MBG O series conversion
Discussion
Hi this is my first post up, but wondering if you can help me. I'm rebuilding a MGB with the aim of turning it into a long distance tourer cross track day special. I've had a tuned B and now I'm using a brand new rover sd1 O1 series engine in a conversion (stronger torque band, better bhp etc). Eventually it will have a Peter Burgess tuned head and EDIS, but for now its new and pretty standard. Googling this topic I found that some of you guys have already done this or thought about it- ace. Can you provide me with some more details.
Ta
Ta
Why an O series? The Rover M series and T series engines were derived from this and can also be fitted without too many difficulties. 16 vave 2 litre twin cam looks good under the bonnet of a B. - Have to admit though, that the C on triples posted above looks better - but aren't they considered too heavy for the chassis and upset the handling?
Edited by restoman on Friday 21st September 21:02
Edited by restoman on Friday 21st September 21:03
restoman said:
the C on triples posted above looks better - but aren't they considered too heavy for the chassis and upset the handling?
The weight distribution of a 'C' is actually remarkably good, just 'not as good' as a 'B'.Get a Rover V8, easy to pop in (apparently) sound great, plenty of cheap horses/parts available.
I want a V8.
O series because it has some simple benefits which have attracted me to it, and because I happened across it. Its fairly cheap, a 2.0l complete engine (recently rebuilt to 2.1l) was £100, and can bolt straight onto the B gearbox (as it uses a sherpa bell housing which used the B box), I like the 4 +2x o/d set up. The mid range torque and OHC make for a more reliable engine to IMHO. I'd taken the B as far as I could without spending silly money. I had a very good set up and it was very quick, yet for motorway cruising and touring, I didn't think the B would cut it. Just my experience from motoring around in the B for ages. So I plumped for the O. I agree that the M or even the T (Turbo) would be great, and yes I couldn't get near a flat 6 (which I would love) or a V8 which would probably Kill me, so I ended on the O. 110 bhp as standard plus another 15% at least with fairly easy tweaks. Ok, not past the 150bhp+ that a K for ex. could deliver but then we're all different aren't we. Anyway, its not all about the engine. I've ripped out the back seats, heater, bumpers, valence, steel bonnet (now ali), radio etc etc using the m3 principle, I hope to get good soild peformance and fun from it; anything I don;t need for touring will go. Power to weight ratio will hopefully be improved and so peformance.
I know its not the M, but I don't care. I've done my research and hope to have a real minter as part of the whole car rebuild..just hoped you could help.
I know its not the M, but I don't care. I've done my research and hope to have a real minter as part of the whole car rebuild..just hoped you could help.
Stephw1 said:
O series because it has some simple benefits which have attracted me to it, and because I happened across it. Its fairly cheap, a 2.0l complete engine (recently rebuilt to 2.1l) was £100, and can bolt straight onto the B gearbox (as it uses a sherpa bell housing which used the B box), I like the 4 +2x o/d set up. The mid range torque and OHC make for a more reliable engine to IMHO. I'd taken the B as far as I could without spending silly money. I had a very good set up and it was very quick, yet for motorway cruising and touring, I didn't think the B would cut it. Just my experience from motoring around in the B for ages. So I plumped for the O. I agree that the M or even the T (Turbo) would be great, and yes I couldn't get near a flat 6 (which I would love) or a V8 which would probably Kill me, so I ended on the O. 110 bhp as standard plus another 15% at least with fairly easy tweaks. Ok, not past the 150bhp+ that a K for ex. could deliver but then we're all different aren't we. Anyway, its not all about the engine. I've ripped out the back seats, heater, bumpers, valence, steel bonnet (now ali), radio etc etc using the m3 principle, I hope to get good soild peformance and fun from it; anything I don;t need for touring will go. Power to weight ratio will hopefully be improved and so peformance.
I know its not the M, but I don't care. I've done my research and hope to have a real minter as part of the whole car rebuild..just hoped you could help.
Sorry, didn't mean to come across with a 'you shouldn't do that' attitude. If you've happened across an O series engine, you're right, it's a decent little number. A few tweaks and yes, you'll be looking at a very quick 'B'. Lightening a car is the cheapest way to get more performance, I too have had the rear seats ripped out, and there's nowt in the car that doesn't need to be there I know its not the M, but I don't care. I've done my research and hope to have a real minter as part of the whole car rebuild..just hoped you could help.
The O Series engine was actually intended for the MGB, it's much lighter than the original B series engines (by about the same amount the six was heavier
20kgs 
) so that in itself is an improvement. I thought stock was around 90 - 100bhp, but then I know diddly. Perhaps this was on a single carb? What else are you planning? I'd say 150bhp is easily achievable with that engine for 'not silly money' as you put it.What was the engine originally in?
No worries, I didn't take offence.
I originally had a stage 2 B (modified head, o/b +0.30, K&N filters, Peco HDR straight through, modified carbs. I ran it on leaded fuel so the car used to fly. I had converted the original rb to semi sebring style, ditched the back seats and parcel shelf and anything else that would come off. I lowered the rear with lowering blocks and chrmome bumper rear springs and then upgraded the whole suspension with poly bushes. I kept the ARB standard but lost the rear ARB. It made the car tuck in more neatly into corners with the front fairly flat and the back quite loose. I put slightly stiifer srings into the front to, refurbished calipers and greenstff pads. All sensible upgrades. System worked very well and I could afford to be pretty brutal with it.
The problem was that the push rod system of the B meant that I couldn't take the car as far as I wanted- it was mechanically to slow and inefficient. Hence my comment about using ££££ to upgrade the engine. I had considered roller rockers and further head mods. I even bought a brand spanking new Weber to put on but then considered again what I wanted. i.e. a long distance tourer/weekend special/ (corsa eating) B. I fel the engine couldn't give me what I wanted so when I had a HGF (crap copper type of gasket) I fixed the engine with Payen and sold it on.
By chance I came across the O series. A re-built unit which had stood for 14 years. A bit dubious about it but with only minor mods could quite easily fit to the B. Like you said, it is still in the family before the M, T, K etc. he engine was used first as a 1700cc in the Sherpa with only 1 carb (HIF 6?). It then spawned other uses into the Rover SD1 (which is where my engine used to live) with a twin carb (HIF 6?) set up, again quotes I have seen say 110bhp was standard for this unit at that time. It then lead to its use in the maestro with EFi. [I have all three engines as I went on a buying frenzy]. The O from the Rover SD1 was mated to an LT77 gearbox and the bell housing is that rare item demanded from people trying the M upgrade! Both sold.
My plan is to use the twin carb set up as a basic set up.(if I could figure out how to put photo's in I'd show you) Not knowing the condition of the engine as teh seller claimed I had the engine stripped and re-built and true to his word it is completely new. I have replaced the gaskets where necessary and put in new parts just for peace of mind. The hone marks are still on the block and the head looks virtually new. So all good.
I'll use the back plate from the Sherpa engine on the O and match it to the B box. I've bought a new B box to mate the two together. Should stand the beating it may get with any improvement in peformance. I'm planning on using EDIS and will probably (when funds allow) take the engine over to PB for a head upgrade and cam change. It will again use the Peco HDR (bought new, old sold with previous system) as the manifold can be mated to the exhaust no probs. My engine is an 01 SOHC, so in that terms it has the dizzy at 90 degs. to the head rather than the later 02 which has the dizzy in line with the head.
I've reseached the cooling of the engine and found it had slightly more capacity than a standard B so I have bought a MG Motorsport high flow capacity rad. 16 row oil cooler and in-line thermostat just to make sure I don't over cool.
I'm also under taking a full body rebuild of c/b 72 B. The idea being that everything is new. I'm upgrading the suspension as per Doug Smith using the neagtive camber kit, new front dampers with peformance valves, new springs and a 7/8 ARB. (new calipers, steering rack, etc etc).
I'm now upto sand blasting and red oxidising the body of the car ( i also have some welding to do, but I have asked a professional) and then trial fits with the Engine and mounts. The rest is mechanno, fingers crossed.
I'm interested in tuning of the engine- is there anything you think I can do?
(as a ps I'm fitting re trimmed BMW mini cooper seats as they fit nicely and are more snug than the old B deck chairs I have).
I originally had a stage 2 B (modified head, o/b +0.30, K&N filters, Peco HDR straight through, modified carbs. I ran it on leaded fuel so the car used to fly. I had converted the original rb to semi sebring style, ditched the back seats and parcel shelf and anything else that would come off. I lowered the rear with lowering blocks and chrmome bumper rear springs and then upgraded the whole suspension with poly bushes. I kept the ARB standard but lost the rear ARB. It made the car tuck in more neatly into corners with the front fairly flat and the back quite loose. I put slightly stiifer srings into the front to, refurbished calipers and greenstff pads. All sensible upgrades. System worked very well and I could afford to be pretty brutal with it.
The problem was that the push rod system of the B meant that I couldn't take the car as far as I wanted- it was mechanically to slow and inefficient. Hence my comment about using ££££ to upgrade the engine. I had considered roller rockers and further head mods. I even bought a brand spanking new Weber to put on but then considered again what I wanted. i.e. a long distance tourer/weekend special/ (corsa eating) B. I fel the engine couldn't give me what I wanted so when I had a HGF (crap copper type of gasket) I fixed the engine with Payen and sold it on.
By chance I came across the O series. A re-built unit which had stood for 14 years. A bit dubious about it but with only minor mods could quite easily fit to the B. Like you said, it is still in the family before the M, T, K etc. he engine was used first as a 1700cc in the Sherpa with only 1 carb (HIF 6?). It then spawned other uses into the Rover SD1 (which is where my engine used to live) with a twin carb (HIF 6?) set up, again quotes I have seen say 110bhp was standard for this unit at that time. It then lead to its use in the maestro with EFi. [I have all three engines as I went on a buying frenzy]. The O from the Rover SD1 was mated to an LT77 gearbox and the bell housing is that rare item demanded from people trying the M upgrade! Both sold.
My plan is to use the twin carb set up as a basic set up.(if I could figure out how to put photo's in I'd show you) Not knowing the condition of the engine as teh seller claimed I had the engine stripped and re-built and true to his word it is completely new. I have replaced the gaskets where necessary and put in new parts just for peace of mind. The hone marks are still on the block and the head looks virtually new. So all good.
I'll use the back plate from the Sherpa engine on the O and match it to the B box. I've bought a new B box to mate the two together. Should stand the beating it may get with any improvement in peformance. I'm planning on using EDIS and will probably (when funds allow) take the engine over to PB for a head upgrade and cam change. It will again use the Peco HDR (bought new, old sold with previous system) as the manifold can be mated to the exhaust no probs. My engine is an 01 SOHC, so in that terms it has the dizzy at 90 degs. to the head rather than the later 02 which has the dizzy in line with the head.
I've reseached the cooling of the engine and found it had slightly more capacity than a standard B so I have bought a MG Motorsport high flow capacity rad. 16 row oil cooler and in-line thermostat just to make sure I don't over cool.
I'm also under taking a full body rebuild of c/b 72 B. The idea being that everything is new. I'm upgrading the suspension as per Doug Smith using the neagtive camber kit, new front dampers with peformance valves, new springs and a 7/8 ARB. (new calipers, steering rack, etc etc).
I'm now upto sand blasting and red oxidising the body of the car ( i also have some welding to do, but I have asked a professional) and then trial fits with the Engine and mounts. The rest is mechanno, fingers crossed.
I'm interested in tuning of the engine- is there anything you think I can do?
(as a ps I'm fitting re trimmed BMW mini cooper seats as they fit nicely and are more snug than the old B deck chairs I have).
Well seeing as you're already in contact with Doug, I suggest you make him your first port of call, although I'm not too sure what his experience with the O Series is. Failing that speak to the Montego/Maestro owners, although I think they all seem to stick turbos on?
I think you seem to have a fairly good idea of what you want, I on the other hand like history of cars and engines, but technical stuff tends to be out of my spectrum.
The search for more will always go on....next year I'm hoping to install Cosworth Conrods and pistons, a steel crank, and the bigger jets on the webbers.
Would like to see some pics, if you uploads to somewhere like 'webshots' then they have a link on the right hand side wich you can copy and paste on here, make sure you have size about 500.
I think you seem to have a fairly good idea of what you want, I on the other hand like history of cars and engines, but technical stuff tends to be out of my spectrum.
The search for more will always go on....next year I'm hoping to install Cosworth Conrods and pistons, a steel crank, and the bigger jets on the webbers.
Would like to see some pics, if you uploads to somewhere like 'webshots' then they have a link on the right hand side wich you can copy and paste on here, make sure you have size about 500.
Watch what you're doing with the torque! The police tried V8s with standard gearbox and overdrive and discovered that the torque on a mild V8 would trash overdrive in 3rd - hence overdrive on V8s was only on 4th. You may find you need to upgrade the propshaft too. Don't know enough about the figures for each engine, but I suspect a tuned O series could get close to the detuned range rover v8 they used in production V8s.
surely not? are you pulling my leg?
I'd spoken to PB who has stack loads of experience with modifying heads for Maestroes which had the O and had said that the peformance could be increased a bit. But I can't imagine that it would even touch a ropey v8 for torque. The cubic displacement for my SOHC O1 series is 2098cc (flat 4). I have heard that the engine is 'torquey' but I'd never thought that much...?
I have a 'new' gearbox,overdrive and recent 'new' prop. I thought the half shafts on the axle may be a worry but neither of the other items. Mind you, o/d 3rd may push it a bit in the middle of the band,....hmmm.
When I accerlate hard I use 1,2,3 (red line) 3o/d, 4, 4o/d are you suggesting that I take the car to redline in 3rd and skip the o/d? I've not got the engine firing yet so I hadn't given 'my style' any thought. I always found to much of a gap between 3rd and 4th...
(Working on putting up pictures, watch this space)
I'd spoken to PB who has stack loads of experience with modifying heads for Maestroes which had the O and had said that the peformance could be increased a bit. But I can't imagine that it would even touch a ropey v8 for torque. The cubic displacement for my SOHC O1 series is 2098cc (flat 4). I have heard that the engine is 'torquey' but I'd never thought that much...?
I have a 'new' gearbox,overdrive and recent 'new' prop. I thought the half shafts on the axle may be a worry but neither of the other items. Mind you, o/d 3rd may push it a bit in the middle of the band,....hmmm.
When I accerlate hard I use 1,2,3 (red line) 3o/d, 4, 4o/d are you suggesting that I take the car to redline in 3rd and skip the o/d? I've not got the engine firing yet so I hadn't given 'my style' any thought. I always found to much of a gap between 3rd and 4th...
(Working on putting up pictures, watch this space)
(still trying to fiddle with pictures)
general update...
upgrade is a bit of a 'mare fitting the sherpa clutch to the 4 syncro box...problem being the avaliability of parts...bought a new clutch today which was the only one on the Northwest!! However, I have also been told that a standard B clutch would have worked equally as well... The upgrade and beauty of the Sherpa unit is that it uses a roller release bearing onto the pressure plate, which should hopefully make for smoother gear changes?! watch this space.
still very worried about 3rd o/d now.
car off for shot blasting this weekend...
general update...
upgrade is a bit of a 'mare fitting the sherpa clutch to the 4 syncro box...problem being the avaliability of parts...bought a new clutch today which was the only one on the Northwest!! However, I have also been told that a standard B clutch would have worked equally as well... The upgrade and beauty of the Sherpa unit is that it uses a roller release bearing onto the pressure plate, which should hopefully make for smoother gear changes?! watch this space.
still very worried about 3rd o/d now.
car off for shot blasting this weekend...
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