14-12-2019, 12:50 AM
In answer to the question posed by this thread, the simple response is: Got it running again! To be fair, this remark requires a certain amount of explanation, as it is more of a case of "What have you done this week with your Austin Seven?"
I have noticed the last few times I have had the RP out that, when cold, there was a sharp noise on 'throttle on' conditions, especially when cold, rather reminiscent of a blown manifold gasket. The little car also seemed down on power. having recently had my spare cylinder head modified by Robert Foreman, it therefore seemed an opportune moment to decarbonise the engine and fit the new head. At the same time, I thought it would be a good idea to replace the block to crankcase gasket to cure a persistent weep from the rear of the engine that has been there since i had bought the car over twelve months ago.
So, having organised the gasket sets and other bits and pieces that i thought I should need, last Sunday, I pulled the engine to bits. The first problem came when the cylinder head simply refused all efforts to remove it. Having removed all the head nuts and having already removed the manifold and dynamo, I was not in a position to start the engine and hope that it head would move that way, although I did try to turn the engine over in the vain hope that the compression would shift it. It was at this point that I noticed that, as the engine was being turned over, there was a sigh from number 3 exhaust port " Aha!" I thought. "A leaking valve!" After a bit of 'studying form', I poured penetrating oil down all the head studs until no more would go in and went and had dinner. Returning about two hours later, and with the judicious use of a couple of big screwdrivers, I managed to prise the head off.
The head gasket was not the usual copper/asbestos gasket, but a composition item that looked a bit like baekelite and was very very brittle. However, I noticed that there was a small track across the gasket between number 2 and number 3 exhaust valves, hence the ticking noise and lack of power. It did, however, surprise me a little as the engine had always run evenly, even at tickover. For the record, the manifold gasket hadn't blown.
Removing the block (yes folks, I did it with the engine still in the car), the very last nut to be undone came out with its stud and the aluminium thread from the crankcase. So, apart from removing the block, everything came to a stop.
I ordered a 5/16 BSF helicoil set from fleabay but this was not due to arrive until Wednesday, so Monday was spent cleaning off the old gaskets, most of which, including the base gasket, had been glued into place with Wellseal or something similar, grinding in the valves and generally getting everything fettled ready for reassembly. Interestingly enough, my engine is fitted with pin type valves and I was under the impression that these were not fitted until the three bearing crank engines were introduced. It got the impression that the engine had probably not been to bits for at least half a century and possibly more. I also painted the block and 'new' head with some blue engine paint that I found on the shelf, left over from a tractor overhaul many years ago.
The helicoil kit arrived on Wednesday, but as I was otherwise engaged that day, work did not resume until yesterday, when I put the engine back together, leaving just the radiator and one or two other bits to fit. I had a new 'old stock' C/A head gasket left over from my previous love affair with Sevens many years ago which I have used rather than the one that came with the top overhaul kit.
Having again been out all day, I fitted the radiator this evening, filled the engine with oil and antifreeze, and, after dealing with one or two silly coolant leaks, most notably from the stud that hold the top elbow onto the head, I started the engine which, I am pleased to say, sprang into life almost immediately. I hvae run it up to temperature and set the carb and it seems to run very sweetly. As it is now half past eleven at night, I have abandoned things for tonight. Tomorrow, I shall recheck the cylinder head nuts and go for a test drive to see if the car's hill climbing ability has improved. I shall also have to tidy up the garage; it looks as if terrorists have been in there!
So, tired but happy!
No photos, I'm afraid, my garage is dank dark hole at this time of year, but I shall probably post some tomorrow assuming that the test drive goes as expected.
I have noticed the last few times I have had the RP out that, when cold, there was a sharp noise on 'throttle on' conditions, especially when cold, rather reminiscent of a blown manifold gasket. The little car also seemed down on power. having recently had my spare cylinder head modified by Robert Foreman, it therefore seemed an opportune moment to decarbonise the engine and fit the new head. At the same time, I thought it would be a good idea to replace the block to crankcase gasket to cure a persistent weep from the rear of the engine that has been there since i had bought the car over twelve months ago.
So, having organised the gasket sets and other bits and pieces that i thought I should need, last Sunday, I pulled the engine to bits. The first problem came when the cylinder head simply refused all efforts to remove it. Having removed all the head nuts and having already removed the manifold and dynamo, I was not in a position to start the engine and hope that it head would move that way, although I did try to turn the engine over in the vain hope that the compression would shift it. It was at this point that I noticed that, as the engine was being turned over, there was a sigh from number 3 exhaust port " Aha!" I thought. "A leaking valve!" After a bit of 'studying form', I poured penetrating oil down all the head studs until no more would go in and went and had dinner. Returning about two hours later, and with the judicious use of a couple of big screwdrivers, I managed to prise the head off.
The head gasket was not the usual copper/asbestos gasket, but a composition item that looked a bit like baekelite and was very very brittle. However, I noticed that there was a small track across the gasket between number 2 and number 3 exhaust valves, hence the ticking noise and lack of power. It did, however, surprise me a little as the engine had always run evenly, even at tickover. For the record, the manifold gasket hadn't blown.
Removing the block (yes folks, I did it with the engine still in the car), the very last nut to be undone came out with its stud and the aluminium thread from the crankcase. So, apart from removing the block, everything came to a stop.
I ordered a 5/16 BSF helicoil set from fleabay but this was not due to arrive until Wednesday, so Monday was spent cleaning off the old gaskets, most of which, including the base gasket, had been glued into place with Wellseal or something similar, grinding in the valves and generally getting everything fettled ready for reassembly. Interestingly enough, my engine is fitted with pin type valves and I was under the impression that these were not fitted until the three bearing crank engines were introduced. It got the impression that the engine had probably not been to bits for at least half a century and possibly more. I also painted the block and 'new' head with some blue engine paint that I found on the shelf, left over from a tractor overhaul many years ago.
The helicoil kit arrived on Wednesday, but as I was otherwise engaged that day, work did not resume until yesterday, when I put the engine back together, leaving just the radiator and one or two other bits to fit. I had a new 'old stock' C/A head gasket left over from my previous love affair with Sevens many years ago which I have used rather than the one that came with the top overhaul kit.
Having again been out all day, I fitted the radiator this evening, filled the engine with oil and antifreeze, and, after dealing with one or two silly coolant leaks, most notably from the stud that hold the top elbow onto the head, I started the engine which, I am pleased to say, sprang into life almost immediately. I hvae run it up to temperature and set the carb and it seems to run very sweetly. As it is now half past eleven at night, I have abandoned things for tonight. Tomorrow, I shall recheck the cylinder head nuts and go for a test drive to see if the car's hill climbing ability has improved. I shall also have to tidy up the garage; it looks as if terrorists have been in there!
So, tired but happy!
No photos, I'm afraid, my garage is dank dark hole at this time of year, but I shall probably post some tomorrow assuming that the test drive goes as expected.