Hartech proper Engine rebuild after bodge job

Picked up my 977 c2s yesterday after having a complete engine rebuild after my last engine rebuild lasted two months before it blew up!

I'm live in Worcestershire and for legal reasons can't name my local Indy garage that took my money and rebuilt my engine to a "bullet proof" standard to have it fail from IMS bearing failure 1800 miles later.

Despite my Indy garage claiming to offer a warranty they would not be held responsible as the car reported an over Rev in 1-5 at the exact operating hours that they had the car in their garage for a new alternator.

My car is tiptronic by the way and despite having a signed letter from Porsche stating that it's impossible to overrev a tiptronic car my Indy garage refused to pay up.

Three months of solicitors letters and faced with having to take him to court with costs looking in the £10,000 region in fees I settled out of court for a sum that was less than I would have preferred but a small win all the same.

My advice to anyone wanting an engine rebuild in the Worcestershire area would be head north to Bolton and go and get it done my hartech engineering as they are the experts and know how to treat customers and explain everything so clearly.

My cars now running like a champ and I can put all this behind me-well after trading standards have their turn as I've just informed them of this garages shoddy practice's. When my engine was dismantled the uprated IMS with the larger sized bearing which I had paid for hadn't been fitted. Instead I had a standard IMS with a LN bearing fitted. Overall quality of the Indy's rebuild was described as shoddy to say the least with cross threaded and Sheard bolts on the engine.

Not the same Worcester place that were recently and wrongly accusing Hartech of bad engine building. :?:

infrasilver said:

Not the same Worcester place that were recently and wrongly accusing Hartech of bad engine building. :?:

Click to expand...

Not able to confirm that for legal reasons. I love playing bingo!

If Hartech will provide you a technical report confirming the IMS bearing you paid for had not been installed, you may have a stronger lever.

Sorry to hear of your plight.

cheshire911 said:

If Hartech will provide you a technical report confirming the IMS bearing you paid for had not been installed, you may have a stronger lever.

Sorry to hear of your plight.

Click to expand...

Ive spent the last5 months and £2,500 in solicitors bills doing everything to get this idiot to admit his mistakes but he just kept trying to wriggle out of it. With all the evidence I had I could have taken him to court but that would have cost upwards of £10,000 which he would have had to pay if I won but the law can often go the wrong way so I settled out of court.
I'd advice anyone needing an engine rebuild to just go to Hartech as the difference in customer service and the quality of their work is unbelievable!
They don't ***** their abilities!

Once solicitors are involved it is they who win and fleece the client with their "you have a strong case but on the other hand....." approach.

It is sometimes cited that "the Law is an ass" and how true!

I guess you have taken a mature approach by having a go up to this amount, accepted a small out of court settlement and moved on with a proper fix.

A bruising experience for sure. If its any consolation, I'm sure there are others who can recall similar episodes in other ways.

I think choosing a specialist for ANY work must not be undertaken lightly.

With an engine rebuild, it is key to enquire how many they have done, assess how well they understand what is required and which parts to use, if they give a full technical report with recommendations, if they use Porsche parts or OEM, what else they recommend whilst the engine is apart and of course do they sub-contract any of the work to another specialist.

I have met Baz and the whole set-up at Hartech at an open morning and Grant was very helpful when I was mulling over the C4S vs Turbo debate in my head. I'd be surprised if other specialists do not send work their way on behalf of a customer such as new liners but that is Baz's business and I would not want to pry into how much he does from 3rd party sub-contracted work. My point is that if you use a specialist only to discover he sub-contracts some major parts to another specialist, it may be better to consider going to the source of the River Nile and fish upstream for the expertise.

At least you now have the engine sorted and I wish you many years of enjoyment.

Sorry to hear this. I know what it's like to have troubles like this with courts etc. it looks over you for a long time. Not a pleasant experience at all. The good tng is you can put it behind you now that it's been done properly and enjoy your car.

cheshire911 said:

Once solicitors are involved it is they who win and fleece the client with their "you have a strong case but on the other hand....." approach.

It is sometimes cited that "the Law is an ass" and how true!

I guess you have taken a mature approach by having a go up to this amount, accepted a small out of court settlement and moved on with a proper fix.

A bruising experience for sure. If its any consolation, I'm sure there are others who can recall similar episodes in other ways.

I think choosing a specialist for ANY work must not be undertaken lightly.

With an engine rebuild, it is key to enquire how many they have done, assess how well they understand what is required and which parts to use, if they give a full technical report with recommendations, if they use Porsche parts or OEM, what else they recommend whilst the engine is apart and of course do they sub-contract any of the work to another specialist.

I have met Baz and the whole set-up at Hartech at an open morning and Grant was very helpful when I was mulling over the C4S vs Turbo debate in my head. I'd be surprised if other specialists do not send work their way on behalf of a customer such as new liners but that is Baz's business and I would not want to pry into how much he does from 3rd party sub-contracted work. My point is that if you use a specialist only to discover he sub-contracts some major parts to another specialist, it may be better to consider going to the source of the River Nile and fish upstream for the expertise.

At least you now have the engine sorted and I wish you many years of enjoyment.

Click to expand...

That's exactly why I took the money on offer which wasn't enough to pay for the Hartech rebuild but some compensation. I just hope others don't have the same experience as I have.

Elliot, Can I ask what exactly you had done? Was it bore score repair, in which case do you know what liners they used? Was your engine failure the result of the new LN Engineering IMS bearing failling or being fitted incorrectly? I have the early smaller IMS in my 54 reg car and was planning to replace the bearing with the LN item at clutch time.... If the engine is apart then I'd prefer the complete later >2006 larger IMS fitting instead, but believe it is only Hartech that offer this, (not sure if is because extra machining is involved).

For legal reasons and to prevent anything handicapping future action - I am not going to identify anyone in this comment not do I claim it refers to anything in particular. It is instead a collection of general points that would apply universally but provide a scenario that could be relevant
.
HARTECH CYLINDERS

Around 10 years ago - when theses engines first had IMS and "D" chunk failures and were first re-assembled with new Porsche crankcases in the UK by other specialists - there were reports of some not having had the piston circlip correctly fitted (by the unusual method and tooling recommended by Porsche and those unfamiliar with using it) that didn't last more than a few miles before blowing apart.

To avoid this potential problem - our early Hartech engines were assembled by a different method devised to allow all circlips to be fitted before fitting the piston in the cylinders (and no failures resulted) and as a result they didn't need the assembly holes in the bottom of the cylinders in bank 2 of the engine.

When we started fitting replacement liners for some of our specialist customers (often just one liner - who then went on to put the rest of the engine together themselves) - we originally trained them into this new method of fool proof assembly with 100% success.

If some years later - such an engine had a failure (not connected to the cylinder or anything else connected to Hartech) and was stripped by someone unfamiliar with this assembly method - they would probably be unable to assemble it without seeking advice from Hartech.

If a Hartech cylinder had failed it would have been guaranteed and so contact would have to have been made if there was a cylinder fault - but if the specialist decided not to contact Hartech (because there was actually nothing wrong with the cylinder) but could not work out how to assemble the engine again - this would be difficult to explain to their customer - unless they used their own incompetence to rubbish the existing liner and supplier and suggested replacing ALL the cylinders (so they could add some
Porsche assembly holes) as a solution.

For some unethical people - this could then be construed as a good way to promote their business, increase their income and discredit competitors - to blame the liner and the people that manufactured it (even though there was nothing wrong with it and they could not produce any photographic evidence of a problem with it) as this would enable them to escape criticism and gain the extra work from fitting 6 new iron liners instead - and they could now put it together again. Some unscrupulous businesses may regard this as a "win/win" situation - especially if they used that same excuse to promote the fitting of iron liners by themselves for others.

If that engine also had to have an IMS bearing replaced - the real reason for the need to strip it down in the first place may then also become apparent - that it had no connection with the single replaced cylinder.

Of course - if they could not put the engine together but used a false accusation that the cylinder was at fault - they then could not contact Hartech for advice about how to assemble the engine - because the true condition of the perfectly good liner would then become apparent.

If anyone ever followed the above tactics to benefit their business - I would not regard them as trustworthy nor good engineers - as capable engineers never use such tactics to gain work and never discredit other good engineers (unless they deserve it through bad engineering) relying instead on their own engineering qualities with pride and being prepared to value others even though they may be competitors. For example - when we receive an engine for repair that is supposed to have scored cylinders but discover it has not - we always tell the truth (even though it consequently losses us business) because we are driven by good engineering and ethical behaviour.

If a business publicised the fact that it could not work out how to assemble an engine that someone else clearly managed a different way - it would also be rather like shooting yourself in your own foot to admit you couldn't work out how to assemble it - and then claim that was proof of someone else's incompetence - instead of your own!

As the years went by and with the increase in familiarity of the unusual Porsche method of assembly by so many specialists (in the UK and Worldwide) sending their crankcases to Hartech for new alloy Nikasil liners - it became impossible to train them to Hartech's old method and preferential for them to be manufactured to suit the Porsche assembly tools that they could by now use reliably - and so a long time ago the product was developed and changed and for many years now - all Hartech liners have been manufactured to a newer specification with the standard Porsche assembly cut outs and holes (that some incorrectly refer to as windage slots as were put there to enable a Porsche assembly method to be used) so they can be assembled with standard Porsche tooling anywhere Worldwide.

These cylinders now number over 1,500 successfully manufactured with 3 known failures caused entirely by unrelated issues that were nothing connected to the cylinders (like coolant loss) and that is a fantastic record for a superb product.

WINDAGE SLOTS.

Because pistons only touch (and run with pressure) against the cylinder on the front and the back - in order to reduce friction losses and make them lighter - they have been manufactured without any metal on each side at the bottom - creating a "cut out area" that wouldn't have touched the cylinder wall anyway. High revving engines with parallel cylinders sometimes mirror that "cut out area" at the bottom of the cylinders on each side to reduce weight and allow the air being moved down by the piston to move sideways more easily - making a very small impact on pumping losses of a fraction of a horsepower/cylinder. With Porsche engines being specifically designed to produce good torque at low and mid range revs - such minor losses are insignificant.

It is no surprise then that all 911 engines made in the previous decades up to the M96 engine did not have windage slots. Neither did the 944 2.5, nor the 996/997 Turbo or GT3 (including as well all the bank 1 cylinders in all the 996 M96 engines). This calls into question the competence of anyone claiming that a cylinder or engine without windage slots is inferior and anyone involved that doesn't use them - doesn't know what they are doing - especially as this engine range without them was probably Porsche's most reliable.

Windage is losses cause by moving air inside the engine as the piston rises and falls. It is calculated to absorb less than 1bhp in most linear or V cylinder engines but far less in an apposed cylinder engine as the opposite sides of the cylinder blocks tend to provide the space (as one piston rises and another falls) for the windage movement caused to pass across the block from one side to the other where one piston is rising - in a constant direction rather than be forced sideways. In addition those irrelevantly small losses would only be at very high revs anyway (if at all).

The early M96 cylinders had a hole at the bottom in bank 2 only (and then not on both sides of every cylinder) that coincided with the "cut out area" of the piston but this was only put there to allow the Porsche assembly tool to be fed through the cylinder holes to locate the piston circlip.

When Porsche lengthened the stroke without increasing the cylinder block height (for the 3.6 and 3.8 engines) it lowered the gudgeon pin position @ Bottom dead centre and so the hole used to assemble would then need to be lower and would partially cut out of the bottom of the cylinder wall leaving a bad mechanical shape for potential thermal distortion.

So to avoid this if possible - later engines had a modified "cut out" shape (instead of a hole) so that on bank 1 a centre cylinder had two "cut outs" and the two outer cylinders had one (with bank 2 having two centre slots, one on one end and a hole that cuts through the bottom of the cylinder on the other - used to enable the same tool to assemble the circlips with a shape similar to the piston cut out and similar to "windage slots" in other engines - having a convenient dual purpose.

Experienced, qualified and capable engineers would understand these issues and would never use either of the above scenarios to try and discredit competitors with the best reputation for engine repairs and who carry out by far the greatest number of rebuilds and have the very highest quality and success rating.

Similarly - we at Hartech never try to discredit anyone unless we find they are promoting solutions that we genuinely believe are misleading potential customers lacking sufficient automotive engineering experience to judge for themselves and/or inferior products that we have knowledge of regularly failing when there is evidence of unsuitability - and to protect consumers.

The use of dry iron liners (instead of Nikasil alloy wet liners or cylinders) is a classic example where we regularly receive engines fitted with them to rebuild again because they have failed (and have the evidence to prove it). Even then if we mention this we only use engineering explanations to describe our position thereby enabling others to defend their position without resorting to underhand personal tactics.

This is not because there is anything wrong with the quality of the actual iron liners - but mainly because they are less suitable for this particular application. This is contributed to by the fact that they are usually fitted by engine re-boring specialists - to their own individual different specifications and in small quantities without the level of qualifications, research and development we at Hartech have applied - and cost almost the same anyway as the Hartech Nikasil Alloy cylinders (that are very similar to the solution Porsche themselves have successfully used for many years and in M96 and M97 Turbos and GT3's).

At Hartech we always apply the policy not to concern ourselves too much about what other competitors do but just concentrate instead on trying to be the best ourselves - allowing reputation and referral to provide sufficient new customers to exist. It would not be difficult instead to run down some others - but that is not our style (nor in our experience is it that of other good engineers providing reliable and honest service and comment to the market).

There are always differences of opinion between good engineers that are healthy and they encourage competitiveness - motivating people to try harder and harder to provide the best solutions - a main advantage of a competitive economy. People that are not capable of that approach frequently resort to trying to run down their competitors since they themselves are not capable of standing their own ground through the lack of quality of their own engineering ability or the inferior products that result.

In conclusion - there are two ways to get on top, put your energy into trying to run everyone else down so they appear inferior (leaving yourself at a higher level) or just try to be the best - so it is self evident you are above everyone else anyway.

Baz

krispe said:

Elliot, Can I ask what exactly you had done? TOTAL ENGINE REBUILD Was it bore score repair, in which case do you know what liners they used? STEEL WHICH I GOT HARTECH TO REPLACE AS THEY HAD MOVED Was your engine failure the result of the new LN Engineering IMS bearing failling or being fitted incorrectly? BEARING FAILURE THAT COULD BE ARGUED AS THE BEARING OR FITTING HARD TO SAY AS THE IMS SHAFT WAS TOAST I have the early smaller IMS in my 54 reg car and was planning to replace the bearing with the LN item at clutch time.... If the engine is apart then I'd prefer the complete later >2006 larger IMS fitting instead, but believe it is only Hartech that offer this, (not sure if is because extra machining is involved).

Click to expand...

My best advice is give Grant a call at Hartech and he will explain it perfectly to you. These guys are so helpful and reasonable on price. If you want peace of mind and to know that you only need to pay to have the job done right then theres nowhere better to take it in my opinion.

Excellent reply Baz as always, the most poignant part of which was the business etiquette you apply, something which my business partner and I abide by too. However, as you say far too many people are quick to put the boot in to 'score points' when not in possession of all the facts, particularly in this internet age in which we live.

The windage 'debate' is something I deal with every day with racing engines. We have tested inline fours that rev very high by conventional standards, by adding windage slots or 'air management' windows and testing. One engine in question was the venerable A series Mini engine, with an 81.28mm stroke.

Windows were cut into the block between adjacent cylinders, with the following results; peak power on our engine dyno before ,127@ 7800rpm. At this point, the power curve rolled over. Peak power after, 128.6@ 7800-9000 rpm, the slots/windows kept the power curve completely flat across this range. The engine was tested under accelerative conditions, at a 300 rpm/second rate. On the track, the car was pulled past 10000 rpm (a mean piston speed of 27.09m/s, or 5333 ft/min in old money), by an old racer by the name of John Rhodes. He said to the owner of the car that the power didn't appreciably drop off, even at these very high revs. In race two at the Goodwood Revival, he still pulled it 9750! This was a good few years ago, the car having won the St Mary's Saloon car race outright the year before in the hands of Richard Dodkins.

In the future, I feel that active internal air management will be on the horizon. In 2012, we stripped a prototype Moto 3 Honda NSF250 engine. It was pretty conventional, with one exception; there was a reed valve in the cam chain tunnel, set to reduce pumping losses on the down stroke but shut again when the piston rose. Contrastingly, a Rotax Twin cam 600cc single had a timed breather designed, according to the factory in Austria, to deliver 0.1 bar of positive pressure within the crank cases. We tried many times to alter the breather diameter, each time losing power and reverting to the factory set up. Interestingly, playing with the crankcase pressure altered the shape of the torque (and therefore power) curve, sometimes making more lower down than stock but losing out at high rpm.

All current inline four bike engines have holes between the cylinders. Small changes to these holes does much the same as the Rotax engine did- altering the shape of the power curve but in general, making the power hang on for longer. These alterations were only carried out where the rules allowed.

I think the reason the early Porsche inline fours you mention do not have windage slots, is that when they were made less was known about the interaction between the cylinders within the block. However, you are right about rpm playing a part. The high revving bikes respond to the holes being altered, despite having a mean piston speed lower than that of the Mini we tested, typically being in the order of 23 to 25 m/s. So it appears that it is the frequency of air movement that counts, not the speed of the air volume being displaced. One probable reason for rpm/frequency showing potential problems is cumulative blow-by entering the picture.

With the flat six boxer motors, you are probably right about the displaced air but any time that air passes through the crank assembly, windage losses can appear, as I'm sure you are aware. As you have mentioned, rpm would play a part but overall the system is inherently better balanced from a windage perspective.

Mike

Along with many others I cannot help but be impressed by Baz@Hartech.

Porsche as marque are fortunate to be supported by such an industrious organisation as are we as owners/users.

And when Baz makes a comment you get the whole nine yards - Top Bloke !

Interesting Mike and thanks for the contribution and 1.6bhp @ high revs in a high revving in line engine is about what I would expect.

Most of my early dyno testing and development work was with two strokes but the good thing is it helped me understand a lot about specific time area and the need for variable controls on volumes and timing (which is common place these days in 4 strokes as well) and of course under piston pumping losses (which were crucial).

Designing gearboxes also helped understand the influence of revs on power bands as any increase in revs also increases the rev band between gear change requiring a wider power band or a narrower set of ratios and then another gear if they get compressed too much!

Returning to the M96 and M97 engines - you may have misunderstood that even the more recent Cayman S has no windage slots at all on the thee cylinders on Bank 1 and only the round holes on bank 2 where the centre cylinder has 2 and the ends 1 (because the air can only go in one direction from the ends to the centre).

It is clear from this that even these later engines only have the holes in bank 2 to assemble the engine!

With road cars having to plod around in Town and average speeds over years working out around mid 30mph - it is right for Porsche to consider economy and a wide torque spread as more important than pumping losses at peak revs.

This is a different scenario with motorcycles (due to different power to weight ratios) and of course the peak revs they achieve and different with racing engines when the rev range to produce the best power is very much higher and narrower.

Thinking about the rise and fall of the pistons - although blow by could be a contributing factor - when engines near peak poser the internal losses are ramping up on the outcome and moving air quickly is not linear resistance equation - so sheer speed could influence the top end more as a result. Also momentary pressure rises under the piston would be higher at high speed due to timing and inertia or air flow reaction times.

When a piston falls it moves the capacity downwards increasing under piston pressure and pushing air downwards.

Nearby another piston is doing the opposite and moving upwards creating a reduction in pressure and a space for the air to move to.

Given time - air will try and move between the two but it loses more energy to move that air sideways through a hole or cut out at 90 degrees twice than to keep it moving more or less in the same direction through the crankcase to a rising piston nearby on the other side.

So with low and mid range torque being the aim - windage is in my opinion more insignificant in these horizontally apposed engines than most others - so that other considerations could dominate a decision to include them or not.

At very high revs I would imagine there is not even enough time for much air to move anywhere anyway and probably pressure rises and falls are more significant causes of energy losses than volume movement (agreeing with you about resonances etc).

Regarding power production, many people refer to mass air flow being the key and the bigger the holes or valving the higher the mass air flow at given pressure drops and the greater the power - but equally the narrower the power band (unless you vary timings and areas with variocams, variorams and variable valve lifts - to stretch the power band.

I envy your time spent developing engines and testing them - I really enjoyed doing that over 35 years ago.

The most significant thing I ever discovered during dyno engine testing was that there is also a critical compression pressure that petrol produces a fast burn and pressure rise at but that below that the burn is too slow and weak to produce power. The change is a dramatic sudden increase when the compression pressure at ignition is high enough (often assumed to be caused by some resonant frequency).

So (for example) if we fitted a 10 to 1 compression cylinder head, then a 14 to 1 then an 18 to 1 etc to the same engine - one that was all peaky and top end with the correct say 10 to 1 head for power at peak revs would become torquey at powerful at low revs (well outside the original power band when we are told resonant frequencies have killed the power) as the higher compression ratio heads were fitted (but it also killed the top end and rev band). it would seize up with the higher compression heads of course as the revs rose but be perfectly Ok at lower revs with a very high compression ratio.

It meant that a variable compression ratio engine (as pioneered in a two stroke by Aspin in the 1930's (I think) and as a 4 stroke by Saab more recently) can result in an engine with huge specific time areas and top end power - yet massive torque all through the rev range as the compression ratio is reduced with the rise in revs and the actual compression pressure before ignition remains more constant.

This means the best area to look at for wide power is to be able to vary the specific time areas with revs and support a constant cylinder filling and thus a high compression pressure throughout the range. This also explains why years ago fitting H/C pistons was a simple route to increase top end power.

The introduction of variable valve lift, valve timing, resonant flap timing and ignition and fuel adjustments has enabled companies like Porsche to create road engines with superb power spread and far more relevant and influential on output in comparison to any advantages windage may create at the top end.

Coincidentally this also explains why turbos and superchargers increase output by increasing the compression pressures over a higher rev range (despite have large time area designs) and why low pressure turbos increase torque and range.

It is just a question of substituting "cylinder filling" for "compression pressure" (although they effectively achieve the same thing) - except that even an engine with low cylinder filling at lower revs will produce exceptionally good power if at those revs the compression ratio and pressures are ramped up by some variable device.

As you can tell I just love all things to do with engine design and development but now back to the comparative drudgery of fulfilling production orders, repairing engines and fitting in some R & D or race car work in between (well we have to make a living as well!).

Baz

No sooner had I posted the above relating to the problem with some that fit iron liners than I was called to the stripping and assessment room to look at a classic example.

The pictures can be seen on www.facebook.com/hartech.porsche and show how someone has decided to fit thin liners and locate them at the bottom of the cylinder with a narrow flange.

One has become lose and rotated and slipped down breaking the bottom flange off.

Another must have broken the flange when they fitted it and an attempt has been made afterwards to weld it up at the bottom.

These are typical of the examples we get in almost weekly indicating that someone is making a lot of money out of fitting iron liners that soon afterwards have to be done again.

The liners themselves are usually OK as far as the material goes but the design and fitting lets them down.

There seems to be 7 or 8 places doing them (judging by the different designs and specifications that have failed that we see here) and as they see smaller numbers than us - the proportion that have to be redone properly by us is huge.

For those that criticise us for conveying this - please look at the photos on facebook - should we really say nothing and leave these people to profit from the misfortune of others persuaded into that solution only for it all to turn pear shaped so soon afterwards?

This engine casting design and the crankcase materials and space just is not suitable for iron liners that will anyway always have cold to hot running clearance problems and differential expansion difficulties with the three layer thin steel head gasket design.

Baz