Cletus' '68 Plymouth post car

[Bearded Baldy]

Have you tried going to a PV that opens earlier, and put a piece of safety tie wire through the PV ports in the metering plate. Can work wonders sometimes. 

Bit of reading here explains it better than i can.

https://www.aussiespeedshop.com/carb-tuning-help/

 

[RUNAMUCK]

^^ that odd, cos all the books I've read say to open those up for more gas. 

Theres a new carb released by edlebrock (apparently Holley are getting out of carbs all together) which is in the Holley style, and has removable jets in the power valve orifaces. 

Rule of thumb is to pick a number half your idle vacuum figure. 

[cletus]

Yeah it had a 6.5 in it , I put a 3.5 in yesterday and it does seem to be better

The carb has had a few mods for blow thru, the pv chamber has been boost referenced. It was done by a guy in Australia a while back who specialized in blow thru carbs. At the time I just bolted it on but this time I've been trying to figure out why he did what he did, and how it works

 

there's an external vac line from the throttle plate with a check valve , to a t piece.

The t piece goes to the pv chamber 

Off the other part of the t piece is a small tap with a small hole, and a tiny one. This goes to the hat on top of the carb

 

I *think* it works like this

Idle, low load cruise, the vac is enough to keep the pv shut even though there's a 'leak' through the little tap

As it starts to make boost the positive pressure overcomes any vacuum (this is where it gets funky as there can be a vacuum under the carb but pressure above it. This can mess with the pv because the fuel bowl gets pressure as that is vented to the hat which creates a pressure difference between the 2 sides of the pv 

Getting the balance of various vacuum and boost leaks to go in the right places at the right times seems to be the key 

 

I know efi would be better and more efficient but I'm a derp and like the simplicity 

 

[cletus]

I don't have a super clear pic but you can see the hoses on the side of the carb here

[RUNAMUCK]

^interesting.

Mine I just ran the line from the throttle plate to the manifold well after the carb. I used a 2, (or 2.5? I dont recall exactly) inch of vacuum PV. (It was the lowest number you can buy)  this must have had the weakest spring, meaning it could be held shut by only 2 inches.  I only had to breath on the throttle, and my vacuum dropped to zero. (In most cases it was near impossible to accelerate without making at least some boost) but at cruise, it was defo closed. (Which made it fucking amazing on gas on a long run. (Compared to the 32/36 it replaced) 

 

[RUNAMUCK]

Is that port on the block the vacuum advance feed nipple?

[cletus]

One is vacuum and the other is ported vacuum I believe 

It's in the 'has vacuum all the time' hole  

[RUNAMUCK]

Venturing vacuum vs manifold vacuum 

[slopez]

Hiya, Saw this on the weekend at Morrinsville, looks awesome, you've done a great job on it.

[cletus]

Thanks! 

Pretty good turnout considering the weather, there was some cool cars there  

[Bling]

Do you watch the Skid Factory? Their latest video was dealing with a turbo 1UZ, not sure if any of that can transfer across to your setup or not. That had pretty hefty cooling in it but it still got too hot. Just thought i'd mention it in case you don't watch them anyway. It might give you some ideas. I know the setup is pretty different, but perhaps something will cross over and help if cooling becomes a problem down the road.

Cars looking gooood, gotta be happy to have it on the road.

 

 

 

[RXFORD]

Is the alt one that can wizz over either way? If not is it spinning the correct way?

Does it have a decent earth to block? Paint on engine mount might be an issue? 

[sheepers]

its Nick's fault.

i dont know how but its Nick's fault. 

[BlownCorona]

11 hours ago, RXFORD said:

Is the alt one that can wizz over either way? If not is it spinning the correct way?

Does it have a decent earth to block? Paint on engine mount might be an issue? 

this was my first thought too. heaps of alternators have the belt kinda do like a reverse loop around them to get max wrap/traction, but then the pully spins reverse to the crank. 



edit - bonus points for random internet diagram including a blower.  thats the problem Clint, you need to install a supercharger for it to charge. its all in the name, always has been!

[Tele29]

So do you reckon it was a bad batch of cable or something?

[cletus]

Must be. It's not new cable, I got given a lot of welding cable many years ago, I think this is the third car I've done with it 

The cable isn't damaged or squashed or anything so it must just be bung inside

[KKtrips]

Stupid question, does it need an exciter wire?

[cletus]

Yes, it has one , in which I have tried 1w, 3w, and 5w bulbs

Also has a battery sense wire which runs all the way to the battery on a separate wire

[mjrstar]

I wonder if it's a winding issue which is only apparent when belt tension is applied. I'm assuming the bench test is driven directly on the front..

[Bearded Baldy]

Stupid question. If it works on the bench but not the car, have you tried testing it with the revs up at  2.5k ish. 

Could be something stupid like the pulley size is too big, so at idle speeds it spins too slow.