1970 Mk III hot engine, hard to start

[sasilverbullet]

Originally Posted By: artificialist
Originally Posted By: SteveSRT8

While I would agree that a Holley is easier to tune I think your post implies that an Edelbrock/Quadrajet style carb cannot make high horsepower. Definitely not true.

I thought an Edelbrock carb was more like a Carter AFB than either a Holley carb or a Q-jet.

But I'm not sure because I hardly ever encounter an engine that doesn't have EFI.


Yes, Edelbrock is the same basic design as the Carter.

 

[sasilverbullet]

Fixed! Thanks all for the inputs. I put a Holley heat shield on and it seems to have fixed the heat soak problem. Car starts up MUCH better!

Here's a few pics of the heat shield and the engine:
links to engine pics

Temps after a 25 minute hot soak were 30 degrees colder than without the shield! (on the carb, was 180, now 150)

 

[andyd]

X2 Heat soaked ignition parts don't help. Early Ford electronics were none too sturdy.

 

[SteveSRT8]

Originally Posted By: sasilverbullet
Originally Posted By: artificialist
Originally Posted By: SteveSRT8

While I would agree that a Holley is easier to tune I think your post implies that an Edelbrock/Quadrajet style carb cannot make high horsepower. Definitely not true.

I thought an Edelbrock carb was more like a Carter AFB than either a Holley carb or a Q-jet.

But I'm not sure because I hardly ever encounter an engine that doesn't have EFI.


Yes, Edelbrock is the same basic design as the Carter.


Of course it is. But the basic idea of constant velocity through vacuum secondary control and precision, smaller primaries is why I lump them together. These three designs are very complex and difficult for folks who are not familiar with them to tune.

Holleys are simplistic, even they offer vacuum secondaries, but their primary fueling isn't nearly as precise nor is their driveabilty (once set up right) as good IMO.

Street cars can be about more than just HP numbers...

 

[Volvohead]

Originally Posted By: andyd
X2 Heat soaked ignition parts don't help. Early Ford electronics were none too sturdy.

In 1970? Just about everything outside the radio was still electro-mechanical. Even the standard regulator then was still a contact point design. The Marks might have had the optional electronic one, but that was pretty hardy. I think the OP added some aftermarket ignition bits, and they could have issues, but who knows.

I still don't know if the OP even fixed his advance problem, so it's hard to intelligently diagnose these other issues on top of it.

I agree with SteveSRT8 on the carb sizing. On a street car, going too large causes all sorts of tuning and driveability issues.

 

[sasilverbullet]

Originally Posted By: Volvohead
Originally Posted By: andyd
X2 Heat soaked ignition parts don't help. Early Ford electronics were none too sturdy.

In 1970? Just about everything outside the radio was still electro-mechanical. Even the standard regulator then was still a contact point design. The Marks might have had the optional electronic one, but that was pretty hardy. I think the OP added some aftermarket ignition bits, and they could have issues, but who knows.

I still don't know if the OP even fixed his advance problem, so it's hard to intelligently diagnose these other issues on top of it.

I agree with SteveSRT8 on the carb sizing. On a street car, going too large causes all sorts of tuning and driveability issues.


Yes, advance problem is fixed. I installed a adjustable one and tweaked it some. No more pinging.

 

[fpracha]

Originally Posted By: sasilverbullet
Car starts and runs great except when hot and sits for 15 min or so. Starting it takes quite a few cranks and when it fires, it seems to be running on two cylinders. I have to baby the gas pedal and get the rpm up to about 2500 for about 5 secs, then it runs fine.

what fuel are you using ?
do you change stations or fillup at same at every fillup ?

 

[Colt45ws]

Originally Posted By: fpracha
Originally Posted By: sasilverbullet
Car starts and runs great except when hot and sits for 15 min or so. Starting it takes quite a few cranks and when it fires, it seems to be running on two cylinders. I have to baby the gas pedal and get the rpm up to about 2500 for about 5 secs, then it runs fine.

what fuel are you using ?
do you change stations or fillup at same at every fillup ?

This post is several months old and he sold the car.
Just fyi.