What have YOU being doing or are you planning to do with your Vette?

Chuffer

CCCUK regional rep
I was not aware James had a hi lift lump cam shaft . They certainly don`t like pootling around in slow traffic , they are intended for `balls out` performance . Being an auto try manually selecting a lower gear to keep engine spiining over faster a slow road speeds .
 

HJG

CCCUK Member
Took the Goofball for its MOT the other day. If nothing else gives me an opportunity to spend an hour or so underneath the car. Worth the money just for the ease of having it in the air on a 4post ramp. All good. the sump has made some contact with something at some point so I'm thinking of fitting a guard. Any recommendations?
More of this unusual Vette, my automotive rambling and occasional beer consumption can be found at my Instagram page (1nternal_combustion)



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Chuffer

CCCUK regional rep
Took the Goofball for its MOT the other day. If nothing else gives me an opportunity to spend an hour or so underneath the car. Worth the money just for the ease of having it in the air on a 4post ramp. All good. the sump has made some contact with something at some point so I'm thinking of fitting a guard. Any recommendations?
More of this unusual Vette, my automotive rambling and occasional beer consumption can be found at my Instagram page (1nternal_combustion)



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(y). They are bit of a squeeze on an MOT lift aren`t they ? I always hold my breath driving it on , especially with a low front splitter as I approach the sliding jack . :eek:
 

HJG

CCCUK Member
(y). They are bit of a squeeze on an MOT lift aren`t they ? I always hold my breath driving it on , especially with a low front splitter as I approach the sliding jack . :eek:
They sure are. I made sure they moved that sliding jack as far forward as possible. One of the younger guys there was very puzzled by the transverse leaf spring :ROFLMAO:
 

Chuffer

CCCUK regional rep
They sure are. I made sure they moved that sliding jack as far forward as possible. One of the younger guys there was very puzzled by the transverse leaf spring :ROFLMAO:
He probably thought you had parked the horse outside and only brought the cart in ! :ROFLMAO:
 
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Roscobbc

Moderator
I was not aware James had a hi lift lump cam shaft . They certainly don`t like pootling around in slow traffic , they are intended for `balls out` performance . Being an auto try manually selecting a lower gear to keep engine spiining over faster a slow road speeds .
There are all kinds of 'high performance' cams - you'll get the 'Yee Ha' Comp Cams 'Thumper' and 'Mother Thumper' series of cams specifically designed to give that 'lumpy' old school sound. Like 'old school' cams from the 60's and 70's they simply have a a higher lift and increased duration, perhaps moving the operating zone up a thousand or so rpm higher. Issue with cams like this is that one tends to looses bottom end flexibility, especially with smaller capacity engines. A modern cam can be far more cleverly designed and low rpm lumpyness isn't always apparent. I have already asked James what cam has been fitted, what inlet the car has and whether or not it has a hi-stall converter (and its rear end ratio) once we have that info we can perhaps advise him what needs to be done (if anything).
 

Roscobbc

Moderator
Cylinder head design is the most important part of engine design. Better head design, more flow, higher velocity of that flow all means less of a need for radical camshafts. If James has good aftermarket heads and a matching cam, intake and heads it could be a formidable combination.
 

antijam

CCCUK Member
Cylinder head design is the most important part of engine design......

That's one of the reasons I like 'Hemi's'. As with any head design they have disadvantages - extra valves are a problem - but their fast burn and pressure rise give relatively good efficiency.
 

Roscobbc

Moderator
That's one of the reasons I like 'Hemi's'. As with any head design they have disadvantages - extra valves are a problem - but their fast burn and pressure rise give relatively good efficiency.
One only needs to look at period motorcycle and more significantly aero piston engine design to prove the point. So 'hemi' design combustion chambers, short direct inlet tracts, no concerns about silencing, 4 valve heads on most aero engines and 'during the war years' high octane fuels and even turbo's and nitrous.......whats not to like?
 

Chuffer

CCCUK regional rep
One only needs to look at period motorcycle and more significantly aero piston engine design to prove the point. So 'hemi' design combustion chambers, short direct inlet tracts, no concerns about silencing, 4 valve heads on most aero engines and 'during the war years' high octane fuels and even turbo's and nitrous.......whats not to like?
Love the Hemi in my Jeep , twin plugs per cylinder and variable displacement to ease the fuel consumption , smooth cruising and lairy when you want `lean on it` a bit . :D
 

Roscobbc

Moderator
Love the Hemi in my Jeep , twin plugs per cylinder and variable displacement to ease the fuel consumption , smooth cruising and lairy when you want `lean on it` a bit . :D
Chuffer - 'Variable Displacement' - does that mean that engine uses an Atkinson Cycle?
 

Chuffer

CCCUK regional rep
Chuffer - 'Variable Displacement' - does that mean that engine uses an Atkinson Cycle?
No , but I do have a mountain bike . :ROFLMAO: Seriously though , it shuts down 4 cylinders under light load until the engine management system senses the need for more power .Is that a modern variation of the Atkinson Cycle that was invented way back in time ? :unsure:
 

Roscobbc

Moderator
No , but I do have a mountain bike . :ROFLMAO: Seriously though , it shuts down 4 cylinders under light load until the engine management system senses the need for more power .Is that a modern variation of the Atkinson Cycle that was invented way back in time ? :unsure:
Kinda.......uses the theory by closing inlet valve after piston has gone past BTDC on induction stroke. Effect is of returning some of the inlet charge back in to the inlet tract (and will be used on the next induction stroke) - compression ratio is high - typically 12 or 13 to 1.
See How does an Atkinson cycle engine work? - Lexus UK Magazine
 

HJG

CCCUK Member
The Atkinson Cycle closes the intake valve late, such that it is still open for part of the compression stroke. This has the effect of reducing the compression ratio with respect to the expansion ratio, leading to greater efficiency. Good for efficiency, but not so good for power output. Used a lot in hybrid cars, where the electric part of the powertrain can compensate for the shortcomings of late intake valve closure.
 

Roscobbc

Moderator
I did 70K miles in a Lexus IS300H - it a 2.4 litre 4 banger - mainly used on M25 and London Postal -never dropped below 41/42 mpg inner city use and 44 mpg urban. Probably much the same a a similar capacity diesel - but quieter (and less smelly!)
 

Mad4slalom

CCCUK Member
Love the Hemi in my Jeep , twin plugs per cylinder and variable displacement to ease the fuel consumption , smooth cruising and lairy when you want `lean on it` a bit . :D
Variable displacement ? How does that work? Iā€™m guessing shutting off fuel and spark to a couple of cylinders. ? šŸ‘
 

Mad4slalom

CCCUK Member
If stalling when pulling away and its an auto (or manual for that matter) it'll be an insufficient 'squirt' from the accelerator pump jets - specifically the primary squirters. A tuned engine will need much more 'squirt' than a stock engine. I the carb is a generic bolt-on less expensive Holley it may run quite lean. The stalling will tend to be more noticable in cold weather. Check there's no crud blocking the jets. There should be a level of adjustability with the pump actuating mechanism. A new carb will come with several operating cams - you can choose one that either gives a smaller 'squirt' over a longer duration.......or a shorter duration, (but higher volume output). Even the one fitted can be tweaked to give a higher and quicker output. Adjust the operating lever so there is minimal clearance between it and the cam. Could be you need a 'squirter' with larger jets (more fuel to cover the 'bogging') - you'll get there from American specialists. We're not talking about huge volumes of gas here, just a few CC's - won't make any difference to fuel economy.
When mine first arrived , I was just starting it for short periods and putting it back into the shed as the registration took 6 weeks. When I finally hit the road it was a bit lumpy , very hard to tell if on 7 or 8 cylinders even when pulling leads whilst running. I raised the idle to about 950 which was too much and it would sometimes run on a bit. Gave it a set of plugs and dropped the idle and its been fine since. The other issue I had which caused a big bog down was a bit of the blue gasket from the metering block had broken off and was blocking a main jet.šŸ‘
 

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Roscobbc

Moderator
When mine first arrived , I was just starting it for short periods and putting it back into the shed as the registration took 6 weeks. When I finally hit the road it was a bit lumpy , very hard to tell if on 7 or 8 cylinders even when pulling leads whilst running. I raised the idle to about 950 which was too much and it would sometimes run on a bit. Gave it a set of plugs and dropped the idle and its been fine since. The other issue I had which caused a big bog down was a bit of the blue gasket from the metering block had broken off and was blocking a main jet.šŸ‘
I've had that issue - the Holley blue gaskets are supposed to be re-usable. I suspect if the engine isn't used for long periods and the float bowls dry out........its when they get re-filled when the engine is re-used that small pieces of the exposed blue gasket material brake off and block jets etc. My experience has been a particle 'jamming' one of the float needles causing major flooding.
 
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