IMS bearing - Sellers
Discussion
Hi
Fitting an IMS bearing is much more complicated than internet chatter suggests and is an area of the car best left alone IMHO unless you fully understand what you're doing and understand the pros and cons of such work with the associated risks. Looking at the big picture we're not great fans of fitting the bearing to an assembled engine anyway - probably contrary to a lot of internet talk, although we're strong believers in doing so when the engine's apart.
We don't supply our kit as a parts only package as we don't want to encourage people to do something which could lead to a disaster if they run into a snag or do it wrong and all the associated fall out of such. There are other suppliers who will happily supply their kits so you shouldn't have any problem sourcing.
Grant
Fitting an IMS bearing is much more complicated than internet chatter suggests and is an area of the car best left alone IMHO unless you fully understand what you're doing and understand the pros and cons of such work with the associated risks. Looking at the big picture we're not great fans of fitting the bearing to an assembled engine anyway - probably contrary to a lot of internet talk, although we're strong believers in doing so when the engine's apart.
We don't supply our kit as a parts only package as we don't want to encourage people to do something which could lead to a disaster if they run into a snag or do it wrong and all the associated fall out of such. There are other suppliers who will happily supply their kits so you shouldn't have any problem sourcing.
Grant
I resent your implications of a “conflict of interest because we rebuild engines” Mr Sump and they are completely wrong. You don’t know enough about us or the technicalities to make such accusations nor to advise people what to do for the best - let me explain why.
Firstly we have a reputation on here for honest assessments - having frequently advised customers (who confirmed this on here) that the expensive fault they thought they had - was misdiagnosed by others and instead we fixed their cars for far less than they expected (depriving us of potential income we could easily have obtained).
Secondly there are very few IMS failures and the chances of it happening are minimal.
Thirdly - by now - most of the older smaller bearing IMS bearings have been running for so long they have cleared out the debris from running in, worn the seal (so it now allows fresh oil to enter and leave the bearing) and will probably last until something else causes the engine to need a rebuild.
In our view it is poor advice to have it changed unless there is clear evidence it is noisy or failing.
Although we have made special tools and procedures to avoid damage, we have seen the consequences of other people (including garages) trying to do the job and damaging other parts in the process. So actually changing the bearing in situ is prone to a lot of potential problems.
It is necessary to pull it out and press it back in and while this is being undertaken the forces necessary can cause damage to several internal components. We have even seen a crankcase broken in the process.
Moving the bearing around can pull the chains that fit around it against the plastic runners which by now have grooves in where the chains have worn a shape into them and the side loads can snap small parts off the runners that then sit in the engine and can damage all sorts of other parts. Chains can also be strained.
We made a sleeve to support them and try and avoid this but others would not understand this need.
It is also essential to remove or slacken the two hydraulic drive chain tensioners (one of which needs special tools to access easily) and there is a danger of the cam timing slipping as a result of the shaft being pulled across the engine when the bearing carrier housing is prized out of the crankcases.
Pulling the bearing out can also damage the accurate interference fit by leaving surface friction drag marks so the new bearing fits more tightly. The original bearing may have been fitted too tightly (compound interference fit tolerances can cause this) and we often find that a failed bearing has done so because the original hole was slightly too tight.
Pushing it back in can do the same damage to the runners and oil pump drive pin which sits at the other end of the shaft. It is a hexagonal drive pin sitting inside the shaft to drive the oil pump but it is fitted into a blind hole and pressing the bearing back into the other end has been known to push the whole intermediate shaft back and break the bottom of the blind hole allowing the oil pump drive pin to slide away internally and stop the oil pump from driving with obvious consequences to the whole engine.
To do the job properly you need special tools (which we have made) and internal precision measuring tools to check the fit etc.
Then you must consider what would happen if a business fitted a new bearing and some time shortly afterwards – say the chain snapped (probably because in doing so something else was damaged – but possibly because it was going to fail anyway) would the customer accept the consequences - having recently paid to avoid a problem but now needing an engine rebuild!
Quite apart from that many home mechanics work dangerously under wobbly stands and can actually cause a lot of damage because they don’t really understand what they are doing.
We are responsible people and if we think the customers best interests are served by not helping them to try and do something that may very well make things worse – we will say so – even if it does us out of some business.
We will fit our kit if a customer insists and we charge £800 plus Vat to do so – but we operate a disclaimer relating to the above typical scenarios (for internal damage) and do not think it is therefore good value for money set against the very low likelihood of it needing to be replaced.
Your implied accusation that we would make more money repairing engines that have failed (so do not want to prevent it) does not sit well with the low temperature thermostat we spent a considerable amount of time and money developing and testing to avoid or delay cylinder bore scoring. If we were (as you imply) simply after turnover and profit – we would surely not have bothered as we will never recover the cost of developing that solution out of the minute profit in a small number of thermostat sales. Offering this to the public absolutely deprives us of potential turnover – we do it to help in a situation we think is serious for those that would be devastated if they had to find the kind of money it takes to repair that fault.
We also offer lots of advice here on the Internet about how to avoid similar problems by modifying driving styles etc and none of this effort results in more work for us – it just costs us our time and loses us business.
Fortunately our reputation keeps us extremely busy and allows us to make a living while doing everything we can to help owners avoid unnecessary failures and expenses.
Numerous other Independent dealers have copied our solutions and now offer their own version without having incurred all the development and testing costs we did originally – so there are plenty of sources of the parts without us needing to supply them to the public.
We also operate our “Lifetime Maintenance Plan” which for less than the typical cost of servicing and Warranty payments at a Main Agent – covers the free labour to fix an IMS failure (for which the parts cost would be very small indeed). If (as you imply) all the bearings need replacing to avoid engine failure – we would surely make it a condition of acceptance on the scheme – but we do not.
Furthermore if a customer on the scheme even wanted to have it done we would probably discourage them (on the general grounds above). In taking this decision we are inviting a massive labour cost that we have to cover in full IF (as you suggest) not fitting the replacement bearing is a commercial decision that will increase engine failures.
We take that risk because – in our opinion – the chances of failure are simply too small and as there is no time, mileage or cost limit to that scheme - we run that risk for the lifetime of the car.
This year we have rebuilt over 100 engines of which only 2 were the result of IMS bearing failure. There are therefore many more other reasons for engines to fail and the IMS bearing is simply low down on that priority list for us to try and make a small profit from selling a bearing kit to people who – on the whole – are more likely to have a lot of problems fitting it – and are quite likely to damage something else doing so – and in a risk assessment way – would be making a poor decision.
We carry out more research and development than any other independent Worldwide I am aware of and as a result offer more solutions than anyone else. We also offer more Internet advice (and a thorough and comprehensive “buyers guide” on the Internet (www.hartech.org) that has explanations and photos of all these (and other problems) to help prevent people being misinformed and taken for a ride elsewhere.
I think we must be the last people who should be categorised as allowing conflicts of interest to influence our business decisions and I think we deserve your apology!
Baz
Firstly we have a reputation on here for honest assessments - having frequently advised customers (who confirmed this on here) that the expensive fault they thought they had - was misdiagnosed by others and instead we fixed their cars for far less than they expected (depriving us of potential income we could easily have obtained).
Secondly there are very few IMS failures and the chances of it happening are minimal.
Thirdly - by now - most of the older smaller bearing IMS bearings have been running for so long they have cleared out the debris from running in, worn the seal (so it now allows fresh oil to enter and leave the bearing) and will probably last until something else causes the engine to need a rebuild.
In our view it is poor advice to have it changed unless there is clear evidence it is noisy or failing.
Although we have made special tools and procedures to avoid damage, we have seen the consequences of other people (including garages) trying to do the job and damaging other parts in the process. So actually changing the bearing in situ is prone to a lot of potential problems.
It is necessary to pull it out and press it back in and while this is being undertaken the forces necessary can cause damage to several internal components. We have even seen a crankcase broken in the process.
Moving the bearing around can pull the chains that fit around it against the plastic runners which by now have grooves in where the chains have worn a shape into them and the side loads can snap small parts off the runners that then sit in the engine and can damage all sorts of other parts. Chains can also be strained.
We made a sleeve to support them and try and avoid this but others would not understand this need.
It is also essential to remove or slacken the two hydraulic drive chain tensioners (one of which needs special tools to access easily) and there is a danger of the cam timing slipping as a result of the shaft being pulled across the engine when the bearing carrier housing is prized out of the crankcases.
Pulling the bearing out can also damage the accurate interference fit by leaving surface friction drag marks so the new bearing fits more tightly. The original bearing may have been fitted too tightly (compound interference fit tolerances can cause this) and we often find that a failed bearing has done so because the original hole was slightly too tight.
Pushing it back in can do the same damage to the runners and oil pump drive pin which sits at the other end of the shaft. It is a hexagonal drive pin sitting inside the shaft to drive the oil pump but it is fitted into a blind hole and pressing the bearing back into the other end has been known to push the whole intermediate shaft back and break the bottom of the blind hole allowing the oil pump drive pin to slide away internally and stop the oil pump from driving with obvious consequences to the whole engine.
To do the job properly you need special tools (which we have made) and internal precision measuring tools to check the fit etc.
Then you must consider what would happen if a business fitted a new bearing and some time shortly afterwards – say the chain snapped (probably because in doing so something else was damaged – but possibly because it was going to fail anyway) would the customer accept the consequences - having recently paid to avoid a problem but now needing an engine rebuild!
Quite apart from that many home mechanics work dangerously under wobbly stands and can actually cause a lot of damage because they don’t really understand what they are doing.
We are responsible people and if we think the customers best interests are served by not helping them to try and do something that may very well make things worse – we will say so – even if it does us out of some business.
We will fit our kit if a customer insists and we charge £800 plus Vat to do so – but we operate a disclaimer relating to the above typical scenarios (for internal damage) and do not think it is therefore good value for money set against the very low likelihood of it needing to be replaced.
Your implied accusation that we would make more money repairing engines that have failed (so do not want to prevent it) does not sit well with the low temperature thermostat we spent a considerable amount of time and money developing and testing to avoid or delay cylinder bore scoring. If we were (as you imply) simply after turnover and profit – we would surely not have bothered as we will never recover the cost of developing that solution out of the minute profit in a small number of thermostat sales. Offering this to the public absolutely deprives us of potential turnover – we do it to help in a situation we think is serious for those that would be devastated if they had to find the kind of money it takes to repair that fault.
We also offer lots of advice here on the Internet about how to avoid similar problems by modifying driving styles etc and none of this effort results in more work for us – it just costs us our time and loses us business.
Fortunately our reputation keeps us extremely busy and allows us to make a living while doing everything we can to help owners avoid unnecessary failures and expenses.
Numerous other Independent dealers have copied our solutions and now offer their own version without having incurred all the development and testing costs we did originally – so there are plenty of sources of the parts without us needing to supply them to the public.
We also operate our “Lifetime Maintenance Plan” which for less than the typical cost of servicing and Warranty payments at a Main Agent – covers the free labour to fix an IMS failure (for which the parts cost would be very small indeed). If (as you imply) all the bearings need replacing to avoid engine failure – we would surely make it a condition of acceptance on the scheme – but we do not.
Furthermore if a customer on the scheme even wanted to have it done we would probably discourage them (on the general grounds above). In taking this decision we are inviting a massive labour cost that we have to cover in full IF (as you suggest) not fitting the replacement bearing is a commercial decision that will increase engine failures.
We take that risk because – in our opinion – the chances of failure are simply too small and as there is no time, mileage or cost limit to that scheme - we run that risk for the lifetime of the car.
This year we have rebuilt over 100 engines of which only 2 were the result of IMS bearing failure. There are therefore many more other reasons for engines to fail and the IMS bearing is simply low down on that priority list for us to try and make a small profit from selling a bearing kit to people who – on the whole – are more likely to have a lot of problems fitting it – and are quite likely to damage something else doing so – and in a risk assessment way – would be making a poor decision.
We carry out more research and development than any other independent Worldwide I am aware of and as a result offer more solutions than anyone else. We also offer more Internet advice (and a thorough and comprehensive “buyers guide” on the Internet (www.hartech.org) that has explanations and photos of all these (and other problems) to help prevent people being misinformed and taken for a ride elsewhere.
I think we must be the last people who should be categorised as allowing conflicts of interest to influence our business decisions and I think we deserve your apology!
Baz
hartech said:
Hi
Fitting an IMS bearing is much more complicated than internet chatter suggests and is an area of the car best left alone IMHO unless you fully understand what you're doing and understand the pros and cons of such work with the associated risks. Looking at the big picture we're not great fans of fitting the bearing to an assembled engine anyway - probably contrary to a lot of internet talk, although we're strong believers in doing so when the engine's apart.
We don't supply our kit as a parts only package as we don't want to encourage people to do something which could lead to a disaster if they run into a snag or do it wrong and all the associated fall out of such. There are other suppliers who will happily supply their kits so you shouldn't have any problem sourcing.
Grant
Totally agree Grant with your view.Fitting an IMS bearing is much more complicated than internet chatter suggests and is an area of the car best left alone IMHO unless you fully understand what you're doing and understand the pros and cons of such work with the associated risks. Looking at the big picture we're not great fans of fitting the bearing to an assembled engine anyway - probably contrary to a lot of internet talk, although we're strong believers in doing so when the engine's apart.
We don't supply our kit as a parts only package as we don't want to encourage people to do something which could lead to a disaster if they run into a snag or do it wrong and all the associated fall out of such. There are other suppliers who will happily supply their kits so you shouldn't have any problem sourcing.
Grant
We refuse to fit the bearing in situ because of the associated risk of making this change. It is a constant question that we get asked by customers. If the engine was being rebuilt then of course it makes sense to do this along with LTT etc. Otherwise leave alone. Why take the risk on a healthy engine.
Ken
Meh, not convinced. There are too many successful reports of it being done in situ perfectly fine. In fact, I'd like to see one where it wasn't fine! Unless your team is scared of replacing them 
I've genuinely seen Rolls Royce manuals for the Trent 900 that are more relaxed than your approach to this IMS.
So even though that was a nice long winded reply, I'm sticking with the conflict of interest.
Selling a thermostat that's available everywhere doesn't deter conflict of interests either!
Well lets see what happens to my engine, should be interesting.
I've genuinely seen Rolls Royce manuals for the Trent 900 that are more relaxed than your approach to this IMS.
So even though that was a nice long winded reply, I'm sticking with the conflict of interest.
Selling a thermostat that's available everywhere doesn't deter conflict of interests either!
Well lets see what happens to my engine, should be interesting.
Edited by Sump on Thursday 27th June 17:42
Your cynical view of the World is wrong Sump, this is not "sales talk" it is good free well intentioned advice to people who know less than us about the issues.
"Scared to replace them" - no - we do it if the customers insists - but we are scared about what might happen if “Jo Public” try - having had to pick up the pieces of some failed attempts and read reports about others and this is what this post was about!
We have offered free advice for 2 decades that eventually became the established rules for problems with certain engines - starting with the cam chain and sprockets in 944 S, S2 and 968's. This has saved owners thousands of pounds over the years by good reliable preventative maintenance - so we do offer advice that enables us or the general public to avoid unnecessary failures when appropriate.
Our excellent engineering technical pedigree has resulted in us being the first to fix major problems in the M96 engines and we had the guts and confidence to manufacture special parts and invest in special machinery to fix the problems in a way that advantages the general public compared to the alternatives available.
We also had the guts to go racing for the first time with a new model 2 years ago and pit ourselves against Porsche specialists that have been racing for decades – exposing our inexperience to public scrutiny. With a win in our first race meeting then and this season leading the Class 1 Championship and Team Award (with 5 wins, 6 fastest laps and 7 pole positions) I think you cannot cast dispersions on our engineering capabilities.
I don’t mind at all if anyone decides to fit the new bearing themselves and I expect most to manage it OK – we don’t need to fit them or not or sell them or not to make any difference to our business (it is irrelevant). I think however that it would be irresponsible of us not to point out the pitfalls we have experienced others encountering to enable others with less experience (and probably less general engineering knowledge and facilities) to make well informed decisions.
I also think it should be helpful to reassure people about the low statistics and mention alternatives to protect themselves from huge costs (like our Maintenance Plan).
None of this forces anyone to do anything it is just additional information to balance the responses to the subject and allow individuals to make up their own minds what to do for the best.
The problem always rears itself when those with far less experience of the subject find someone disagreeing with them and try to force their opinion on others to appear right – by discrediting the valuable information others contribute by claiming it is just commercially motivated.
Please everyone just read everything available and make up your own minds and understand I have no issues with whatever you decide or for whatever reason – good luck!
Baz
"Scared to replace them" - no - we do it if the customers insists - but we are scared about what might happen if “Jo Public” try - having had to pick up the pieces of some failed attempts and read reports about others and this is what this post was about!
We have offered free advice for 2 decades that eventually became the established rules for problems with certain engines - starting with the cam chain and sprockets in 944 S, S2 and 968's. This has saved owners thousands of pounds over the years by good reliable preventative maintenance - so we do offer advice that enables us or the general public to avoid unnecessary failures when appropriate.
Our excellent engineering technical pedigree has resulted in us being the first to fix major problems in the M96 engines and we had the guts and confidence to manufacture special parts and invest in special machinery to fix the problems in a way that advantages the general public compared to the alternatives available.
We also had the guts to go racing for the first time with a new model 2 years ago and pit ourselves against Porsche specialists that have been racing for decades – exposing our inexperience to public scrutiny. With a win in our first race meeting then and this season leading the Class 1 Championship and Team Award (with 5 wins, 6 fastest laps and 7 pole positions) I think you cannot cast dispersions on our engineering capabilities.
I don’t mind at all if anyone decides to fit the new bearing themselves and I expect most to manage it OK – we don’t need to fit them or not or sell them or not to make any difference to our business (it is irrelevant). I think however that it would be irresponsible of us not to point out the pitfalls we have experienced others encountering to enable others with less experience (and probably less general engineering knowledge and facilities) to make well informed decisions.
I also think it should be helpful to reassure people about the low statistics and mention alternatives to protect themselves from huge costs (like our Maintenance Plan).
None of this forces anyone to do anything it is just additional information to balance the responses to the subject and allow individuals to make up their own minds what to do for the best.
The problem always rears itself when those with far less experience of the subject find someone disagreeing with them and try to force their opinion on others to appear right – by discrediting the valuable information others contribute by claiming it is just commercially motivated.
Please everyone just read everything available and make up your own minds and understand I have no issues with whatever you decide or for whatever reason – good luck!
Baz
Hopefully sump has come round this morning and realised what a 'chump' he is. I'm sure you've seen enough of this to just brush it off Baz, your contributions, advice and help are priceless to us swimming in these uncharted waters. I was surprised at the low number of IMS failures that you deal with, looks like 1%, puts things into perspective, I presume that bore scoring is a much bigger issue. Many thanks.
alexisn said:
Hopefully sump has come round this morning and realised what a 'chump' he is. I'm sure you've seen enough of this to just brush it off Baz, your contributions, advice and help are priceless to us swimming in these uncharted waters. I was surprised at the low number of IMS failures that you deal with, looks like 1%, puts things into perspective, I presume that bore scoring is a much bigger issue. Many thanks.
Extrapolating that figure to a failure rate it is even less than 1% because that figure is derived from those engines needing a rebuild which in itself is a small %age of active and good engines.Yes bore scoring is number one by a long way (and we have reports of some Gen 2 scoring now), cracked cylinders number 2 (eventually when the mileage is high enough will probably overtake or equal scoring), and things like cracked heads, chain failure, crank bearing failures and IMS bearing failure feature relatively very low down on the statistics.
Baz
Baz
That's not the point Sump - which is that we know of people (including specialists) who have tried and created a problem that needed the engine removing and rebuilding because they did not get it right. They may be small in number but we also understand technically what else can go wrong and what tools, equipment, experience and expertise would reduce that possibility and most people don't have enough.
You are suggesting that we should not warn people of this nor advise them of how small the chances of failure are but instead sell them the part because "it would be their fault if it went wrong" - and then you accuse us of commercial interests!
We are the ones withdrawing from pressure selling those parts in the best interests of our customers (not us) but will fit them if they want us to as we are less likely to encounter the problems than them - presumably you would sell them in our position regardless!
Just to let you know how dangerous it is to advise people who don't understand things fully - someone once read about back filling the coolant in a 944 turbo from the bleed nipple. He removed the boost pressure control pipe boltinstead by mistake and put 2 litres of coolant in to the inlet system, started it up and had rods coming out of the side as it hydraulic locked.
We are being responsible in the way we are handling this but if you want to buy the bearing elsewhere and go to all the trouble of fitting it - that is your choice but at least you have done so knowing the potential pit falls which I have taken the time to explain.
Yes 2% rebuilds for IMS failure and about 5% engine rebuilds in their lifetime (say 6 owners) = the likelyhood of you experiencing this failure in your ownership as 0.016% - so worth the risk? - you decide!
Putting the other side to your argument is not stopping you from doing it I presume but balances the argument - or should everyone just listen to your point of view and rush out and buy bearings and try and fit them because you think it is OK and no one should post their vastly greater experience from a better background on the same subject to warn them it may be difficult?
Baz
You are suggesting that we should not warn people of this nor advise them of how small the chances of failure are but instead sell them the part because "it would be their fault if it went wrong" - and then you accuse us of commercial interests!
We are the ones withdrawing from pressure selling those parts in the best interests of our customers (not us) but will fit them if they want us to as we are less likely to encounter the problems than them - presumably you would sell them in our position regardless!
Just to let you know how dangerous it is to advise people who don't understand things fully - someone once read about back filling the coolant in a 944 turbo from the bleed nipple. He removed the boost pressure control pipe boltinstead by mistake and put 2 litres of coolant in to the inlet system, started it up and had rods coming out of the side as it hydraulic locked.
We are being responsible in the way we are handling this but if you want to buy the bearing elsewhere and go to all the trouble of fitting it - that is your choice but at least you have done so knowing the potential pit falls which I have taken the time to explain.
Yes 2% rebuilds for IMS failure and about 5% engine rebuilds in their lifetime (say 6 owners) = the likelyhood of you experiencing this failure in your ownership as 0.016% - so worth the risk? - you decide!
Putting the other side to your argument is not stopping you from doing it I presume but balances the argument - or should everyone just listen to your point of view and rush out and buy bearings and try and fit them because you think it is OK and no one should post their vastly greater experience from a better background on the same subject to warn them it may be difficult?
Baz
I think there is a difference between, I won't supply it because you will screw it up to I warn you that there is a chance you will screw it up but we will supply it anyway.
I think you need to stop acting like you're the only people in the world who can fit an IMS bearing.
I mean really, are you this arrogant?
"but will fit them if they want us to as we are less likely to encounter the problems than them"
I think you need to stop acting like you're the only people in the world who can fit an IMS bearing.
I mean really, are you this arrogant?
"but will fit them if they want us to as we are less likely to encounter the problems than them"
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