High power turbo engine using oil

[stevieturbo]

So the circlip is actually from something inside the turbo ?

Pretty amazing it hasnt had any rel adverse effect on it ! You'd think a circlip is important lol

Moving to Syvecs...a good decision

I actually changed to an S8 earlier in the year myself and DBW, although just a single throttle

[andygtt]

Bad move telling me you have S8 experience... Im currently working on the base start Cals and its very different to the Motec M800 cals, so cue me asking you load of questions lol

[stevieturbo]

andygtt said:

Bad move telling me you have S8 experience... Im currently working on the base start Cals and its very different to the Motec M800 cals, so cue me asking you load of questions lol

No worries, will help where I can.

It's a lot to take in for sure, but equally there is a lot in there you can ignore to get started as many features may not be used.

[andygtt]

So to update this thread... I had an experienced engine builder round so we can strip/inspect my engine.

First job leak down test, apparently 10% max on a rebuilt engine and 20% indicates an issue needing sorting.
3 were 10%, 2 were 18-20% one was 70%... lea was from the inlet valves!

Inspection of the cam showed mild marking were I clearly had experienced valve bounce (i have upgrade springs), however one lobe had a huge impact probably 0.5-1mm deep and a proper indentation if the rocker shape.... this was the exhaust valve on the same cylinder the intake was leaking 70%!

As mentioned earlier the valve stems had failed on a number of the exhaust and intake valves.. therefore after all these issues we hoped the bottom end would be ok.

Unfortunately not.

Piston to bore gap was 280 tho.... and of cause the bores were now out of shape slightly as a result, pistons were worn with very small signs of Det I told probably caused by reduced octain due to it using so much oil.

Bore clearence at the base of the block where wear was almost zero was still way outside tolerance so it seems I should have had new pistons at the last rebuild (something i was unaware of). Also the pistons I was running are max oversize anyhow.

One fact of note is that I cant get the same cosworth pistons again without ordering 10 sets which was probably the reason the pistons were reused last time (All moaning aside had I known i would have still run them last time as I didn't have the funds for new pistons etc then, it was supposed to be a simple check over refresh).


So I need almost an entire new engine... either get the block re-sleeved or start again and pay £500 to have the spray squirters machined into a new block.
Crank, rods and hopefully valves can be reused.

Anyone have a good guide as to how much decent sleeves will cost for 6 cylinders?

[stevieturbo]

I feel your pain....

Getting a set of pistons made should be relatively painless...but is there nothing off the shelf that might work ?

Dave at Performance Unlimited has always been good for me with custom pistons.

Or Steve at Roland Allsop's would be another option who could supply and sort any machining work etc.

As for sleeve options...I guess it depends on the block itself ? For most a fairly standard re-sleeve should be viable, wild guess maybe £100 per pot fitted ?

Is there definitely no life left in your block at all ?

[turbotoaster]

omega will probably have something you can use, they have a minimum of 20 pistons for anything completely custom as i did an order with them earlier in the year.

I think JE and wiseco do one off sets.

Serdi to machine work to fit Westwood ductiles into your block, again maybe have a set machined in that give a standard bore for off the shelf pistons either for a noble or something similar

[andygtt]

There are pistons available off the shelf (JE and diaomond etc), but they are a downgrade from the cosworth ones I have now (have used the other in the past).... I gained nearly 50 bhp on 0.6bar actuator pressure when I changed to these pistons and it was very noticeable on the road.

Im considering getting wossner to do me some custom pistons.

Block needs liners, it’s already taken out more than I’d like.... I need as much strength in it as I can get. I’ve scrapped previous blocks with less damage/ wear.

I want the engine 110% ready for me to put the ITBs and DBW on

[stevieturbo]

andygtt said:

There are pistons available off the shelf (JE and diaomond etc), but they are a downgrade from the cosworth ones I have now (have used the other in the past).... I gained nearly 50 bhp on 0.6bar actuator pressure when I changed to these pistons and it was very noticeable on the road.

Im considering getting wossner to do me some custom pistons.

Block needs liners, it’s already taken out more than I’d like.... I need as much strength in it as I can get. I’ve scrapped previous blocks with less damage/ wear.

I want the engine 110% ready for me to put the ITBs and DBW on

50hp change from no other changes at all from pistons ? compression etc all the same, boost ?

Visibly what were the differences ?

Wossner for the most part are cheap crap, unless they can also do some better stuff ? IMO they are just a replacement part, rather than a true performance item.

I would use JE or Diamond long before I'd even think about Wossner...nevermind actually use Wossner. ( and I currently use Diamond, and have to say after a recent incident where I blew the head off and bent a rod....the Diamond pistons were still spot on ! Very strong pistons )

[andygtt]

Wossner use the same material as Cosworth I'm told, i would be replicating what i have.

Do you have experience of them? or is there any meaningful feedback about them... i've been recommended sung them by someone who has far better experience than me but don't want to put anything sub standard in the engine.

regarding the power increase, the piston is different from the JE ones although i have no idea if they changed the CR or not... I will find that out when i get everything measured.

[stevieturbo]

andygtt said:

Wossner use the same material as Cosworth I'm told, i would be replicating what i have.

Do you have experience of them? or is there any meaningful feedback about them... i've been recommended sung them by someone who has far better experience than me but don't want to put anything sub standard in the engine.

regarding the power increase, the piston is different from the JE ones although i have no idea if they changed the CR or not... I will find that out when i get everything measured.

I've had a few of them in my hand for different vehicles.

Nothing has ever inspired me to want to use them myself for anything though. And more recently on a friends YB build where he was supplied them, we simply told him get rid of them, they are not suitable for an engine making the sort of power he wanted.

He did that and bought CP instead, and the difference in quality is just night and day.

It's not just material, and AFAIK most Wossners use the softer 4032 alloy, which again is more of a road orientated piston than a proper performance item. And most of their designs seem to be big heavy full skirt rather than a lighter shorter skirt design.
Just nothing nice about them really compared to nice stuff like CP, JE, Mahle, Diamond

Maybe they can do custom stuff that is better than their shelf stuff, but I just dont like Wossner at all having used all of those other brands before.

If I'd never done that, maybe I'd think Wossner were ok, and they probably are ok. But not great....just ok.

[Evoluzione]

Wossner tend to be the carthorse of the piston world, they get the job done though and you can't fault them for that. The machining and material quality are fine.
They are like a lot of cam manufacturers, often they don't have enough knowledge of what they are actually making from a technical design or performance viewpoint, they just get told what to make from suppliers and do it, the man on the street buys it and doesn't know any different.
If you design a piston or give them one to copy and stipulate the vital points they are perfectly capable of producing them. We don't use them for special stuff, but I don't remember why, it's either the cost or minimum order.
There are manufacturers and designers, not all manufacturers have designers or have ones that are any good.

[stevieturbo]

Another brand a user here mentioned before who'll do custom was Gibtec

http://gibtecpistons.com/

Although you wont have a UK contact for those.

[andygtt]

Ok advice on pistons is noted.... Id rather have the cosworth ones as they made more power than the JE ones, probably because they are a better design and CR... the only JE one I kept was a melted one so i can't weigh them to see if there is a significant weight difference (which might be the reason the gain occurred).
Trouble is 8 sets have to be ordered and last time it took a while to sell them all hence the company that got them made are not interested in doing it again... and I can't afford 8 sets!

I was going to get Wossner copy the ones I have now although id want an exact copy including weight and material.

Back to the drawing board

[andygtt]

From what i found cosworth also use 4032 alloy for the forged pistons? is that not the best material to use for them?

[Evoluzione]

andygtt said:

I was going to get Wossner copy the ones I have now although id want an exact copy including weight and material.

Do it then, ring Wossner dealers PEC and see what they say.

[andygtt]

Evoluzione said:

andygtt said:

I was going to get Wossner copy the ones I have now although id want an exact copy including weight and material.

Do it then, ring Wossner dealers PEC and see what they say.

Thats exactly what I did last week, they were confident there material used was almost identical to cosworth and they should be able to replicate it and i was close to being convinced.

NOTHING can replace genuine experience which is why I'm prepared to listen to a select few who i know have vastly more experience at this level of charged motors... hence I am all ears.

No rear rush as Im still developing a new box for the car to take the extra power, i just don't like not having a plan.

Incidentally and internally identical engine to mine (one of the few that bought the cosworth pistons when i did) made 945bhp on race fuel with a new inlet manifold design (old one was holding us back), previously it made 750bhp on race fuel (his is twin turbo).... My engine was making 646bhp at the hubs on road fuel with about 1.45bar... my turbo can make 2bar (and has accidentally when we got the electronic boost mapping the wrong way around) however additional boost didn't increase power, we hit a wall.

[Boosted LS1]

OP, what was your bore clearance again?

I've used Ross pistons for eons in turbocharged cosworth 24v v6 motors without any issues. That said the Mahle alloy is a very good one but when they couldn't supply the US demand the yanks developed their own alloys.

Also, PEC has been mentioned. I've only bought a few zetec parts from them but they were a very pleasing price unlike CP who I think are very expensive. I've not bought from them though. JE are an awful company to do business with as are Omega (who have a good alloy).

[stevieturbo]

andygtt said:

Ok advice on pistons is noted.... Id rather have the cosworth ones as they made more power than the JE ones, probably because they are a better design and CR... the only JE one I kept was a melted one so i can't weigh them to see if there is a significant weight difference (which might be the reason the gain occurred).
Trouble is 8 sets have to be ordered and last time it took a while to sell them all hence the company that got them made are not interested in doing it again... and I can't afford 8 sets!

I was going to get Wossner copy the ones I have now although id want an exact copy including weight and material.

Back to the drawing board

I'm sure you can get Cosworth pistons in either material.....both are used for many applications.

There's nothing wrong with 4032 as such, but it is deemed to be a slightly weaker material and less forgiving to detonation etc..
Although some say for a road vehicle....it is perhaps the better choice.

Other than one set of cheap Mahle pistons many years ago, I've always used 2618 though

But any decent piston maker should make you a set of custom pistons no problem, as said, speak to the people I mentioned. As to whether any of them would attempt to simply replicate another brand ? That's a bigger question and I can imagine not a route most piston makers would want to take. Each make will have their own forging designs, and ideas about how pistons should be made etc....simply copying verbatim another brand ? Bound to be considered sacrilege lol

I also struggle to believe the power difference was from pistons alone and absolutely no other changes. There'd need to be some dramatic difference in crown design to achieve that.
A simple couple deg of timing could account for that power difference if tuning was adjusted too.

It'd be interesting to see both piston designs though.

[andygtt]

Boosted LS1 said:

OP, what was your bore clearance again?

I've used Ross pistons for eons in turbocharged cosworth 24v v6 motors without any issues. That said the Mahle alloy is a very good one but when they couldn't supply the US demand the yanks developed their own alloys.

Also, PEC has been mentioned. I've only bought a few zetec parts from them but they were a very pleasing price unlike CP who I think are very expensive. I've not bought from them though. JE are an awful company to do business with as are Omega (who have a good alloy).

Piston to bore clearance was measured at 280 microns, that wasn't in a wear location apparently.

Omega pistons are a possibility, however i have to put the standard length noble rods back in. These rods are actually arrow items around 2mm shorter (this is how noble lowered the CR using stock pistons) but are 50 grams heavier than my Mountune Rods.
So the rotating mass would be slightly heavier and the piston geometry slightly compromised over what i had before... Im thinking of using these to build a 'cheap' spare engine as they would be oversize.

What I have done in the last week is manage to source a brand new complete engine, of cause its a stock NA unit so I would need to drill oil squirters in the block and get the heads flowed... and whilst not cheap it was only around £300 more than simply re-sleaving my existing block

As it stands I don't actually have the money to build a full spec engine up as I have spent my entire budget on the Syvec, loom, new gearbox design and thus drive shafts etc.... I hadn't planned on spending £7k on an engine refresh lol.

If I build a spare engine using an old block, it won't make the big numbers my old one does (would do over 600bhp tho), but i will at least get on the road and can then steadily build up the full monty engine over the coming year or so... alternatively the car will be off the road till the big engine is done....
Im undecided at the moment lol