Actual 998 Chat about rebuilds

General Chat with an emphasis on BMC Minis & Other iconic cars of the 1960's. Includes information on MK1 Action days.
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Exminiman
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Re: Actual 998 Chat about rebuilds

Post by Exminiman »

snoopy64 wrote: Tue Jan 17, 2023 2:18 pm Ok, machining all sorted, now +20.

Can anyone recommend a cam close to std and is it worth fitting a duplex timing setup?
Racers will fit Simplex to reduce rotational weight, but in a road car, I would go for Duplex, I dont think Simplex is likely to break, but long term, Duplex is likely to be less prone to stretching and rattling.
Last edited by Exminiman on Sun Jan 22, 2023 2:30 pm, edited 1 time in total.
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Costafortune
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Re: Actual 998 Chat about rebuilds

Post by Costafortune »

snoopy64 wrote: Fri Jan 20, 2023 7:27 pm
mk1 wrote: Tue Jan 17, 2023 2:40 pm Another vote for the evo 1 or alternatively Calvers CST229 is a good bet too.

Personally I put duplex's on all my engines, not sure whether it's really necessary though.
997 type cam isn’t quite the same as the 998 so will the dizzy need re curving?

Please excuse my ignorance!
Absolutely.

The 998 Cooper camshaft is very timid (230/252?) from the Austin 1100. BMC undoubtedly fitted this to restrict power to 55 bhp or so. You only have to compare period road tests to see how much faster it was than a 997.

The 997 Cooper/MG Metro cam is 252/252 degrees and that cam has been improved further still.
Minisprinter
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Re: Actual 998 Chat about rebuilds

Post by Minisprinter »

Costafortune wrote: Sat Jan 21, 2023 12:54 pm
snoopy64 wrote: Fri Jan 20, 2023 7:27 pm
mk1 wrote: Tue Jan 17, 2023 2:40 pm Another vote for the evo 1 or alternatively Calvers CST229 is a good bet too.

Personally I put duplex's on all my engines, not sure whether it's really necessary though.
997 type cam isn’t quite the same as the 998 so will the dizzy need re curving?

Please excuse my ignorance!
Absolutely.

The 998 Cooper camshaft is very timid (230/252?) from the Austin 1100. BMC undoubtedly fitted this to restrict power to 55 bhp or so. You only have to compare period road tests to see how much faster it was than a 997.

The 997 Cooper/MG Metro cam is 252/252 degrees and that cam has been improved further still.

The MG metro cam isn't 252/252 it's 252/268 which is closer to the MS Evo1 cam, basically the MG Metro camshaft has a 997 inlet lobe and a 731 exhaust lobe, in a 998 you will loose bottom end power or if you want you will shift the power up the rev range, all you need to do is look where engines make peak torque, a 997 made peak torque around 3500 rpm and the MG Metro 4000 rpm and that's in a 1275 so a 998 could well be worse. With camshafts the old saying of " less is more" is never more true. Be honest with yourself, where will the engine spend most of its time rpm wise, If you cruise in the 3000-3500 rpm range buy a camshaft that makes maximum torque in that area.

MS
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snoopy64
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Re: Actual 998 Chat about rebuilds

Post by snoopy64 »

As previous posted.. I’m not looking for more performance.. just yeh closest modern equivalent to what I had (not confident in having the old cam reprofiled and treated)

Would the infamous sw5 be better low down or is that another 997 variant?
Cheers

Kevin
OzOAP
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Re: Actual 998 Chat about rebuilds

Post by OzOAP »

Choices to liven up a 998, but still very civilised, would be....Piper 255, then either EVO1 or 567.
No more than 10.5:1 CR
Last edited by OzOAP on Sun Jan 22, 2023 9:42 pm, edited 1 time in total.
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tweedy998
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Re: Actual 998 Chat about rebuilds

Post by tweedy998 »

Many moons ago, my cam of choice for my 998's was the Kent MD266, it's a cam I really enjoyed at the time, but it definitely moved power and torque further up the rev range. This was in the days before the Calver and Minispares items existed and these are more than likely better cams now for all round road use.
1965 Tweed Grey Mk1 Morris Cooper 998
2005 Renaultsport Clio 182 Trophy 407/500
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Peter Laidler
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Re: Actual 998 Chat about rebuilds

Post by Peter Laidler »

Good thread for 998 Cooper and standard 1000 car owners wanting to keep them almost standard - and civilised. I like your take on this subject Snoopy. I'm following it with interest if I get this bloody late 1970 reg Cooper that I want to get my hands on.....
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snoopy64
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Re: Actual 998 Chat about rebuilds

Post by snoopy64 »

It’s messing with my head Peter, lots of info but I haven’t distilled it to a conclusion yet!!
Cheers

Kevin
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Peter Laidler
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Re: Actual 998 Chat about rebuilds

Post by Peter Laidler »

Yep....., know wot you mean. I have been printing the thread off and one windy and rainy evening I'll sit down with a glass of fine Scotch and condense it into a rough book.

I am taking on board what Minisprinter and Costa Brava have to say about cams.
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Costafortune
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Re: Actual 998 Chat about rebuilds

Post by Costafortune »

snoopy64 wrote: Sun Jan 22, 2023 9:34 pm It’s messing with my head Peter, lots of info but I haven’t distilled it to a conclusion yet!!
I understand about not wanting to modify it, but you can tweak a 998 to great effect making it a bit more lively without ruining it. Just 5-10 bhp, a bit more torque but still the same idle and flexibility.
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