thinking on fuel line size

[Nacho-RT74]

My car originally is 5/16 ( 400 engine )

when I replaced the fuel sender, installed a 3/8" sender thinking on a future upgrade.

Now is an stroked 400 ( 448, being 400+.20 on 3.75" stroke )

and... I have pinging over 3.5K to 3.7K Rpms ( that is around 120 Mph or so on the highway ) OR getting the car load going up a hill.

COULD IT BE THE FUEL LINE GETTING ME A LEAN MIXTURE ?


just thought on that just a few minutes ago!!!

Otherwise the car runs great! still pinging!

[Challenger340]

What static Compression Ratio ?
What Heads ?
What Camshaft ?

I would make sure the above is patent for pump gas compatibility first, before looking for rich/lean mixture conditions as causes for pinging ?
however, yes....
mixtures can and will cause pinging.

[Nacho-RT74]

Iron 452 ported and big valves

Eddy performer intake ( yes I know but I still want the stock look under the hood ) with "jetted" TQ. Adjusted the rear bbls air valve spring to be stiffer.

CR around 10.2:1

282HDP Crower cam Installed point to point on gears

MP dist, I THINK 14* initial. I recall have adjusted 38* full advance, and allmost unnapreciable vacuum advance action ( adjusted on the hex adjuster inside )  Can't recall the springs used. Pings still with unplugged vaacum.

I began with XR5 NGK spark plugs, but now got colder, grade 7 ( was trying another option, but can't recall the PN of the NGK plugs in it now ). No change.

Rev-N-Nator module, and Firecore 250 wires... MSD 2 coil

HP manifolds

I haven't run my car in last 3 years. Its on a deep body job

which is true is this engine gets really hot the engine bay, manifolds able to fade the valve covers paint... and burn the machine gun red finish. Temp gauge normally between 1/3 and 2/3 of the scale.

exhaust fumes makes me cry!!! but that's of course iddling ( maybe too rich but just on that moment, but still lean at high revs ? ).
Spark plugs electrodes gets a bit "whitey"

[cdr]

Iron heads & 10.2 compression   

[c00nhunterjoe]

If it is a true 10.2:1 440, that cam has an ivc of 42° which makes your dynamic 9.3:1 which is too high for 93. 8.5 is about the max. You need a larger cam.

[cdr]

bigger cam is just gonna make it less streetable & it's still gonna ping under full load at a little higher rpm than before.

[c00nhunterjoe]

I beg to differ. The running engine could care less what the static compression ratio is.

[cdr]

I beg to differ. The running engine could care less what the static compression ratio is.

you can beg to differ all you want, I DONT GIVE A RATS ASS.

[1974dodgecharger]

people all they care about is static c.r. when there is more to than that....YES dynamic is just as important.  You can have a 8 to 1 static, but if that cam make it seem like 11 to 1 dynamic then yeah its not streetable at all. 

So both are important, but dyamic can be changed easier than static.  I don't know exactly where my static is maybe 9 to 1 or 8.5 to, but with blower its tough to, 'street' but luckily I have a manual also.

[b5blue]

  I would run the larger line and have a proper fuel pump pressure AND volume rating. I just swapped to Sidewinder heads after chasing ping a very long time. I tried/checked fuel mix, heat range of plugs, ignition settings...I could reduce but never eliminate ping in certain ranges/load conditions. In the end the pistons just had a bit too much for the iron heads to handle. With no other changes, just heads swap ping is gone. (Dizzy and carb untouched, nothing moved.)
  If the car was running I'd say boost octane and test. That was the only way I could eliminate ping...raising octane with additive. 

[c00nhunterjoe]

I beg to differ. The running engine could care less what the static compression ratio is.

you can beg to differ all you want, I DONT GIVE A RATS ASS.

So then you just went on the record stating that static compression ratio dictates octane requirement?

[Nacho-RT74]

95 gas octane locally, not more...

once used those octane boosters to give a try... didn't make a big difference... just A BIT better.

I have to square the deck height that will get me more consistent CR on all pistons, but will get me more compression to, however will use the larger Felpro gaskets available... larger bore and .51 thickness ( PN 1039 ). IF the machine shop makes this CORRECTLY this time, should reduce the CR maybe to 10

I have the felpro copper shims thought  ( .20" ) just in case, and regular .41" felpro gaskets too. have to play then.

( no money for cometic gaskets, or anything similar, sorry )

when engine was built, I allways though on the quench area and I really approached to, but some pistons are still a bit below the deck ( maybe 0.15 ). Rear pistons are maybe .05" above the deck. I barelly could feel the piston over.

( Sorry I had to build it on the way it was because mechanic needed the place, he was making the job allmost for free to me )

So, I though maybe the fuel line could be affecting too.

Bigger fuel lines engines didn't got bigger fuel pumps too ? and bigger line up to carb ?

[Nacho-RT74]

Fuel line size could be a reason then ?

[b5blue]

Possible but is pump high flow (Not high pressure.) also? You need both. 

[HPP]

Dual quad Hemis ran 3/8" out of the factory. Can't see that being a limiting factor on a 452 with a Thermoquad.

I'd suggest checking cylinder cranking pressure before jumping into a bunch of parts replacement.

[Nacho-RT74]

145 to 160 psi in all 8 cylinders

[Nacho-RT74]

Possible but is pump high flow (Not high pressure.) also? You need both. 

there were diff gas pumps witn diff pressure rates to different engines from assembly line?

Need to note, my gas line even never touched, seems to be flattened going around the rear frame, however doesn't seem to be smashed!

[b5blue]

THIS Pump..29 Gal. per hr. @ 5.5-6.5 PSI.

[Nacho-RT74]

But that's not stock piece or replacement... Right?

[b5blue]

  Sorry Nacho I forgot the link: http://www.manciniracing.com/ca404455tp66.html  This pump should look and work correctly and may be even cheaper @ Rockauto.
  My best advise is to do as much as possible as "correctly" as possible to eliminate worry. You can buy aluminum fuel line and make your own run from tank to pump for low cost. I did years ago, I used the old as a return for vapor separator after flushing it out. (Cost like 30.00 USD )
  For my swap from 6BBL to 4BBL I used the much more costly Mancini pump, but my situation is not the same as yours. If you know the pump rod is good, use this pump and have a nice round line you made to fit you'll at least know all this can't be the problem! 
  I'll eventually replace my "made line" but with prices today it's not cheap!

[BSB67]

I think this is what you want.

http://www.manciniracing.com/cabheen5psis.html

5/6" line is not likely your problem unless there is something wrong with it.  You do need good pressure at the carb at WOT.  I would check that before you start changing parts.

[b5blue]

That is the one I got.  He mentioned the line was kinda flattened by the axle?

[birdsandbees]

Take a kicker can from an outboard and hook it directly to your pump input.. and put all the questions to bed.

[HPP]

5/6" line is not likely your problem unless there is something wrong with it.  You do need good pressure at the carb at WOT.  I would check that before you start changing parts.

Ditto. Your cylinder pressure isn't that high. I'd certainly verify timing, dampner position, piston position, ignition advance curve and fuel mix before bolting on more parts.

[Nacho-RT74]

That is the one I got.  He mentioned the line was kinda flattened by the axle?

yes but really doesn't look to be smashed by anything... simply seems it got like that when was made