4722 replies to this topic

[Nev]

 

 

Outer edge of tyres rubbing?

  Yea, I also noticed that as I rolled the car about in the garage to line it up for disassembly. It's not due to rubbage, it's to do with camber on the rears and the fact that they are wide enough to notice the angle and pick-up of garage dust when not cornering, and also because they are designed to give "extra" grip when the car "leans over" under harder cornering.   You are the first to observe this point, brownie point . If you carry on like this with objective analysis/comments you might even get into my good books   The weak point of those v70 tyres is poor ability to cope with high speed though, they deform at high speed and wear VERY quickly in the centre line. My last pair had almost no tread in the centre line and about 3.5 mm on the outside edges (even though they were only inflated to 24 to 25 PSI (cold)) - as detected by Mbes2 at a RR session. My old R888s (approx. 5 sets) were slightly better for this issue, but they too have other problems IMHO. The big problem with modern tyres is that they "expect" only a certain rotational force to be exerted. Once you go above this, they deform outwards (due to centrifugal forces) at the weakest point (which is usually the centre line in my experience).    

Not just me then I noticed this about the v70 tyres thought I had them over inflated ,but have tried different pressures in tyres but still the same :-(

 

 

Yea, it's somewhat crap if the tyres ony cope with 2500 miles before replacement (at £500 for a pair).

[cnrandall]

 

I can upgrade blocks to LEH spec and supply squirters...

I have found that not all zlet cylinder blocks can be machined to take the leh jets, not enough material to accept the thread for the oil jet banjo bolt. Steve

 

 

That's interesting.  Do you machine them in the exact same place as the LEH ones?  I've done two so far and both have ended up exactly as the LEH and loads of thread in the block.  Seems strange to me as the oil way is drilled and the bottom face of the blocks seem the same so the only way that could happen if the oil ways are drilled in different places or to different sizes?

 

I'll be doing another one soon as I need to replace my block so I'll let you know how that goes!

[Zoobeef]

Damn you and your temptations. You know me too well I'm insulating and plaster boarding my brothers living room today though and have a christening tomorrow! Such bad timing!

[completechip]

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...

[Nev]

Another hour and a bit in the garage got most of the wires and pipes off the car. All that is left is taking the exhaust off, a couple more water pipes, engine mounts and then disenguaging the drive shafts.

Edited by Nev, 17 November 2013 - 04:46 PM.

[Duncan VXR]

Nothing to do with standalone work in anyway and knock most def monitored. Engine had woes prior to work and agreement to convert in current status was requested as you cant guarantee others work. Same as any mapper would confirm yet to drive any oem map on vxt running decent power. Some are better than others but a definite Improvement on standalone Be interesting to confirm the weak link in the engine and Nev coming back stronger than before DG

[Duncan VXR]

Another hour in the garage got most of the wires and pipes off the car. All that is left is taking the exhaust off, a couple more water pipes and then disenguaging the drive shafts.

Good progress Nev, getting bloody cold again for tinkering with car DG

[Nev]

Alex very kindly came round last weekend and helped me take the engine out, thank again Alex - if it wasn't for you I'd have probably not got round to it for another 3 months.

 

Anyway, the pic of the sump shows the copper/shiney metal residue from a failed bearing. I will have to strip more of it apart to see which one, hopefully it won't have failed so badly as to blue or erode the crank or con rod.

 

Also, I added a pic of the burnt out turbo gasket, that thing is only 1700 miles old and made of stainless steel yet it melted !

 

 

Edited by Nev, 01 December 2013 - 09:02 PM.

[siztenboots]

looks like you've been panning for gold with that sump

[cnrandall]

Looks messy :-(

 

On the turbo flange… I have found that, as far as exhausts and turbo cars go, if its not inconel its not going to work in the long term.  V-band + inconel manifold is the (expensive!) way forwards!

[siztenboots]

from memory Nev had some special bearings , it seems a very short time for one to fail

[Ormes]

It's a real shame... sure it will be back on the road stronger than ever pretty soon... assume your going to get a new bottom end swap the rest over?

 

Give me a shout when you want to put the engine back in and I will come over 

[fezzasus]

Can you give me details of the bearings? If I remember correctly they were multi laminates, the downside to this is the bonding between the layers is weaker and it's more likely to delaminate, which is what looks like here. Unfortunately there isn't one sound bearing solution as the bearings simply aren't wide enough to cope with the torque. Higher viscosity oil will help to some extent.

[steveboyslim]

Mahle lead copper bearings used in Nev,s engine same spec used in more powerful clet and zlet engines. Lack of lubrication causes bearings to fail. The Pikes Peak RS200 EVO uses similar spec bearings but are narrower and that has 600ft/lbs torque and 850 bhp. Steve

[fezzasus]

Mahle lead copper bearings used in Nev,s engine same spec used in more powerful clet and zlet engines. Lack of lubrication causes bearings to fail. The Pikes Peak RS200 EVO uses similar spec bearings but are narrower and that has 600ft/lbs torque and 850 bhp. Steve

 

Steve, i'm aware of bearing modes of failure, and there are plenty more than just lack of lubrication.

 

Do you have any explanation as to why there wasn't sufficient lubrication? The valve train will see oil starvation before the bearings, is there any excessive wear there? Were the oil levels low, or had the oil pump failed? With any aftermarket build I would be looking at poor installation before looking at the lubricant, simply because the tools and the quality control used aren't up to the OEM standards.

 

Oil pressures, and bearing diameters will be different with the Pikes Peak RS200 EVO so not really a fair comparison. Bearing diameter also has a significant impact on bearing durability and power handling. Secondly this car will have much more regular maintenance/rebuild schedules than a road car.

Edited by fezzasus, 06 December 2013 - 10:01 AM.

[fezzasus]

Nev, looking at your photos again there appears to be a lot of metallic sludge in the sump. I suspect the damage is quite extensive (unfortunately)

[FLD]

Fezz, do you know much about clevite shells?  I've always insisted on them in the past as they were considered 'the best'.  I'm interested to see if they are worth the premium.

[steveboyslim]

Mahle lead copper bearings used in Nev,s engine same spec used in more powerful clet and zlet engines. Lack of lubrication causes bearings to fail. The Pikes Peak RS200 EVO uses similar spec bearings but are narrower and that has 600ft/lbs torque and 850 bhp. Steve

  Steve, i'm aware of bearing modes of failure, and there are plenty more than just lack of lubrication.   Do you have any explanation as to why there wasn't sufficient lubrication? The valve train will see oil starvation before the bearings, is there any excessive wear there? Were the oil levels low, or had the oil pump failed? With any aftermarket build I would be looking at poor installation before looking at the lubricant, simply because the tools and the quality control used aren't up to the OEM standards.   Oil pressures, and bearing diameters will be different with the Pikes Peak RS200 EVO so not really a fair comparison. Bearing diameter also has a significant impact on bearing durability and power handling. Secondly this car will have much more regular maintenance/rebuild schedules than a road car.

Bearing sizes both width and diameter are very similar as are minimum and maximum oil pressures although different lubrication set ups. I guess there could be any/or several problem with the lubrication. Oil not returning to the sump quick enough, engine will have been held at full throttle for longer whilst strapped to the rolling road. Oil dilution. Low oil level. Oil pump cavitation. Oil contamination. Oil pump problem. I have just unshrouded the oil pick up strainer (and baffled the sump)on a Renault Clio F4R I do wonder if something similar is needed. I am really just guessing. Usually with hydraulic followers low oil pressure can be heard, with Nev's engine it is solid lifters so you would not hear it rattle (hydraulic follower not fully filling with oil) The installation is quite simple so as long as everything was clean and checked during assembly it should have been ok, Nev did the best part of 8k miles before without lubrication problem. Nev changes the oil regular also. I cannot explain why it has started smoking again, as after deglazing the bores and fitting new pistons and rings there was no sign of any smoke. I would like to know myself what has happened even if Nev decides to take the engine elsewhere to be rebuilt/repaired or does it himself. Steve

[fezzasus]

Fezz, do you know much about clevite shells?  I've always insisted on them in the past as they were considered 'the best'.  I'm interested to see if they are worth the premium.

 

Just a product name for typical tri and bi metallic bearings made by MAHLE. I'd use MAHLE given that they supply a lot of OEM parts anyway, but metallic bearings don't have any novel features and the design has stayed static for years, so no, they don't offer anything novel, but yes they're worth it because they are from a reputable manufacturer who supply a vast amount of OEM equipment.

 

That said, if you picked between Clevite and the OEM brand, odds are you're buying the same thing.

[FLD]

 

Thanks