4722 replies to this topic

[steveboyslim]

The polishing is very high, i'm also concerned about the scoring. both could be due to fuel dilution. Get the cylinders properly honed next time, the lack of proper honing will also exacerbate wear.

Bores did not need anything other than a 'glaze bust'. Fuel dilution is what I would guess. Steve

[fezzasus]

 

 

 

 special 'low friction coating' 

  Sounds like DLC. Not suitable for bearings,  

  Try to tell that to all F1 teams  

  Very different running conditions. If anyone has the time to strip and rebuild an engine every two hours then they can run much more exotic materials which would, in normal conditions, lead to premature failure.   

  F1 engine are not striped every 2 hours since (10+) years... they now do at least 3000km each, very close to LeMans engines in fact. DLC coating is in fact the main reason they work so well and do not loose power even near their end of life.   Btw, DLC is used on production engines too... on low end ones in fact (stupid CO2 rules)   In truth, my point was there is no way someone can have something DLC coated, especially bearings, for an acceptable cost; tooling and process costs are just immense for small production parts. There are loads of other bearings coatings used by Clevite/Mahle and so on on production and aftermarket bearings which are way more likely what have been done

DLC isn't used in production bearings, it's used on steel. If you apply DLC to soft metal bearing which are designed to wear to fit to shape, you lose the ability to wear. When they do eventually fit to shape, the substrate collapses under the DLC, causing the DLC to delaminate

Edited by fezzasus, 11 December 2013 - 07:15 AM.

[FLD]

Is it possible that these coatings are detrimental to the oil film on the bearings?  I assume you need a certain surface to retain a good film so any changes to the surface could result in inadequate lubrication.  Just a thought that went through my head!  the ones I had done were teflon I think.

 

 

A post detailing inadequate lubrication with no inuendo.  I must be ill

[alanoo]

 

 

 

 

 

 special 'low friction coating' 

  Sounds like DLC. Not suitable for bearings,  

  Try to tell that to all F1 teams  

  Very different running conditions. If anyone has the time to strip and rebuild an engine every two hours then they can run much more exotic materials which would, in normal conditions, lead to premature failure.   

  F1 engine are not striped every 2 hours since (10+) years... they now do at least 3000km each, very close to LeMans engines in fact. DLC coating is in fact the main reason they work so well and do not loose power even near their end of life.   Btw, DLC is used on production engines too... on low end ones in fact (stupid CO2 rules)   In truth, my point was there is no way someone can have something DLC coated, especially bearings, for an acceptable cost; tooling and process costs are just immense for small production parts. There are loads of other bearings coatings used by Clevite/Mahle and so on on production and aftermarket bearings which are way more likely what have been done

DLC isn't used in production bearings, it's used on steel. If you apply DLC to soft metal bearing which are designed to wear to fit to shape, you lose the ability to wear. When they do eventually fit to shape, the substrate collapses under the DLC, causing the DLC to delaminate

 

 

Yep true, on production engines DLC is only used on lifters/followers AFAIK. (maybe some piston pins too)

I understand some engines are coming soon with DLC coated piston rings.

DLC delamination issues are indeed a problem, but things have evolved quickly on that... doubt it will get into production anytime soon for those "advanced" solutions, too little to gain for the cost involved

[fezzasus]

 

 

Yep true, on production engines DLC is only used on lifters/followers AFAIK. (maybe some piston pins too)

I understand some engines are coming soon with DLC coated piston rings.

DLC delamination issues are indeed a problem, but things have evolved quickly on that... doubt it will get into production anytime soon for those "advanced" solutions, too little to gain for the cost involved

 

 

Certainly piston pins. I have a DLC coated one from the latest VW 3 cylinder diesel on my desk at work.

 

I'm not aware of any DLC coated piston rings, most manufacturers are removing the friction contribution from the cylinder wall instead by using plasma arch deposition to create a smooth surface.

 

My company works with a few DLC suppliers and the general chemistry behind DLC doesn't change much, you basically use a DLC-metal substrate under the pure DLC layer, that DLC-metal layer is varied depending on the application, but there are limited options.

 

However it is cheap to do, but most aftermarket places offering it should be avoided as they tend to coat parts which are not designed for DLC and as such don't have the tolerances or surface finishes required. 

[fezzasus]

Is it possible that these coatings are detrimental to the oil film on the bearings?  I assume you need a certain surface to retain a good film so any changes to the surface could result in inadequate lubrication.  Just a thought that went through my head!  the ones I had done were teflon I think.

 

 

A post detailing inadequate lubrication with no inuendo.  I must be ill

 

Let's be clear here. It's very rare for the bearing surface to have a DLC coating, usually the opposing surface has the coating. Bearings are classically designed for 3 body abrasion; one surface is soft to conform and absorb particles, while the other surface is hard. You can make the hard surface harder (steel to DLC on steel) but making the soft surface hard leads to significant abrasive wear.

 

Oil film thickness is determined by entrainment speed (basically the speed the parts are moving relative to one another) and surface roughness, so all things being equal the film thickness with not change, the real change is the additive chemistry. I can't go into much detail about this because it's proprietary however there are significant differences between steel and some coatings (however most steel/iron modifications such as various modes of hardening are usually fine) and these changes are not always for the better. Some friction modifiers are known to degrade certain DLC types.

[siztenboots]

slick 50

[Chris @ EFI Parts]

Sorry to hear about this engine failure, Nev....but...isn't it a coincidence that suddenly the engine breaks once you swap to stand alone engine management? Has detonation been monitored? I would not have interfered with this engine at 550hp on standard OE electronics, torque delivery could have been changed by numerous factors inside the ecu mapping to keep it low...but you know me, I am one of the fans of original ECU...

 

In case you decide to give up the old engine block, I am willing to buy it, as I have no way to strengthen an original Z20LET block here in Romania and I want to give up the C20XE block I am currently running...

 

I hope Nev does not mind me posting in here but I'd just like to put everyone's mind at rest by assuring them that Nev's unfortunate engine failure was not due as a result of engine tune.

 

I don't post on forums very often, time doesn't allow, but in cases like this I like to make sure that people are left with no doubt in their minds at all.  Reputation is everything in my industry - I have an untarnished one and I like to keep it that way if I can.

 

I tune a lot of big HP 4 cylinder engines and 100% of my work is related to standalone engine management and calibration.  It's something I enjoy a lot, but which I take very seriously also.   I look after a number of 600hp+ 16v Vauxhall engines and even more Renault engines besides.  Nev's engine is typical of the motors I tune.

 

So yes, every parameter is monitored carefully, as you would expect.   It's a shame that in this industry there are a lot of dyno places and garages which think they are master tuners because they've wired a DTA S40 once and had some success.   Then try their hand at tuning a big HP turbo engine, and bore wash it, or detonate it to hell. These people give standalone a bad name.    I have good knock monitoring though a modified "knock box" (brand name) and stethoscope setup.   It's much better than headphones alone.   I can hear the very onset of knock, even in an open-piped race engine at 8500rpm.      Those with understanding  will be able to look at Nev's engine pictures and know that the engine tune and/or detonation was not a factor.

 

The truth is that with a good standalone ECU, a good tune and a good configuration you can accomplish everything you want from your engines management.  Nev's setup is clever.  He has switchable power levels, a programmable DBW throttle controller, variable traction control, launch control, all with easily definable parameters with free software.    These things to not come easily with the stock ECU.  It's not just about the quality of the calibration.

 

Regards fuel dilution, I was under the impression Nev's engine was a new build which had only been run-in before it came to me for the new ECU.  So if we're going to blame over-fuel and bore wash then that can only have happened with the stock ECU during the running in period.   Maybe thats possible, but I ran Nev's car on the dyno through a mixture of driving and a couple of WOT runs and saw no sign of overfuel at idle and part throttle.    The engine did breath a little more than I was comfortable with so I think the problem in the bore was already there, or on its way before we began.

 

Hope you fix it soon Nev.   Give me a call if I can help.

 

Cheers, Chris

[Nev]

Got a quote off Farndon to replace my bent rod, and managed to haggle them down from £300 to £240; posted it off this morning. I have bought an "unseen" crank off some guy I vaguely know in Nottingham, hopefully it will be fit for purpose with decent journals.

[Nev]

It seems I have been sold a junk crankshaft, I/Steve am still trying to get hold of a decent second hand one if possible. Once we get a good one, the engine can be built up fast as the machineing is done now and Steve has all the parts.

Edited by Nev, 06 March 2014 - 10:28 AM.

[siztenboots]

bugger sorry to hear this

[mbes2]

Are you planning on coming to the national Nev ? 

 

good luck with the build

[Nev]

Are you planning on coming to the national Nev ?    good luck with the build

Hopefully, lets see if I can get the bloody thing working again first and then whether I still have the balls to drive it !

[The Batman]

Nev this is on eBay 171269157084

[techieboy]

But you can't buy something from somebody who's username is: sexdrugsnvauxhalls 

[Nev]

But you can't buy something from somebody who's username is: sexdrugsnvauxhalls 

Indeed Joe, he is the dishonest bloke who sold me a completely duff crank. There is a big thread about it here: http://www.migweb.co...tml#post5071850 I hope nobody on here ever deals with him, he is a charlatan who hides behind words, horrible man.

Edited by Nev, 14 March 2014 - 05:46 PM.

[The Batman]

ah my bad

 

(i thought that username was awesome!!! but obviously the guy isnt..)

[Nev]

I've posted a bit of an update here.

[Ormes]

When you putting it back in?  Shout if you want a hand

[Nev]

Hi Alex, thankyou for the kind offer. I will try and stick the ancillaries onto the engine during the evenings this week. Would you be around next Sat or Sun perhaps ?