Ex-Works Xu5 Engine

[mollisk 2 1 Cars]

I recently obtained a XU5 engine which was, I believe, fitted to one of the early Group 'A' works cars ( 1984/5 ? ).

The engine was modified in a number of areas, but particularly relating to the combustion chambers. The area of the cylinder head opposite the spark plug has been removed to create a round combustion chamber.

The pistons fitted were Cosworth with raised sections on the piston crown to increase compression and possibly to promote better squish properties, perhaps the engine builders could comment ?

The valves were 41.6 m/m inlet and 34.5 m/m exhaust. The exhaust valves were of a "penny on a stick " design

The connecting rods were also modified be machining the big end area to reduce weight

 

I believe that these engines produced approx. 160 hp.

 

Does any one have any further info. on who built the engines ( In house or Longmans perhaps ? )

The only markings are 2901 and 31.5 stamped on the cylinder head.

 

Regards

 

Mollisk

[Vili 18]

Do you have any pictures of the combustion chambers and the pistons? I'm not an engine builder as such but just interested to see how they did it.

[pug_ham 244 3 Cars]

The valves were 41.6 m/m inlet and 34.5 m/m exhaust.

This is the standard size valves for the later XU5JA 115bhp spec engines.

 

I think quite a bit of the factory cars engine work was done by a company called Ravic who had ties with Peugeot Talbot UK but hopefully someone else might be able to expand on this to confirm & give further info.

 

g

[welshpug 1,661]

had a quick google about and there's a fair few mentions on the name Ravic with Group A engines but no more on the specs, unfortunately the company was dissolved in 2003.

[mollisk 2 1 Cars]

The works Sunbeam Lotus engines were built in house by Phil Davidson ( Ravic ) . I believe that after the end of the Sunbeam program, the factory built a T16 followed by 205 1.6 group 'A' cars, so the 1.6 engines may well have been built by Ravic.

[Baz 421]

Numbers on head sound Longman, last three being the combustion chamber volume iirc.

[mollisk 2 1 Cars]

I'll try to get a few pics posted of the various parts

[mollisk 2 1 Cars]

Pic of modified combustion chamber

 

http://www.flickr.com/photos/87358315@N04/8000358544/in/photostream

 

Cosworth pistons and modified rod.

 

http://www.flickr.com/photos/87358315@N04/8000368522/in/photostream/

 

Comparison of exhaust valves

 

http://www.flickr.com/photos/87358315@N04/8000349468/in/photostream/

 

ID on head

 

http://www.flickr.com/photos/87358315@N04/7999280857/in/photostream/

[Chris H 10]

Phil Davidson of Ravic stil does engine builds from a small unit near Weedon in northamptonshire. If you want to ask him to see if it's one of his hengine pm me and i'll pass on his number.

[Baz 421]

Definitely a Longman number on the head, i have two very similar, Brett Sims may be able to tell you about it.

 

The pistons etc ring a bell as being what was available from PTS/Special Tuning at the time.