My C2S engine after 50,000 miles and over ten trackdays

Gibbo

Gibbo

Gibbo

OcUK Staff
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Hi there

As many of you know I've modified my C2S, now making 375BHP and do several track days a year.

When I purchased the car it had 27,000 miles and roughly 1700 operating hours with quite a lot of R1 and R2 ignitions. A bore inspection by Mike at S&C revealed a spotless engine with zero scoring when I purchased the car.

Now at 49,000 miles and many trackdays later I'm at Hartech for a low temp stat to be fitted, bore inspection and looking at my corrupted DME, though DME is fine just operating hours corrupted due to welding exhaust.

Good news is Hartech also said it's a rare occasion that a 3.8s with such mileage to be so clean as the bores are still spotless, all of them, so very happy. :)

Bad news bolt snapped on thermostat housing so need to leave with them and DME they are gonna check over.

So my regular oil changes, driving the car as intended and trackdays have kept the engine in good order. :)

Hartech say fitting the 3rd radiator was a good move when I got the car. :)

To be honest I expected my bores to be scored as you read so much about t and how most cars have it due to flaws in the engine design. So to be told not a single mark is great, fingers crossed it stays that way and I've taken every precaution to keep the engine safe. :)
 
Also, 911's need a good spanking, they thrive on it in my experience. It's ones that aren't used that start to protest. When I got my GT3 it had done 6K in 2.5 years from new and wouldn't tick over and kept stalling. The GT3 is a very lumpy tick over anyway but mine was stalling at lights and stuff. A few miles under some proper use and all was sorted. My dads is the same. 10K miles in 3 years and using oil. Since he added 15k it has started to use a lot less oil and is running better and better. I am not surprised to hear your car is fine, track days (as long as you dont start buzzing the engine) does them more good than bad I think if you maintain them well.
 
Matt82 said:
What oil change intervals have you used and what are the manufacturer recommended intervals?
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20k / 2yr which is part of the problem.
I change mine every 5-6000 miles, plugs every 20k.

Car only fed vpower, allowed to warm properly and then spanked. :D
 
The Running Man said:
Must be a relief but good to hear. Do you drive the car in winter?
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Not as much as summer but yes, typically once to twice a week depending on conditions.

Porsche seem to hate not being used or driven like miss daisy and they hate traffic jams, seems to be the cause of many issues.

Like Housey says treat them right, spanking them often is what they seem to like. Mine uses very little oil, even less now I'm on 10W-50 :)
 
[TW]Fox;24495279 said:
Seriously? It has 49k not 349k?!
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Yes engines dying from scoring with as little as 15k major issue on the pre 2009 cars, cooling design flaws, Porsche just won't admit it! Bore scoring is the biggest killer of the engines, more so than ims failure!

Hartech had 20ish cars in, 996 and 997s all having an engine rebuild of some kind.
 
Your driving is nothing close to the testing these engines go under in development. I don't see why the track day is irrelevant.

If everything is fine though. Why are you forcing the engine to run at a lower tenperature than it is designed to?

These engines can have issues if they overheat but a thermostat isn't going to help that.
 
Simon said:
Your driving is nothing close to the testing these engines go under in development. I don't see why the track day is irrelevant.

If everything is fine though. Why are you forcing the engine to run at a lower tenperature than it is designed to?

These engines can have issues if they overheat but a thermostat isn't going to help that.
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It's a proven preventive measure to help prevent scoring by autofarm, hartech and LN engineering.

Just taking every measure to keep it spot on but like Housey says the most influencing factor is driving style and regular oil changes.
 
The bores don't score even with 140C oil temperatures,

The biggest issue is fuel dilution thinning out the oil film on the bores and a lower temperature thermostat is only going to make this worse. It's a band aid for a marginal cooling system
 
Simon said:
The bores don't score even with 140C oil temperatures,

The biggest issue is fuel dilution thinning out the oil film on the bores and a lower temperature thermostat is only going to make this worse. It's a band aid for a marginal cooling system
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I see your point but as explained by Hartech this is not an issue in the Porsche engine, explanation below:-

It becomes increasingly hard to explain why so many questions make assumptions that are wrong and therefore become misleading. I don't know how many times I have explained that the cylinder block runs at a different temperature to the heads and the thermostat only operates at the resulting mixed together temperature. This is such a basic issue that is the root cause of the problems but can only be modified with a stripped engine.

This being the case the temperatures in the block with the lower temperature thermostat are about the same as almost every engine used to run on in the last 50 years - but with the standard thermostat are much higher. I think this totally negates comments about the polutants escaping past the rings etc. The thermostat we supply warms up slightly quicker than a standard one anyway and so the temperature the internal cylinder area reaches normal running temperatures as quickly as any normal engine would do. Frankly discussing this level of polutant transfer is so minimal anyway - it is just an unnecessary smoke screen to the fundamental problem - diverting attention from the true problem.

By measuring the creep to ovality of engines that have covered all mileages from about 15K to 150K it seems to us that the creep is at much the same rate and regular - following almost a straight line graph - and therefore will occur to all engines eventually and carry on during their life.

There is a difference in the rate of ovality creep between cylinders (as is common with composite constructions) and it has been a technical subject upon which accurate predictable guidelines have been slow to appear (due to this unpredictability) - it is not like metallic molecular alloys.

I have already explained that the area the support rings present to the coolant is actually higher than the original material AND that the top of the bore never seizes anyway and only ever a long way down - and that pistons are made smaller where the rings are and don't touch the cylinder wall anyway and that the rings don't reach the top of the piston anyway - so - not really sure how many times I need to repeat this simple fact that makes comments about the upper cylinder temperature a little irrelevant. However the support rings - by re-rounding the cylinders - increase the contact between the piston, rings and bore - where it does matter - which is extremely relevant.

Trying to find solutions to manufacturers problems are far more difficult than designing it right in the first place or re-designing the engine for a newer version while addressing these problems.

We do not claim that fitting a lower temperature thermostat is a permanent fix for all problems - for ever - only that it is inexpensive, and should increase lifespan.

None of our modification remove all weak areas of the engine because it was designed to just be capable of reliably providing the output planned and if you needed a more powerful example for track use they manufactured a more expansive engine with different internals. Unfortunately they got things (IMHO) too near the wire with new materials technology and risky design ideas that in some cases fail. We will be racing an example next season to try and find all the weak areas - in sequence and try and provide answers before they hit the general public. This will also prove our own existing solutions and hopefully enable the process of making these engines more reliable to keep up with them as they age.

Our IMS replaces the original bearing with one without seals (and therefore lubricated by the splash oil provided by the chain rotation) - a stronger spindle and nut (plus a lock nut) a fit checked by measurement. It is much the same as the LN solution except they use a more expensive but more fragile ceramic bearing that our tests have proven unnecessary. I don't think there is anything wrong with their solution and if you want to pay more for something that is similarly reliable - please do so - I have no problem with that.

Hope these replies help.

Baz


Very popular mod and proven by many of the Porsche engine rebuilders, not just Hartech. See full thread on PH here:-
http://www.pistonheads.com/gassing/topic.asp?t=1046386
 
Simon said:
Doesn't seem to mention fuel dilution and its effects on oil film in that ?
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That was in response to the below from someone asking the very same as you:-

Finally and possibly more important to Forum members is the effect on oil dilution. This occurs when fuel leaks past the piston rings when the engine is first started. Also you get condensation of water lurking at the bottom of the sump. These pollutants can seriously degrade the function of the oil. An engine that does lots of cold starts and does not get properly hot will be very prone to this. Running a cooler stat will mean the pollutants take longer to be driven out of the sump oil. A 70 C stat should really only be used in engines that are going to get a darned good thrashing every time they are used
 
They obviously don't understand the function of oil, nor the effect it can have. Fuel is constantly filling the sump, especially on hard driven cars. My response to this thread is based on discussions with the people who designed the engine and now are responsible for oil approvals.

The fact is liner scuffing can be controlled via the type of detergent in the oil aswell as how it copes with fuel dilution

Shorter drain intervals and hard driving is the reason yours is still ok, will be interesting to see how it looks in a few more miles.

Next oil change send me some old oil and we can have a look how much fuel is in it
 
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I learnt very quickly that reversing the car out of the garage, washing it and then putting it straight back in was not a good move. The next time I came to start it I got blue smoke and a strong petrol smell as the flat 6 is prone to that. So I use to reverse it out take it for a blast for 20 miles or so, no hardship and then park it up and wash it. When washed I'd go out again for another blast and then park it up. They really don't like short trips and HATE 20 yard trips from cold.
 
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