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MG MGB Technical - 1950 cc B Engine
|Hi Everyone Has anybody had any experience of this modification, I've read that this size overbore can result in oil consumption and other problems, some machine shops recommend offset boring, some say not. I'm undecided what to do with my engine, any comments would be appreciated|
|I had a 1950cc B 3-main engine in an MGA I had. I cannot tell you anything about how to do it, since the car came to me with this already done. |
What I can tell you is that I put approx 30K miles on it, and had no real problems. Perhaps not enough miles to really test its mettle, but enough to realize that it would produce more power, and that it also produces much more heat. Cooling could be an issue, and I would recommend doing all possible to minimize its effects.
As to burning more oil? I never found it to be a real oil guzzler, consuming about 1/2 qt. in about 3K miles (oil/filter change).
Hopefully, others here will have much more info on the process of creating this engine mod. You might want to check the general power production comments offered at this site, http://www.studdsey.fsnet.co.uk/mgbtunings.htm Note that is article will print out at about 45 pages, but it is well worth the read.
|I think 1950cc for fun , 1860 for a daily driver . I beleive the bores can squirm around a bit when they are taken out to 1950, I must admit that my car does go quite well though!|
|My car has a 1950cc engine, had no troubles since it was installed over a year ago, oil consumption is low unless you drive it like you stole it. Goes very well!|
|I have a 1950 (aldon) in my mgbgt, daily use, he has 80000kms (50000mls), HR270 camshaft, SU carbs with KN air filters, maniflow exhaust, a very good engine, powerful and flexible, just one fault it wastes oil.|
|My 1950 in a '71 B-GT is running now for 4 years, 20,000 miles. Build specs are similar to Michel's by the sounds of it. I have headers and K&N filters installed on the SU's. Electronic ignition. I really don't rev it high, and it is very, very reliable. No oil consumption to speak of. Fuel mileage is 25-28 mpg.|
|This is possibly aimed at UK only so apologies to our non UK friends.|
However I'm i the market for a new 5 bearing pre 69 engine and am currently undecided as to what to go for. The chioces seem to be 1860cc . Stage 2 (obviously fully balanced etc.) or fast road 1950cc (there is a stage 2 version of these available).
Which is best for my use? I'm sticking with standard carbs but already run an extractor manifold, single box s/s exhaust k&ns and B&G competiton dizzy.
Mileage wise I guess 10k per annum would be the norm although I have been known to do more.
Any advice greatfully received. Also can anybody recommend a supplier (my race prep man will fit it for me).
|P A F Mallett|
|The 1950 produces only marginally more power than the 1868 and in my opinion the 1868 fast road engine is the best value for money.|
As to oil consumption, I build 1950cc engines with cast and forged pistons - oil consumption hasn't been an issue because I normally liner them - the excessive oil consumption is likely to be the result of cylinder wall porosity and we sometimes see that on any size of rebore - perhaps the reason why MG linered even some new engines and always the gold seals.
|Chris at Octarine Services|
|Hi P A F you didn't give your name ( Paul, Peter,Phil, Timmy? ) Since I started this thread I've spoke to several people about this, it seem 1950 is OK but after I measured my cylinders I can't persuade myself to do this, as the cylinders are getting pretty thin (approx 4mm) so I've compromised and gone for +80 oversize which equates to approx 1890cc, I don't know who to suggest as I like to build my own engines. Try somebody like Oselli, MG Motorsport or Peter Burgess. I apologise for any speeling missteaks as mi speelin is knot veri gud|
|1950 using Lotus TC pistons is not worth the headaches and expense you will go through to get there. If you have to have the HP, go with the Moss super charger on a stock rebuilt engine instead. How do I know? I've got a 1950/Merkur 5-speed in a 72 B. Got almost double the cost of the supercharger in the engine and less horsepower to show for it.|
|I will say this:|
If you're not going to be using an uprated (professionally ported) head coupled with good intake and exhaust components to match, proper cam, distributor and all the related go-fast goodies, you're going to be spending a lot of money to get little improvement.
The weakest link with any stock MGB is the cylinder head. If you read Peter's book, he states essentially the same basic thing. You can do any mods you want to the short-block (including radical cams) but if it's not matched up above, you're not going to get anywhere.
This isn't to say that over-boring the cylinders won't increase torque or horsepower, but it is to say that this sort of modification is more of an extravagance than a first consideration. At least in my book (and I'll gamble that of a few others as well).
|[Quote]Terry Drinkwater, Somerset, United Kingdom, email@example.com|
Hi P A F you didn't give your name ( Paul, Peter,Phil, Timmy? ) Since I started this thread I've spoke to several people about this, it seem 1950 is OK but after I measured my cylinders I can't persuade myself to do this, as the cylinders are getting pretty thin (approx 4mm) so I've compromised and gone for +80 oversize which equates to approx 1890cc, I don't know who to suggest as I like to build my own engines. Try somebody like Oselli, MG Motorsport or Peter Burgess. I apologise for any speeling missteaks as mi speelin is knot veri gud
This is an old style board and whilst I put my name in for registration I also registered this "handle". The name is Peter BTW.
Thanks for the advice, I know Peter B quite well because he's produced heads for me on many occaisions (in fact I'm running a pair on my current race car and he helped me win a few MGCC races in '93) and I also used him for a head for the current B engine in 1986 (pre lead free in UK).
Looks like for overall reliability I'm looking at an 1860 stage 2, which so far I've been offered by MGB Hive. Might look to purchasing new/refurbed carbs rather than go the Weber route.
Thanks for the replies to my question.
You might like to look at my site - I built Alex's engine (see above) and offer a balanced 1868cc fast road engine using a Peter Burgess head & Piper 270/285 cam for £1195.
All my engines are built to customer order so there is a lead time of around 5 weeks at the moment.
Apologies if I upset anyone with this commercial posting - Peter doesn't have an e-mail link.
|Chris at Octarine Services|
|Thanks Chris, I'll e mail you.|
|Reply to Sean Brown, thanks for your comments, yes, I have got all the necessary to go with my rebore, nice head, fast road cam, aldon distributor etc etc. I'll let you all know the result when its on the road. Thanks to everybody for your interest. Terry|
|Sounds like you got it in hand Terry and I hope it works out great for you! |
Do let us know how it runs.
This thread was discussed between 04/04/2005 and 11/04/2005
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