RE: woof's Porsche 930 Turbo
Discussion
Hi
I was just updating my profile and was adding some of the costs spent on my 930 - and it's a little horrifying.
OK I'd admit to insanity but over 32 months the car as cost me on average £1001.18 per month - ouch !
Of course I have no intention of selling it - it's now almost running perfectly !
I was just updating my profile and was adding some of the costs spent on my 930 - and it's a little horrifying.
OK I'd admit to insanity but over 32 months the car as cost me on average £1001.18 per month - ouch !
Of course I have no intention of selling it - it's now almost running perfectly !
It's back in the work shop at the moment but off the top of my head:
G50 gearbox (replacing the 4 speed)
Penske custom made shocks
Turbo 2 993 intercooler
Turbo 4 calipers
Ceramic bores
SC cams
ceramic turbo
powerhaus sports exhaust system
Veloce Gt 1 wheels
2 engine rebuilds (first one was cocked up and then company went under than did it)
Complete Respray
Various mods to Metering head - eventually gone back to an original.
K&N Air intake/filter
The engine compartment looks pretty normal - apart from the bigger intercooler and the K&N air intake.
The car does look great and goes bloody well. Out performs a GT3 fairly easily on performance - not on handling - recently drove the new GT3 and what a piece of kit that is. It's almost forgiving !!
G50 gearbox (replacing the 4 speed)
Penske custom made shocks
Turbo 2 993 intercooler
Turbo 4 calipers
Ceramic bores
SC cams
ceramic turbo
powerhaus sports exhaust system
Veloce Gt 1 wheels
2 engine rebuilds (first one was cocked up and then company went under than did it)
Complete Respray
Various mods to Metering head - eventually gone back to an original.
K&N Air intake/filter
The engine compartment looks pretty normal - apart from the bigger intercooler and the K&N air intake.
The car does look great and goes bloody well. Out performs a GT3 fairly easily on performance - not on handling - recently drove the new GT3 and what a piece of kit that is. It's almost forgiving !!
power - well it was initially supposed to be 380 - but it's probably only just that with the mods - needs to go on a rolling road to be certain.
Top speed 180+ haven't actually found the limit of it - but it's gearing that will cap it. It pulls all the way to 160 without any sign of it giving up (speeds are actually speeds). Should of stuck a 6 speed box in !
0 - 60 4.2 sec'ish - got to do a timed run in it since the mods.
Of course like all turbos it's better from 30 - 100 - but with the new turbo and the exhaust system the turbo starts to spin at 1000rpm !
I'll do some runs with it once the clutch plate slipping problem has been sorted.
It's a quick one even as standard.
It's OK in the wet - just need to respect it. Braking is the real issue - which I'm still trying to sort. There's a bias problem - where basically the fronts lock up before the rears come in. Replacing the rear pistons at the moment otherwise it will be a pedal box with front to rear bias selection.
Top speed 180+ haven't actually found the limit of it - but it's gearing that will cap it. It pulls all the way to 160 without any sign of it giving up (speeds are actually speeds). Should of stuck a 6 speed box in !
0 - 60 4.2 sec'ish - got to do a timed run in it since the mods.
Of course like all turbos it's better from 30 - 100 - but with the new turbo and the exhaust system the turbo starts to spin at 1000rpm !
I'll do some runs with it once the clutch plate slipping problem has been sorted.
It's a quick one even as standard.
It's OK in the wet - just need to respect it. Braking is the real issue - which I'm still trying to sort. There's a bias problem - where basically the fronts lock up before the rears come in. Replacing the rear pistons at the moment otherwise it will be a pedal box with front to rear bias selection.
Hiya Woof,
Sounds like you have a useful brain to pick!
I found out yesterday from JZ Machtech that my 930 has a broken head stud (hence the noise on boost - qv other post). They are quoting me £2750+VAT for the labour to overhaul the top-end (valve seats, guides, piston rings, cam chains and head studs). Where did you get your engine rebuilt at (the second time), would you recommend them and how much was it?
How much was the modded turbo? I was thinking of replacing the wastegate spring and diaphragm but leaving it otherwise standard, is this a worthwhile mod?
Sounds like you have a useful brain to pick!
I found out yesterday from JZ Machtech that my 930 has a broken head stud (hence the noise on boost - qv other post). They are quoting me £2750+VAT for the labour to overhaul the top-end (valve seats, guides, piston rings, cam chains and head studs). Where did you get your engine rebuilt at (the second time), would you recommend them and how much was it?
How much was the modded turbo? I was thinking of replacing the wastegate spring and diaphragm but leaving it otherwise standard, is this a worthwhile mod?
2750+VAT is a good price and JZ a good outfit. Be careful going cheaper.
That said, Rubystone knows someone who may be able to help...
ATB
Domster
(PS Sorry to hear about the probs - bad luck, inspection may have found it - but sounded a cheap enough deal for you to afford the rebuild
)
That said, Rubystone knows someone who may be able to help...
ATB
Domster
(PS Sorry to hear about the probs - bad luck, inspection may have found it - but sounded a cheap enough deal for you to afford the rebuild
)Hmmm, you may be right but I guess the final bill will probably be somewhere between 4 & 5k though. 
I know I got a good deal, even with the broken stud JZ gave me a valuation above what I paid for it but a £5k rebuild would push my outlay way above the value of the car. (yes, I know that's not the point but I'm trying to be sensible for once).
My biggest fear is that the head/barrel has burned and will need replacing/machining, I'm pretty sure it's been like this for a while. JZ reckon the rocker cover gaskets have recently been replaced so it's probable that the guy I bought it from new about the issue. I asked him directly about the noise and any 'known problems' and he said the noise was normal and there weren't any problems.
I'm thinking along the lines of repairing what I know is broken rather than carrying out a full overhaul on the entire top-end. Where does one stop? One guy has suggested I have the turbo overhauled at the same time whilst another has suggested a bottom end rebuild and a third suggested getting the gearbox rebuilt. All I want to do is drive the bl**dy thing.
I'll probably end up pulling the engine out myself then getting JZ to overhaul the engine after I've assessed the condition - I'm a chartered engineer after all, no point in having all these qualifications and not using them
I know I got a good deal, even with the broken stud JZ gave me a valuation above what I paid for it but a £5k rebuild would push my outlay way above the value of the car. (yes, I know that's not the point but I'm trying to be sensible for once). My biggest fear is that the head/barrel has burned and will need replacing/machining, I'm pretty sure it's been like this for a while. JZ reckon the rocker cover gaskets have recently been replaced so it's probable that the guy I bought it from new about the issue. I asked him directly about the noise and any 'known problems' and he said the noise was normal and there weren't any problems.
I'm thinking along the lines of repairing what I know is broken rather than carrying out a full overhaul on the entire top-end. Where does one stop? One guy has suggested I have the turbo overhauled at the same time whilst another has suggested a bottom end rebuild and a third suggested getting the gearbox rebuilt. All I want to do is drive the bl**dy thing.
I'll probably end up pulling the engine out myself then getting JZ to overhaul the engine after I've assessed the condition - I'm a chartered engineer after all, no point in having all these qualifications and not using them
Demolition Dan - I use JZ and would have no hesitation to recommend them if you want a specialist to replace the head stud. However, as you obviously have the skills/time/inclination to be considering dropping the engine out why not just replace the head stud yourself and stick the engine back in and save yourself a packet. There are loads of books/website etc that well help you, as already touched on by UV. It ought to be a fairly low tech job.
A full top end rebuild is starting to get specialised (for me anyway) but does your engine really need it? Did JZ do any kind of compression or leak-down test that suggested you had problems on cylinders other than the one with the broken stud?
Why are people suggesting you need to do anything to the bottom end or turbo? I'd be surprised if that was essential at 92k miles. Or are you just thinking of taking advantage of the engine being out to strap on one of those fancy hybrid turbos for monster performance.
A full top end rebuild is starting to get specialised (for me anyway) but does your engine really need it? Did JZ do any kind of compression or leak-down test that suggested you had problems on cylinders other than the one with the broken stud?
Why are people suggesting you need to do anything to the bottom end or turbo? I'd be surprised if that was essential at 92k miles. Or are you just thinking of taking advantage of the engine being out to strap on one of those fancy hybrid turbos for monster performance.
Chris N,
Like the way you're thinking (the same as me). It's amazing how good other people are at spending my money!!
JZ's philosophy is obviously geared towards returning the engine to 'as-new' type condition. Obviously as the engine would be out of the car it makes sense to do certain repairs but there are obviously different levels to which one can go.
JZ weren't able to do any conventional leak/compression checks as the problem only manifests itself on boost and under power. I don't think you could replicate this with compressed air as cylinder pressures must be getting on for 1000psi (I can't be bothered to do the maths right now) when the mixture fires. Basically when the mixture does go bang the head is lifting slightly off the barrel and gas is escaping. They only found one broken stud (RHS of engine) but suspect more on the LHS - they didn't check LHS inlet cam cover as it is difficult to get off. All Head bolts in the lower (exhaust) cam covers were fine. My personal view is that the LHS is probably OK but won't know until I have the engine out.
I expect my procedure will be to get the engine out, assess the damage (strip-down) then rebuild but get JZ to check all the head bolt torques and set-up the valve gear. Whilst it's out I'll change the wastegate spring and fix anything else I find broken. I am assuming I will also have to get JZ to machine the heads.
Keep the suggestions coming, I was a bit down about this yesterday but now that I'm thinking about doing the job myself I'm quite looking forward to it.
I am still going to take the car to Cadwell on Saturday, I am assuming the heads are already burned so I might as well have a bit of fun in it before I take it off the road.
>> Edited by demolitiondan on Thursday 16th October 18:54
>> Edited by demolitiondan on Thursday 16th October 18:55
Like the way you're thinking (the same as me). It's amazing how good other people are at spending my money!!
JZ's philosophy is obviously geared towards returning the engine to 'as-new' type condition. Obviously as the engine would be out of the car it makes sense to do certain repairs but there are obviously different levels to which one can go.
JZ weren't able to do any conventional leak/compression checks as the problem only manifests itself on boost and under power. I don't think you could replicate this with compressed air as cylinder pressures must be getting on for 1000psi (I can't be bothered to do the maths right now) when the mixture fires. Basically when the mixture does go bang the head is lifting slightly off the barrel and gas is escaping. They only found one broken stud (RHS of engine) but suspect more on the LHS - they didn't check LHS inlet cam cover as it is difficult to get off. All Head bolts in the lower (exhaust) cam covers were fine. My personal view is that the LHS is probably OK but won't know until I have the engine out.
I expect my procedure will be to get the engine out, assess the damage (strip-down) then rebuild but get JZ to check all the head bolt torques and set-up the valve gear. Whilst it's out I'll change the wastegate spring and fix anything else I find broken. I am assuming I will also have to get JZ to machine the heads.
Keep the suggestions coming, I was a bit down about this yesterday but now that I'm thinking about doing the job myself I'm quite looking forward to it.
I am still going to take the car to Cadwell on Saturday, I am assuming the heads are already burned so I might as well have a bit of fun in it before I take it off the road.
>> Edited by demolitiondan on Thursday 16th October 18:54
>> Edited by demolitiondan on Thursday 16th October 18:55
agree that I cna't see any reason for the bottom end to be touched - 3.3 turbo bottom ends are virtually bulletproof and I think the used it for 911 up until C4's ? Anyway I can recommend 9miester and RSR Engineering.
JZ are pretty professional but seem expensive but hey we'll all need to make money !
JZ are pretty professional but seem expensive but hey we'll all need to make money !
Demolition dan, mate I don't mean to sound arrogant here & appologies if thats how this sounds, but come on you bought a high miles turbo charged supercar which is one of the most expensive 911s to work on, it has high'ish' miles for a 930 that has not already have had a top end rebuild or numerous other bits replaced ie the turbo & all without having it professionally inspected.
To be honest what did you expect? its a bit like shagging a Thai hooker without a welly boot on the little fella & not expecting to catch a dose of knob rot!
Replacing just the head studs is a waste of cash, it most likely needs a top end rebuild at these miles anyway & with the other bits thet are undoubtably wrong with it a £5k+ bill would not be unreasonable.
Anyway ref 1000 psi where did you get that figure from?? nearer 150 psi is closer to the mark.
I certainly wouldnt track day the car in its present state & to be honest Cadwell is a bit of a handful track in a 911 esp a 930 with the extra lard hanging out teh back end, down through the gooseneck it will be a tail happy beast & I know of more 911s that have been spanked at cadwell than any other track other than the nurburg ring.
To be honest what did you expect? its a bit like shagging a Thai hooker without a welly boot on the little fella & not expecting to catch a dose of knob rot!
Replacing just the head studs is a waste of cash, it most likely needs a top end rebuild at these miles anyway & with the other bits thet are undoubtably wrong with it a £5k+ bill would not be unreasonable.
Anyway ref 1000 psi where did you get that figure from?? nearer 150 psi is closer to the mark.
I certainly wouldnt track day the car in its present state & to be honest Cadwell is a bit of a handful track in a 911 esp a 930 with the extra lard hanging out teh back end, down through the gooseneck it will be a tail happy beast & I know of more 911s that have been spanked at cadwell than any other track other than the nurburg ring.
Hi Iguana,
You don't sound arrogant, a little superior perhaps ;^)
Actually the car has already had a top end rebuild and a re-con turbo. I didn't expect the car to be trouble free, I have budgeted for repairs/improvements but didn't expect I'd have to implemet them so soon.
I kind of expected to be shot down in flames but the reason I added my posts is because you lot know about living with Porsches and this is my first one.
None of you were able to identify the crackling noise which JZ found yesterday and I have the ultimate respect for them from an Engineering standpoint, I would also recommend them. However, I am not going to spend unnecessary amounts of money on maintaining my car when I am perfectly capable of doing it myself.
Can't answer the question re piston pressures right now 'cos I'm going to the pub and can't be a*sed with the calculations - I will do it tomorrow at work and post the calculation. I expect it will be half way between your figure and mine but we'll see.
I love your use of the vernacular particularly with respect to the Thai hooker, do you speak from personal experience <g>
As far as the last paragraph goes, I'll post the photos and you'll see why it's worth it.
D. Hart BEng (hon's) CEng MIMECHE lolraotf
>> Edited by demolitiondan on Thursday 16th October 21:32
You don't sound arrogant, a little superior perhaps ;^)
Actually the car has already had a top end rebuild and a re-con turbo. I didn't expect the car to be trouble free, I have budgeted for repairs/improvements but didn't expect I'd have to implemet them so soon.
I kind of expected to be shot down in flames but the reason I added my posts is because you lot know about living with Porsches and this is my first one.
None of you were able to identify the crackling noise which JZ found yesterday and I have the ultimate respect for them from an Engineering standpoint, I would also recommend them. However, I am not going to spend unnecessary amounts of money on maintaining my car when I am perfectly capable of doing it myself.
Can't answer the question re piston pressures right now 'cos I'm going to the pub and can't be a*sed with the calculations - I will do it tomorrow at work and post the calculation. I expect it will be half way between your figure and mine but we'll see.
I love your use of the vernacular particularly with respect to the Thai hooker, do you speak from personal experience <g>
As far as the last paragraph goes, I'll post the photos and you'll see why it's worth it.
D. Hart BEng (hon's) CEng MIMECHE lolraotf
>> Edited by demolitiondan on Thursday 16th October 21:32
demolitiondan said:
None of you were able to identify the crackling noise which JZ found yesterday
Hmm so no one suggested head studs huh-
well how about chris n with this-
"Hard to guess at the misfire noise on full boost from a written description but could be related to a broken or loose head stud or studs, which is quite common on the 930. You can get some strange noises at full boost which are actually related to the head lifting off the barrel or the barrel moving around in the crankcase"
Ps no I don't have any personal experiece of Thai hookers
Iguana,
GCSE woodwork, 50m swimming award & Cub scout map reading badge.
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