Bore scoring on refurbished engine

[Budweiser]

A very interesting and informative thread.

Advice please.. I am a new to me owner of a 204MY C4S 996. 73K one owner with a full OPC service history. The previous owner took the attitude, if OPC says it needs doing, do it so no expense spared. I have all the invoices for the work carried out for the life of the car.

I've just had a minor service carried out at OPC Colchester and a low temp thermostat fitted by Autostrasse, my local indie.

The car drives and sounds fantastic and there are no obvious problems.

Like a lot of owners I am concerned about BS and IMS so believing prevention is better than cure would it make sense to have the bores checked visually and if clear have a new modified IMS bearing fitted? Don't get me wrong I'm as keen as anyone to save money but an investment now may prove prudent in the future? Any thoughts would be appreciated.

If I did decide to change the IMS what is considered the best bearing to use? And what are the likely costs involved?

The car is a manual..

Thanks. Don.

Edited by Budweiser on Friday 24th May 13:09

[AlexH997]

petop said:

Sorry, this was paid for by previous owner. But i got the 2 year warranty on the engine alone from Porsche.

you done well there. Owner must have had deep pockets

[AlexH997]

Budweiser said:

A very interesting and informative thread.

Advice please.. I am a new to me owner of a 204MY C4S 996. 73K one owner with a full OPC service history. The previous owner took the attitude, if OPC says it needs doing, do it so no expense spared. I have all the invoices for the work carried out for the life of the car.

I've just had a minor service carried out at OPC Colchester and a low temp thermostat fitted by Autostrasse, my local indie.

The car drives and sounds fantastic and there are no obvious problems.

Like a lot of owners I am concerned about BS and IMS so believing prevention is better than cure would it make sense to have the bores checked visually and if clear have a new modified IMS bearing fitted? Don't get me wrong I'm as keen as anyone to save money but an investment now may prove prudent in the future? Any thoughts would be appreciated.



If I did decide to change the IMS what is considered the best bearing to use? And what are the likely costs involved?

The car is a manual..

Thanks. Don.

Edited by Budweiser on Friday 24th May 13:09

Don I'm with you on this one seems quite a few owners have the same thoughts. i got opc warranty left to cover me short term but a rebuild and ims update could be on the cards.

hopefully baz can answer some of the questions he seems to be the subject matter expert on all this engine related.

[premio]

Budweiser said:

A very interesting and informative thread.

Advice please.. I am a new to me owner of a 204MY C4S 996. 73K one owner with a full OPC service history. The previous owner took the attitude, if OPC says it needs doing, do it so no expense spared. I have all the invoices for the work carried out for the life of the car.

I've just had a minor service carried out at OPC Colchester and a low temp thermostat fitted by Autostrasse, my local indie.

The car drives and sounds fantastic and there are no obvious problems.

Like a lot of owners I am concerned about BS and IMS so believing prevention is better than cure would it make sense to have the bores checked visually and if clear have a new modified IMS bearing fitted? Don't get me wrong I'm as keen as anyone to save money but an investment now may prove prudent in the future? Any thoughts would be appreciated.

If I did decide to change the IMS what is considered the best bearing to use? And what are the likely costs involved?

The car is a manual..

Thanks. Don.

Edited by Budweiser on Friday 24th May 13:09

I had a borescopy performed for about £150 at GT One in Chertsey, and it was definitely a good investment as not a single bore wasn't scored! Without that I'd never have had a refund in my car.

I'd thoroughly recommend a borescopy to anyone who has a few worries, saves them taking the engine apart and is a very quick job. Then if its damaged you can go from there

[hartech]

The original IMS problems came about because (1) the ball bearing was on the small side for its task, (2) it was grease filled and shrouded with seals to limit oil entry and debris washout, eventually the grease escaped leaving the bearing short of cool fresh oil supply, (3) the spindle was weak, (4) the heavy interference fit could shrink the thin outside diameter to run tight on the balls and create a lot of debris/running in hard steel wear particles that were trapped by the seals and mixed with the grease inside that could not escape and damage the bearings tracks.

A new bearing with a stronger spindle and no seals (so it is lubricated by splash engine oil) is an improvement but probably would not last for ever but longer than before.

A ceramic bearing is an alternative but they are expensive and may suffer from shock loading eventually.

We are presently testing a different type of bearing that is less expensive than the ceramic type and should last better than anything else.

All early cars could be retro fitted with a new bearing without stripping the engine (as long as there was no further damage).

Later cars circa 2005 to 2006 were at a cross over when a newer larger bearing was fitted - but also with similar grease and seals. The bearing is stronger and does not get shrunk so tightly by the interference fit and the spindle is stronger so it lasts longer but can still fail eventually when the only way to fix it involves a complete engine strip as the bearing is bigger than the hole in the crankcase that you can remove the older smaller bearing through.

Early IMS shafts will not run with later crankshafts due to a change in the chain design (and visa versa) so you cannot fix a badly damaged early IMS shaft unless you also replace the crankshaft.

However we are also testing shafts we have re-designed with a new end bearing and chain drive carrier that we can fit the new larger bearing to that have both types of chain drive enabling any engine to benefit from the larger bearing (just as soon as we have covered enough test miles to release the product which would be about half the price of the latest IMS shaft that you cannot fit to the earlier engines anyway).

Baz

[AlexH997]

So baz i have a 2005 997 is there any point in have an ims bearing upgrade or should i just wait until it's failed and then send it to yours to to have ims bearing and nikasil liners installed as part of a refurb>

[318touring]

Baz, when would you release your new IMS solution? I'm looking to do a replacement in the near future, and have two choices at the moment, the $700 LNE one and $170 from Pelican Parts. Would like to have more options if possible.

[LasseV]

I have let myself to understand that m96 in carrera (3.4) doesn't suffer from bore scoring. Am i right?

[nick_968]

hartech said:

The only way we could operate a South East version of Hartech would be at increased prices (due to the higher cost of industrial space and wage levels there). How much extra would you consider it viable at?

Baz

Baz

Would it be possible to offer a collection and delivery service to those in the South for a premium on the standard warranty?

[_Batty_]

nick_968 said:

Baz

Would it be possible to offer a collection and delivery service to those in the South for a premium on the standard warranty?

Dads just had his collected (near Bath).
I pushed him into using Hartech, and am sure it's worth the small fee on transport costs.
We do have a 6000sqft warehouse going cheap mind...

[L200animal]

I have a low mileage FPSH 02 996 Carrera 2. A fabulous car which I enjoy driving not quite as a daily driver but for all sorts of different journeys some short some long. I have a horrible facination for reading these 996 disaster stories which tend to spoil my experience somewhat so can anyone tell me what are the stats? How many were sold and how many had the sort of serious engine failure that seem to worry a high number of owners? I am sure it will be a very small percentage but I would like to know

[Magic919]

I'm sure a lot of people would love to know. The stats aren't out there.

[L200animal]

I bet it's not many and if you take out rogue cars, poor maintenance, track day thrashings and burst hoses leading to overheating, I bet it's really small!

Does Hartech have any informed guess?

[Magic919]

It was so small, Hartech would not be viable.

[itsybitsy]

Magic919 said:

It was so small, Hartech would not be viable.

this is a quess but

if say 100000 units of 986/7 and 996/7 were sold in the uk(fact circa 10k boxsterS manuals from 2001-2008 sold) and he got 1% so thats a 1k units which would probably keep him busy for 5 years plus the units he recieves worldwide.
i would hazard a quess and which has been quoted before about 5% but that could be a mixture of bore scoring,ims,d clunk,poor maintenance,random failure and abuse.
so thats a lot of cars trouble free

[roofrack996]

Not quite on topic but I am always surprised by the premium the 996 c4s commands over the 3.4 c2 when you take in to account this additional problem (and the fairly marginal performance gains). Amazing what looks can do to cloud judgement (and that is subjective as I prefer the original anyway).

Remember going to a Porsche club meet at Autofarm a few years ago and them mentioning this issue, particularly in regards the 3.8.

I would argue the n/a 3.4s is the driver's choice (something Evo would probably agree with). I can't even quite see the logic of going "turbo" as the premium more than covers the incidental costs of an issue with a n/a car (and fails to take in to account day to day issues with what is an even more costly car to repair).

Each to their own and what is clear is that a generation of indies have porsche's dodgy design decisions to thank for their trade.

[Gibbo205]

L200animal said:

I bet it's not many and if you take out rogue cars, poor maintenance, track day thrashings and burst hoses leading to overheating, I bet it's really small!

Does Hartech have any informed guess?

How would trackday thrashing cause bore scoring, from every that Hartech has said, use on a track does not cause bore scoring, in fact most cars which see track days tend to have a much higher level of maintenance and better servicing.

I'd say bore scoring is down too:-

Poor maintenance
Over-heating due to coolant issues or very bad traffic sitting in jams and then booting the car.
Using very thin oils such as 0W-40
Abusing the car such as thrashing it from cold

[mollytherocker]

Gibbo205 said:

How would trackday thrashing cause bore scoring, from every that Hartech has said, use on a track does not cause bore scoring, in fact most cars which see track days tend to have a much higher level of maintenance and better servicing.

I'd say bore scoring is down too:-

Poor maintenance
Over-heating due to coolant issues or very bad traffic sitting in jams and then booting the car.
Using very thin oils such as 0W-40
Abusing the car such as thrashing it from cold

It's due to various crap materials and a poor block design in terms of coolant flow management isn't it?

[L200animal]

Rule out obvious reasons for failure and see what's left. I was postulating that failure rates were gonna be low in real terms. Just a guess, meanwhile I am out enjoying my car and not sitting wringing my hands in case it should go wrong which, frankly, I doubt and if it does I will follow Baz's suggestions and get it fixed.

[Gibbo205]

mollytherocker said:

It's due to various crap materials and a poor block design in terms of coolant flow management isn't it?

Yup and after speaking to Baz there are precautions you can take to help reduce scoring.