david brown td30

[XS650]

Fred , get stuck in , I don't mind corrections at all, on a high quality forum such as this you would expect nothing else. All adds to our knowledge.

[FOWLER MAN]

Hi there Ian and John,
Just having a quick scan through this thread and I must say that it would be very unusual if not unique to have a pre-combustion chamber in such a large diesel engine. Pre-combustion chambers were for smaller high revving diesel engines like those fitted into cars and thats why they all sound so dammed "rattly" when they are running.
Jeremy

Hello Jeremy,
I would like if I may to take issue with the above statement. You probably didn't have the dubious pleasure of working on the diesels of the late 50's and early 60's as I did. At that time direct injection engines were the "wonderfull newly designed instant starting diesels."
Among the indirect injection engines with precomb. or swirl chambers were not only the Cats with the screw in chambers mentioned, but International from the small right up to the 180 h.p. TD24. Their chambers were iserted into the head through, and held in place by large diameter injector housings. I had one break up once and drop into the engine destroying the head and piston.
Lots of Allis Chalmers engines had precomb chambers too, including the 204 h.p. HD21P which I ran in the 1970's.
Moving on to road transport, the Perkins P3,4 and P6 the L4 and R6 all had precomb chambers, together with Thornycrofts.
Other engines addopted the Ricardo designed and patented precomb. chambers. These were marketed with the Ricardo name. Two which spring to mind are Dorman Ricardo and Sentinel Ricardo.
The Sentinel was a horizontal 6 cyl. engine designed to sit under the bed of Sentinel lorrys. A company I worked for in the mid 1960's had four of these on 60KVA generators driving electric screening plants.
Best wishes.
Fred.

[Jeremy Rowland]

Hi Fred,

Yes I was aware of the Cat pre-combustion chamber type diesel and the Perkins too although with Perkins I have considered most of their diesels to be small anyway. Whilst some older larger diesels may of had pre-combustion chambers most of the large diesels were direct injection amongst them the famous Gardner Diesels and which date back to the 1940's and Leyland Diesels too, there are many other makes too that used direct injection.
Only small to medium sized diesels use pre-combustion chambers, Cat were probably the main exception to the rule here, I have several old books on this subject too so when I get five minutes I will have a look out of interest but the majority of large diesels were direct injection and the reason for this is simple its to do with the burning speed of the fuel which is slower than in conventional petrol engines.

Jeremy

[FOWLER MAN]

Hello Jeremy,
Thank you for your reply . I was aware of the Gardner which I think goes back even further to the 1930's, and the Leyland, AEC and the Rolls direct injection engines and others from this period . I have worked on most of them.
The point I was making was that it would not have been unusual or unique to find precoms in diesels the age and size of the David Brown being discussed in the thread.(though not in this particular engine).
Nor would it have been unusual to find them in slow revving engines governed to about 1,500 revs. or less.
Best wishes
Fred

[Peter Dickson]

Hi,
I was interested in the DB30-TD as back in the 60's some of these were used to break in steep hill country in N.Z. i was having a clearout of stuff at home and came across an old David Brown foldout product range sales brochure which shows the specs for the 30 and the td50 which was powered by the 6 cylinder diesel (50 bhp). Interesting!

Cheers,

Dick'o.

[Holger]

Hi Peter,

welcome to CMN!
Any chance that you could scan and upload the brochure?

Best regards