Is my 318 broken? UPDATE, and the answer is NO!

[chargd72]

Ok guys, I finally have my car to the point to where I can turn the key and drive around the neighborhood.  The problem is that the car is a freakin dud!  I didn't go crazy with the engine build but did enough to make it have a little 'go'.  

Here is what I did:
- Sealed power pistons
- 340 resto cam with matching springs (new lifters)
- Cast 302 heads (closed chamber) with home port job but added larger 1.88 intake & 1.60 exhaust valves
- Air Gap manifold
- HVH tapered spacer
- Eddy 600cfm 4bbl
- Headman headers w/ h-pipe and dynomax exhaust

Here is what I didn't do:
- change out my 2.73 gears because I'm looking for an 8 3/4 full axle swap
- still have stock torque converter

I know the gears and converter are killing some power, but if these were behind a stock '72 low compression 318 I don't see how it could move the car at all (based on how slow it is will all the mods).  Also, is the 340 resto cam supposed to be that hard to get to idle?  I can't get it under 1000rpm without it stalling.  Maybe a vacuum leak?    

I wasn't expecting to be the fastest small block out there, I've just heard a lot of people say they've made some fairly potent 318s.  What am I missing?

[Cooter]

Ok guys,  What am I missing?

Someone to tune it....

[Troy]

I'm no mechanic but at least I'll try to help. What's your timing set at? Do you have a vacuum gauge? If so, what's the vacuum at idle. That 600 may be ok for the engine the way you've built it but those Edelbrocks are almost always too rich at idle (even with the screws all the way in) and lean at WOT. I don't know how much more power you have than stock but the converter probably isn't nearly as harmful as the gears. I wouldn't touch either until you get the engine running right. I've had several 318s with 2.76 gears and all would spin the tires easily. The worst was the only one with a 4bbl. Too much carb on that one I think.

Troy

[chargd72]

Someone to tune it....

Thanks, very helpful.

I'm no mechanic but at least I'll try to help. What's your timing set at? Do you have a vacuum gauge? If so, what's the vacuum at idle. That 600 may be ok for the engine the way you've built it but those Edelbrocks are almost always too rich at idle (even with the screws all the way in) and lean at WOT. I don't know how much more power you have than stock but the converter probably isn't nearly as harmful as the gears. I wouldn't touch either until you get the engine running right. I've had several 318s with 2.76 gears and all would spin the tires easily. The worst was the only one with a 4bbl. Too much carb on that one I think.

Troy

Thanks, Troy.

The timing WAS set at 34* at 3,000 rpm.  I say was because I set the timing with a 750 carb on it and assume changing the carb wouldn't mess with the timing, right?  I don't have a vacuum gauge but it looks like that will be the direction I need to go.  What should my vacuum at idle be?

[1BAD68]

I've had several 318s with 2.76 gears and all would spin the tires easily.

you mean spin the tire (singular) right?
My 318 stock with a Edelbrock 600 and 340 cam would not spin the tires on dry pavement with a sure grip and 3:55's

[RallyeMike]

318 and 273 gears in a B-body? Prepare to be dissapointed even after its sorted out.

If the timing is really at 34 and it wont idle under 1000 you have a problem to find: Double check and set total timing at 36. Double check firing order. Make sure you are using the correct port for vacuum advance. Look for a vacuum leak at the carb base and anywhere else you can think of..

[Troy]

With your idle so high it is likely that the carb is not running solely on the idle circuit. Does it smell rich? There's no point in adjusting the carb until you can get the idle sorted. If it has a choke, is it set properly? Can you spot (or hear) any vacuum leaks?

If those check out, start with the timing. Some people say small blocks like a lot of initial timing - which can throw off the total timing number (depending on the mechanical advance of the distributor). If your initial timing is not advanced enough the engine will run poorly. Timing and carb tuning are unrelated mechanically (replacing a carb won't change timing) but they have to work together for the engine to run correctly.

You can use the vacuum gauge *instead of* - or along with - the timing light to dial in the engine. It's really handy once you start adjusting the carb. Since you've changed parts it's hard to say what the vacuum should be. You basically tune for the highest vacuum at idle (this will make sure you have brakes too!). My last 318 would pull about 22 in/hg. It was mostly stock except for the 4bbl carb and intake. Most of my 440s are between 12 and 18.

Advance the timing and see if the idle increases. Keep advancing until it stumbles then back off a couple degrees. If you leave it on the ragged edge you can guarantee detonation (pinging) the second you take it for a drive. Make a note of the timing here. Reset your idle and see what you've got. Try to get it down to about 900 RPM.

Make sure the vacuum gauge is plugged into a manifold vacuum source. On the Edelbrock this is the port at the base on the right side (looking into the engine bay). The other side should be going to your distributor's vacuum advance. Plug that one for the time being.

I had written a few paragraphs on carb tuning but this article explains it better:
http://www.fordmuscle.com/archives/2005/08/EdelbrockCarburetor/

When you have it idling well, check the timing at 3,000 RPM to see how much mechanical advance you're getting. I think you want about 36 degrees total(?). The difference between what your engine is happy with at idle and 36 is what your mechanical advance should be set to. My last distributor was adding 20 degrees mechanical in but my engine liked 24 degrees at idle so my total timing was way too high!

I've had several 318s with 2.76 gears and all would spin the tires easily.

you mean spin the tire (singular) right?
My 318 stock with a Edelbrock 600 and 340 cam would not spin the tires on dry pavement with a sure grip and 3:55's

You're assuming that no one would ever have a Sure-Grip with 2.76 gears. That's a bad assumption... My high school 68 Charger had a 318 with a giant 2bbl (some big Carter that circle track racers preferred) and headers. The rear end was a 2.76 SureGrip. I could spin the tires if I mashed it but preferred to "launch" and shift into 2nd gear somewhere past 60 mph. The 70 Challenger that I had at the same time was a bone stock 318 auto with 2.76 gears and it would spin a tire at will. No Sure-Grip there! It had skinnier tires and was actually a pain to drive. My 73 Barracuda had a (presumably stock internally) 318 with a later 4bbl intake and Edelbrock 600 carb. It definitely didn't have a Sure-Grip but it also had a huge bog off the line. It took a LOT of work to get that one to spin any tire. I later put 2.55s on back and that made it even worse. The poor performance likely also had something to do with the lower power output of the motor in the first place (post 72).

Troy

[chargd72]

Excellent write up, Troy.  Thanks a ton!  Looks like I have plenty of things to check.  I will get started this weekend and let you guys know if I make any good progress.  I hope to get this sorted out quickly.

[74calicharger]

I had a similar problem when I had to rebuild my 318 some years ago. my engine guy put the biggest cam in it possible to still pass smog (CA sucks like that). it wasnt too big though. 214/224 @.50 . just a step up from the edelbrock power package size i believe. anyway, after the rebuild and install it wouldnt idle. turns out the distributor needed to be rebuilt. something about the springs being too weak. i replaced it with an MSD billet my buddy had and it ran great. then after it became smog exempt i swapped a 625 carter on and it would loose like 500 rpm from nuetral to drive or reverse. that turned out to be the converter. swapped in a 10 or 11in. mopar hi po factory style converter and fixed that problem. not sure if this helps but its what i had to deal with. and yes a 318 in a 74 charger with 3.55s and 30" tall tires will spin the tires

[Plumcrazy]

If you're talking hardware.

Edelbrock 2176 manifold
More gearing, 3.23 at least and maybe a different converter.  If you're running a 904, consider the low ratio gearset.
Not familiar with the HVH spacer but you want to keep the dual plane intake divided up to the carb for the best low end grunt.

[FLG]

Do whats stated above, but honestly...

Grab this

http://austin.craigslist.org/pts/3010029374.html


Get a cheap 727 (could find a good used one for 50-100$ and rebuild it yourself)

And you will be happy.

Ive driven a stock 318 charger and was thankful i never had to deal with that misery.

[chargd72]

Thanks for the suggestions guys.  I fired it up and did the 'less efficient' vacuum test with some good 'ol carb cleaner and didn't find anything.  Advance was out of vacuum testers so still need to to get one.  Checked the timing again and holy crap it was way off.  At idle I was at around 30*.  Don't know how I wasn't getting any pinging.  Dialed it back to 10* at idle and about 33* at 3,000rpm.  It helped a lot especially in the higher rpms but still no tire squeaker.  I don't see how I can get much more out of it even if I can do some vacuum tuning.  This engine only needs to hold me over until I finish the bodywork, interior and get some paint but if anyone has any other advice to pep this one up I'll take it.  Long term plans are a 408 stroker, 727 w/ manual valve body with a 8 3/4 rear with 3.55.  But that doesn't start until the rest of the car is done.  

Frank, that short block does look nice.  Especially for the price...

[Scaregrabber]

Stock convertor, 2.76 gears, 318. It just isn't going to be a torque monster. Just keep it tuned up and it will be a reliable driver.

Sheldon

[Chryco Psycho]

try disconnecting the vacuum advance , you get more initial timing & still have around 36* @ 3000 rpm .,Loosen the plates above the metering rods & see if the rods stay down at idle in gear , if not you need lighter springs under the rods .

[chargd72]

try disconnecting the vacuum advance , you get more initial timing & still have around 36* @ 3000 rpm .,Loosen the plates above the metering rods & see if the rods stay down at idle in gear , if not you need lighter springs under the rods .

Vacuum advance is always plugged.  I've read enough testimonies from Ron's followers suggesting to keep it plugged full time.  I will try the metering rod thing.  I haven't heard that one before.  Care to educate me what exactly that does?

[chargd72]

I was previously running my old points system which had new points, a new rotor and new (cheap) plug wires.  I just upgraded to a Mallory HyFire 6a box, Promaster coil, Unilite Dizzy and 8mm SideWinder plug wires and holy crap what a difference.  I know most will say that upgraded ignitions system mostly gives you reliability but there is a huge difference in power.  With my stock converter and 2.73 grandma gears, my 318 can now lay some rubber.  Acceleration and throttle response have increased tenfold as well.  Maybe the mechanics in the old dizzy were shot but I'm very happy with the power increase due to the upgrade.  Once I find a 8.75 rear with 3.23-3.55s it will be a fun little package.  

[elacruze]

Try connecting the vacuum advance to a manifold source instead of carb source. This allows much more idle timing without changing off-idle timing.

[Chryco Psycho]

Vacuum holds the metering rods down , they act like a power valve allowing more fuel under load so if the vacuum is low they will rise up

[Paul G]

I was previously running my old points system which had new points, a new rotor and new (cheap) plug wires.  I just upgraded to a Mallory HyFire 6a box, Promaster coil, Unilite Dizzy and 8mm SideWinder plug wires and holy crap what a difference.  I know most will say that upgraded ignitions system mostly gives you reliability but there is a huge difference in power.  With my stock converter and 2.73 grandma gears, my 318 can now lay some rubber.  Acceleration and throttle response have increased tenfold as well.  Maybe the mechanics in the old dizzy were shot but I'm very happy with the power increase due to the upgrade.  Once I find a 8.75 rear with 3.23-3.55s it will be a fun little package. 

I would atribute most of the power gains here to a good working ignition coil. Probably makes the car much more fun to drive.