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The Block
The block ends are resurfaced for Cosmetic Purposes, the sump is ground with a rough cut and fast machine feed rate, the surface finish this creates is ideal to seal and grip the cork gasket. When fitting the sump cork gaskets no sealant should be used with the exception of joints between the gasket ends and where the flexible plastic bows butt up to the ends of the cork gaskets, a small blob of the RTV Type sealant is applied. The cork gasket can be secured by sticking them in position with a few tacks of impact adhesive.
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Crankcase Main Line
All of the five main bearing caps are lightly ground on the joint faces, the caps are fitted to the Cylinder Block and the securing bolts are torqued to the original manufacturers torque tension. The main line bore is then measured to check that sufficient stock has been ground off the joint faces to allow stock to be honed from the main line bore therefore correcting the bore diameter and most importantly the precision alignment of all 5 bearing housings resulting in a freely turning crankshaft reducing any bending stresses in the Crankshaft. The alignment is maintained to less than half a thousandths of an inch (0.0005”) the main line bore is kept to a roundness of 0.000” – 0.0003” (zero to 3 tenths of a thousandths of an inch.
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Conrods
The rods and caps are precision ground on the joint faces, approx. 0.003” (thou) is ground
off the four joint faces. The caps are assembled to the rods and the conrod bolts are torqued
to the makers recommended torque tension. The big end bore is measured to ensure efficient that sufficient stock has been removed from the joint faces to allow the conrod bore to be honed to the manufacturers original size, the bore is honed on our Sunnen LB 1810 precision honing
machine. The roundness of the bore is maintained to 2 tenths if a thousandths of an inch
(0.0002”), the small end of the conrod is milled on the sides, this is done to allow the 93mm
V6 piston to be fitted to the conrod giving the correct side clearance between the inner
piston bosses and the conrod eye. Each conrod is subjected to a Magnetic Particle Luminor
NDT Crack Test. All four conrods are weighed and balanced in sets, the tolerance maintained
between each set is 0.00 – 0.5 grams.
Crankshaft
The Crankshaft is first inspected and assessed for suitability, the Crank is set up on “Vee Blocks” and checked for bend, then all the Crankpins and main bearing journals are measured to ensure the pins and journals are suitable for regrinding. The conditions of the front snout and flywheel bolthole threads are checked along with the front keyway. The Crank is set up in the Crankshaft regrinding machine, on completion of regrinding the front and rear oil seal tracks are lightly reground with the absolute minimum of metal removed, this process ensures the there is zero run out between the main bearing journals and the oil seal tracks ensuring oil seal reliability and longevity.
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Crankshaft Regrinding
The rear Crankshaft flywheel mounting flange is also reground eliminating any runout and this ensures minimal flywheel face runout. On completion of the regrinding process the oil holes are lightly honed to remove any sharpness at the mouth of the holes and this also allows the lubricating oil to spread across the bearing quicker and more evenly resulting in improved bearing lubrication. All the Crankpins and main bearing journals are polished to give the correct surface finish required to ensure good bearing life. Each Crankshaft is subjected to a magnetic particle non-destructive “NDT” Crank Test where any cracks are identified under ultra violet light.
Pistons:
The pistons used in engines are propriety brand @ 93mm diameter. The are cast aluminium alloy incorporating cast in steel reinforcing struts. The cast in reinforcement plates control the expansion of the piston body and allow the piston to run with less piston to bore clearance than with traditional cast pistons therefore reducing piston noise (commonly known as slap) especially at cold start up. These reinforcing plates also stiffen the piston body increasing the strength of the piston body and reduce the risk fatigue cracks where the piston skirt joins the piston pin bosses. The piston pins are of the semi floating type and are retained by a transition fit in the eye of the conrod.
Fitting Pistons :
The Gudgeon Pins are semi floating and are retained by being a transition fit in the conrod small end eye. There are two methods of fitting the pin to the conrod, the first method is to
support the piston on a shaped bolster and press the gudgeon pin through the conrod small
end eye to the correct installed position however this is not good practice as distortion and
damage are common occurrences and if the piston becomes distorted this will probably
result in piston wear or failure. The correct method of fitting the gudgeon pins to the conrod is to use specially designed equipment. The conrod small eyes are placed in special timed heater cells and when the conrod eye is heated over a pre-determined time the conrod eye is expanded sufficiently to gently push the new gudgeon pin into position and the installing jig is adjusted to give the correct final position of the gudgeon pin, soon after the pin is in position the cold gudgeon pin quenches the hot rod eye and the fit is complete without stressing the piston.
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The Dummy Build
Limits & Fits :- The Conrods are fitted to the Crankshaft out of the Cylinder Block and the
bearing running clearances are checked – ( radial clearance) using plastiguage, the conrod free end play is also measured – ( axial clearance). All the piston ring gaps are measured relative to the Cylinder they are to be fitted to. Each piston running clearance is measured relative to the Cylinder it is to be installed in. The Crankshaft is fitted to the Cylinder Block main line and
again all the main bearing running clearances are measured finally the crank end float is set up. The pistons are fitted to the conrods using special dummy gudgeon pins and these assemblies fitted to the engine.
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Checking Big End Clearances
Each piston is set precisely to TDC, and the piston height in relation to the Cylinder Head Block top Deck is measured To determine the amount of stock to be removed from the Block Top Face. On completion of the bearing and piston clearances the pistons and conrods are removed and also the Crankshaft & Bearings -
Checking Ring Gaps
- the dummy gudgeon pins are also removed. The pistons, conrods & crankshaft are balanced. All components are finally inspected any final cleaning required.
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The Assembly
Pistons are fitted to the conrods using special sunnen equipment, the Crank and Conrod assemblies are refitted to the Cylinder Block, each connecting rod nut is secured with a little loctite. The block ends and sump faces are lightly coated with clear lacquer. The oil seals are pressed into the plates and the rear crank seal fitted and the rear main cap is fitted
with the application of the relevant sealant. The auxiliary Jack Shaft is fitted checking
the running clearance. The front seal carriers are fitted to the block front end. At this stage the two timing belt pulleys are fitted and secured. Sealant is applied to the core plug bores and the new core plugs are fitted. A new pilot bearing is fitted to the rear crankshaft flange. Finally the Cylinder Block is painted also the conrods and pistons are stamped with the appropriate piston numbers. Each main bearing and conrod fasteners are paint spotted after final torqueing.
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The Block
The block ends are resurfaced for Cosmetic Purposes, the sump is ground with a rough cut and fast machine feed rate, the surface finish this creates is ideal to seal and grip the cork gasket. When fitting the sump cork gaskets no sealant should be used with the exception of joints between the gasket ends and where the flexible plastic bows butt up to the ends of the cork gaskets, a small blob of the RTV Type sealant is applied. The cork gasket can be secured by sticking them in position with a few tacks of impact adhesive.
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Crankcase Main Line
All of the five main bearing caps are lightly ground on the joint faces, the caps are fitted to the Cylinder Block and the securing bolts are torqued to the original manufacturers torque tension. The main line bore is then measured to check that sufficient stock has been ground off the joint faces to allow stock to be honed from the main line bore therefore correcting the bore diameter and most importantly the precision alignment of all 5 bearing housings resulting in a freely turning crankshaft reducing any bending stresses in the Crankshaft. The alignment is maintained to less than half a thousandths of an inch (0.0005”) the main line bore is kept to a roundness of 0.000” – 0.0003” (zero to 3 tenths of a thousandths of an inch.
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Conrods
The rods and caps are precision ground on the joint faces, approx. 0.003” (thou) is ground
off the four joint faces. The caps are assembled to the rods and the conrod bolts are torqued
to the makers recommended torque tension. The big end bore is measured to ensure efficient that sufficient stock has been removed from the joint faces to allow the conrod bore to be honed to the manufacturers original size, the bore is honed on our Sunnen LB 1810 precision honing
machine. The roundness of the bore is maintained to 2 tenths if a thousandths of an inch
(0.0002”), the small end of the conrod is milled on the sides, this is done to allow the 93mm
V6 piston to be fitted to the conrod giving the correct side clearance between the inner
piston bosses and the conrod eye. Each conrod is subjected to a Magnetic Particle Luminor
NDT Crack Test. All four conrods are weighed and balanced in sets, the tolerance maintained
between each set is 0.00 – 0.5 grams.
Crankshaft
The Crankshaft is first inspected and assessed for suitability, the Crank is set up on “Vee Blocks” and checked for bend, then all the Crankpins and main bearing journals are measured to ensure the pins and journals are suitable for regrinding. The conditions of the front snout and flywheel bolthole threads are checked along with the front keyway. The Crank is set up in the Crankshaft regrinding machine, on completion of regrinding the front and rear oil seal tracks are lightly reground with the absolute minimum of metal removed, this process ensures the there is zero run out between the main bearing journals and the oil seal tracks ensuring oil seal reliability and longevity.
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Crankshaft Regrinding
The rear Crankshaft flywheel mounting flange is also reground eliminating any runout and this ensures minimal flywheel face runout. On completion of the regrinding process the oil holes are lightly honed to remove any sharpness at the mouth of the holes and this also allows the lubricating oil to spread across the bearing quicker and more evenly resulting in improved bearing lubrication. All the Crankpins and main bearing journals are polished to give the correct surface finish required to ensure good bearing life. Each Crankshaft is subjected to a magnetic particle non-destructive “NDT” Crank Test where any cracks are identified under ultra violet light.
Pistons:
The pistons used in engines are propriety brand @ 93mm diameter. The are cast aluminium alloy incorporating cast in steel reinforcing struts. The cast in reinforcement plates control the expansion of the piston body and allow the piston to run with less piston to bore clearance than with traditional cast pistons therefore reducing piston noise (commonly known as slap) especially at cold start up. These reinforcing plates also stiffen the piston body increasing the strength of the piston body and reduce the risk fatigue cracks where the piston skirt joins the piston pin bosses. The piston pins are of the semi floating type and are retained by a transition fit in the eye of the conrod.
Fitting Pistons :
The Gudgeon Pins are semi floating and are retained by being a transition fit in the conrod small end eye. There are two methods of fitting the pin to the conrod, the first method is to
support the piston on a shaped bolster and press the gudgeon pin through the conrod small
end eye to the correct installed position however this is not good practice as distortion and
damage are common occurrences and if the piston becomes distorted this will probably
result in piston wear or failure. The correct method of fitting the gudgeon pins to the conrod is to use specially designed equipment. The conrod small eyes are placed in special timed heater cells and when the conrod eye is heated over a pre-determined time the conrod eye is expanded sufficiently to gently push the new gudgeon pin into position and the installing jig is adjusted to give the correct final position of the gudgeon pin, soon after the pin is in position the cold gudgeon pin quenches the hot rod eye and the fit is complete without stressing the piston.
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The Dummy Build
Limits & Fits :- The Conrods are fitted to the Crankshaft out of the Cylinder Block and the
bearing running clearances are checked – ( radial clearance) using plastiguage, the conrod free end play is also measured – ( axial clearance). All the piston ring gaps are measured relative to the Cylinder they are to be fitted to. Each piston running clearance is measured relative to the Cylinder it is to be installed in. The Crankshaft is fitted to the Cylinder Block main line and
again all the main bearing running clearances are measured finally the crank end float is set up. The pistons are fitted to the conrods using special dummy gudgeon pins and these assemblies fitted to the engine.
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Checking Big End Clearances
Each piston is set precisely to TDC, and the piston height in relation to the Cylinder Head Block top Deck is measured To determine the amount of stock to be removed from the Block Top Face. On completion of the bearing and piston clearances the pistons and conrods are removed and also the Crankshaft & Bearings -
Checking Ring Gaps
- the dummy gudgeon pins are also removed. The pistons, conrods & crankshaft are balanced. All components are finally inspected any final cleaning required.
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The Assembly
Pistons are fitted to the conrods using special sunnen equipment, the Crank and Conrod assemblies are refitted to the Cylinder Block, each connecting rod nut is secured with a little loctite. The block ends and sump faces are lightly coated with clear lacquer. The oil seals are pressed into the plates and the rear crank seal fitted and the rear main cap is fitted
with the application of the relevant sealant. The auxiliary Jack Shaft is fitted checking
the running clearance. The front seal carriers are fitted to the block front end. At this stage the two timing belt pulleys are fitted and secured. Sealant is applied to the core plug bores and the new core plugs are fitted. A new pilot bearing is fitted to the rear crankshaft flange. Finally the Cylinder Block is painted also the conrods and pistons are stamped with the appropriate piston numbers. Each main bearing and conrod fasteners are paint spotted after final torqueing.
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Big valve into cylinder head
Each Cylinder Head is dismantled completely and the casting chemically cleaned back to bare iron. A visual inspection of the casting is carried out. The Cylinder Head is crack tested in the critical areas, all threads are also checked. The valves guide bores are machined to accept special thin wall bronze valve guide inserts. These inserts are fitted into position and followed by expanding the bores of the thin wall guides by a succession of broaches being driven
through the guides and are expanded until the required gauge size is achieved resulting in the desired valve to guide clearance is attained. The Exhaust valve runs at a slightly greater clearance than the inlet valve this is required because the exhaust valve stem runs much hotter than the inlet therefore requiring more running clearance. Each Cylinder Head is fitted with special hardened exhaust valve seat inserts suitable for unleaded fuel. The Cylinder Head is set up on a specialized machine and a counterbore is machined to a precise diameter and depth. The hardened valve seat insert is then fitted to the prepared Cylinder Head. After fitting the
valve seat is profile cut to give throat, valve and clearance angles. After fitting the Valve guide and Valve seat inserts the inlet and exhaust ports are worked out to the required shapes and sizes, each combustion chamber is shaped and polished and finally each chamber is measured by using fluid and a burette and all chambers arre balanced with 0.5cc. On completion of all major metal removal the Cylinder Head casting is pressure tested to prove that the water jacket has not been ground through during the various process to remove metal from combustion chambers and ports. The head is fitted with a jig that closes off all the water ports, the head is submerged in hot water approx 80◌۫c which simulates the actual running temperature of
the Cylinder Head. The head is then charged with compressed air at approx 120psi, the charged Cylinder Head is re-submerged in the temp controlled hot tank and the casting observed for leaks. The Valves used are of high quality material EN21-4N. The inlet valve head size is 44.5mm and the exhaust head size is 38mm. The valve stems are chrome flashed to give long life and reduce wear. These valves are of Standard Length 111mm and not the long group one
length. Both Manifiold faces are machined with the minimum of stock removal. This is done to ensure these surfaces are flat and achieve a positive seal at the manifold joints. The main face is
machined with the required amount of stock removed to give the correct compression ratio. Once all the major machine work has been carried out the Cylinder Head is nearing completion and a few, final requirements are taken care of, the cam bearings are replaced using high quality bronze overlay bushes, the valve springs “although new” are checked for their spring rate. Once all the work has been completed the head and associated components are finally chemical cleaned and inspected. The casting is painted in all the external casting areas. The fitted heights of the valves and springs are checked, the new valve stem seals are fitted and the valves are sprung up. After the valves have been assembled a vacuum test is carried out on each valve via the port and this test proves that there is no leakage at the valve and seat.
Each Cylinder Head is dismantled completely and the casting chemically cleaned back to bare iron. A visual inspection of the casting is carried out. The Cylinder Head is crack tested in the critical areas, all threads are also checked. The valves guide bores are machined to accept special thin wall bronze valve guide inserts. These inserts are fitted into position and followed by expanding the bores of the thin wall guides by a succession of broaches being driven
through the guides and are expanded until the required gauge size is achieved resulting in the desired valve to guide clearance is attained. The Exhaust valve runs at a slightly greater clearance than the inlet valve this is required because the exhaust valve stem runs much hotter than the inlet therefore requiring more running clearance. Each Cylinder Head is fitted with special hardened exhaust valve seat inserts suitable for unleaded fuel. The Cylinder Head is set up on a specialized machine and a counterbore is machined to a precise diameter and depth. The hardened valve seat insert is then fitted to the prepared Cylinder Head. After fitting the
valve seat is profile cut to give throat, valve and clearance angles. After fitting the Valve guide and Valve seat inserts the inlet and exhaust ports are worked out to the required shapes and sizes, each combustion chamber is shaped and polished and finally each chamber is measured by using fluid and a burette and all chambers arre balanced with 0.5cc. On completion of all major metal removal the Cylinder Head casting is pressure tested to prove that the water jacket has not been ground through during the various process to remove metal from combustion chambers and ports. The head is fitted with a jig that closes off all the water ports, the head is submerged in hot water approx 80◌۫c which simulates the actual running temperature of
the Cylinder Head. The head is then charged with compressed air at approx 120psi, the charged Cylinder Head is re-submerged in the temp controlled hot tank and the casting observed for leaks. The Valves used are of high quality material EN21-4N. The inlet valve head size is 44.5mm and the exhaust head size is 38mm. The valve stems are chrome flashed to give long life and reduce wear. These valves are of Standard Length 111mm and not the long group one
length. Both Manifiold faces are machined with the minimum of stock removal. This is done to ensure these surfaces are flat and achieve a positive seal at the manifold joints. The main face is
machined with the required amount of stock removed to give the correct compression ratio. Once all the major machine work has been carried out the Cylinder Head is nearing completion and a few, final requirements are taken care of, the cam bearings are replaced using high quality bronze overlay bushes, the valve springs “although new” are checked for their spring rate. Once all the work has been completed the head and associated components are finally chemical cleaned and inspected. The casting is painted in all the external casting areas. The fitted heights of the valves and springs are checked, the new valve stem seals are fitted and the valves are sprung up. After the valves have been assembled a vacuum test is carried out on each valve via the port and this test proves that there is no leakage at the valve and seat.
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