Thanks Hodgo!
Yeah ive spent many hours studying the cams rule book, wow isnt it a head F..., really ambigous in certain areas, which is quite frustrating, as many hours & $$$ could be spent on doing the wrong thing!
Yes i intend it to be a group C3 4d/e?! The engine size regs is one of those ambigous areas, i really cant work out the true definition of their max engine size (i suspect its to let the porsche guys slip the bigger motors in while screwing everyone else)! So i cant really tell if the big bore stroker is allowed or not!
quoted from cams c3:
Engine:
1.1 Engine requirements:
a replacement cylinder block/engine is permitted subject to the following requirements:
(i) The replacement must be: a production cylinder block of the same configuration, with more than 2500 units sold for road use, which upon application may be approved for tarmac rallies by the CAMS Recognition Committee as a suitable replacement engine; or
(ii) Be a documented CAMS Historic Commission recognised replacement or substitute for use in this period, in which case the approved item shall be utilised in its entirety.
The guidelines for approval of replacement cylinder blocks are that the block shall:
• be produced prior to 1982
• be produced by the same manufacturer as the original
• have the same number of camshafts and location as the original
• have the same number of cylinders
• be made of the same material as original
• be able to be located in the same general location as the original. No body modification is permitted to allow the fitment of the replacement cylinder block.
In regard to Articles 1.2, 1.8, 1.9 and 1.10 following, references to ‘original’ shall mean the original engine fitted to that model, and not the replacement.
(iii) Be a substitute engine approved for use in that automobile in either Group 3C – Production Rally Cars or Classic Rally Cars.
1.2 Capacity: The capacity shall not exceed 6000cc, unless the original was larger capacity.
For the purpose of engine capacity increase, other than those over 6000cc, the capacity of the original automobile may be increased within the following requirements:
(i) Within the limits of the original capacity class, listed below:
...
2001cc - 2500cc
2501cc - 3000cc
3001cc - 3500cc
...
OR
(ii) Alternatively, a maximum of 17% increase over the original capacity of the automobile is permitted.
The automobile will be classified according to its actual capacity inclusive of any bore or stroke increases (or decreases)
1.8 The ignition system is free, save that electronic engine management systems are not permitted unless fitted as original equipment. If so, the electronic engine management system may be modified or replaced, provided the replacement system is from the same period as the original system.
1.10 For naturally aspirated automobiles the complete induction system is free save that fuel injection shall not replace carburettors, unless it was an option on another model of the same family of automobile from the same period.
BodyWork:
• Front mudguards, bonnet, nose panel, boot lid or rear hatch of alternative material are permitted, provided they are of the same external shape as the original panel. The following minimum specifications of alternative materials shall be respected: aluminium – 1.25mm thick; glass fibre/glass fibre reinforced plastic – 3mm thick.
7.2 (i) The use of any under trays, fairings, scoops, louvres, air intakes or exits is not permitted (except as provided for in 6.3) unless supplied by the automobile manufacturer as standard equipment in original production or the competitor can prove their legitimate use on the particular make and model in national or international level rally & circuit racing competition during the period in which the automobile was manufactured.
(6.3 Cooling ducts may be added but these must remain within the perimeter of the bodywork when viewed from above.)
(ii) Notwithstanding the above, the addition of period style bonnet louvres and engine cooling ducts within the bonnet and/or front valance panel is permitted.
7.3 Easily demountable windscreens may be replaced by another screen of a period type. Other glass in all windows except for the windscreen may be replaced by any transparent material of adequate strength (eg, polycarbonate), which must be fixed and operate in the same manner as the glass replaced. Such material shall be not less than 3mm thickness. Safety straps or clips on front and rear windows are permitted.
7.4 The addition of front and rear aerodynamic aids, side skirts and mudguard/wheel arch flares is permitted, provided these are identical with the components originally fitted to a production model of the same body shape and the items are fitted in accordance with the total original package configuration.
Where an automobile does not have access to such components, wheel arch flares may be added by integrating the flare with the guard or bodywork or by bolt-on means, provided that the increase in the total width of the bodywork is less than 100mm and that the flare may not exceed the radius of the original wheel arch opening by more than 200mm. (Refer to diagram 7.) In this case, the maximum track increase allowed is 100mm and for the purpose of wheel and tyre clearance, it is permitted to remove up to 75mm of original bodywork measured radially from the edge of the wheel arch outwards. Any cavity exposed in a door or wheel arch through the removal of metal must be covered by the addition of a metal closing panel. Any body joint protrusions must be rendered safe. The operation of any door must not be affected.
7.5 Bumper bars and over riders may be removed, or replaced by others of the same shape, but of alternate material.
7.11 Wheels and tyres
(ii) The minimum tyre aspect ratio percentages are:
Groups C1, C2, C3
* 1947-1971 = 50
* post-1971 = 40
For Groups C2 and C3, wheel diameters may be varied by a maximum of ±2”, and the width by up to 2” from the standard (not optional) dimensions.
So according to that i might be able run a 3.1/2 stroker kit??? as its within the 17% increase of capacity of an engine (L28) that was originally fitted to an S30 chassis! ...may mean i have to run in 4E?
or
that i can run an engine that is under 3000cc (2501-3000cc), so a lightly bored stroker? = 4D! (ie: 86.5mm bore x 85mm kameari or OSGiken stroke = 2997cc OR 87.5mm bore & an LD28 83mm stroke = 2994cc OR the elusive rumoured 84mm stroker crank? with a 87mm bore = 2996cc)
or
be under 2500cc using a L24 so 84.5mm bore x 73.7mm std stroke = 2479cc OR +17% over stock is 2799cc (86mm wafferthin bore with L26 79mm crank = 2753cc)?!?!?!?!
OSGiken stroker kit :
hmmm its still alittle confusing as to what i can use......
Both the 280z (L28e) and a Jap 240z (L20e) (*s30 chassis) used electronic fuel injection so that covers "1.10" and had electronic dizzys with an ecu, so i think that covers "1.8"! (I did see a 240Z using efi throttle boddies in the classic adelaide a few years ago, maybe it was from the prc rule? hmm....)
The bodywork rules seem to clear the use of fibre panles, polycarbonate windows, flares, certain aero aids etc! As there is plenty of that stuff used on various models of S30 over the years of production (z432, zg etc...) & also the optioned parts used on all the s30 race vehicles of the time (ie: rule 7.2)!
Also according to the rules a 2" increase in rim width & dia. is allowed, so as the 280z & Z432 both used 14x5.5" inch rims a 16x7.5" rim is technically allowed, even though many seem to think a 7" is the max allowed (mainly due to porsche guys that complain i think) as the standard 240z & 260z used a 4.5 to 5" rim (depending on location..?)! (pitty the factory didnt go through with the Z432R rumoured use of 15x7 magnesium rims, but instead opted for the use of 14x4.5 steel rims as they stated that race teams will use their own rims and therefore it would be an unnessessary cost...arrgghhhh where was the foresight?!)
Well thats my understanding of the Cams rules anyway, but will investigate much further before i part with my cash & time modifiying! But thanks for informing me of the AASA rules, i will look into that too!
yeah thankfully the driveline is fairly free to mods, so i will probably use the kameari int gear set in the 240z box & a GTR R200 diff.
I honestly dont care what class i have to run in (may have to run in cat 5), so long as i get to race my dream Z, i will be one very happy chappy!
_________________
"The only way of discovering the limits of the possible, is to venture a little way past, into the impossible." ~ Arthur C. Clarke
'68 Datsun 510sss
'71 Datsun S30 240z
'87 Nissan Skyline R31 wagon
'97 Nissan Stagea RSfourV