2011 5:14 pm

Thanks BMC!

That's exactly what I hoped to hear :D

I am absolutely not afraid of frequent oil changes, so it sounds like this might work! "Climbing mountains" is useful around here!

You are right about the B-series, especially if someone is creative with a grinder! Backplate top mounting holes are the only real visible clue.

Once again, thank you for yet another great contribution to the forum, much appreciated!
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

rayofleamington
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Re: Another engine swap advice thread...

Postby rayofleamington » Wed Feb 09, 2011 5:25 pm

Having run a 1275 using a minor 1000 carb, exhaust and manifold (twice now with different Minors) I have to say it was nowhere near as strangled as people like to assume.
Therefore a 1098 with the SII carb & manifold might not be too much different.

However - the 1098 block has more external differences - If you want it to be convincing, then a 948 might be the better option, or you can use the grinder in a few places :o
Ray. MMOC#47368. Forum moderator.

Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block :(

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Wed Feb 09, 2011 6:10 pm

At least it doesn't have '950' cast in the side as a dead give-away......
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Neil MG
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Re: Another engine swap advice thread...

Postby Neil MG » Wed Feb 09, 2011 7:02 pm

Ok, I know of the oil filter and pipe connection area and also the mechanical fuel pump blanking plate and the stud below that. What are the other differences?
1956 Morris Minor Series II
1959 MGA 1600 Roadster
1966 Jaguar Mk2 3.8 MOD

bmcecosse
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Re: Another engine swap advice thread...

Postby bmcecosse » Wed Feb 09, 2011 7:52 pm

Nothing terribly obvious - the 803 does use a different (hard to get) water pump.
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