Fuel consumption

[dwomby]

Well, I am in the 8mpg club too it seems. That is based on only 87 miles of local driving though.

I am still getting to know this car. It does have a replacement engine - a 360 - and I know it has a 'hotter' cam fitted - but still, 8mpg is ridiculous. It seems even worse here because that 8mpg is per Imperial gallon and equates to only 6.4mpg per US gallon .

The carb is one of these https://www.summitracing.com/parts/sum-m08600vs apparently 600cfm. It may be too much or it may need tuning. There certainly seems to be a smell of fuel in the exhaust.

Anyway, the car is now on jacks, laid up for the summer while we escape to our summer home in Nova Scotia.

David

[peter dowdle]

Kevin the 400 motors do have different heads and you are right this motor with aluminium head different pistons and cam are very popular with the Hot Rod Boys. The biggest difference between the series one and two 383 motor is they are much higher in compression ( approx 10.2 to 1 ) as against the late 383 motors and the 400 which were about 8.3 to 1 . This leads to about 80 more rated horsepower.

[Kevin H]

Originally Posted by peter dowdle

Kevin the 400 motors do have different heads and you are right this motor with aluminium head different pistons and cam are very popular with the Hot Rod Boys. The biggest difference between the series one and two 383 motor is they are much higher in compression ( approx 10.2 to 1 ) as against the late 383 motors and the 400 which were about 8.3 to 1 . This leads to about 80 more rated horsepower.

Peter,
I should have said, it's the earlier "906 core" 383 heads that are much more free flowing. However, I have read that if the 400 heads are ported to same as the 906 core 383 heads, the 400 heads will flow just the same, so you don't have to change them!

Wish I had known that about 18 years ago when I bought a pair of 906 core 383 heads.

[Kevin H]

Originally Posted by dwomby

Anyway, the car is now on jacks, laid up for the summer while we escape to our summer home in Nova Scotia.

David, this may be stating the obvious, but if the wheels are off the ground for a long period of time, make sure you support the front suspension, otherwise you will risk destroying the rubber rebound stops.

[dwomby]

Originally Posted by Kevin H

David, this may be stating the obvious, but if the wheels are off the ground for a long period of time, make sure you support the front suspension, otherwise you will risk destroying the rubber rebound stops.

Thanks, Kevin. I didn't think of that and will ram the roll on ramps as hard as I can under the suspended front wheels. Hopefully that will stop them drooping more while the car is suspended.

David

[dwomby]

Originally Posted by Kevin H

David, this may be stating the obvious, but if the wheels are off the ground for a long period of time, make sure you support the front suspension, otherwise you will risk destroying the rubber rebound stops.

I rammed the roll-on ramps as far as I could under the front wheels. That will have to suffice but I have a question: how do others store the cars for long term? Would I have been better leaving it on its tyres but inflating them to, say, 40psi, to resist flat spots? Bear in mind, this particular car is not in winter storage. It's stored indoors at 25C to 30C for about 3 months.

Thanks

David

[David C]

My two 410s used to average about 18 to the gallon over a single tank, but most of my mileage was fairly long distance with a fair bit of motorway. If commuting across London it could drop to about 15mpg but I don't remember much worse than that. On trips to France I could do as well as 20. One had a stock cam and Carter carb. The other a slightly hotter cam and Edelbrock carb. I was enjoying my driving and not making a great effort to save fuel, but not going berserk.

[Sam410]

According to my app, my 410 has averaged 16.7 mpg (calculated tank by tank) over the last 35,000 miles. High is around 22mpg, achievable if I sit at a steady 70-80mph on the motorway for the whole tank. (I have sometimes filled up from empty three times in a day if travelling long distances.) Low was 7.7 mpg, achieved by filling up in east London one Friday afternoon and after taking well over two hours to get across town I filled up again in west London, just out of interest to see how low the mpg could go.

The overall average reflects quite a lot of short journeys, as I frequently use the car locally, but also my lead footed driving style. The engine is the 318, but was slightly overbored in a 1990s rebuild, and I think it has a slightly hotter camshaft than standard. Gearbox is standard 3-speed.

[PEU186F]

17mpg sounds about right for a 410 on the standard transmission. My experience being that it doesn’t vary much whatever the circumstances.. Be aware that the needle valves on the standard carb do wear over time resulting in overfilled float chambers and an over rich mixture - hesitation on pick up when hot in traffic is one symptom of this issue

[dwomby]

Clearly I need to investigate why my consumption is so high when I get back to the car in October.

David