Hot start kit?
Discussion
I may have removed a hot start thingy when I stripped out the old engine.
The car now turns over slower when hot!
What does the kit look like?
I removed what looks like an ally heat sink bolted to the chassis adjacent to the starter with a 25 amp fuse link a 3 terminal relay bolted to it and a few heavyish gauge wires hanging off!
The car now turns over slower when hot!
What does the kit look like?
I removed what looks like an ally heat sink bolted to the chassis adjacent to the starter with a 25 amp fuse link a 3 terminal relay bolted to it and a few heavyish gauge wires hanging off!
http://www.chimaerapages.com/resources_hotstart.ph...
failing that ive still got the original instructions SOMEWHERE i could scan and post?
max
failing that ive still got the original instructions SOMEWHERE i could scan and post?
max
haircutmike said:
I don't really understand what fails when the engine is hot?
Main power is there direct from the battery.
The engine is well earthed.
A circuit is required to activate the solinoid, that obviously works as the motor wouldn't spin.
What's going wrong.
I believe its to do with the small wire that goes to the starter, when its hot it cant cope. I used to have the hot start problem before my rebuild. I replaced this wire down to the starter with bigger stuff and covered in heat shield and never had the problem again (touch lots of wood!). And my engine with the turbos has a lot of heat going on.Main power is there direct from the battery.
The engine is well earthed.
A circuit is required to activate the solinoid, that obviously works as the motor wouldn't spin.
What's going wrong.
Regards
Neal
It fails when its hot as the starter solenoid gets hot, so its resistance goes up, so it takes less current. This would not matter, execept you also have a long feed wire via the imobiliser for the starter, so a few vital volts get dropped along the way, so you get a double whammy. The hot start kit provides a good 12v feed via a relay to the solenoid. If the starter is turning, its not a hot start issue.
The thing you describe sounds like the main fuse link from the battery. You need to make sure everthing is clean and good connections and the fuse links are good (you can have 3 or 4 of these bolted together) or it may drop a few volts.
The thing you describe sounds like the main fuse link from the battery. You need to make sure everthing is clean and good connections and the fuse links are good (you can have 3 or 4 of these bolted together) or it may drop a few volts.
The problem is that the solenoid does two things: Yes it activates the starter gear but it also makes the main contact that allows the motor current to flow. The solenoid takes around 30-40A and anything that reduces this will affect the pressure on the motor contacts. These can pit and eventually will put some resistance in the circuit which causes the current to the motor to drop. THis is why changing the solenoid can solve the problem but it may reappear as the contacts start to pit.
The currents are horrendous: 600 on start up, 2-300 while going and 400-500 if the motor starts to stall/stop.
On the Chimpari, the solenoid wire is a bit feeble and the voltage/current drop is frequently insufficient to energise the solenoid completely so only partial contact is made. Replacing it with a bigger wire decreases the drop and allows the solenoid to work correctly. Better contact is made, more current flows and the engine turns over faster. The problem can also be made worse because the solenoid signal also goes through the immobiliser.
The problem is more apparent when hot because the motor winding resistance is higher when warm.
On the Cerbera Ls conversions, I feed the solenoid direct from a 70A relay with a 70A cable directly onto the battery. Solenoid wire energises the relay. All this is right next to the starter to keep wire length to a minimum. I also use a bigger diameter power lead to the starter as the TVR original is on the small side and as they are old, they also tend to corrode internally. With this setup, I have had the engine turning over at nearly 300 rpm!
The currents are horrendous: 600 on start up, 2-300 while going and 400-500 if the motor starts to stall/stop.
On the Chimpari, the solenoid wire is a bit feeble and the voltage/current drop is frequently insufficient to energise the solenoid completely so only partial contact is made. Replacing it with a bigger wire decreases the drop and allows the solenoid to work correctly. Better contact is made, more current flows and the engine turns over faster. The problem can also be made worse because the solenoid signal also goes through the immobiliser.
The problem is more apparent when hot because the motor winding resistance is higher when warm.
On the Cerbera Ls conversions, I feed the solenoid direct from a 70A relay with a 70A cable directly onto the battery. Solenoid wire energises the relay. All this is right next to the starter to keep wire length to a minimum. I also use a bigger diameter power lead to the starter as the TVR original is on the small side and as they are old, they also tend to corrode internally. With this setup, I have had the engine turning over at nearly 300 rpm!
haircutmike said:
I don't really understand what fails when the engine is hot?
Main power is there direct from the battery.
The engine is well earthed.
A circuit is required to activate the solinoid, that obviously works as the motor wouldn't spin.
What's going wrong.
As far as i understand the problem, its heat from the manifolds over a period of time affecting the solenoid itself.Main power is there direct from the battery.
The engine is well earthed.
A circuit is required to activate the solinoid, that obviously works as the motor wouldn't spin.
What's going wrong.
Many have posted with a "hotstart" problem and solved it by stripping down and cleaning/greasing the solenoid.I would rather do this than put more current to the solenoid.
You can refit the hotstart kit but i think that just bypasses the real problem. I would strip and clean the solonoid down, but also fit a heat shield to deflect heat away.
All the above is only my thoughts on the hotstart problem, but i did strip down and clean both the starter and solenoid and fit a homemade but very efficient heat shield and no hotstart problems for me for the past 3 years.
I would offer, as a summary, the following thoughts.
When TVR first delivered these vehicles to the new owners there was no such thing as a hot start problem. Otherwise they would have all ended up back at the factory.
Wear and tear over the years in a particularly hot and hostile environment has led the starter motors to age prematurely when compared to standard production cars.
The adoption of a 'hot start kit' has provided a bigger oomph to the starter to overcome some wear issues but the underlying problem of advanced wear still remains.
The wiring itself is not to blame other than its lack of ability to supply sufficient energy to a knackered starter motor. In my case a hot start kit helped for a while but the starter aged to the point that a fuse in the 'kit' was blowing.
The cure is either to overhaul the starter/solonoid or to replace it.
I went the latter route and had a new starter fitted and some heat protection applied.
No problems ever since but I am sure they will return in several years time.
When TVR first delivered these vehicles to the new owners there was no such thing as a hot start problem. Otherwise they would have all ended up back at the factory.
Wear and tear over the years in a particularly hot and hostile environment has led the starter motors to age prematurely when compared to standard production cars.
The adoption of a 'hot start kit' has provided a bigger oomph to the starter to overcome some wear issues but the underlying problem of advanced wear still remains.
The wiring itself is not to blame other than its lack of ability to supply sufficient energy to a knackered starter motor. In my case a hot start kit helped for a while but the starter aged to the point that a fuse in the 'kit' was blowing.
The cure is either to overhaul the starter/solonoid or to replace it.
I went the latter route and had a new starter fitted and some heat protection applied.
No problems ever since but I am sure they will return in several years time.
The hot start kit is a way of restoring the power feed to the solenoid so that it operates in the correct spec and maintains good internal contact.
It is not supercharging the feed to overcome wear in the solenoid, it is there to make sure the solenoid operates correctly. It's what TVR should have done in the first place. BTW TVR fitted this to the T cars BTW and the wiring is several sizes bigger.
The hot start problem can be caused by a single problem or several combining. It happens when the starter is hot because that is when the most electrical and mechanical stress is on it. Reducing the temp can help if the starter is borderline.
Heat shielding can help but equally it can hinder as it can prevent the starter from losing heat. It is bolted to a block that is around 150C anyway.
Not all solenoids are the same. I have swapped them from one starter to another to get a working starter to turn over an LS engine for example. Both starters worked fine on the bench.
The problem is caused by TVR not providing a circuit that could reliably operate the solenoid correctly. It never showed up initially because everything was new. As the wiring and starter ages, the working margin degrades which is why the hot start kit is a very good idea. Without it the margin is small with it, the margin is bigger.
It is not supercharging the feed to overcome wear in the solenoid, it is there to make sure the solenoid operates correctly. It's what TVR should have done in the first place. BTW TVR fitted this to the T cars BTW and the wiring is several sizes bigger.
The hot start problem can be caused by a single problem or several combining. It happens when the starter is hot because that is when the most electrical and mechanical stress is on it. Reducing the temp can help if the starter is borderline.
Heat shielding can help but equally it can hinder as it can prevent the starter from losing heat. It is bolted to a block that is around 150C anyway.
Not all solenoids are the same. I have swapped them from one starter to another to get a working starter to turn over an LS engine for example. Both starters worked fine on the bench.
The problem is caused by TVR not providing a circuit that could reliably operate the solenoid correctly. It never showed up initially because everything was new. As the wiring and starter ages, the working margin degrades which is why the hot start kit is a very good idea. Without it the margin is small with it, the margin is bigger.
scruggs said:
The wiring itself is not to blame other than its lack of ability to supply sufficient energy to a knackered starter motor. In my case a hot start kit helped for a while but the starter aged to the point that a fuse in the 'kit' was blowing.
The current surge taken by the solenoid is big. That's why the fuse was blowing. Even on brand new starters, I have measured over 30A for the solenoid. This will also stress the fuse and cause it to weaken. I have never read a post on this forum that has solved a problem for me that had me baffled so much. Steve Heath's explanation has done that.
I purchased a 2000 450 Chimaera 5 years old with 32K on the clock, after a while Dream Machines replaced the starter under warranty as I clearly had the hot start problem.
After a year or so the problem was back in part so I fitted the hot start kit which was very easy. In addition DM had replaced the alarm with an aftermarket Thatcham 1 unit as at that stage TVR could not provide the Meta one, whether this had any effect I don't know.
What I do know is that until I sold the car earlier this year it always suffered a reluctance to start when hot.
When turning the key the starter would turn very slowly for about a second then turn OK but this never inspired confidence.
It seems to me that DM repacing the starter cured the result of the weak wiring, but because the hot start kit was not fitted at that stage the contacts on the new starter eventually pitted causing the problem.
Because the starter had been replaced I had ruled that out as being at fault, I now think that with the hot start kit fitted if I had replaced the solonoid this may have cured the problem once and for all.
If I was to ever buy another Chim I think I would fit the kit without delay as its easier to fit than a starter motor.
I purchased a 2000 450 Chimaera 5 years old with 32K on the clock, after a while Dream Machines replaced the starter under warranty as I clearly had the hot start problem.
After a year or so the problem was back in part so I fitted the hot start kit which was very easy. In addition DM had replaced the alarm with an aftermarket Thatcham 1 unit as at that stage TVR could not provide the Meta one, whether this had any effect I don't know.
What I do know is that until I sold the car earlier this year it always suffered a reluctance to start when hot.
When turning the key the starter would turn very slowly for about a second then turn OK but this never inspired confidence.
It seems to me that DM repacing the starter cured the result of the weak wiring, but because the hot start kit was not fitted at that stage the contacts on the new starter eventually pitted causing the problem.
Because the starter had been replaced I had ruled that out as being at fault, I now think that with the hot start kit fitted if I had replaced the solonoid this may have cured the problem once and for all.
If I was to ever buy another Chim I think I would fit the kit without delay as its easier to fit than a starter motor.
scruggs said:
I would offer, as a summary, the following thoughts.
When TVR first delivered these vehicles to the new owners there was no such thing as a hot start problem. Otherwise they would have all ended up back at the factory.
Wear and tear over the years in a particularly hot and hostile environment has led the starter motors to age prematurely when compared to standard production cars.
The adoption of a 'hot start kit' has provided a bigger oomph to the starter to overcome some wear issues but the underlying problem of advanced wear still remains.
The wiring itself is not to blame other than its lack of ability to supply sufficient energy to a knackered starter motor. In my case a hot start kit helped for a while but the starter aged to the point that a fuse in the 'kit' was blowing.
The cure is either to overhaul the starter/solonoid or to replace it.
I went the latter route and had a new starter fitted and some heat protection applied.
No problems ever since but I am sure they will return in several years time.
Each to there own opinion and all that but this explains it perfectly, and it gets a big When TVR first delivered these vehicles to the new owners there was no such thing as a hot start problem. Otherwise they would have all ended up back at the factory.
Wear and tear over the years in a particularly hot and hostile environment has led the starter motors to age prematurely when compared to standard production cars.
The adoption of a 'hot start kit' has provided a bigger oomph to the starter to overcome some wear issues but the underlying problem of advanced wear still remains.
The wiring itself is not to blame other than its lack of ability to supply sufficient energy to a knackered starter motor. In my case a hot start kit helped for a while but the starter aged to the point that a fuse in the 'kit' was blowing.
The cure is either to overhaul the starter/solonoid or to replace it.
I went the latter route and had a new starter fitted and some heat protection applied.
No problems ever since but I am sure they will return in several years time.
and a big 
from me.Tis' only my opinion and there will always be variations.
Maybe I should have added that, as has been mentioned by others more technically knowledgeable than myself, the wiring degrades with time and heat as well. Perhaps that should be inspected, tested and replaced where necessary at the same time as the starter overhaul or replacement.
Maybe I should have added that, as has been mentioned by others more technically knowledgeable than myself, the wiring degrades with time and heat as well. Perhaps that should be inspected, tested and replaced where necessary at the same time as the starter overhaul or replacement.
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