4722 replies to this topic

[CocoPops]

Out of interest Nev, how many times can you rebore a block? How much do they remove each time? Or does it just depend on how scored the cylinders are?

[techieboy]

£1100 for 2 chunks of metal is beyond my budget. I know they take some effort to design and reverse engineer from the OEM units, and an hour or two of machine time, but that is too much for me. Many of our cars are only worth £6000 to £12000 now, so spending 15% of their value is hard to justify unless you are racing or somesuch.

The front S2 GT Uprights are "only" £700'ish now and I'll bet you'll struggle to beat that in reality, unless you can totally DIY it. I'm pretty sure a pair of new OEM uprights costs a similar amount (or more) from Vauxhall. How much money have you spent on your (sorry but, somewhat flakey) engine and turbo, not to mention bodywork/wheels/tyres on your £10k base car? How much money are you still considering spending on a proper aftermarket ECU to actually get it running properly? None of the money we fritter away on these cars improves the value by anything more than a nominal amount at best and quite possibly devalues the car or at least makes the market for it so small as to be almost unsellable.  

Also, based on the truly terrible postings by Simon Southam, I want to avoid Elise Parts. Geary, Ian and others are fine and professional to deal with, but "Scuffers" is losing them trade, certainly from me anyway and I suspect from others too if what I hear on the grapevine is true.

If Geary and Ian are fine, why would you avoid Elise Parts? That's smacks of cutting off your nose to spite your face. Scuffers' posting style may be abrasive but his knowledge/experience is valuable. He doesn't suffer fools gladly and there's nothing wrong with that. He isn't Elise Parts, he doesn't own it, he doesn't work for them. He's just helped Geary develop some of their more race orientated parts. If you're too fragile to read his posts or, you want your view of the world to be wrapped in nice fluffy cotton wool, you could stop reading them. There's even a fantastic built-in option on the forum where you can automatically ignore his posts and never have to be bothered again, if he offends you so much. Personally, if I wanted new uprights (I'm not and likely never will be, because I don't want to run stupid ride heights on a road car), I'd much rather buy the EP uprights than something you've "developed" (can you even get a 30mm relocation of the hub centre? Sounds like too much to me) or somebody has reverse engineered from a picture or two. At least I'll know they've been properly specified in the first place, they're made from suitable material, they've been thoroughly tested, they'll survive the first kerb you run over and they'll actually do the job they're meant to. Better yet, there won't be a 3/4/5 month wait to even get started on making them, let alone the months of to'ing and fro'ing as the problems are resolved.

[techieboy]

Out of interest Nev, how many times can you rebore a block? How much do they remove each time? Or does it just depend on how scored the cylinders are?

Depends on how thick the liners are and how much has already been taken out. Once in the case of the Z22SE.

[Gedi]

Surely you can replace the liners as many times as you like, making the number of times you can rebore irrelevant?

[techieboy]

Cheaper to buy a brand new block (let alone a secondhand one) than replace the liners, on the Z22SE at least. No idea if that applies to the Z20LET block but I can't imagine it's much different.

[Nev]

The front S2 GT Uprights are "only" £700'ish now and I'll bet you'll struggle to beat that in reality, unless you can totally DIY it. I'm pretty sure a pair of new OEM uprights costs a similar amount (or more) from Vauxhall.

 

[color=#0000ff;]Those uprights only raise the hubs by 16mm, even in conjuntion with their/my rack riser plate spacers they would not fully accomplish what I have in mind (based on my new wheels and different tyre profiles to anyone else I know of).[/color]

 

 

How much money have you spent on your (sorry but, somewhat flakey) engine and turbo, not to mention bodywork/wheels/tyres on your £10k base car? How much money are you still considering spending on a proper aftermarket ECU to actually get it running properly? None of the money we fritter away on these cars improves the value by anything more than a nominal amount at best and quite possibly devalues the car or at least makes the market for it so small as to be almost unsellable.

 

[color=#0000ff;]If you could be bothered to read my thread before you start your usual turbo bashing, you'd see that the likely problem is not with the engine or turbo at all, but most likely to do with over fueling in the CS + Klassen map.[/color] [color=#0000ff;]The engine itself is good order apart from where the bore wash has affected it (measurements yet to be taken to confirm this). Having spent a lot on the project I am all too aware that spending another big chunk on uprights needs to be justified. [/color]

 

 

If Geary and Ian are fine, why would you avoid Elise Parts? That's smacks of cutting off your nose to spite your face.

 

[color=#0000ff;]I'm sorry, but even though Scuffers could have a lot to offer this place he has wound me up. The consequence of this is that I would prefer not to buy from a company that he is associated with. I do have other EP parts on my car anyway and know them to be good, if it were vital I would still buy from them.[/color]

 

 

Scuffers' posting style may be abrasive but his knowledge/experience is valuable. He doesn't suffer fools gladly and there's nothing wrong with that. He isn't Elise Parts, he doesn't own it, he doesn't work for them. He's just helped Geary develop some of their more race orientated parts. If you're too fragile to read his posts or, you want your view of the world to be wrapped in nice fluffy cotton wool, you could stop reading them. There's even a fantastic built-in option on the forum where you can automatically ignore his posts and never have to be bothered again, if he offends you so much.

 

[color=#0000ff;]Let's not spoil my thread with another anti-Scuffers chain of postings. I mentioned him as it was pertinent to my decission making and want to leave it at that.[/color]

 

 

Personally, if I wanted new uprights (I'm not and likely never will be, because I don't want to run stupid ride heights on a road car), I'd much rather buy the EP uprights than something you've "developed" (can you even get a 30mm relocation of the hub centre? Sounds like too much to me) or somebody has reverse engineered from a picture or two. At least I'll know they've been properly specified in the first place, they're made from suitable material, they've been thoroughly tested, they'll survive the first kerb you run over and they'll actually do the job they're meant to. Better yet, there won't be a 3/4/5 month wait to even get started on making them, let alone the months of to'ing and fro'ing as the problems are resolved.

 

[color=#0000ff;]I'm not really interested in what sort of uprights you consider correct for your car as the aims for my car are clearly different to yours (be that better or most likely worse in your opinion). As far as spec'ing is concerned, I am happy that the EP GT Race uprights would be fine for my car. This is not to say that someone else could not build/machine up similar ones that are just as good at half the price. You are probably unaware, but one of the reasons I chose MK Motorsport was because of the uprights they made for 2 TA cars (one of which is Dave Jacksons), both front engined (ie heavy over the front) and with 600 to 800 HP. They were clearly fit for purpose.[/color]

 

 

 

Cheaper to buy a brand new block (let alone a secondhand one) than replace the liners, on the Z22SE at least. No idea if that applies to the Z20LET block but I can't imagine it's much different.

 

[color=#0000ff;]This is incorrect. Firstly my block (and almost all Z20LET blocks to my knowledge) do not have liners. Secondly my block has had fiddly/time consuming strengthing work done on it so is more valuable than a normal one. Also it is valuable in the sense that I know that the crank in it is good for circa 550 BHP, which others may not be (due to the variability of metalurgy/casting). Thus I would prefer to keep it if possible, however reboring it to 87mm might weaken it too much - hard to estimate, as there nobody I know of who has done this to ask.[/color]

 

 

Edited by Nev, 29 May 2013 - 02:40 PM.

[Korkey]

Having myself been in a "Nev" position as it were with a previous car build I sympathise with him totally. 

 

Here I point to NO-ONE in particular; ( Unless you think that it is you. ) but to a sometimes theme through out his project thread. Which I have read again from its beginning.

 

As a forum why don't we take a step back and look at what Nev has achieved.

He has pushed the project Nipper car to a very high point and consequently had his issues with it.

I don't think that it matters if one agrees or disagrees with his project, his thinking or his point of view.

 

For me he has always posted honestly and as scientifically as he can. He has given freely of his research and time. More than some may do.

He has shared his successes and his failures with a frank degree of openness. All of these things should be encouraged in this ...........  the "Projects" thread.

 

It serves no purpose whatsoever to put him down, in fact, it profits no one.

Heaven forbid that he just says screw you lot and clears off.

Keep posting Nev and at least save me from yet another ....... Oooo look, shiny parts and painted wheel hub posts. Or lets put someone else down.

 

Your in depth project is one of the top threads on the forum.

 

Regards.

Rich.

[fezzasus]

 

Was the block bored under tension? As you tension the block the cylinders will change shape, so they will be out of round if they didn't tension them.

I have no idea TBH, is it normal practice to tension the block (lengthways?) while the machining takes place? Would you mind explaining why would this be necessary as I'm out of my depth here... possibly the compressive force of the head bolts clamping down and squeezing the block out sideways??

 

 

A tensioned block (with cylinder head on) distorts the cylinders into round. We have recently experienced a very large OEM remanufacturing engine blocks to support old engine tests, they switched the process to bore the block before being tensioned. The result in the worst case was liner scoring after run in and failure after 200 hours of running. We did our own measurements and found the cylinders were round before tensioning and distorted to a clover leaf shape once the same amount of tension as a cylinder head was applied. This is not correct practice.

 

I would seriously investigate this as it's likely the place that did the machining did not tension the block. distorted cylinders will result in poor compression test results and performance loss. It will also lead to rapid wear as the liner conforms.

 

Fez, if I were to send you a sample of original oil and the drained oil out of the sump would you be able to test them some how please? That would be ace if you could, but I don't want to cause a bother. Mind you the drained oil has been sitting around with just a rag over the basin that it is in, exposed to the garage air (dunno if that will have an effect).

 

I had a look into it today, there's are very few methods which look into normal fuel dilution because fuel is so chemically similar to oil it's hard to distinguish between. Most have been developed to identified biofuel, of which you will have very little of using premium fuel  and the relationship between amount of biofuel in the sump vs fuel is complex as they evaporate at different rates.

 

A simple test is to measure the volatility of the used oil vs. fresh oil, however having sat around in your garage you are likely to have a much lower reading than when it was fresh. At this point i'd recommend taking a new sample when you have refitted the engine and storing it in an air tight container for postage to me. 

[Nev]

I had a look into it today, there's are very few methods which look into normal fuel dilution because fuel is so chemically similar to oil it's hard to distinguish between. Most have been developed to identified biofuel, of which you will have very little of using premium fuel  and the relationship between amount of biofuel in the sump vs fuel is complex as they evaporate at different rates.   A simple test is to measure the volatility of the used oil vs. fresh oil, however having sat around in your garage you are likely to have a much lower reading than when it was fresh. At this point i'd recommend taking a new sample when you have refitted the engine and storing it in an air tight container for postage to me.

Thanks for investigating that. At times I can remember seeing AFRs just dipping into the high 9s on my wideband, and commonly 10 to 12 just when accelerating moderately hard. I knew this was rich, but assumed that it would be acceptable. I remember at the last RR session that my new mapper thought that dropping below 11.5 or 12 AFR was unnecessary/unadvisable.

Edited by Nev, 01 June 2013 - 06:01 AM.

[fezzasus]

That would lead to excessive bore wash, have you heard anything more about the state of the engine?

[Nev]

There is evidence of bore wash on the thrust side of the skirts. Pistons and rings have been inspected and are visually fine with no signs of detonation/warping etc, the bores still have some honing marks and no striations. The last check I am still waiting on is the measurements of the each of the bores, to see if they are in tolerance. We are deliberating as to whether it is worth (or even safe) to rebore and install fully forged pistons.

I've just come out of the garage after re-wrapping the exhaust manifold. The old wrap on it looked rather tired and tatty, so I decided to take it off. Some of the flexible glass weave (mainly around the collector of the 4 pipes) had melted with the heat and become brittle, such that when I tapped it shards of glass were coming off making the same sound as broken glass! This kind of thing really brings home how amazingly hot parts of our engine get, yet still survive. Hat's off to Jamie at Jam-Sport for making such a strong and robust manifold; I can see why he warrantees his fabrications for life with no quibbles.

Edited by Nev, 01 June 2013 - 09:59 AM.

[Nev]

Steve has just rung me with the full news on the engine after it's been measured by his machiner. The good news: 1. The cylinders are virtually unworn with only 0.0012 mm of variation in width. 2. The C20LET pistons are slightly worn on the skirts, but acceptable to be re-used. The bad news: 1. On taking the pistons out, it has become clear that the bores are glazed (due to over fueling most likely). In theory the same C20LET pistons could be put back in with a new set of rings. However, Mahle oversized ring sets are on back order at the moment and I can't risk waiting indefinitely for them to make some. Instead we have decided to fit a set of new fully forged Omega pistons in there with their own rings. The head will also get new valve seals as a precaution and the re-shimmed as it is out. Lastly the main bearings might get replaced as the engine is apart (based on inspection). I am hoping to get the engine in and running by Sat evening !! *gulp*

Edited by Nev, 02 June 2013 - 02:32 PM.

[cs_]

Hi Nev,

 

just popped in quite randomly reading this thread (for me the most interesting of whole .org btw.).

 

I drive my VX since 2006 with power stages of 280HP and much more. Ever since(!) I had full power AFRs peaking down to ~9.7 (Lambda 0.66), depending mainly on the temperature of the intake gas. As rough numbers:

- big air-to-air-intercooler AFR going down to 9.7

- ProAlloy water-to-air-chargecooler AFR going down to 11.0

 

My engines are running properly this way and it is intended that they run this "wet" by the tuner. But 9.7 usually is the engine self protection bringing down the exhaust gas temperatures if the intercooler has been heating up too much after some seconds of constant and hard acceleration. This is normal, IF the tuner has left the protection functions active. Some don't.

 

Furthermore I have seen massive wears on the bore walls on the compression side, even right after the first few hundreds of kilometers running the engine in with low power and special power reduced software. I first panicked a lot when I saw the pictures. I reclaimed with Klasen about the bad state of the engine but at the end of the day we remounted the cylinder head again without replacing anything beneath. Uwe Regelin said to me he had seen engines looking a lot worse and they lived a long time afterwards. Sometimes best thing to do is not to look inside. And that's what I do right now. I drive the car, having fun. Using the engine with the worn cylinder walls. It runs. It's a real beast with 378 BHP. I takes some 0.5 liters of oil every 1.000 kilometers. I live with that. The engine lives with that.

 

tl;dr

Running rich with AFR getting under 10 doesn't have to harm your engine.

Pulling excessive power out of small engines HAS to shorten their life. Man, you have some 500 HP under the bonnet. What do you expect if you press this out of only 2 liters?

[Ormes]

Steve has just rung me with the full news on the engine after it's been measured by his machiner. The good news: 1. The cylinders are virtually unworn with only 0.0012 mm of variation in width. 2. The C20LET pistons are slightly worn on the skirts, but acceptable to be re-used. The bad news: 1. On taking the pistons out, it has become clear that the bores are glazed (due to over fueling most likely). In theory the same C20LET pistons could be put back in with a new set of rings. However, Mahle oversized ring sets are on back order at the moment and I can't risk waiting indefinitely for them to make some. Instead we have decided to fit a set of new fully forged Omega pistons in there with their own rings. The head will also get new valve seals as a precaution and the re-shimmed as it is out. Lastly the main bearings might get replaced as the engine is apart (based on inspection). I am hoping to get the engine in and running by Sat evening !! *gulp*

What day you popping it back in Nev?

[Nev]

I am tentatively hoping to pick the engine up on Weds night. Then dress it on Thurs eve. Then start installing it Fri eve and all Sat. Fancy oiling it up with me in my den again ?! LOL

[Nev]

Hi Nev,   just popped in quite randomly reading this thread (for me the most interesting of whole .org btw.).   I drive my VX since 2006 with power stages of 280HP and much more. Ever since(!) I had full power AFRs peaking down to ~9.7 (Lambda 0.66), depending mainly on the temperature of the intake gas. As rough numbers: - big air-to-air-intercooler AFR going down to 9.7 - ProAlloy water-to-air-chargecooler AFR going down to 11.0   My engines are running properly this way and it is intended that they run this "wet" by the tuner. But 9.7 usually is the engine self protection bringing down the exhaust gas temperatures if the intercooler has been heating up too much after some seconds of constant and hard acceleration. This is normal, IF the tuner has left the protection functions active. Some don't.   Furthermore I have seen massive wears on the bore walls on the compression side, even right after the first few hundreds of kilometers running the engine in with low power and special power reduced software. I first panicked a lot when I saw the pictures. I reclaimed with Klasen about the bad state of the engine but at the end of the day we remounted the cylinder head again without replacing anything beneath. Uwe Regelin said to me he had seen engines looking a lot worse and they lived a long time afterwards. Sometimes best thing to do is not to look inside. And that's what I do right now. I drive the car, having fun. Using the engine with the worn cylinder walls. It runs. It's a real beast with 378 BHP. I takes some 0.5 liters of oil every 1.000 kilometers. I live with that. The engine lives with that.   tl;dr Running rich with AFR getting under 10 doesn't have to harm your engine. Pulling excessive power out of small engines HAS to shorten their life. Man, you have some 500 HP under the bonnet. What do you expect if you press this out of only 2 liters?

Thanks for the kind words Carsten. It is interesting to compare your experience with mine. The more info like this that gets posted up objectively will hopefully help the community. My mistake was to not switch to a stand alone ECU when I installed the new engine 2.5 years ago, even though I was pestered by my friends to spend the extra money. If I had done this I could have adjusted the map as and when necessary. Every step of this project teaches me something new, sometimes by learning from a mistake :o/ As you say, we push these tiny little engines so hard it is not surprising that any weakness in them is highlighted pretty fast. Now that the turbo compressor blade has been sorted out and also I have fixed a slight boost leak at the re-circ valve, I suspect the engine might be making a fair bit more than 500 BHP now. Steve thinks I should get it mapped for full boost, but I think it would make it too scary and shorten it's life.

Edited by Nev, 02 June 2013 - 06:28 PM.

[Ormes]

Fancy oiling it up with me in my den again ?! LOL

I wouldn't have put it quite like that but yes, sure, happy to help. Can pop round for some of Friday evening and most of Saturday. Give me a shout and confirm you are running to plan and I will be there.

[Nev]

Engine is back, re-honed, new forged pistons (Omega, same SCR), welded ring gear on the flywheel, new gaskets, new stem seams. Got to dress it and install it. Also need to make/weld up a new crank to rocker cover breather pipe. Alex I'll give you a ring once my slave cylinder turns up in the post (can't start anything till I get that)

Edited by Nev, 05 June 2013 - 09:20 PM.

[VXT Tim]

Fingers crossed for tomorrow. Are you sticking with the std ecu?

[Nev]

Fingers crossed for tomorrow. Are you sticking with the std ecu?

Thanks Tim, probably gonna dig deep into my wallet and switch ECUs.