A few questions about 998 997 cams and cranks engine ????

[migliacars]

Ok Ive a few questions id like some help with.

First of all cams and rings. identifying them.

Ive got a few cams lying around and would like to know what there from.

1> slot drive, 1/2 inch lobes, fuel pump lobe present, no rings.
I think its a standard A plus 998cc ???????????

2> pin drive, 3/8 lobes, fuel pump lobe present, 1 ring
Im thinking 997cc cooper cam????????????

3> slot drive 1/2 lobes, fuel pump lobe present, 2 rings.
mg metro ??????????

4> pin drive, 1/2 lobes, fuel pump lobe present, 3 rings marked en32
998cc cooper 731 ??????????



now the crank bit.

Well ive a box off bits that came in a deal a few months ago, was told it was a works 997cc engine but i took that with a pinch of salt.
Anyway

block is a 12a497 which i beleive to be a 998 cooper as its pre A plus. bored .020 with a main strap on it, Its pre 1965, going on the old old style timing cover without the strengthening recesses

pistons are .020 d tops 3 ring

rods are 12g127

cam is the one ive spoke of above
4> pin drive, 1/2 lobes, fuel pump lobe present, 3 rings marked en32
998cc cooper 731 ??????????


Crank
en16
its been balanced at some point and the original numbers are missing, its be restamped aeg601, i cannot find anywhere what this is/ the stamping looks professional

what could it be???????????

my ideal is to use the engine but get the block pocketed so i can bolt on a 12g940 and mate it to a 1275gt c/r box i have
run it on a hif44 or a hs6.
which should make a reasonable fast road mini.
?????

[Spider]

Actually measuring any cam (degree vs lift and logging it) is the best way of assuring yourself as to exactly what it is. Many cams have been reground and not otherwise marked up, also you're never too sure how worn or accurate they are, unless they are a long way out!

Ok Ive a few questions id like some help with.
1> slot drive, 1/2 inch lobes, fuel pump lobe present, no rings.
I think its a standard A plus 998cc ???????????

It probably is likely to be a 998 A+ but it seems there were a few different grinds from the factory by this time that had little to ID them by.

2> pin drive, 3/8 lobes, fuel pump lobe present, 1 ring
Im thinking 997cc cooper cam????????????

Yes, you get a cookie

3> slot drive 1/2 lobes, fuel pump lobe present, 2 rings.
mg metro ??????????

No cigar on that one. Low Compression 998 A+

4> pin drive, 1/2 lobes, fuel pump lobe present, 3 rings marked en32
998cc cooper 731 ??????????

The original 731 factory grind had 3/8 lobes - according to ST paperwork, but I'm very sure they also did them on 1/2" lobed cams too, however, the marking en32 could suggest it has been reground. I would strongly suggest measuring this cam to be sure.

[migliacars]

Thank-you for the advise.
So next question is

if it is a 731 cam should i use that or the 997 cooper cam in my new engine build
998cc plus .020
high compression d shaped pistons
going to pocket the block and use a 33,29 12g940 head in standard trim and a hs6 or hif44

[rich@minispares.com]

Thank-you for the advise.
So next question is

if it is a 731 cam should i use that or the 997 cooper cam in my new engine build
998cc plus .020
high compression d shaped pistons
going to pocket the block and use a 33,29 12g940 head in standard trim and a hs6 or hif44

would d tops work with a 12g940 head?

a distant memory tells me that they wont, don't they wallop the chamber shape / or up the compression too much?

dry build it first and check!

ive always used flat tops on the odd 12g940 headed mini 1000 ive done,

[Spider]

Well, before we go running off on a funny tangent about cams and heads, what do you expect from the engine?

I'd suggest too that fitting a 12G940 head to a small bore engine, especially a 997, is not really a good idea. Flow with these heads is poor on the small bore engines because they have a small bore and the bore centres are quite different to a 1275, so further shrouding the valves and a 997 having the smallest bores of all of them, well,,,,,,,,,,,,,

Also, the big bore heads having bigger ports and valves will have a slower flow velocity, so that will reduce low end RPM flexibility.

So, fitting a bog bore head, to a small bore engine, at low revs, flow velocity is low, reducing potential output and higher RPM flow is shrouded also reducing output at these engine speeds.

[migliacars]

Well it seems good advise so far.

The block is a 998cc not the 997cc so i think the bores are bigger plus its at .020 already, and ive the pistons and rods to suit.
as this engine is just lying around i thought Id put it to good use.
Ive no good small bore heads but Ive a few recon 12g940 heads on the shelf so im thinking more cost verses what I have lying around.
Also got a rod change c/r gearbox with a central oil pickup thats not doing much, got the turbo clutch assemble <new> lying around.

prurpose?
well as i wouldn't drive a mini everyday I think it will just be a summer afternoon sunday dusk car, or a spring morning blast round the country road car. But it would have to tick over very nicely and I wouldnt want a cammy car on the road, im to old for that now. but id like it to be brisk, free revving and red lining at 7000rpm, not after a rocket ship.

Im aware that a standard 1275 would be the better option but Im really liking of the idea of a small bore screamer,!!!!!!!

[Pandora]

Forgive me if this is a silly question, but it's been a while since I thought about the details of this....

I'm on the look out for a 286 cam to use in my inline 998 build (1098 block, 948 Crank, 998 flat top pistons and 295 head), but is there a difference between the cams for A and A+ blocks? (aside from oil pump drive type)

The 1098 block has cam bearings, hence the choice of it over bverboring the 948 block

Cheers,

Al

[InimiaD]

Not 100% sure, but i think you'll need a spacer under the oil pump. 5mm i think.

[rich@minispares.com]

no difference at all

[Pandora]

Excallent, Cheers!

Am I right in thinking an MG Metro cam is equivelent to a 286?

Al

[CooperTune]

I'd say the MG Metro cam is no where near a 286. The MG cam is a cross between a 997 cam and a 731. I like the MG cam and use it in mild street units wanting a good idle. Be careful with used ones. All I have found are worn on at least one lobe if not more. MSC sells a Kent copy as a Kent 500 I think. Ground on a new blank with late slot drive OP. Steve (CTR)

[pigpen]

MG Metro=Kent 266 I think.

[CooperTune]

If you take a look at the Kent Cams book you will see a Kent 266 has in/ex duration of 260/ 270 while a Kent 500 ( also known as a MG Metro has ) 252/268. I plan to pull my SW5 and replace with a Kent 500. Steve (CTR)