My nova: 1.55 bar = 457bhp, 2.1 bar = update on page 5
30-01-2010, 07:17 PM
#201
PassionFord Post Whore!!
Yeah its a real shame.
What I need to do now, is decide what to do next with the engine, wether I just chalk this one up as me getting unucky picking a secondhand block that had an existing defect from manufacture or wether this is going to be indicative of the realistic limits for these engines for sustained use.
TBH I could happily turn the power back down to 1.5 bar and it still be brilliant fun on track with only the 450bhp it had before, so maybe thats the way I should be going, as ultimately the extra power wouldnt have been of any real benefit to me, and would have put massive strain on the box etc.
Sadly there are very few people using these engines at big power (ie 500+) in the world for anything other than drag racing, so Ive no other examples to look at to see if its a freak occurance the block crack with that sort of power for sustained use, or if its just going to keep happening.
What I need to do now, is decide what to do next with the engine, wether I just chalk this one up as me getting unucky picking a secondhand block that had an existing defect from manufacture or wether this is going to be indicative of the realistic limits for these engines for sustained use.
TBH I could happily turn the power back down to 1.5 bar and it still be brilliant fun on track with only the 450bhp it had before, so maybe thats the way I should be going, as ultimately the extra power wouldnt have been of any real benefit to me, and would have put massive strain on the box etc.
Sadly there are very few people using these engines at big power (ie 500+) in the world for anything other than drag racing, so Ive no other examples to look at to see if its a freak occurance the block crack with that sort of power for sustained use, or if its just going to keep happening.
other wise would it not cause a slight feeling of regret you didnt try it again?
30-01-2010, 07:22 PM
#203
But thats going to be a very expensive curiousity if it keeps doing this potentially, not just in terms of cash (probably only cost me a grand or so to get it back together again realistically) but in terms of time that I am really short of too.
Developing blocks is very expensive, with the YB people like mountune have done all the hard work already, with this block, no one really has, and for an individual to do so could end up being a nearly bottomless pit to throw time and money at!
I think I'm more likely to just accept that I know that the 457bhp boost level seemed fine for the block, and it went very very well at that level anyway, and just go for that and stop there if I put it back together exactly the same again.
I have no real use for anymore power than that on a racetrack anyway in a relatively light 2wd car TBH mate, so I would be chasing numbers without really having any purpose besides curiousity.
Last edited by Chip; 30-01-2010 at 07:23 PM.
30-01-2010, 07:31 PM
#205
Abroad people are claiming far more, but some of them arent using the waterways with water anymore, which is fine in dragracing to fill them with resin to strengthen it, but no use in a track car which needs to do 20 mins of non stop abuse at a time, not just 8 seconds or whatever.
30-01-2010, 07:43 PM
#209
PassionFord Post Whore!!
big shame m8
if it was me i would put a block back in it.
just for now, run it at 1.5 bar, have some great fun for this season, then get it on the rollers at the end of the season wack the boost up to 2+ and see what see what it does.
then for me myself i would put a gt3076 on it and limit power to 480ish really responsive and hopefully reliable.
if it was me i would put a block back in it.
just for now, run it at 1.5 bar, have some great fun for this season, then get it on the rollers at the end of the season wack the boost up to 2+ and see what see what it does.
then for me myself i would put a gt3076 on it and limit power to 480ish really responsive and hopefully reliable.
30-01-2010, 07:44 PM
#210
Ultimately though, I suspect that I just need to decide that based on having now driven my car with engines making roughly
150
280
330
400
450
500+
That the right amount of power for it is probably around the 400-450 mark and just go down to a smaller turbo which means that I can also have massively improved spool over what I get on the GT35R at the moment!
30-01-2010, 07:45 PM
#211
big shame m8
if it was me i would put a block back in it.
just for now, run it at 1.5 bar, have some great fun for this season, then get it on the rollers at the end of the season wack the boost up to 2+ and see what see what it does.
then for me myself i would put a gt3076 on it and limit power to 480ish really responsive and hopefully reliable.
if it was me i would put a block back in it.
just for now, run it at 1.5 bar, have some great fun for this season, then get it on the rollers at the end of the season wack the boost up to 2+ and see what see what it does.
then for me myself i would put a gt3076 on it and limit power to 480ish really responsive and hopefully reliable.
30-01-2010, 08:18 PM
#217
Yeah I think ultimately thats the right place for it to be, which would be 450 or so sort of ball park and a much bigger useable rev range (I would expect it to work well 4K-8K, versus 5K-8K now)
Thats what I said I was going to do after the last rolling road day funnily enough, to settle on the power I had, and go down a turbo size, but then temptation got the better of me and I just had to find out what it could do
Think for this year, I'll just chuck a standard LET engine in it, with my inlet and exhaust etc, and run a very gay 1 bar of boost which will be about 330-350bhp or so.
Still enough to be fun on a trackday, even if it will feel very slow to start with now that Im used to 500 odd in it, lol
Thats what I said I was going to do after the last rolling road day funnily enough, to settle on the power I had, and go down a turbo size, but then temptation got the better of me and I just had to find out what it could do
Think for this year, I'll just chuck a standard LET engine in it, with my inlet and exhaust etc, and run a very gay 1 bar of boost which will be about 330-350bhp or so.
Still enough to be fun on a trackday, even if it will feel very slow to start with now that Im used to 500 odd in it, lol
30-01-2010, 08:31 PM
#218
Advanced PassionFord User
iTrader: (1)
Join Date: Mar 2005
Location: Newcastle
Posts: 1,587
Likes: 0
Received 0 Likes
on
0 Posts
Bit of a shame it gave in as i would of liked to have seen the figures. I hope mine doesnt go down the same route.... i'm pretty sure it wont though.
30-01-2010, 08:38 PM
#219
If you are going for similar power, and planning to have it under loads for long periods, then its certainly a realistic concern to have, if you are running less power though im sure it will be fine, Rob's has taken a monstrous beating at 400bhp or so, likewise if you want this sort of power but just for short bursts drag racing, im sure it will last ages.
30-01-2010, 08:46 PM
#221
PS
Annoyingly, its not like I didnt do my homework on the block first, this is one that I used to insure that a standard casting had uniform wall thickness, so its not even like I just went into it blind, lol
I overbored it again and again and again, until it broke through, so that I could check where best to centralise the bore (sometimes in the past I have found engines can be overbored offcentre to end up with a better thickness of wall on the weaker side)
DSC00018.jpg?t=1264887882
As you can see from where it has broken through in multiple places at once, the standard block is actually very good uniformity of wall thickness on the standard bore centre on these engines.
So I had no reason to suspect I was going to have this problem particuarly.
Annoyingly, its not like I didnt do my homework on the block first, this is one that I used to insure that a standard casting had uniform wall thickness, so its not even like I just went into it blind, lol
I overbored it again and again and again, until it broke through, so that I could check where best to centralise the bore (sometimes in the past I have found engines can be overbored offcentre to end up with a better thickness of wall on the weaker side)
DSC00018.jpg?t=1264887882
As you can see from where it has broken through in multiple places at once, the standard block is actually very good uniformity of wall thickness on the standard bore centre on these engines.
So I had no reason to suspect I was going to have this problem particuarly.
30-01-2010, 08:59 PM
#223
I've found that life I needed.. It's HERE!!
cant you just get the block sleeved like on the cossies so you can run 2 bar safe,as its only the boost thats caused the problem
30-01-2010, 09:00 PM
#224
Its possible though, but would probably take a few iterations to get right, which just isnt something I have the time/money for, i'd be better just swapping to the saab block, which is monstrously strong anyway.
30-01-2010, 09:01 PM
#225
Advanced PassionFord User
iTrader: (1)
Join Date: Mar 2005
Location: Newcastle
Posts: 1,587
Likes: 0
Received 0 Likes
on
0 Posts
If you are going for similar power, and planning to have it under loads for long periods, then its certainly a realistic concern to have, if you are running less power though im sure it will be fine, Rob's has taken a monstrous beating at 400bhp or so, likewise if you want this sort of power but just for short bursts drag racing, im sure it will last ages.
30-01-2010, 09:03 PM
#226
If yours is going in a lightweight FWD nova, then it will never see the loads that mine did, so that may help you
Last edited by Chip; 30-01-2010 at 09:04 PM.
30-01-2010, 09:08 PM
#227
I've found that life I needed.. It's HERE!!
Join Date: Nov 2006
Location: Rotherham
Posts: 1,398
Likes: 0
Received 0 Likes
on
0 Posts
I've mapped a few of these with 500+bhp. Well, same couple of cars but MANY engine/turbo/cam etc etc specs.
Never had a block failure. I've had block failures in the past though, (a honda and Z20let) have you any pictures of the failure. Where the crack is sometimes helps to tell whats happened. DET can double PCP's as you know, did you run a lot of advance? Bad fuel if its been sat etc etc. I suspect if none of the above it was just a bad block. Most of the above car's have done top speed runs, lots of hard road and track use. Visually the C20 looks stronger than the Z, and a LOT stronger than the honda, both of these were making pretty big power to fail.
As for going smaller turbo, remember torque/cylinder pressures can be just as high, if your going to crack the block its at the point of peak torque (unless you done something wrong on the map) a gt30 might increase cylinder pressures lower in the RPM range.
Lastly, if you cracked the block and didn't blow the rad/hoses to bits i'd guess it could have done it when cooling down/driving slowly. What was the p2w clearance? I'd say you was unlucky.
Never had a block failure. I've had block failures in the past though, (a honda and Z20let) have you any pictures of the failure. Where the crack is sometimes helps to tell whats happened. DET can double PCP's as you know, did you run a lot of advance? Bad fuel if its been sat etc etc. I suspect if none of the above it was just a bad block. Most of the above car's have done top speed runs, lots of hard road and track use. Visually the C20 looks stronger than the Z, and a LOT stronger than the honda, both of these were making pretty big power to fail.
As for going smaller turbo, remember torque/cylinder pressures can be just as high, if your going to crack the block its at the point of peak torque (unless you done something wrong on the map) a gt30 might increase cylinder pressures lower in the RPM range.
Lastly, if you cracked the block and didn't blow the rad/hoses to bits i'd guess it could have done it when cooling down/driving slowly. What was the p2w clearance? I'd say you was unlucky.
30-01-2010, 10:15 PM
#228
Well, Ive been out today in the nova, with the boost wound up to finish off the mapping and see how it went in preperation for going back onto the rollers for a final power figure next saturday when im meant to be renting the rollers again at mtech.
Have increased boost from the 1.55 bar to 2.1 bar, and fuck me it was going well, in fact so much so that there is NO way I would ever want to use it like that on track anywhere other than a bloody long straight (it was a big dual carriageway I was using it on and even there it felt fast!)
Came back home after a really good session out just enjoying driving it on a dry day at last, its handling SO much better now, ive altered the front suspension to give me more caster which seems to have worked well, and I was just generally over the moon with it.
When I left it idling to cool down though, I noticed that there was a bit of steam coming out of the exhaust, which was obviously a very worrying sign.
Compression tested it, and 2/3/4 were all perfectly on 11, exactly where they always are, but number one was up on 13, so I feared it had done the head gasket.
Me and gary ripped it apart figuring that if we could get it apart today, get my old man to get the head skimmed in the week and get a new gasket off steve we could get it all back together on friday ready for the rollers on saturday.
The head gasket looked mint though, no signs of any problems at all, so I started inspecting the head very closely, again no signs of any problems, so I finally turned my attention to the block, the mating face looks perfect, but when I wound that cylinder number 1's piston down the bore and cleaned the bore off very carefully, I can just make out a slightly darker coloured wiggly very feint line about an inch long, which can only be one thing, a crack!
Game over for me for a while until I decide what to do, no point just rebuilding it exactly the same as obviously I am almost certainly going to run into the problem again on another block if I start using it as hard.
Im not aware of anyone using one of these engines for anything other than short bursts drag racing at this sort of power level (must have been well over 500 judging by how much faster it was on the 2.1 bar setting than on the 1.55 bar setting that made 457bhp) so I need to decide if perhaps I need to be using a different engine instead to get this power, or accepting running less power to prevent me killing another block.
VERY bad day sadly!
Looks like the snotty old clio is going to have to get dragged back out for bedford on the 20th now.
Might see about just putting a standard bottom end into the nova and just run at a bar of boost or something in order to just get it out and get some seat time so I can work a bit more on the handling.
Will have a go at getting a picture of the crack, but TBH its just such a tiny little line I suspect I wont be able to get the camera to pick it up even on the macro setting.
Have increased boost from the 1.55 bar to 2.1 bar, and fuck me it was going well, in fact so much so that there is NO way I would ever want to use it like that on track anywhere other than a bloody long straight (it was a big dual carriageway I was using it on and even there it felt fast!)
Came back home after a really good session out just enjoying driving it on a dry day at last, its handling SO much better now, ive altered the front suspension to give me more caster which seems to have worked well, and I was just generally over the moon with it.
When I left it idling to cool down though, I noticed that there was a bit of steam coming out of the exhaust, which was obviously a very worrying sign.
Compression tested it, and 2/3/4 were all perfectly on 11, exactly where they always are, but number one was up on 13, so I feared it had done the head gasket.
Me and gary ripped it apart figuring that if we could get it apart today, get my old man to get the head skimmed in the week and get a new gasket off steve we could get it all back together on friday ready for the rollers on saturday.
The head gasket looked mint though, no signs of any problems at all, so I started inspecting the head very closely, again no signs of any problems, so I finally turned my attention to the block, the mating face looks perfect, but when I wound that cylinder number 1's piston down the bore and cleaned the bore off very carefully, I can just make out a slightly darker coloured wiggly very feint line about an inch long, which can only be one thing, a crack!
Game over for me for a while until I decide what to do, no point just rebuilding it exactly the same as obviously I am almost certainly going to run into the problem again on another block if I start using it as hard.
Im not aware of anyone using one of these engines for anything other than short bursts drag racing at this sort of power level (must have been well over 500 judging by how much faster it was on the 2.1 bar setting than on the 1.55 bar setting that made 457bhp) so I need to decide if perhaps I need to be using a different engine instead to get this power, or accepting running less power to prevent me killing another block.
VERY bad day sadly!
Looks like the snotty old clio is going to have to get dragged back out for bedford on the 20th now.
Might see about just putting a standard bottom end into the nova and just run at a bar of boost or something in order to just get it out and get some seat time so I can work a bit more on the handling.
Will have a go at getting a picture of the crack, but TBH its just such a tiny little line I suspect I wont be able to get the camera to pick it up even on the macro setting.
is it possible that bore was already weak before you even started? could you consider using nikasil liners, or are they to expensive?
all the best with it
30-01-2010, 11:00 PM
#230
I suspect if none of the above it was just a bad block.
Visually the C20 looks stronger than the Z, and a LOT stronger than the honda, both of these were making pretty big power to fail.
As for going smaller turbo, remember torque/cylinder pressures can be just as high, if your going to crack the block its at the point of peak torque (unless you done something wrong on the map) a gt30 might increase cylinder pressures lower in the RPM range.
What was the p2w clearance? I'd say you was unlucky.
It was still running perfectly, absolutely no hint from the way it sounded on idle or anything, the moisture in the exhaust was the only clue at all, so I think I was very lucky to catch it straight away TBH, few more hard miles and I could have been a lot less lucky.
4.5 thou piston to bore clearance, it was always intended for big boost and some nitrous as well so I was fairly generous on the clearance.
30-01-2010, 11:02 PM
#231
Very possible, its a 20 year old block at the end of the day, with multiple previous owners etc
Its a possibility, likely to be pretty expensive if there arent any already specced and tested etc
Thanks 
could you consider using nikasil liners, or are they to expensive?
all the best with it
30-01-2010, 11:39 PM
#232
Advanced PassionFord User
Join Date: Jun 2004
Location: Leicester le7
Posts: 1,715
Likes: 0
Received 0 Likes
on
0 Posts
sorry to hear the bad news chip
what was the spec of the engine ?
was it std compression with rods pistons ported head?
and good luck with the new engine build mate
what was the spec of the engine ?
was it std compression with rods pistons ported head?
and good luck with the new engine build mate
30-01-2010, 11:47 PM
#233
Engine Bottom End:
C20XE block
Line Bored
Sump surface machined flat
Head mating surface machined perfectly parrellel to bearing tunnel
Bores exactly perpendicular to bearing tunnel
Block stress releived by hand to remove casting marks and other stress raisers
ARP mains
ARP headstuds
ARP2000 rod bolts
Steel XEV crank
Arrow Conrods
Arias Pistons, 8.2:1
Oil Squirters
Cylinder Head:
Coscast casting
Neil Roper Developments port bored inlets
Neil Roper Developments port bored exhausts
Neil Roper Developments hand finished inlets
Neil Roper Developments hand finished exhausts
Piper double valve springs
Solid lifters
+1mm 214n stainless exhaust valves with stelite seats
+1mm 214n wasted stem stainless inlet valves
Cometic 1.9mm gasket
Gearbox
VX220 Turbo F23 gearbox
Quaiffe ATB diff
Twin plate paddle clutch
Lightweight flywheel
Inlet
SBD/Jenvey throttle body manifold
Jenvey throttle body spacers, 50mm
Custom made inlet adapter plate
19mm ally trumpets
RS200 inlet plenum
Vectra V6 64mm throttle body
2.5" ally inlet piping
silicon hoses and joiners
Turbo
GT35R Garrett
Tial 38mm wastegate
Earls filter
Braided feed line with inline flow restrictor
Exhaust
Garage19 manifold to my specs
Garage19 produced exhaust to my specs
Garage19 wastegate pipework to my specs
Steel exhaust gasket
Ignition system:
NGK Iridium plugs
Nologoy hotwire leads
Coilpack conversion
Autronic SM4 engine management
Last edited by Chip; 30-01-2010 at 11:48 PM.
31-01-2010, 12:05 AM
#234
Advanced PassionFord User
Join Date: Jun 2004
Location: Leicester le7
Posts: 1,715
Likes: 0
Received 0 Likes
on
0 Posts
bloody hell you dont do things by half do you :cry
goes to show what a sorted head can do! and a big turbo
what are your plans with the saab engine ?
same spec but with more boost?
can you salvage may parts to use on the next engine?
i cant think of any more stupid questions
goes to show what a sorted head can do! and a big turbo
what are your plans with the saab engine ?
same spec but with more boost?
can you salvage may parts to use on the next engine?
i cant think of any more stupid questions
Last edited by mrviper; 31-01-2010 at 12:08 AM.
31-01-2010, 12:12 AM
#235
It was a pretty comprehensive build, about the only thing not upgraded much was the block, typical eh? lol
TBH it needs a smaller turbo really, if im going to keep the power back down at 450ish next time if I go LET again
If I go down that route, it will be a case of fit a totally standard engine, bolt a big turbo on, remap it, and whatever it makes, it makes, then that way if it dies I know its just a few hundred quid and a couple of afternoons to swap another one in again.
Everything mate, nothing other than the block has any sign of damage at all, although ive also got an Arrow crank as well now that I hadnt got round to fitting yet so if i fit that i might go dry sump too, as it will see me safe to 9Krpm or so then.
If I do that, it will be to go into my mini though, so will need different manifolds too, not really sure on that yet though, might got ST185 GT4 engine instead, will decide nearer the time I guess
goes to show what a sorted head can do! and a big turbo
what are your plans with the saab engine ?
can you salvage may parts to use on the next engine?
If I do that, it will be to go into my mini though, so will need different manifolds too, not really sure on that yet though, might got ST185 GT4 engine instead, will decide nearer the time I guess
i cant think of any more stupid questions
31-01-2010, 02:54 PM
#236
15000
Join Date: May 2004
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Chip the block must be a old one as i have built no end over 500bhp and in all the years doing them never seen it happen before the cranks move about abit which causes the block to crack down below but thats at 9000rpm.
31-01-2010, 09:46 PM
#238
Too many posts.. I need a life!!
Join Date: May 2004
Location: UK
Posts: 964
Likes: 0
Received 0 Likes
on
0 Posts
TBH its hardly ground breaking. You broke a block, not epic failure. Countless other people around the world are claiming 500+ from a unproven RR'd let...
Its not much cash to rebuild it and if you have not got the time farm it out to steve, he could probably rebuild it totally for under £2k.
Its not much cash to rebuild it and if you have not got the time farm it out to steve, he could probably rebuild it totally for under £2k.
31-01-2010, 10:18 PM
#239
I've found that life I needed.. It's HERE!!
Join Date: Nov 2006
Location: Rotherham
Posts: 1,398
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE=Chip;4690209] 1)Not got a picture, its about half an inch or an inch down the bore that it starts though (c20let is closed deck not like the z20let)
2)Was running 8 degrees of advance, and fresh optimax running down in the 10s AFR, I hadnt got to the stage of advancing and leaning it yet, so I dont believe it was anywhere near DET, also the head is totally unmarked which isnt indicative of bore breaking DET either.
3)Perfectly possible, as mentioned previously its possible its not indicative of what other c20let blocks will do, it might have once had no antifreeze in it 10 years ago and frozen up and put a stress fracture in the back edge of the water jacket or similar.
4)Top of the block appears stronger (if this was a Z it would have cracked right up to the mating face probably) but the bottom appears weaker (no girdle)
I've numbered the quote so I can add reply.
1) Thats probably what 40 degrees past TDC then, highly unlikely its DET.
2) As above.
3) Possibly, I don't think i'd build another engine and worry about it.
4) Yes, the 1 that failed on us at probably 520hp blew the whole cylinder wall out, highly likely it cracked, pulled some water in and hydrolocked.
5) Yes probably more luck/quick to diagnose a problem etc. I reckon it probably cracked when running a full chat on the last pull or something. The crack worsened as it cooled and it obviously pulled some water in when cranking it over.
2)Was running 8 degrees of advance, and fresh optimax running down in the 10s AFR, I hadnt got to the stage of advancing and leaning it yet, so I dont believe it was anywhere near DET, also the head is totally unmarked which isnt indicative of bore breaking DET either.
3)Perfectly possible, as mentioned previously its possible its not indicative of what other c20let blocks will do, it might have once had no antifreeze in it 10 years ago and frozen up and put a stress fracture in the back edge of the water jacket or similar.
4)Top of the block appears stronger (if this was a Z it would have cracked right up to the mating face probably) but the bottom appears weaker (no girdle)
5)Lastly, if you cracked the block and didn't blow the rad/hoses to bits i'd guess it could have done it when cooling down/driving slowly.
Its pushed a little water out of one of the joints in a hose at the front, (there is water sat on top of the petrol tank) not actually split though, I guess if there wasnt perfect seal this has let the pressure off, its lost very little water though, not even a litre I should think.
It was still running perfectly, absolutely no hint from the way it sounded on idle or anything, the moisture in the exhaust was the only clue at all, so I think I was very lucky to catch it straight away TBH, few more hard miles and I could have been a lot less lucky.
4.5 thou piston to bore clearance, it was always intended for big boost and some nitrous as well so I was fairly generous on the clearance.
Its pushed a little water out of one of the joints in a hose at the front, (there is water sat on top of the petrol tank) not actually split though, I guess if there wasnt perfect seal this has let the pressure off, its lost very little water though, not even a litre I should think.
It was still running perfectly, absolutely no hint from the way it sounded on idle or anything, the moisture in the exhaust was the only clue at all, so I think I was very lucky to catch it straight away TBH, few more hard miles and I could have been a lot less lucky.
4.5 thou piston to bore clearance, it was always intended for big boost and some nitrous as well so I was fairly generous on the clearance.
1) Thats probably what 40 degrees past TDC then, highly unlikely its DET.
2) As above.
3) Possibly, I don't think i'd build another engine and worry about it.
4) Yes, the 1 that failed on us at probably 520hp blew the whole cylinder wall out, highly likely it cracked, pulled some water in and hydrolocked.
5) Yes probably more luck/quick to diagnose a problem etc. I reckon it probably cracked when running a full chat on the last pull or something. The crack worsened as it cooled and it obviously pulled some water in when cranking it over.
