Ministock Rule Update 08-08-17 Following on from the positive feedback received under the Consultation process in late 2016, the Board have agreed to the following rule updates to be made on the Ministocks. Please note that the changes that are to be implemented immediately are only clarification of existing rules. The Board would like to thank you for the high number of responses and positive feedback received which has made the implementation of these rule changes achievable. Note: Rule clarifications in green apply immediately. Rules printed in RED will be implemented in the 2018/19 season. Those printed in Blue will be implemented in the 2019/20 season T15-1-22 Tyres Standard road tyres only permitted. (No winter type treads, Town and Country, off road, Sherpas, racing type or slick retread tyres.) Tyres may be grooved to original tread patterns, maximum width of groove 10 mm, for 2017/18 season only. From 1 st September 2018 regrooving of tyres is not permitted. Maximum tyre width 190mm. A standard road tyre is defined as a non-studded tyre that is legal for highway use in New Zealand. T15-1-23 Restrictor Plate (a) The approved 2015 Restrictor plate supplied by SNZ must be fitted between the inlet manifold and the carburettor insulator or between carburettor insulator and carburettor. (b) The restrictor plate must have two circular holes each with a maximum diameter of 17mm. diameter circular holes. (c) The internal holes of the restrictor plate must not be modified in any way. The restrictor plate must not be modified in any way T15-1-24 Engine (a) Engine must be standard (no hot cams), standard two choke carb, standard exhaust & inlet manifold, standard head (eg: no porting etc), standard pistons, maximum piston oversize - 60th. UNLESS IT SAYS YOU CAN MODIFIY THEN YOU MUST NOT! (a) The engine to be OEM unless otherwise stated in the sections below. Modification of components is not permitted in anyway except where a specific modification is stated in these regulations. Unless it says you can then you MUST NOT.
(b) The head, manifold and gasket cannot be modified. All Nissans must use the Payen/ACL gasket part # JA010, and the stud pattern of the head and manifold must match the gasket without modification. (c)(b) The use and fitment of alternator is optional. (d)(c) Standard OE air cleaner housing, not cut, drilled or modified in any way, with the exception of T15-1-24(i)-(xii) below. Air filter element is free; refer Rule E3-3-5. (e)(d) No SSS, GT or any other performance parts. No lightening or polishing of any engine parts. No electric fuel pumps, fans or electronic ignitions. No offset rockers or shafts, cam timing must be STD. (e) All engines must be measured for capacity compliance and have two SNZ Approved Seals applied to the block and sump and to be sealed. Engines are subject to inspection at any time. If a car performs too well, the driver can supply gaskets so the engine can be stripped down, checked and reassembled ready to race (if it complies) at the protester's expense. (f) Only single valve springs may be fitted to inlet and exhaust valves. (h)(f) Any engine inspected and found to contravene the rules will be declared an illegal engine. Refer Section M7-4 Specific Technical Offences. Engine - Things you can do: (i) Any radiator may be used. (ii) Engines may be balanced. (iii) Valve spring tension may be altered. (iv) Electric idle solenoid may be removed and the resulting holes blocked off. Carburettor jets may be drilled out. All other carburettor parts must be in place and be functional. (v) Maximum piston oversize: 0.060in. (vi) Max compression ratio 10.0 to 1. (vii) One piece of box steel may be used in place of rubber block in engine mounts. (viii) Strop may be fitted to help hold engine (ix) The exhaust hot box flapper valve, shaft, counterweight and spring may be removed from the manifold. The holes left in the manifold can be suitably plugged to stop the escape of exhaust gases. (x) Distributor must be standard in appearance. It may be recurved and the vacuum advance does not need to be functional. (xi) Air cleaner to tappet cover breather hoses and Positive Crankcase Ventilation (PCV) hoses are optional and if removed may be replaced with aftermarket breathers. (xii) The air cleaner Air Reed breather valve may be removed.
(g) (h) (i) Cylinder Head (i) Cylinder head must be in OEM form and must retain the original manifold stud pattern. (ii) Heads with the casting number M30 064 are NOT PERMITTED. (iii) Aftermarket head studs are not permitted. OE and Aftermarket Cylinder Head Bolts are permitted. (iv) The head must NOT be modified in any way, unless otherwise stated in the sections below. (v) Material can be removed from the cylinder head surface. (vi) Max Compression ratio 10.000 to 1. (vii) Polishing of any components is NOT PERMITTED. This includes but is not limited to Valves, Valve Spring Retainers, Ports and Chambers. (ix) Valve seats can be refaced and valves can be refaced. (x) Valve spring tension may be altered. OE Spring retainer to be used.. Shims must be flat. Stepped shims and valve spring locators are NOT PERMITTED. (xi) Modified rockers or shafts are not permitted. (xii) Datsun engines must use the Payen/ACL/Permaseal gasket part# JA010, Toyota engines must use the ACL# Intake:EJ290, Exhaust: JA029 and the stud pattern of the head and manifold must match the gasket without modification. Engine Block (i) Engine block must be in OE form. (ii) Modification of oil galleries is NOT PERMITTED (iii) Offsetting of Bores is not permitted. (iv) Removing material from or polishing the block, bearing caps and bolts is NOT PERMITTED. (v) Aftermarket Main bearing cap bolts or studs are not permitted. (vi) Block face can be machined. (vii) Main and Big End Bearings may be replaced with an aftermarket bearing. (viii) Permitted Engine Stroke Toyota 66mm +/- 0.127mm. Datsun 70mm +/- 0.127mm. Rotating and Reciprocating Mass (i) Balancing of the Rotating and Reciprocating Mass is permitted subject to the following being adhered to: (ii) Crankshaft may be drilled perpendicular to the rotational axis for balancing purposes. No other material is permitted to be removed. Polishing of crankshaft counterweights is NOT PERMITTED. Crankshaft grinding to suit max 0.5mm undersize bearings is permitted. (iii) Material can be removed from the small end of a maximum of three conrods only for balancing purposes. (iv) Polishing of conrods and crankshaft counterweights is NOT PERMITTED. (v) Shot penning of Crankshaft, Conrods or Pistons is NOT PERMITTED (vi) Conrod bolts are to be standard with no modification; NO aftermarket Rod, bolts or nuts are permitted.
(vii) Pistons are to be OE Datsun, or a standard replacement piston with the following part numbers: PNIA 1240603E, PNIA 1240403E and PNIA 1240203E, PNIA 1240003E, PS201A12.50, PS201A121.00, PS201A121.50, PKN1407301G. (viii) Pistons are to be OE Toyota, or a standard replacement piston with the following part numbers: PT03K40004E, PT03K40201E, PT03K40204E, PT03K40404E, PT03K40604E, PS2023K1.00, PS2023K1.50. (ix) It is not permitted to remove material from the pistons, with the exception of the top ring land groove to allow the use of a ring saver insert. (x) Piston Rings are to be standard or standard replacement and meet the following measurements: Top Ring: 2mm, Second Ring 2mm and oil Ring 4mm. (j) (k) Camshaft Refer to current cam shaft specs list in the tables below. (i) Cam gear to be OE only. (ii) It is not permitted timing chain sprockets to be modified, dowel hole must not be moved and no extra holes drilled or machined. Offset dowels and keys not permitted. (iii) Timing chain must be OE or OE replacement. (iv) Camshaft timing in relation to crankshaft must not be altered. (v) Camshafts are subject to inspection at any time. Inlet, Exhaust Manifold and Carburettor (i) Inlet and exhaust manifolds must be OE (ii) Modification to inlet or exhaust manifold is not permitted. (iii) No porting or polishing of inlet or exhaust manifold is permitted. (iv) The exhaust hot box flapper valve, shaft, counter weight and spring can be removed from the manifold. The flapper valve shaft holes left in the manifold can be suitably plugged to stop the escape of exhaust gases. If hot box flapper valve, shaft, counterweight and spring remains in the manifold it must retain OE form and function. The OE or an SNZ approved alternative hotbox gasket must be in place. (v) It is not permitted for the hot box flapper valve to be welded in an open or closed position. (vi) OE two choke carburettor is to be used. (vii) Model # Datsun: Hitachi DCG06 or 6010-H1602 or Chinese replacement carb # 16010-H1602. (viii) Model # Toyota: 3K Aisan ISO (ix) Modification of the carburettor is NOT PERMITTED. (x) Electric idle solenoid may be removed and the resulting holes blocked off. (xi) OE carburettor jets may be modified. All other carburettor parts must be in place and functional.
(l) Engine - Things you can do (i) The use and fitment of an alternator is optional. (ii) Any radiator may be used. (iii) One piece of box steel may be used in place of rubber block in engine mounts. (iv) Engine can be fitted with secondary securing device: (a) Flexible steel wire cable (strops) can be fitted. (b) Two steel flat bars, size 25mm x 3mm x 50mm, with a maximum of four 10mm lightening holes, mounted to existing engine mount holes. See drawing below. (v) (vi) (vii) (vii) Distributor must be standard in appearance. It can be recurved and the vacuum advance does not need to be functional. OE or OE replacement points and condenser must be fitted and be operational. Additional electronic devices are not permitted to control ignition function. Air cleaner to tappet cover breather hoses is optional and if removed from air cleaner, must have breather on end of pipe from block. Positive Crankcase Ventilation (PCV) valve and hose must be removed and hole in intake manifold must be plugged. The air cleaner Air Reed breather valve may be removed.
T15-1-25 T15-1-26 Gearbox: Gearbox will be standard from the donor vehicle, and will be unmodified both internally and externally, with the exception of the gear lever which may be bent to allow for seat clearance. Donor Cars as per rule T15-1(c): TOYOTA 3K 1166cc Bore: 2.95 inches (75.0mm) up to.60th Stroke: 2.598 inches (66.0 mm) Camshaft Lift: Inlet.225" Exhaust.237" Camshaft Duration: Inlet: 66 DGS Exhaust: 66 DGS Valve Head Diameter: Inlet: 36mm Exhaust: 29mm Carburettor Type: Aisan ISO Venturi Diameter: Primary: 21mm Secondary: 24mm Flywheel Weight: 7kg (Min) DATSUN A12 1171cc Bore: 2.87 inches (73.S0mm) up to.60th Stroke: 2.76 inches (70.0mm) only Camshaft Lift: Inlet.222" Exhaust.233" Camshaft Duration: Inlet: 68 DGS Exhaust: 68 DGS Valve Head Diameter: Inlet: 35mm Exhaust: 29mm Carburettor Type: Hitachi DCG 306 or 6010-H1602 Venturi Diameter: Primary: 20mm Secondary: 26mm Flywheel Weight: 8kg (Min)