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Jul 08, 2014 12:57 pm
Jul 08, 2014 12:57 pm
Subject: Re: 4.5 litre engine problems and upgrades
Very sorry to hear of your woes but very grateful to you for sharing them and I congratulate you for keeping your car as a saloon.
About 15/20 years ago we did have problems with that bottom hose, I discovered (eventually) that it would collapse when revs were up. The collapse was not obvious at first as the hose went back to its usual shape when the revs dropped and it wasn't easy to see through the blur of the fan – but sudden temp changes and boiling were the result. It is just starting to show signs of collapse again above 1500rpm but not so badly as to cause any noticeable cooling problems. On our car the exit from the rad and the entry to the pump are slightly misaligned which puts an extra stress on the hose distorting it very slightly and making this problem more likely to occur. The rad was re-cored before the problem first occurred and had been run with either a sock or stocking for most of the time since so I do not think rad blockage was an issue, its just that that section of connector/hose/connector presents one of the greater restrictions in the system I suspect, and in our particular case one which can easily accommodate the pressures on it by collapsing.
Thank you both David and Alec for the links about Evans which are very helpful. In light of the above I think pressurisation is essential and consequently I would not choose to use Evans. However, I also have great doubts about replacing water with a coolant with lower specific heat capacity in a cooling system which is already compromised by a wide variation in coolant flow rates through the engine (or so it appears to me!), and crucially which lacks the ability to be as self circulating as water is when heat is applied to a motionless or very slow moving volume.
A cooling system oddity came to light in the late 80s when my father replaced the coolant manifold and discovered that the tank engine manifold was substantially obstructed between the two block connections by an irregularity in the internal diameter of the manifold. The result of this was that 4,5,6 would probably have been getting a lot less coolant than 1,2,3. The spares scheme replacement did not have any such obstruction/constriction, nor did the manifold that my father had removed from the car's original (blown up!) engine. We dismissed it at the time as a casting failure that we had been lucky not to be affected by. More recently I have begun to wonder if it might just have been intentional - your own case adds to my suspicions. However, it is also odd that historically 5 and 6 seem to be the problem bores (my father had no5 rod through the side of the original engine when the piston seized/broke up) but our tank engine had survived this manifold obstruction for 35 years before it was removed. This could be partly due to the fact that it is (now) a well worn engine and uses a lot of oil – so rings and pistons are kept cool by this as much as by anything else.
On the subject of a bigger waterpump: has anyone else ever had the experience of finding a central heating radiator very hot at the bottom and barely warm at the top, and not having any air to be bled? I found that normal flow through the radiator could be restored by further closing the return/exit valve (and not the flow/entry valve) until normality was restored. This happened after I turned up the pump speed during cold weather to improve flow to rads at the very end of the system. Too strong a pump and thermo circulation/turbulence in the extremities could be reduced perhaps? Its just a thought, I have no direct experience of this in a car engine!
The only time I have ever seen melted HT leads was on a modern with a head gasket leak that had been driven flat out on the motorway until all the coolant had gone and eventually it melted a hole in a piston. On our M45 the distributor side HT leads are perilously close to the exhaust downpipe but still they haven't melted.
It would be interesting to know what clearance Adam Pointer went for on the new rings, I will need to consider new rings very soon as oil consumption is not good, that is unless a more profound and expensive remedy is required.
Apologies for being late to the party on this topic - my first post too!
James
Very sorry to hear of your woes but very grateful to you for sharing them and I congratulate you for keeping your car as a saloon.
About 15/20 years ago we did have problems with that bottom hose, I discovered (eventually) that it would collapse when revs were up. The collapse was not obvious at first as the hose went back to its usual shape when the revs dropped and it wasn't easy to see through the blur of the fan – but sudden temp changes and boiling were the result. It is just starting to show signs of collapse again above 1500rpm but not so badly as to cause any noticeable cooling problems. On our car the exit from the rad and the entry to the pump are slightly misaligned which puts an extra stress on the hose distorting it very slightly and making this problem more likely to occur. The rad was re-cored before the problem first occurred and had been run with either a sock or stocking for most of the time since so I do not think rad blockage was an issue, its just that that section of connector/hose/connector presents one of the greater restrictions in the system I suspect, and in our particular case one which can easily accommodate the pressures on it by collapsing.
Thank you both David and Alec for the links about Evans which are very helpful. In light of the above I think pressurisation is essential and consequently I would not choose to use Evans. However, I also have great doubts about replacing water with a coolant with lower specific heat capacity in a cooling system which is already compromised by a wide variation in coolant flow rates through the engine (or so it appears to me!), and crucially which lacks the ability to be as self circulating as water is when heat is applied to a motionless or very slow moving volume.
A cooling system oddity came to light in the late 80s when my father replaced the coolant manifold and discovered that the tank engine manifold was substantially obstructed between the two block connections by an irregularity in the internal diameter of the manifold. The result of this was that 4,5,6 would probably have been getting a lot less coolant than 1,2,3. The spares scheme replacement did not have any such obstruction/constriction, nor did the manifold that my father had removed from the car's original (blown up!) engine. We dismissed it at the time as a casting failure that we had been lucky not to be affected by. More recently I have begun to wonder if it might just have been intentional - your own case adds to my suspicions. However, it is also odd that historically 5 and 6 seem to be the problem bores (my father had no5 rod through the side of the original engine when the piston seized/broke up) but our tank engine had survived this manifold obstruction for 35 years before it was removed. This could be partly due to the fact that it is (now) a well worn engine and uses a lot of oil – so rings and pistons are kept cool by this as much as by anything else.
On the subject of a bigger waterpump: has anyone else ever had the experience of finding a central heating radiator very hot at the bottom and barely warm at the top, and not having any air to be bled? I found that normal flow through the radiator could be restored by further closing the return/exit valve (and not the flow/entry valve) until normality was restored. This happened after I turned up the pump speed during cold weather to improve flow to rads at the very end of the system. Too strong a pump and thermo circulation/turbulence in the extremities could be reduced perhaps? Its just a thought, I have no direct experience of this in a car engine!
The only time I have ever seen melted HT leads was on a modern with a head gasket leak that had been driven flat out on the motorway until all the coolant had gone and eventually it melted a hole in a piston. On our M45 the distributor side HT leads are perilously close to the exhaust downpipe but still they haven't melted.
It would be interesting to know what clearance Adam Pointer went for on the new rings, I will need to consider new rings very soon as oil consumption is not good, that is unless a more profound and expensive remedy is required.
Apologies for being late to the party on this topic - my first post too!
James