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Posted

Any thoughts on this camshaft profile for a stock rebuilt 2500 S engine which will be running on twin SUs?

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I sent my 307621 for a regrind but the specs on what's come back doesn't seem to match the profile I expected. From what I can find online it's closer to the 311399 camshaft profile. Paperwork says it's a Wade profile 0480B but I can't find any details about that.

I admit camshafts and timing boggle my mind somewhat so I'm not sure whether to kick up a fuss about this or whether to just fit it and forget about it. I'm not a particularly spirited driver but obviously don't want to go through the hassle of an engine rebuild to end up driving around in something unnecessarily asthmatic.

Posted

I can't answer as to what that profile is on the ticket but with duration of 253 degrees inlet/257 exhaust, it looks only a marginal improvement over the original 2500S cam which from memory is 10/50 inlet and exhaust for duration of 240 degrees.

The Triumph 308778 profile with duration of 270 degrees gives perfect road manners with noticeably better top end performance, or Chris Witor's CW3021 which has the same timing as the 308778 with extra lift on the inlet valves. I have a CW3021 in a 2500S engine in my GT6, with twin HS6 SUs and I'm impressed by how well mannered it is at low revs but pulls hard to 5,500 rpm redline! Chris Witor also advises skimming the head for compression ratio of around 9.5:1.

Hope this is of some help.

Nigel

Posted

Thanks Nigel, reply is much appreciated.

As long as this profile is an improvement, however small, on the original I guess I'll live with it. I just didn't want to go backwards.

I did tell the company I wanted to reprofile to the 308778 specs and they seemed to give the impression they knew what that entailed. In hindsight I should have been more specific about the exact specs I wanted. You live and learn I guess...

It's not as if I can send it back to be reprofiled again so my options are limited really.

The car will mainly be used for cruises to the beach, drives through the wine regions etc and won't really see much in the way of speed so top end performance isn't really that important to me. Hopefully if I can get the carbs and ignition set up 100% right then it should be fine for my needs.

 

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