bazhart

Hi Silk,

The only agent that we have authorised to machine cylinder blocks and fit our liners is our agent in Canada.

Our other agents are the people that we have done business with for several years and who send cylinder blocks here to be fitted with our Nikasil plated alloy cylinder liners but strip and re-assemble the engines in their own workshops.

We also supply them with some other items that make the engines suitable for track use.

The most important is our racing sump which unlike many other extensions on the market is a whole new cast sump with valves and flow controls to prevent oil spilling out again in corners (which most other sump extension do not prevent).

If you intend to use slick tires on track then we also supply a machined casting to allow the connection from an ACCUSUMP which is essential at racing speeds and cornering G forces approaching similar cars in race trim with fast drivers (but not necessary for just road tire track use).

Or you can contact us directly.

Baz

bazhart

We have posted a lot on the subject of bore scoring before and on our web site but briefly - hypereutectic alloy cylinders contain hard silicon particles that resist wear providing a cylinder that expands like the piston - keeping close clearances throughout but not wearing out as it would just in aluminium.

With the original Alusil (944, 968) the silicon was cast into the mix in a higher proportion than aluminium can absorb and allowed well distributed growth of silicon to come out of solution and created the hard particles. The problem was it was all over the cylinder block and cost a small fortune to machine because it was so hard. However it also increased the stiffness of the block and hence allowed open deck cylinders to last quite well.

It was found during the original development (mainly the Vega engine) that the pistons needed a thin iron electroplated coating to prevent the silicon interfering with the piston surface on the thrust face.

To overcome the high machining costs of Alusil, Lokasil was a different way to trap silicon particles just where needed - by creating a pre-formed tube that held silicon particles in space with organic binders and this was cast into the main crankcase casting under high pressure that allowed the molten alloy to flow into the preform, burn off much of the binder and end up with a silicon rich distribution near the cylinder surface only.

Unfortunately the remaining alloy was not as stiff as Alusil but the 2.5 to 3.2 Boxster had thick cylinders and not very high piston loads but the increase to the 996 bored out the same block and resulted in thinner cylinders so with the first 3.4 examples the open deck arrangement was prone to go oval under the piston thrust loads and eventually crack. Other than that is was OK and we fitted support rings to the top of the cylinders to prevent ovality and that worked just fine.

Then some European Health &Safety legislation handicapped the process to coat the pistons with hard iron and a softer plastic coating was used instead and at the same time because the pistons were getting larger (with the 3.8) the ratio of silicon and the particle sizes in the Lokasil was increased to stiffen the cylinders which they couldn't make thicker in the same block dimensions of the earlier engines without reducing the coolant volume too much.

The larger silicon particles resisted ovality and cracking better and for much longer but the particles were not as securely bonded into the matrix as with the Alusil method and when a particle became free from the bore it rubbed against the plastic coated piston and damaged the surface and due to its increased size and the higher thrust loads of the bigger capacity engine - could breach the oil film thickness under high torque and score the bore on the side of the thrust (not a seizure on both sides caused by too much piston expansion) just hard particles rubbing between the piston and the bore and damaging it.

Nikasil plates silicon particles in the most secure way possible (so good that even when damaged metal particles enter the combustion area through say valve problems - it often survives.

The lokasil could be replaced by an alloy Nikasil plated thin tube creating a dry liner but a tube inside a tube is not as stiff as a solid tube of the same overall dimensions and so we prefer to completely machine out the original cylinder and fit a whole new alloy one with a Nikasil finish and machine a precision fit at the top the secure the position and prevent movement creating a top closed deck.

The resulting bore finish is similar the air cooled 911 cylinders that last so well and almost identical to the GT3 and turbo versions of the same models (that are so reliable) and have proven extremely reliable in our production over thousands of liners and over a decade of fitting them.

Baz

Silk

Thanks for your feedback.

In fact my engine-block was modified by Hartech back in 2015 by the previous owner of the car. I tried to trace back what exactly was done to the block but I do not know if it was fitted with Nikasil or steel liners, bank 2 only or both cilinder banks. Were you still doing steel liners at that time?

In case I encounter another engine failure I will look for the bigger bore upgrade for a track oriented street car.

I hit the track ocasionally for fun driving. I run Yoko AD08r and do not intend to use slicks now or in the future. I have a X51 style pan (FVD) installed and the spin-on adapter with the washable racing filter. Running Millers CFS 10w50 NT

I know about the Bilt Race deep sump kit with the windage tray sold by LN. which is merely an extended reservoir with the tray creating a sort of closed chamber which holds the oil and prevents excessive foaming.

Does the Hartech solution is more compact? Would you advise such an upgrade compared a X51 style pan for my 'recreational' use? How doesit compare pricewise?

Maybe I better drop you a mail with my enquiries.

bazhart

Hi Silk, please E-mail me direct on baz@hartech.org for more about the racing sump - I do believe it is the only one that physically prevents oil escaping and directs it into the pick up area.

We have never ever supplied steel or iron liners for these models (although it would have been cheaper to do so).

There has to be specific design suitability in the original block to make a ferrous liner work reliably and not drop or become loose because of the differential expansion rates, the thermal conductivity is not so good (so engines run hotter internally) and they wear faster than Nikasil. Furthermore the expansion rate is about 0.001" (0.025mm) less so you have to run with greater cold clearances (which is OK for racing where the engine is always flat out but not suitable for road use when it hardly ever is) That is IMHO.

Iron or steel liners were discarded by most manufacturers years ago (unless they were cast in and ribbed internally and the cooling took account of the expansion rate difference and usually where bores were smaller than 96-100mm and pistons were designed accordingly).

The amount a piston expands is proportional to its diameter so the bigger the bore the more unsuitable a ferrous liner becomes.

Our first cylinders were basically similar to our present ones - they all were wet liners, all closed deck and all ribbed externally to increase heat transfer even more.

However some customers could only afford a damaged cylinder to be replaced - some only bank 2 and some all 6 (now the reliability of the system is proven almost all customers now have all 6).

Baz

James88

Reviving an old thread.

Hi Baz,

January this year I purchased a Porsche 996.2 c2 manual coupe with your 3.9L engine conversion.

I currently have Topgear sports headers, Topgear quiet muffler with bypass mod (To make it louder) and FVD X-Pipe with 200cell RedBack High Flow cats, I believe its running stock oem tune.

Do you recommend remapping? Is there a remapping option that you do or could you recommend anyone that could do it? . I'm located in Melbourne Australia.

Thanks in advance

Kind regards
Jim

James88

If anyone is interested l have been communicating with Baz from Hartec here;
http://911uk.com/viewtopic.php?t=125...r=asc&start=40