2.5 P.I. Cold Start and Engine Number.

[Guest]

Hello, and Seasons Greetings to all.

Maybe not the correct message board to ask this question but worth a try ?.

I have a Triumph Stag with a 2.5 P.I. Engine.

I hope not a silly question but,
Cold start no problem but I do not like to have a choke on for any longer than possible.
Can I assume that choke on, drive as soon as possible, choke off as soon as possible is O.K.
Always worried leaving Choke on for to long, excessive fuel washing oil from cylinders.

I have searched but cannot find. I would like to know what Triumph and what year the Engine came from, it's number is,

MG21730 H EBW

Any information would be gratefully received.

Many thanks, Don Kennedy.

http://www.donkennedy.co.uk/

[stagstr]

imported post

Hi Don,

Thanks for your seasonal greetings - same to you!

Re my earlier post before you bought the car, TR engines either started with CR or CP, and I think yours, beginning with MG is out of a 2.5 PI saloon. The rest means High compression Engine and Borg Warner (auto). Year unknown, I'm afraid.

Last time I suggested you log on to the TR Register site for info on the PI, but it might now be worthwhile also to log onto the Triumph 2000 Register forum for more precise info on the engine.

Your use of the choke is exactly how I used mine on the TR5.

best of luck

Ray

[Gresley]

imported post

Hi Don

Your engine is the pre dowrated 132BHP PI engine from a pre facelift 2.5PI saloon or estate. After MG75000 (1974) the engines were downrated to 125BHP. My own 1972 PI has the original engine which is MG 57451 E, so I would suggest that your engine is 1970 / 1 ish. Its from a MK2 car as the MK1 PI had the prefix MD. The way you describe driving from cold is the way I have driven my PIs from cold for years. I find they sometimes need a little more choke than cars with carbs, in my experience the PI system hates being cold!

Good luck, and season's greetings!

Brian

[seaside bill]

imported post

Don2138 wrote:

I hope not a silly question but,
Cold start no problem but I do not like to have a choke on for any longer than possible.
Can I assume that choke on, drive as soon as possible, choke off as soon as possible is O.K.
Always worried leaving Choke on for to long, excessive fuel washing oil from cylinders.

Don

As already advised you've got a circa 1971 unit originally from a Triumph 2.5PI auto saloon. The PI choke cable splits into two - one bit operates the fuel enrichment lever on the metering unit and the other opens the throttles a tad. Once you've pushed the choke in most of the way, you're not running rich, just opening the throttles a bit to increase idle speed, so nothing wrong with your technique. Don't be surprised if 'hot' starting is helped with a quick pull on the choke when the car has been allowed to cool for an hour or so even in summer (remember those?) - although you certainly shouldn't need to use it other than momentarily while cranking in these circumstances. The Lucas mechanical PI naturally runs a bit rich so a sooty(ish) exhaust is quite normally. If you can get upwards of 22mpg in mixed driving it's running fine.

[Guest]

imported post

Many thanks to all for your time replying. Very interesting.

Looks like ifI need to get normal serviceparts ( Oil filters etc )from my local motor factors I will advise them thatthe engine is from an early 1970s 2.5 P.I. Can I assume that all 2.5 P.I. Engines from the early 1970s are the same ?.

You know what the "Young Lads" are like in some of the motor factors although there is one in Plymouth who are Very good. I realise that more "special" parts will have to ordered from the dealers/suppliers of Triumph parts.

The use of the choke is what I expected, I understand the P.I. system, I just like to "turn off" the choke as soon as possible and keep the revs down until the engine warm.

Once again many thanks, Don Kennedy.