Engine numbers

[judge1489]

Hi. I’m new to your forum and have to admit to being an MGA owner rather than Riley 1.5, but my engine is Riley. I bought it from a friend in 1975 who had prepared it for use in a stock car and replaced my Gold Seal unit for it. I restored the car and engine recently and both are great.
I have also just been given another Riley 1.5 engine and on comparing the two engine numbers, I notice that the prefix is slightly different.
Could someone explain the relevance/difference and is it possible to date the engine from the engine number.
The two numbers are:
15 RA - U - H 10742
15 RB - U - H 8365.
I’m guessing that like MGA, the U refers to manual and the H high compression.
Thanks
Bill.

[judge1489]

In reply to my own question, as no response from the forum and someone here might find it useful.
Engine numbers prefixed R or RA were 1957 to 1960 Mk1 1.5
Engine numbers prefixed RB were 1960 to 1965 Mk2/3.
The main change was engine output increased from 6obhp @ 4800 rpm and 77lb ft torque, to 66bhp @ 5200 and 82lb ft.

[canuck]

Bill,
I know that the MK I engine has a R prefix engine. My somewhat early MK I car does have this R prefix engine and is MG maroon in colour. This engine is touted to have 68 bhp.  
 


FWIW the body number matched the engine number on the early cars.
 
I believe the RA engines MK II  were as the R engines however painted Austin Green colour. 

The RB engines of the later models, painted Austin Green colour also had a 'better' crankshaft I understand, shared I think from the 1622 engine? and is touted to be as MGA with 72 bhp due to improved porting of the cylinder head. 

The major difference in these engines, (Riley to MGA) was the camshaft timing. 

Back to you

Bruce

[jej]

Hi, just catching up on the Forum having been absent for quite some time. with regard to engine numbers i have checked my engine number against the original log book which shows an engine number starting 15RB-U-H but it was first registered on 26 Nov 1959. How can it be that engine numbers prefixed RB are 1960 onwards if i have an original logbook showing an RB engine registered in 1959.

[ozieagle]

Hi Bill,
Also late to this post. I also don't have a Riley, but a Wolseley 1500, a very similar car.

From the MG forum library, this article describes all BMC engines and does mention the Riley 1.5, about half way through thearticle.

www.mgexp.com/article/mg-engine-history.75

Herb

[canuck]

Dec 31, 2021 13:22:49 GMT jej said:

with regard to engine numbers i have checked my engine number against the original log book which shows an engine number starting 15RB-U-H but it was first registered on 26 Nov 1959. How can it be that engine numbers prefixed RB are 1960 onwards if i have an original logbook showing an RB engine registered in 1959.

Hello John,
Curious indeed.  Good news is the 15RB prefix does indicate a Riley engine. 

The MK1 early Rileys have the engine number matched to the chassis number.   My car #'s shown below.




Verify the car number on the driver door post.  Perhaps your late November registration is a very early 1960's registration? Is your car a MK1? external bonnet & boot hinges?

To help a little more to place the car chronologically, what is the chassis number on the door post? the registration number? the body number on a plate at the firewall above the battery? 



Salut
Bruce

[jej]

Hi Bruce, Thanks for your reply. It's a Mk1 and has external bonnet and boot hinges.
Numbers as follows:
Engine number stamped on plate on engine as in your picture is 15RB-U-H 4616
Chassis number stamped on plate on drivers door post Slightly different to your photo States Riley Motors Ltd, Abingdon on Thames England, When ordering replacements Quote, Car No R-HSR1-15286.
Fishlow Plate, Fisher & Ludlow Birmingham Body Number R14184
There is also a number (53144) stamped into the metal bulkhead / firewall next to the Fishlow plate.
Finally, the vehicle Registration is 847 GJO
The Vehicle was first Registered on 26 Nov 1959 according to the old Registration Book. My father-in-Law purchased it second hand on 23 Feb 1961 (at a cost of £690 12s 0p according to the Hire purchase agreement) and was the second named keeper on on 27 Jan 1961 according to the Registration book. My father-in-law confirms that the car is as purchased and the engine or chassis / body was not changed whilst in his possession. The car remained on the road until late 1969 when it was put into a shed A copy of the Oxford Mail was in the car dated 22 Nov 1969. Car is currently going through full restoration since i took possession of it in Aug 2019.

If you can provide me with any other information and confirm the numbers are original etc that would be great.


Kindest Regards. John

[canuck]

Hello John.

If I do some quick math your chassis number is 5158 later than my one. As well your Fisholow body number is  4464 bodies later than my one. My car is an April 1959 build. These numbers appear to be close enough to be meeting each other on the assembly line so it is conceivable to be a build date of 1959,  late year.  

Your engine number is  enigmatic for sure, and if RB engines were installed in MK1 cars late 1959 then there we have it? I surmise of course.

I think you are aware that one can have a factory build record certificate from British Motor Industry Heritage Trust? This certificate will include both build and dispatch dates, car chassis number, engine number and body number.  Also the colours of exterior and trim as well as factory fitted 'options'.    

This 'official' factory build record will clear up any doubt. 

I hope this helps.

Bruce

[timt]

15RA would be a Riley 4/68... 15RB is the early 1.5 ..Mk2 have the designation 15RD...  as for compatibility with MGA 1500..its essentially the same engine ..the differences limited to camshaft profile and distributor advance curve.. the carburetors have different needles and float chambers ( MGA has larger float chambers that extend forward on front and back on rear carbs..the Riley employs same float chambers as the Mk1 sprite,and they are in between the carbs) power output for the 1.5 is same as stated for early MGA , which was 68bhp.. 

[canuck]

Feb 22, 2022 22:40:26 GMT timt said:

15RA would be a Riley 4/68... 15RB is the early 1.5 ..Mk2 have the designation 15RD...  as for compatibility with MGA 1500..its essentially the same engine ..the differences limited to camshaft profile and distributor advance curve.. the carburetors have different needles and float chambers ( MGA has larger float chambers that extend forward on front and back on rear carbs..the Riley employs same float chambers as the Mk1 sprite,and they are in between the carbs) power output for the 1.5 is same as stated for early MGA , which was 68bhp.. 

Interesting information, thanks.

So this 15RA engine will not have a mechanical tachometer drive if it is aimed at the 4/sixty eight?

salut
B