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1990 Crossflow SPR Engineering Racing Class B Spec


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Hi, I'm new to these forums. Having just acquired a 1989 Supersprint that's been sleeping for the past few years, I'm beginning work to bring it back to life.


The history of the car shows that in 1990 it was converted by SPR Engineering to 'Racing Class B Spec'. It has a dry sump and various other mods. The rocker cover says 'SPR Engineering' on it.


I can't find much reference to SPR now - seems they probably went out of business a while ago.


Does anyone have any details about what exactly the modifications would have been that were made? Obviously there's the dry sump and I think some suspension changes, but I'm not sure what was done to the engine.

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My first Caterham - a 1992 Supersprint came with an SPR engine - the company was called SPR Engineering and it was based in Bishop's Stortford. It was an official Caterham 7 Service Centre and it offered Caterham builders a number of bespoke engine packages (a bit like Redline or Raceline do today).


They marketed their own Supersprint and Supersprint+ engines for Caterhams (difference was the Supersprint+ was forged pistons and other nice goodies). The engines had their own unique SPR engine number.


As far as I know they were well regarded. Their engine shop employed Mr Roger King (a well known Ford engine guru). He sometimes pops up on this forum.


Roger had all the spec sheets for all the SPR-built engines, so if you can contact him he might be able to let you know exactly what the spec of your engine is.


He was very informative about mine, and told me its complete history.


I also recall that the Racing Class B Spec engines were very highly tuned and to a high standard. If that is what you have you are a 'lucky' crossflow owner.

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Thanks Midas. A spec sheet would be great, so I'll try and find Mr King.


By all accounts this is a pretty fast Crossflow, although I haven't driven it yet, as we're still sorting it out after a few years sitting in a shed.





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Is this on an AX block ?


If Roger built the engine then he will have the spec sheet for it. You will need to get the engine number for him to trace it.


I am sure he will be along shortly, else you can post a ping request in Chit chat.



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From information in my 1989 price list:

Class A was up to 185bhp

Class B was for 125 to 155bhp

Class C was less than 125bhp


Mine is a dry sumped similar Class B xflow of the same age - done by Dave FLashman at Baldyne Engineering - nothing that special just lighted flywheel, balanced, modified head with big valves, polished head and manifolds to improve gas flow - which they claimed gave an extra 12bhp so about 147bhp.



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My car also started life as a Class B racer, it ran a 234 Cam, forged pistons, dry sump and a bit of head work but not too much else. Not sure of the exact spec but I don't think it ever made any where near 150bhp! still it went very well.


I'm fairly surely I have the original invoice for the engine from when it was built by Churchelm(?), I have a vague memory it cost around £3600! but that was before I bought it.



Rob G




Edited by - rgrigsby on 17 Apr 2009 08:36:51

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Mine is still on 234 cams, no steel internals.


The whole job starting with a 1600 block, so including a 90th thou. overbore, pistons, rods etc cost £810 ex vat in 1990!


It's a sign of getting old when you are amazed by inflation.



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My X-flow wears a SPR rocker cover as well.


When I was lookign at purchasing my 7 (gulp - 7 years ago 😳) I spoke to Roger king at length about the engine. He assured me at the time it the engine was "very solid, and built to a nice spec"


I since added a drysump, and a couple of other bits *smile*


I have to say that whilst I have owned the car, the engine has been pretty much faultless. (About 4 years ago, I had the bores "glazebusted" and new rings fitted as it started to smoke a little on the overrun - been fine since)


Although I never thrash it from cold, I am not nescessarily the kindest person to it, and tend to drive it to within an inch of its life.

The car did the USA2005 trip with not so much as a hiccup, and many of you will have seen it on trackdays as well.


On 2 independant rolling roads, (after settign up & tweaking the carbs) it has produced around 185bhp, and it seems to keep up with 200bhp K-series caterhams pretty well *smile* (until I have to stop for fuel 😳) At full chat on track I reckon its comfortably into single figure mpg! *eek*

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Mines pretty much the same, but I have had a couple of years of Gremlins, most of which are the result of components failing which should not have done (Oil pump, unhardened cam followers and valve springs that are supposedly good for 11,000 revs breaking at 8000 *mad*) I suspect that will always be the case with an ageing engine
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Yes Roger has been in touch and given me a bit of info about the engine (see his post above).


Still got the original invoice from SPR for the work done in 1990... bill came to over £5000. Would still like to know exactly what they did, but looks like some records are missing. Certainly they put in new pistons, dry sump system and various other things.


Anyway, soon I'll be driving it and then I'll see what it's like.

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