red reading
Active Member
Right after someone asked I will explain why they are used on race engines.
A torque plates discription is basically a big lump of metal normally aluminium that has four centred bore holes the same as your engine block and bolt holes in the correct place ,it is used to replicate the forces put on your engine block when the cylinder head is torqued down, you may ask why we'll the reason's listed below will help to explain:-
when the bolts or studs for a block are tightened to the specified figure by the manufacture this pulls the metal around it and compresses it, the area around the stud moves and tends to transfer to the cylinder liners and distorts them slightly, on a race engine or an engine you are trying to make reliable at higher than standard power this is not good.
you will and do get high and low spots in the cylinder or to exaggerate this the cylinder will be more egg shaped than round, now in most cases this means you will get blow by from the piston (the piston crown is supposed to expand to the point on a well built engine at proper running temp to nigh on seal the cylinder to the point you don't need piston rings!) which means you are losing power , and in some areas of Motorsport every little helps ,so you don't want to loose it .
now in the worst case you will actually get distortion to the point that you will get piston and bore scuffing which will eventually destroy your engine as the gases will escape from above the piston crown down the sides and cause even more hot spots ( such as ring lands failing,partial seizure and pistons shattering)
now basically when the torque plate is fitted to the block and torqued to spec (and also the main bearing cap bolts) they then bore and hone the cylinders, when you then build your engine you should find that the cylinders are perfectly round.... Until you take the next thing into account.....all proper engineering companies will do any machine work with the materials stabilised at an industry standard of 20oC in temp.....not the running tempreture of the engine is it! So when building a serious engine you will find that they hot hone the engine, which is exactly as it says they actually in one method pass water thru the water gallery/jacket of the engine block at the running tempreture you specify.
this is actually the nigh on perfect way of building a race engine and also the way F1 etc build there engines (remember every little counts), but there is one issue with setting an engine up like this.....the tolerances are so tight at -5oC on a cold morning you won't be able to start the car with out pre heating the coolent to running temp and the oil........... So basically it's horses for courses on how perfect you want to go and what your target use is for your engine.....I personally cannot see the point of doing the above on stock gtir blocks up to 550bhp and for a predominat road based engine as the blow by is minimal without.....but for a blue printed race block......I definitely would
Any comments or expansion wanted please ask.
A torque plates discription is basically a big lump of metal normally aluminium that has four centred bore holes the same as your engine block and bolt holes in the correct place ,it is used to replicate the forces put on your engine block when the cylinder head is torqued down, you may ask why we'll the reason's listed below will help to explain:-
when the bolts or studs for a block are tightened to the specified figure by the manufacture this pulls the metal around it and compresses it, the area around the stud moves and tends to transfer to the cylinder liners and distorts them slightly, on a race engine or an engine you are trying to make reliable at higher than standard power this is not good.
you will and do get high and low spots in the cylinder or to exaggerate this the cylinder will be more egg shaped than round, now in most cases this means you will get blow by from the piston (the piston crown is supposed to expand to the point on a well built engine at proper running temp to nigh on seal the cylinder to the point you don't need piston rings!) which means you are losing power , and in some areas of Motorsport every little helps ,so you don't want to loose it .
now in the worst case you will actually get distortion to the point that you will get piston and bore scuffing which will eventually destroy your engine as the gases will escape from above the piston crown down the sides and cause even more hot spots ( such as ring lands failing,partial seizure and pistons shattering)
now basically when the torque plate is fitted to the block and torqued to spec (and also the main bearing cap bolts) they then bore and hone the cylinders, when you then build your engine you should find that the cylinders are perfectly round.... Until you take the next thing into account.....all proper engineering companies will do any machine work with the materials stabilised at an industry standard of 20oC in temp.....not the running tempreture of the engine is it! So when building a serious engine you will find that they hot hone the engine, which is exactly as it says they actually in one method pass water thru the water gallery/jacket of the engine block at the running tempreture you specify.
this is actually the nigh on perfect way of building a race engine and also the way F1 etc build there engines (remember every little counts), but there is one issue with setting an engine up like this.....the tolerances are so tight at -5oC on a cold morning you won't be able to start the car with out pre heating the coolent to running temp and the oil........... So basically it's horses for courses on how perfect you want to go and what your target use is for your engine.....I personally cannot see the point of doing the above on stock gtir blocks up to 550bhp and for a predominat road based engine as the blow by is minimal without.....but for a blue printed race block......I definitely would
Any comments or expansion wanted please ask.
