700 double pumper on a road car

Mick · Post by **Mick** » Mon Aug 18, 14 11:21 pm

Yeah we checked the idle in gear and i maxed it out, it was around 8-9" of vacuum.

GJUK · Post by **GJUK** » Mon Aug 18, 14 11:42 pm

MilesnMiles wrote:Can you just borrow a carb from somone local? has Mick got a simple 600vs knocking about. At least that way you could eliminate the carb before diving into the ignition etc..
I'm sure that carb is a wrong un.

My friend rebuilt the carb, he really has a great understanding for these and I know the carb itself is put together right now. Not sure on the settings as this is what im finding tricky...

Mick got the car running well, just this very funny rough running issue when you go on the gas. It's got to be over fueling.

Jon

Mick · Post by **Mick** » Mon Aug 18, 14 11:49 pm

Miles i'm fresh out of carbs except for a 1050 dominator.
If it's over fueling though Jon, why isn't it fouling the plugs. Put a breaker bar on the crank bolt with the dist cap off and turn the bolt and see how far it turns before the dist shaft moves, if the play is excessive, the timing gear might be worn, especially if it's the original timing set.
I'm assuming the motor is low comp and it's got a relatively big hyd in it, so maybe to get it to idle it will need the throttle blades drilling.
Mick

GJUK · Post by **GJUK** » Mon Aug 18, 14 11:59 pm

Cheers Mick.

Pete · Post by **Pete** » Tue Aug 19, 14 7:16 am

If the car needs more air at idel try cracking the secondaries open if you can - it is better than drilling the throttle blades - they are hard to un-drill

Pete · Post by **Pete** » Tue Aug 19, 14 7:33 am

If you have been through the carb and timing then it is starting to sound like a mis-match of parts (including potentially the convertor).

I think Mick is probably right regarding timing backlash - the standard 400s have a sintered Iron timing sprocket that wears badly.

When I dismantled a stock 400, I could almost lift the timing chain off without removing the sprockets.....

I also think that people lob "performance" cams into un-modified engines (low CR, small Port size, etc) and expect them to become monsters, but it does not happen due to the large duration / overlap.........it is like a stock engine but worse.........

Mick · Post by **Mick** » Tue Aug 19, 14 8:17 am

I dont confess to having all the answers, it's just a case of perseverence. If it was my car, i'd just keep trying different things but when it's someone elses 15 miles away you spend 3 or 4 hrs on it and try and test a lot of the obvious things. As soon as i got home, i'm thinking why didn't i try this or that, things i forgot to do.
Mick

Pete · Post by **Pete** » Tue Aug 19, 14 8:20 am

I think you do yourself a dis-service, Mick.

You are very knowledgeable, give good advice, and have got fantastic performance out of your combo in the Dart.

is the Key........

Dave-R · Post by **Dave-R** » Tue Aug 19, 14 8:48 am

Mick it's bloody murder trying to sort a car away from home. I hate doing it. That's why I try to insist people bring their cars to me so I can have them for a week. That way I can bottom out any issues.

Pet is right about cracking open the secondaries a bit instead of drilling holes. I keep forgetting you can do that on a Holley 4bbl.

Dave-R · Post by **Dave-R** » Tue Aug 19, 14 8:50 am

But it is easy to re-fill holes in throttle blades. I just open them to the size of some thin brass brazing rod I have and use it to form a rivet.

Les Szabo · Post by **Les Szabo** » Tue Aug 19, 14 9:28 am

Pete wrote:If you have been through the carb and timing then it is starting to sound like a mis-match of parts (including potentially the convertor).

I think Mick is probably right regarding timing backlash - the standard 400s have a sintered Iron timing sprocket that wears badly.

When I dismantled a stock 400, I could almost lift the timing chain off without removing the sprockets.....

I also think that people lob "performance" cams into un-modified engines (low CR, small Port size, etc) and expect them to become monsters, but it does not happen due to the large duration / overlap.........it is like a stock engine but worse.........

Mick · Post by **Mick** » Tue Aug 19, 14 9:35 am

This is the cam in the car.

http://www.summitracing.com/int/parts/c ... make/dodge

Les Szabo · Post by **Les Szabo** » Tue Aug 19, 14 9:50 am

get him to spend some money on the right parts Mick, either go the stock route or street/strip way as he seems happy with those 4.10's?....but you ain't gonna do much with a 7.9:1CR? motor though....at least you got the cam

Mick · Post by **Mick** » Tue Aug 19, 14 10:07 am

When it's running right it doesn't feel too bad, i think there's an issue somewhere other than the match of parts, assuming the pistons are stock. We drove 3 or 4 miles winding it up through the gears and it revved cleanly and idled fine, it just seemed to break down at low revs after that. Maybe if Jon opens the transfer slot on the secondaries and backs off the idle screw to a square again it may sort it.
Jon has had the distributor to pieces and the plate from turnip wouldn't fit but he also said it had light springs in there already, whether the slots have been altered i'm not sure.
If you're reading this Jon, watch this.
Mick

Dave-R · Post by **Dave-R** » Tue Aug 19, 14 10:48 am

Mick wrote:This is the cam in the car.

http://www.summitracing.com/int/parts/c ... make/dodge

I am guessing you would need 160lbs of cylinder pressure to run that cam.