weber carb

Why would you run flat tops

Some of the older mopar cars that ran the 2.6 had a lil hemi badge on em.

Here is why:

There are dished pistons, dome pistons and flat top pistons. Dished Pistons or notched pistons have a little notch or dish (looks like half a pie and 1/8 to 3/16" deep) on the top of the piston. This increases burn volume but does not improve flame travel or compression.These are very commonon in stock builds etc. Domed pistons are a favorite choice as these improve compression but do not get an even burn reducing the flame travel. Flat top pistons increase your compression, increase your flame travel resulting in a even powerful burn across the entire top of the piston.You get a better flow i.e. quench with flat top pistons. Most of your forged performance pistons are domed and flat top.

Quench Defined:

The quench area is the flat part of the piston that would contact a similar part of the head if you had .000 assembled quench height. In a running engine, the .040 quench height decreases to a close collision between the piston and the cylinder head. The shock wave from the near collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, averages the chamber temperature, reduces detonation and increases power.

Some great info there!

I have a 38/38 and am just about to have the head off to fix a suspected damaged valve. Are there any off the shelf camshafts available for the 2.0? Is it worth giving the head a skim to eek a little more power (I'm on a pretty limited budget)?

Is the MSD 6a essential or can I get away with just a uprated coil? Its a lot more expensive over here in the UK!

When you have the head off it is worth your money to have it checked by a machine shop for fine cracks and fractures. You may want to have the head flow tested as well and make sure it is not warped.

Clearly, the more flow you have through the head the more power you will make...You don't want your intake or exhaust to be a bottleneck. Think of a straw. It has good flow from in to out. If you pinch the straw in the middle your flow decreases - make sense? Intake = sucking in large volume....that volume moves through head with no bottlenecks and that volume now in the form of exhaust leaves the motor with the same velocity.

If your head comes away with a clean bill of health from your machinist, have him do a mild port and polish. Have the intake port matched to the head. If you have a header, have that port matched to the head. If you are running the stock manifold, have that port matched.

You can get a cam grind for your 2.0. There is no off the shelf CAM you can buy for the G52B and G54B. Buy a cold hardened CAM and get it grinded to one of the 3 grinds.

1. .272 - 435 duration
2. .282 - 435 duration
3. .292 - 435 duration

The cost here is very minimal. I paid $95 for my new cam with a #2 grind.

You can get your head work and intake work done for probably a few hundred bucks - maybe less depending on machinist. With you new cam and valves remember to adjust your valves clearances accordingly. With this work and that 38, you will make some good power.

I do not have any experience with just upgrading a coil on these trucks ignition systems. I have always installed the full MSD system. I imagine you will get more spark with a BLASTER 2 coil but when compared to stock coil ?????. Sorry.

so, where's the install DIY on here? got my carb on, she starts and idles up to redline it seems. I read on the sheet there's supposed to be some idle control solenoid.. but no pics of it in my book or instructions.

bringing this post back to life for some final questions. with the carter 40/70 electric fuel pump, what do i need to do to plug the hole where the mechanical fuel pump went? or did you guys just disconect the fuel lines and call it good? also runing a 32/36 would a mild cam be a decent upgrade or is it not even worth trying?

thanks guys!

If you were a glutton for punishment you could remove the fuel pump and remove the pump pushrod and put the pump body back in place.......

While I am here~ I've recently did a valve job on a little '85 ram50 I bought. Non running truck.
It had a burnt valve. Rebuilt head is reinstalled.

Put everthing back together- all timing marks dialed in with new belts and all.

Engine just doesn't want to run. I suspect the Mikuni carb is junk. There is no choke plate in the throat, for one thing. When I do try to start it, if I squirt gas in the throat and choke it with my hand it will sputter and run just a bit, but it won't respond to the throttle.

Stock fuel pump puts out pressure when I pull hose and crank engine.

I read thru the above posts and it makes me wonder how cheap I can get a replacement carburetor for this thing. I see the Weber listed for over $300, and that's a bit much I think.

thats what i said when i first saw the price but its worth it. i think so atleast. ask around and see what you can find. i also heard that holley makes one to fit but knowing holley thats probably going to be more expensive. you might be able to find some guys on this forum selling one that they have laying around. like i said, just ask around. and if you do go with one, go with the electric fuel pump as suggested.

I'm late to the party and this thread is very helpful!
I have an 85 D50 w/ G63B mt...a/c ripped out. I dumped the Mukuni and bought a Weber...and that was my question---
WILL IT RUN WITH ALL THE VACUUM LINES GONE?

I have an electric fuel pump, dumped the canister/return/gastank (doing a spun aluminumtank). It seems that most vacuum lines were for a/c and stuff. My plan is to completely remove everything .....but where should I take the 1 line for the carb and the 1 line for the distributor???????

Also the manual fuel pump is garbage. I don't really wanna yank it, gut it and replace it. Even though it is cam driven, is it logical to remove it and afix a plate (to cover the hole)??
Thanks-Pork