Two steps forward ... four steps back!
07-12-2016, 08:54 AM
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Track Day
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Two steps forward ... four steps back!
Over the next couple of weeks I plan to share some information on a couple of useful DIY enhancements I've discovered for my 964 Targa, along with some requests for help on four current issues which I still need to resolve.
In this email, I thought I'd give some basic descriptions so I can get a feel for the level of interest in learning more about my DIY fixes and for the information on the issues which I need to provide to help potential samaritans understand the exact problem I'm encountering.
Fix 1: Aware that my roof has a tendency to leak in the rain, and having researched what role damaged seals might have in the level of wind roar from the roof at speed, I started to read up on using silicone sealant for repairs to damaged rubber seals. However, I came across details of a product recently launched in the UK called 'Sugru'. More details can be found here: https://sugru.com/. I'm not going to push a commercial product at anyone, but I found it very easy to use in shaping new silicone rubber that bonds extremely well to the existing but damaged sections of my roof seals. The product is inexpensive, comes in multiple colours (including black) and is widely available from one of the leading nationwide UK DIY stores. I'll post some photos of the repaired sections of my roof seals in a further post.
Fix 2: During my research on wind roar, I also came across a post from a US Targa owner who reckoned he had reduced the noise from his roof at speed by using a 5mm-think cardon fibre rod in the centre of his targa roof frame, parallel to the sides of the roof, as a brace. His aim was to ensure the frame remained at tension to help prevent the lift that's otherwise exerted on the targa roof by the airflow passing over the outside of the roof when travelling at speed. I found it easy to find a UK supplier of standard length / diameter carbon fibre rods and, having purchased one (10mm diameter, 1m length), to cut it to the specifications which our American friend had recommended (1/8th of an inch longer than the measurement between the inside of the front and rear sections of the targa frame close to the central hinge). It was easiest to put the brace in place with the roof off the car and I used some thin rubber (from a cycle inner tube) to help ensure the carbon rod didn't slip and damage the crackle finish on the targa frame. The result ... no wind noise at all even at the max. speeds I've travelled thus far (up to 100mph)! Again, I'll post some photos in another post.
Issue 1: I've owned my car for 12 years and it's always had a problem with a misfire / stalling after a period driving in the rain. Various suggestions have been made by mechanics over the years, and expensive components replaced, always without resolving the problem. I've felt we were onto something with the suggestion that it might be an issue with the HT leads. Indeed, one Porsche specialist, with Bosch electrical expertise as one of its claims, reckoned the problem was caused by poor routing of HT leads. Later, when this hadn't worked, they replaced one lead altogether (at a cost of £120 for the lead). However, driving down a wet autoroute en route to Le Mans this year, it quickly became apparent that the misfire and stalling remain a big issue. The problem seems worse with the amount of rainfall on the road. Running in the tyre tracks of cars in front, and keeping the revs high, both clearly reduced the propensity of the car to start misfiring. If the car stalled and came to a standstill, a short wait (to allow damp electrics to dry out with the engine warmth, perhaps?) was all it took before the engine would run smoothly again.
Issue 2: If my engine has been running hot (for example, in the queues at the Eurotunnel terminal), the car's ignition refuses to re-start the car after stopping the engine. The ignition lights some on, but turning the key gives absolutely nothing. No starter motor turning over, no clicks, just nothing. Again, simply waiting (for the engine to cool, it seems) leads to the problem going away. Then the car starts first turn of the key again, with an immediate 'fire-up'. I have an aftermarket alarm / immobiliser and I wonder if this struggles in a hot engine bay. Otherwise, it could be another component that doesn't like the heat. I read somewhere recently that the switch to raise the spoiler at any speed had been added by Porsche to allow owners to address oil leak issues in the early models caused by the engine running hot. Maybe, raising the spoiler will prevent the engine bay from getting so hot that this issue becomes a problem.
Issue 3: I have 2 pretty good quality Bridgestone SO2 tyres on the rear axle, but I really need to replace the fronts. However, I've scoured the websites for new SO2 tyres for my Cup 17" wheels without success. I'm tempted to replace all 4 tyres with some new sticky rubber (Yokohamas or Michelins, maybe), but I could do without the expense given the other issues with the car. Is it possible to still buy new SO2s anywhere, or do I have to simply bite the bullet?
Issue 4: It was an MOT advisory issue last year that the front springs were starting to corrode. The next MOT is due in September, so I'm starting to think about what needs to be done on this. Again, I've read somewhere recently that this is becoming a recurrent issue with the 964, but what does it mean in terms of the remedial work required and what are my options should I need to keep the cost down?
Sorry for the long message. All thoughts and helpful suggestions would be gratefully received.
Paul
In this email, I thought I'd give some basic descriptions so I can get a feel for the level of interest in learning more about my DIY fixes and for the information on the issues which I need to provide to help potential samaritans understand the exact problem I'm encountering.
Fix 1: Aware that my roof has a tendency to leak in the rain, and having researched what role damaged seals might have in the level of wind roar from the roof at speed, I started to read up on using silicone sealant for repairs to damaged rubber seals. However, I came across details of a product recently launched in the UK called 'Sugru'. More details can be found here: https://sugru.com/. I'm not going to push a commercial product at anyone, but I found it very easy to use in shaping new silicone rubber that bonds extremely well to the existing but damaged sections of my roof seals. The product is inexpensive, comes in multiple colours (including black) and is widely available from one of the leading nationwide UK DIY stores. I'll post some photos of the repaired sections of my roof seals in a further post.
Fix 2: During my research on wind roar, I also came across a post from a US Targa owner who reckoned he had reduced the noise from his roof at speed by using a 5mm-think cardon fibre rod in the centre of his targa roof frame, parallel to the sides of the roof, as a brace. His aim was to ensure the frame remained at tension to help prevent the lift that's otherwise exerted on the targa roof by the airflow passing over the outside of the roof when travelling at speed. I found it easy to find a UK supplier of standard length / diameter carbon fibre rods and, having purchased one (10mm diameter, 1m length), to cut it to the specifications which our American friend had recommended (1/8th of an inch longer than the measurement between the inside of the front and rear sections of the targa frame close to the central hinge). It was easiest to put the brace in place with the roof off the car and I used some thin rubber (from a cycle inner tube) to help ensure the carbon rod didn't slip and damage the crackle finish on the targa frame. The result ... no wind noise at all even at the max. speeds I've travelled thus far (up to 100mph)! Again, I'll post some photos in another post.
Issue 1: I've owned my car for 12 years and it's always had a problem with a misfire / stalling after a period driving in the rain. Various suggestions have been made by mechanics over the years, and expensive components replaced, always without resolving the problem. I've felt we were onto something with the suggestion that it might be an issue with the HT leads. Indeed, one Porsche specialist, with Bosch electrical expertise as one of its claims, reckoned the problem was caused by poor routing of HT leads. Later, when this hadn't worked, they replaced one lead altogether (at a cost of £120 for the lead). However, driving down a wet autoroute en route to Le Mans this year, it quickly became apparent that the misfire and stalling remain a big issue. The problem seems worse with the amount of rainfall on the road. Running in the tyre tracks of cars in front, and keeping the revs high, both clearly reduced the propensity of the car to start misfiring. If the car stalled and came to a standstill, a short wait (to allow damp electrics to dry out with the engine warmth, perhaps?) was all it took before the engine would run smoothly again.
Issue 2: If my engine has been running hot (for example, in the queues at the Eurotunnel terminal), the car's ignition refuses to re-start the car after stopping the engine. The ignition lights some on, but turning the key gives absolutely nothing. No starter motor turning over, no clicks, just nothing. Again, simply waiting (for the engine to cool, it seems) leads to the problem going away. Then the car starts first turn of the key again, with an immediate 'fire-up'. I have an aftermarket alarm / immobiliser and I wonder if this struggles in a hot engine bay. Otherwise, it could be another component that doesn't like the heat. I read somewhere recently that the switch to raise the spoiler at any speed had been added by Porsche to allow owners to address oil leak issues in the early models caused by the engine running hot. Maybe, raising the spoiler will prevent the engine bay from getting so hot that this issue becomes a problem.
Issue 3: I have 2 pretty good quality Bridgestone SO2 tyres on the rear axle, but I really need to replace the fronts. However, I've scoured the websites for new SO2 tyres for my Cup 17" wheels without success. I'm tempted to replace all 4 tyres with some new sticky rubber (Yokohamas or Michelins, maybe), but I could do without the expense given the other issues with the car. Is it possible to still buy new SO2s anywhere, or do I have to simply bite the bullet?
Issue 4: It was an MOT advisory issue last year that the front springs were starting to corrode. The next MOT is due in September, so I'm starting to think about what needs to be done on this. Again, I've read somewhere recently that this is becoming a recurrent issue with the 964, but what does it mean in terms of the remedial work required and what are my options should I need to keep the cost down?
Sorry for the long message. All thoughts and helpful suggestions would be gratefully received.
Paul
07-12-2016, 09:37 AM
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IHI KING!
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Issue #1, have you tried simulating the problem by running a hose over the engine while its idling? This should help isolate where the problem is. I've heard that aftermarket oxygen sensors can cause problems when wet but I haven't experienced it myself.
Issue #2 - sounds like a weak starter solenoid. They start showing problems when the starter is hot. You may want to remove it and have it rebuilt or replaced.
Issue #3 - Sorry, can't help with availability. But I do recommend keeping the same type of tire on both axles. When I first got my cab back in '92, I the rear tires wore out first. I replaced them with what I thought were similar tires. The driving behavior became annoying. The car wondered on the highway. Turns out, the shop had installed a new generation of the same tire. Once I installed the same generation on the front, the wandering went away (not an alignment issue).
Issue #2 - sounds like a weak starter solenoid. They start showing problems when the starter is hot. You may want to remove it and have it rebuilt or replaced.
Issue #3 - Sorry, can't help with availability. But I do recommend keeping the same type of tire on both axles. When I first got my cab back in '92, I the rear tires wore out first. I replaced them with what I thought were similar tires. The driving behavior became annoying. The car wondered on the highway. Turns out, the shop had installed a new generation of the same tire. Once I installed the same generation on the front, the wandering went away (not an alignment issue).
07-13-2016, 08:11 PM
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I3: I've had luck finding NLA tires on Ebay. Use care and make sure you get a pic of the tire build date.
I4: Spring and damper swap on these cars is really pretty easy. N.B., easy cheap.
I4: Spring and damper swap on these cars is really pretty easy. N.B., easy cheap.
07-14-2016, 06:05 PM
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Track Day
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Hi, it was your post that inspired me to try the carbon fibre brace!!
I was able to get hold of the 10mm diameter rod over here for about $30 equivalent and it was dead easy to cut it down to the required length. It looks a bit flimsy once in place, but it can take a lot of pressure without flexing or sliding out of place. It really has been 'fit and forget'.
I used a piece of thin rubber from a cycle tire inner tube at one end to protect the finish on the roof frame, but I haven't worked out what would be the best solution for the other end, as it's necessary to slide it into place with someone else stretching the frame apart in the middle. This has left marks from the bare carbon fibre end on the black crackle finish to the frame. Some thin nylon or other plastic might do the job, but there has to be enough friction to stop it from sliding out of position once under pressure.
I think I might have the rod just a little too long, but it works superbly at eliminating the wind roar.
The Sugru product has been a revelation. Something that's very cheap to buy, but which has amazing properties and lots of potential applications. Perhaps I should ask for the US distribution rights :-). Seriously, PM me if you want me to email you a link to the website of the main DIY chain over here that stocks it.
Paul
I was able to get hold of the 10mm diameter rod over here for about $30 equivalent and it was dead easy to cut it down to the required length. It looks a bit flimsy once in place, but it can take a lot of pressure without flexing or sliding out of place. It really has been 'fit and forget'.
I used a piece of thin rubber from a cycle tire inner tube at one end to protect the finish on the roof frame, but I haven't worked out what would be the best solution for the other end, as it's necessary to slide it into place with someone else stretching the frame apart in the middle. This has left marks from the bare carbon fibre end on the black crackle finish to the frame. Some thin nylon or other plastic might do the job, but there has to be enough friction to stop it from sliding out of position once under pressure.
I think I might have the rod just a little too long, but it works superbly at eliminating the wind roar.
The Sugru product has been a revelation. Something that's very cheap to buy, but which has amazing properties and lots of potential applications. Perhaps I should ask for the US distribution rights :-). Seriously, PM me if you want me to email you a link to the website of the main DIY chain over here that stocks it.
Paul
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07-15-2016, 04:32 AM
#8
Hi, it was your post that inspired me to try the carbon fibre brace!!
I was able to get hold of the 10mm diameter rod over here for about $30 equivalent and it was dead easy to cut it down to the required length. It looks a bit flimsy once in place, but it can take a lot of pressure without flexing or sliding out of place. It really has been 'fit and forget'.
I used a piece of thin rubber from a cycle tire inner tube at one end to protect the finish on the roof frame, but I haven't worked out what would be the best solution for the other end, as it's necessary to slide it into place with someone else stretching the frame apart in the middle. This has left marks from the bare carbon fibre end on the black crackle finish to the frame. Some thin nylon or other plastic might do the job, but there has to be enough friction to stop it from sliding out of position once under pressure.
I think I might have the rod just a little too long, but it works superbly at eliminating the wind roar.
The Sugru product has been a revelation. Something that's very cheap to buy, but which has amazing properties and lots of potential applications. Perhaps I should ask for the US distribution rights :-). Seriously, PM me if you want me to email you a link to the website of the main DIY chain over here that stocks it.
Paul
I was able to get hold of the 10mm diameter rod over here for about $30 equivalent and it was dead easy to cut it down to the required length. It looks a bit flimsy once in place, but it can take a lot of pressure without flexing or sliding out of place. It really has been 'fit and forget'.
I used a piece of thin rubber from a cycle tire inner tube at one end to protect the finish on the roof frame, but I haven't worked out what would be the best solution for the other end, as it's necessary to slide it into place with someone else stretching the frame apart in the middle. This has left marks from the bare carbon fibre end on the black crackle finish to the frame. Some thin nylon or other plastic might do the job, but there has to be enough friction to stop it from sliding out of position once under pressure.
I think I might have the rod just a little too long, but it works superbly at eliminating the wind roar.
The Sugru product has been a revelation. Something that's very cheap to buy, but which has amazing properties and lots of potential applications. Perhaps I should ask for the US distribution rights :-). Seriously, PM me if you want me to email you a link to the website of the main DIY chain over here that stocks it.
Paul
07-15-2016, 05:16 PM
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Track Day
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OK, I spoke to the UK agent for the older Laserline alarms, Bridgewater Electronics, earlier about the problems with starting when the car is running hot.
Their first thought, based on my description of the intermittent starting problem, was that it was more likely to be an issue with the starter solenoid and/or the relay than with the Laserline 996 alarm unit. I explained that I was sure both had been changed or checked in recent years, yet the problem has continued.
In their 15 years of experience with the alarm unit, they are not aware of another case where the problem I described has occured due to a fault with the alarm unit. They also discounted any likelihood that the electrics within the siren unit were having any impact on the functioning of the starter. Of course, they pointed out they can't vouch for the various connections made in the installation - a poor connection could lead to an intermittent problem, which is what I am experiencing.
Their suggestion was to trace, disconnect and bridge the connections between the alarm unit and the wiring from the ignition switch to the starter motor. This wouldn't be easy, as all the wires exiting the Laseline 996 unit are black (but it should be possible to work this out with the assistance of a wiring diagram - will need to check if this is in Adrian Streather's book when I get home). Alternatively, this can be achieved by opening up the alarm unit and telephoning Bridgewater Electronics who can then explain how to change the internal wiring to achieve the same aim. If the starting problem goes away, I would have confirmation that it was the alarm unit, or how it has been wired into the car's electrics.
If the installer comes back to me, I might be able to get them to double-check the wiring and/or assist with disconnecting the connection with the starter circuit. Obviously, I'd have to get the OK from the car insurer, in case the alarm ceases to be 'Thatcham 1 approved' at this point (I believe a Thatcham 1 alarm must interrupt two circuits to render the vehicle immobile).
The patient approach would be to rectify just one of the above at a time, in order to definitively identify the cause of the problem (fingers crossed!). I think I'll explore the potential costs for me of both routes (as I wouldn't want to tackle either job by myself) and go with the cheapest fix first.
Their first thought, based on my description of the intermittent starting problem, was that it was more likely to be an issue with the starter solenoid and/or the relay than with the Laserline 996 alarm unit. I explained that I was sure both had been changed or checked in recent years, yet the problem has continued.
In their 15 years of experience with the alarm unit, they are not aware of another case where the problem I described has occured due to a fault with the alarm unit. They also discounted any likelihood that the electrics within the siren unit were having any impact on the functioning of the starter. Of course, they pointed out they can't vouch for the various connections made in the installation - a poor connection could lead to an intermittent problem, which is what I am experiencing.
Their suggestion was to trace, disconnect and bridge the connections between the alarm unit and the wiring from the ignition switch to the starter motor. This wouldn't be easy, as all the wires exiting the Laseline 996 unit are black (but it should be possible to work this out with the assistance of a wiring diagram - will need to check if this is in Adrian Streather's book when I get home). Alternatively, this can be achieved by opening up the alarm unit and telephoning Bridgewater Electronics who can then explain how to change the internal wiring to achieve the same aim. If the starting problem goes away, I would have confirmation that it was the alarm unit, or how it has been wired into the car's electrics.
If the installer comes back to me, I might be able to get them to double-check the wiring and/or assist with disconnecting the connection with the starter circuit. Obviously, I'd have to get the OK from the car insurer, in case the alarm ceases to be 'Thatcham 1 approved' at this point (I believe a Thatcham 1 alarm must interrupt two circuits to render the vehicle immobile).
The patient approach would be to rectify just one of the above at a time, in order to definitively identify the cause of the problem (fingers crossed!). I think I'll explore the potential costs for me of both routes (as I wouldn't want to tackle either job by myself) and go with the cheapest fix first.
07-17-2016, 10:12 AM
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Track Day
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Thanks, Steve. I hadn't realised there was an SO4. They seem to get pretty decent reviews. I'll need to check out how widely available these are in the UK.
I always thought it was important to have the same tire on all four wheels with the 964, but it seems plenty of you have different tires between the two axles. I assume this is no problem, but what are the rules, if any, with mixing tires between axles, please?
Thanks,
Paul
I always thought it was important to have the same tire on all four wheels with the 964, but it seems plenty of you have different tires between the two axles. I assume this is no problem, but what are the rules, if any, with mixing tires between axles, please?
Thanks,
Paul
07-17-2016, 12:20 PM
#12
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Hmmm not me. I always replace all 4 at same time. I don't like older date codes up front (even if they still have tread left) & new rubber on the rear. I tried that once & it just did not track well when hitting it hard in corners.
So I when I need to buy all 4, I just put my fronts on Craigslist & they sell very quickly here in my local. There are a lot of youngster H2O Camber nutts that use that size (225/40x18). Easy enough (although NEVER sell at your home. always meet up at our local police station).
So I when I need to buy all 4, I just put my fronts on Craigslist & they sell very quickly here in my local. There are a lot of youngster H2O Camber nutts that use that size (225/40x18). Easy enough (although NEVER sell at your home. always meet up at our local police station).