Engine re-built and new radiator but........
Discussion
...... I'm not sure if I have another problem. Can you help?
I had the engine of my 450 Chim re-built and a new radiator fitted and am just in the process of running it in. I'm sure there are no problems with the re-build but I may have a couple of problems.
1. The engine has been fitted with a sports cam and matching eprom chip. Idle is a little rough and can fluctuate between 800 and 1100 rpm. Also the engine is very lumpy between 1000 and 2000 rpm in all gears whether hot or cold. It will not look at doing 30mph in fourth gear. Between 2000 and 3000 rpm the engine runs really smoothly. I've not took it over 3000rpm yet but I'm sure it will be fine. Is this situation normal with a sports cam?
2. I drove a couple of hundred miles today, and when cruising at 70mph (yes really!) the temperature gauge never got above 65 degrees. The fuel consumption has also greatly increased. Is this indicative of a faulty thermostat? In stationary traffic the temperature does increase slowly to about 90 degrees and the fans work normally.
BTW the only reason the engine was re-built was because it had done 52000 miles, it sounded a bit tappy, the standard cam was worn, and the clutch was slipping. Other than that it was OK.
I had the engine of my 450 Chim re-built and a new radiator fitted and am just in the process of running it in. I'm sure there are no problems with the re-build but I may have a couple of problems.
1. The engine has been fitted with a sports cam and matching eprom chip. Idle is a little rough and can fluctuate between 800 and 1100 rpm. Also the engine is very lumpy between 1000 and 2000 rpm in all gears whether hot or cold. It will not look at doing 30mph in fourth gear. Between 2000 and 3000 rpm the engine runs really smoothly. I've not took it over 3000rpm yet but I'm sure it will be fine. Is this situation normal with a sports cam?
2. I drove a couple of hundred miles today, and when cruising at 70mph (yes really!) the temperature gauge never got above 65 degrees. The fuel consumption has also greatly increased. Is this indicative of a faulty thermostat? In stationary traffic the temperature does increase slowly to about 90 degrees and the fans work normally.
BTW the only reason the engine was re-built was because it had done 52000 miles, it sounded a bit tappy, the standard cam was worn, and the clutch was slipping. Other than that it was OK.
Well of course I'm no expert but would have thought that with a sports cam, low down would be lumpy, even my bog standard 4.0 is not happy at 30 in fourth.
The weather is cooler today, so I would expect to see the guage a little lower too - perhaps having a new radiator and rebuild everything inside is lovely and clean and so cools more efficiently?
How much worse is the fuel consumption? Sportier cam, and running in the rebuild will probably impact effiecintcy for a while I should think.
Lets wait to see what the experts say.
The weather is cooler today, so I would expect to see the guage a little lower too - perhaps having a new radiator and rebuild everything inside is lovely and clean and so cools more efficiently?
How much worse is the fuel consumption? Sportier cam, and running in the rebuild will probably impact effiecintcy for a while I should think.
Lets wait to see what the experts say.
To some extent it depends which cam you have fitted, but in general the wilder the cam the less tractible it will be at low rpm. Even with a standard cam you'll often find they get a bit grumpy at part throttle below 1500 rpm. On the cooling system I would guess the stat has failed or they have left it out entirely. Worth replacing it since without it you'll get prolonged warm-up times and in colder weather it may not come up to temperature at all. They're cheap enough and very easy to replace.
[quote=.Markski]
How much worse is the fuel consumption? Sportier cam, and running in the rebuild will probably impact effiecintcy for a while I should think.
quote]
Before the work was done I would get approximately 130 miles out of half a tank of petrol. Today I got 100 miles. Is it possible that if the thermostat is stuck open, the ECU will chuck more fuel in the cylinders?
How much worse is the fuel consumption? Sportier cam, and running in the rebuild will probably impact effiecintcy for a while I should think.
quote]
Before the work was done I would get approximately 130 miles out of half a tank of petrol. Today I got 100 miles. Is it possible that if the thermostat is stuck open, the ECU will chuck more fuel in the cylinders?
I'd also check the thermostat as it should be holding your temps to a proper setting and clearly isn't.
Also, just check none of the inlet manifold bolts have loosened off and various hoses connected to the plenum and throttle area are tight. Make sure the rocker covers are screwed down tightly as they can let air enter the engine which then enters the throttle area as unmetered air. You can use a torque wrench for the manifold checks set to 30 lbs/ft.
Lastly just have the timing checked, it may be retarded. Just advancing the distributor may make a noticable difference in responsiveness.
Also, just check none of the inlet manifold bolts have loosened off and various hoses connected to the plenum and throttle area are tight. Make sure the rocker covers are screwed down tightly as they can let air enter the engine which then enters the throttle area as unmetered air. You can use a torque wrench for the manifold checks set to 30 lbs/ft.
Lastly just have the timing checked, it may be retarded. Just advancing the distributor may make a noticable difference in responsiveness.
Boosted Ls1 said:
I'd also check the thermostat as it should be holding your temps to a proper setting and clearly isn't.
Also, just check none of the inlet manifold bolts have loosened off and various hoses connected to the plenum and throttle area are tight. Make sure the rocker covers are screwed down tightly as they can let air enter the engine which then enters the throttle area as unmetered air. You can use a torque wrench for the manifold checks set to 30 lbs/ft.
Lastly just have the timing checked, it may be retarded. Just advancing the distributor may make a noticable difference in responsiveness.
Thanks for that Boosted. I have checked for air leaks already though not as far as checking the bolt torques. The car is due back to the engineers in another 600 miles for an oil service and general check up so I'll will ask them to check the timing. I will change the thermostat next week , if I can get hold of one, and see what difference that will make.
Regards
Dave
>> Edited by ntel on Monday 13th September 00:06
the engine is running cool, therefore using more fuel, i would think?
if you've had the upgrade i think you have then it's an 'HC' type cam isn't it? - are these renowned (SP?) for running lumpy at low revs? or is the chip mapped for thrust rather than driveability ( i guess there may be that assumption to be made if you 'are having a fruity cam put in' )?
if you've had the upgrade i think you have then it's an 'HC' type cam isn't it? - are these renowned (SP?) for running lumpy at low revs? or is the chip mapped for thrust rather than driveability ( i guess there may be that assumption to be made if you 'are having a fruity cam put in' )?
The car went back to TVR Power for some remedial work following the re-build and the 1000 mile oil service. I got it back yesterday and they have done a fantastic job. The cam was changed for one a little less spicy, the chip was changed, and they sorted the cooling problem (thermostat) all FOC. The car is now extremely fast, like fast fast and runs very smooth. They have worked wonders. They have also set up the suspension and done numerous other little jobs. I would recommend those guys to anybody.
>> Edited by ntel on Saturday 25th September 18:53
>> Edited by ntel on Saturday 25th September 18:53
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