The Elephant in the Room - #2 Rod Bearing Failures
04-23-2013, 05:18 PM
#91
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A couple of answers/comments;
Don’t increase the bottom end bearing clearances – you will not have enough oil volume through the pump to keep the flow up and as a result the hot idle pressure will be dangerously low.
‘stock’ clearance range on the mains is .020 to .098mm ( .0008 to .004”) with the max wear allowed at .18mm (.007”) – that is a huge tolerance range! .0025” is a good place to be. The problem is that it is a major pain to decrease the main journals – you have to skim cut the girdle and then align bore the mains to fit. Most used blocks / cranks are not anywhere near the .0008” low end so ‘opening up’ the clearance is rarely an issue.
Accusump – I believe that not only is this a waste of time/money, it also creates more problems than it fixes. The way the accusump works creates a problem with the oil level. The Accusump is precharged with a pressure that you set – whenever the pressure drops below that setting it dumps 3 quarts of oil in to the system. So if you set it to the ‘critical’ oil pressure (using Porsches 1 bar per 1k RPM) you would have to set the trigger pressure fairly high – I see many set at 60 psi (4 bar). So anytime you are under 60 psi you will have an extra 3 quarts of oil in the sump – that means that the crank is actually partially submerged in oil. Fire up the blender!!!!! Now you have severely aerated oil – not good. On the track most hot engines are doing pretty good to keep 20-30psi at idle and will not hit 60psi until half way up the rev range.
Prelubing is nice – for a street car. In reality any engine used hard on the track will need refreshing long before the wear from cold start ups is an issue.
Aftermarket oil pan? I’m in. I tried to get some made up many years ago and gave up. If this works out at a reasonable price I will pick up several of them.
Don’t increase the bottom end bearing clearances – you will not have enough oil volume through the pump to keep the flow up and as a result the hot idle pressure will be dangerously low.
‘stock’ clearance range on the mains is .020 to .098mm ( .0008 to .004”) with the max wear allowed at .18mm (.007”) – that is a huge tolerance range! .0025” is a good place to be. The problem is that it is a major pain to decrease the main journals – you have to skim cut the girdle and then align bore the mains to fit. Most used blocks / cranks are not anywhere near the .0008” low end so ‘opening up’ the clearance is rarely an issue.
Accusump – I believe that not only is this a waste of time/money, it also creates more problems than it fixes. The way the accusump works creates a problem with the oil level. The Accusump is precharged with a pressure that you set – whenever the pressure drops below that setting it dumps 3 quarts of oil in to the system. So if you set it to the ‘critical’ oil pressure (using Porsches 1 bar per 1k RPM) you would have to set the trigger pressure fairly high – I see many set at 60 psi (4 bar). So anytime you are under 60 psi you will have an extra 3 quarts of oil in the sump – that means that the crank is actually partially submerged in oil. Fire up the blender!!!!! Now you have severely aerated oil – not good. On the track most hot engines are doing pretty good to keep 20-30psi at idle and will not hit 60psi until half way up the rev range.
Prelubing is nice – for a street car. In reality any engine used hard on the track will need refreshing long before the wear from cold start ups is an issue.
Aftermarket oil pan? I’m in. I tried to get some made up many years ago and gave up. If this works out at a reasonable price I will pick up several of them.
04-23-2013, 05:36 PM
#92
A couple of answers/comments;
Don’t increase the bottom end bearing clearances – you will not have enough oil volume through the pump to keep the flow up and as a result the hot idle pressure will be dangerously low.
‘stock’ clearance range on the mains is .020 to .098mm ( .0008 to .004”) with the max wear allowed at .18mm (.007”) – that is a huge tolerance range! .0025” is a good place to be. The problem is that it is a major pain to decrease the main journals – you have to skim cut the girdle and then align bore the mains to fit. Most used blocks / cranks are not anywhere near the .0008” low end so ‘opening up’ the clearance is rarely an issue.
Accusump – I believe that not only is this a waste of time/money, it also creates more problems than it fixes. The way the accusump works creates a problem with the oil level. The Accusump is precharged with a pressure that you set – whenever the pressure drops below that setting it dumps 3 quarts of oil in to the system. So if you set it to the ‘critical’ oil pressure (using Porsches 1 bar per 1k RPM) you would have to set the trigger pressure fairly high – I see many set at 60 psi (4 bar). So anytime you are under 60 psi you will have an extra 3 quarts of oil in the sump – that means that the crank is actually partially submerged in oil. Fire up the blender!!!!! Now you have severely aerated oil – not good. On the track most hot engines are doing pretty good to keep 20-30psi at idle and will not hit 60psi until half way up the rev range.
Prelubing is nice – for a street car. In reality any engine used hard on the track will need refreshing long before the wear from cold start ups is an issue.
Aftermarket oil pan? I’m in. I tried to get some made up many years ago and gave up. If this works out at a reasonable price I will pick up several of them.
Don’t increase the bottom end bearing clearances – you will not have enough oil volume through the pump to keep the flow up and as a result the hot idle pressure will be dangerously low.
‘stock’ clearance range on the mains is .020 to .098mm ( .0008 to .004”) with the max wear allowed at .18mm (.007”) – that is a huge tolerance range! .0025” is a good place to be. The problem is that it is a major pain to decrease the main journals – you have to skim cut the girdle and then align bore the mains to fit. Most used blocks / cranks are not anywhere near the .0008” low end so ‘opening up’ the clearance is rarely an issue.
Accusump – I believe that not only is this a waste of time/money, it also creates more problems than it fixes. The way the accusump works creates a problem with the oil level. The Accusump is precharged with a pressure that you set – whenever the pressure drops below that setting it dumps 3 quarts of oil in to the system. So if you set it to the ‘critical’ oil pressure (using Porsches 1 bar per 1k RPM) you would have to set the trigger pressure fairly high – I see many set at 60 psi (4 bar). So anytime you are under 60 psi you will have an extra 3 quarts of oil in the sump – that means that the crank is actually partially submerged in oil. Fire up the blender!!!!! Now you have severely aerated oil – not good. On the track most hot engines are doing pretty good to keep 20-30psi at idle and will not hit 60psi until half way up the rev range.
Prelubing is nice – for a street car. In reality any engine used hard on the track will need refreshing long before the wear from cold start ups is an issue.
Aftermarket oil pan? I’m in. I tried to get some made up many years ago and gave up. If this works out at a reasonable price I will pick up several of them.
04-23-2013, 05:45 PM
#93
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Alleviate? No, but it may help quite a bit. The close fit of the steering rack and suspension cross over mean that there will always be some oil foaming - but anything that reduces the foaming is a good thing!
04-23-2013, 06:39 PM
#94
Burning Brakes
Thanks for chiming in Chris. It really helps for motivation. I have received replies from at least 4 manufacturers who are willing to make the pan. Price will depend on design and numbers. I will make some sketches and post them here for collective feedback and comments.
