1965 BMC 4/25

A place for general BMC questions and chat
Ley154
Posts: 70
Joined: Sun Apr 01, 2018 8:22 am
Great Britain

Re: 1965 BMC 4/25

Post by Ley154 » Wed Oct 24, 2018 7:56 am

Hi again. Your tractor is a UK built Nuffield 4/25 although when exported some carried the BMC badging instead. The serial number indicates its a very early build for the model so that's around October 1968. 25P confirms that it was fitted with the petrol ( gasoline to you) 1622cc engine ( its cast on the side of the engine block). The central long number refers to the build specifcation which would just have indicated whether yours was built with a full lighting kit, rear drawbar , trailer tipping pipe, wheel weights and a few other options. Sorry I haven't got the reference paperwork to be able to tell you exactly what the number meant. Regards John Poulter



CNR
Posts: 20
Joined: Fri Oct 05, 2018 11:34 pm
United States of America

Re: 1965 BMC 4/25

Post by CNR » Sun Oct 28, 2018 5:27 pm

Engine block plate :
16T/217/296

CNR
Posts: 20
Joined: Fri Oct 05, 2018 11:34 pm
United States of America

Re: 1965 BMC 4/25

Post by CNR » Sun Oct 28, 2018 5:38 pm

I think I have a few oil rings that have broke. #2 and #3 spark plug is dripping with oil.
I have 120psi of compression in each cylinder. I'm heading to parts store to buy 4 new spark plugs.
Has everyone ever changed the rings on these tractors before ? How much is a set of rings and gasket kit ? Gasket kit that includes head gasket, valve cover gasket.
Is there rod bearings also ? I would want to change them since I have to remove the rod to get to the rings.
I would go ahead and lap the valves and put new valve stem seals on it too
Can I buy the parts from a local parts store or do I have to order them from England?

Rick Cobley
Senior Member
Posts: 260
Joined: Fri Mar 30, 2018 9:32 pm
Contact:
Great Britain

Re: 1965 BMC 4/25

Post by Rick Cobley » Thu Nov 01, 2018 8:58 am

Hi, Ley154 is really the one to advise here on this subject but the gas engine was used in some English cars of the period and so the parts you want may be available from a european car parts supplier your side of the pond.

Regards Rick Cobley

ploughman
Posts: 106
Joined: Sun Apr 01, 2018 6:21 pm

Re: 1965 BMC 4/25

Post by ploughman » Thu Nov 01, 2018 1:34 pm

Hi,
1622 cc, should be a BMC "B" series engine, and so would share parts with an MGB, so parts should be easy over there.
Regards,
Harry

mike.l
Posts: 109
Joined: Fri Mar 30, 2018 10:29 pm
Canada

Re: 1965 BMC 4/25

Post by mike.l » Fri Nov 02, 2018 12:31 am

Hi not picking at Harry but not a mgb engine as that was 1750 cc The b series engine was used in mg production for the mga and the tf these engines were built in the 1950 -65 area of time so not sure if specs would be the same as in a 1970 tractor + tractor mike

ploughman
Posts: 106
Joined: Sun Apr 01, 2018 6:21 pm

Re: 1965 BMC 4/25

Post by ploughman » Fri Nov 02, 2018 10:29 am

Hi Mike,
As an ex BMC mechanic, I can assure you that early MGBs had the 1622 engine, it was the last upgrade which had the 1800. This was also used in the Marina 1800, amongst others. The original MGA used a twincam,( cant remember the cc) but it was far from reliable so ended up with the 1622 pushrod unit. I nearly bought one of the early ones, it broke down on its delivery run! 1622`s were still common units during the 70`s, they may have been a factory fit option, but again I cant remember for certain. The common cars through the workshop then were Triumph, dolomite, stag, gt6, spitfire and tr7, BMC,Mini, Marina,Ital MGB/C, Midget, Rover SD1,Jaguar EX6/S Daimler double six.Land and range rovers abounded, we also looked after the BMC police vehicles.

mike.l
Posts: 109
Joined: Fri Mar 30, 2018 10:29 pm
Canada

Re: 1965 BMC 4/25

Post by mike.l » Fri Nov 02, 2018 1:17 pm

Hi Harry not wanting to get into a ant pissing contest with you or anyone but the b was 1798 cc all of its life
the extract below is from the Wikipedia of the mgb. Just do not want the guy to order a set of rings for the mgb and they will not fit mike


All MGBs (except the V8 version) utilised the BMC B-Series engine. This engine was essentially an enlarged version of that used in the MGA with displacement being increased from 1,622 to 1,798 cc. The earlier cars used a three-main-bearing crankshaft, 18G-series. In February 1964 positive crank-case breathing was introduced and the engine prefix changed to 18GA, until October 1964, when a five-bearing crankshaft design was introduced, the engine prefix became 18GB. Horsepower was rated at 95 net bhp on both five-main-bearing and earlier three-bearing cars with peak power coming at 5,400 rpm with a 6,000 rpm redline. Torque output on the MGB had a peak of 110 lb⋅ft (150 N⋅m) and fuel consumption was around 25 mpg.[9] US specification cars saw power fall in 1968 with the introduction of emission

Ley154
Posts: 70
Joined: Sun Apr 01, 2018 8:22 am
Great Britain

Re: 1965 BMC 4/25

Post by Ley154 » Fri Nov 02, 2018 5:05 pm

Hi. The 1622 gasoline engine ( no diesel version at that capacity ) was fitted to the MGA MK2 with twin carbs and high compression pistons. It was also fitted to the Austin A60 saloon car with single SU carb and 8.3:1 compression pistons and to the JU250 and early Sherpa commercials with low compression pistons 7.2:1. The gasoline version fitted to the 4/25 and 154 tractors was the commercial low compression unit fitted with a small bore downdraught Zenith carburettor ( to limit engine power) and a crankshaft modified to use the diesel engine rear main oil seal and engine end plate. Pistons may have 5 rings normally but the HC ones are likely to have 4 so be careful when ordering replacement rings. Cylinder heads should really have hardened exhaust valve seats fitted to cope with unleaded fuel.
For engine parts I believe in the USA there is a company called Northwood plus look for any classic car parts companies that deal with British 60's vehicles. Two companies in the Uk who will post to the USA are www.charnleys.com and www.tractorspareparts.co.uk. Get yourself a workshop manual as it's invaluable when rebuilding the engine. Regards John Poulter.

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