How NOT to build an economical or powerful 'teen

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RAMM

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This is a thread that may not sit well with some but it is an excellent example of a poorly chosen combo and good money thrown after bad. I had a customer bring in .04" over 318 (325) for dyno testing recently. Very nice looking engine. The customer had a huge say in the parts chosen and purchased many of them himself off the good 'ole internet. Customer also must have gleaned all of his info from the internet as well.

The engine here ran flawlessly, no smoke, no leaks, no noises, revved clean etc..

The combo: '78 318 block .040" cast flat top piston (more than likely at least .030" or more in the hole), stock turned crank, Scat I-beam rods, pressed pins, Mopar cam flat tappet hydraulic .430" .450" 110, Edelbrock LA heads, Comp Magnum steel shaft rockers--LOL, Endurashine Eddy RPM Air-Gap, QFT 600 Slayer.

Peak power of 320 hp @ 5600 340 tq @ 4000 and this was really searching for optimum timing/jetting. The HV oil pump @ 104 psi probably didn't help, and the very nice custom aluminum oil pan probably put a $500.00 dent in the budget as well.

I had some time alone with it and was able to check lifter pre-load and compression test a few holes which pumped 135-145 psi.

This is a perfect example of throwing a lot of money with very little knowledge at an engine build. J.Rob
 

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Here's a comparison of the last 318 (321) I built and tested. Similar compression. J.Rob
 

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Jezz!!! No need for aluminium 2.02 heads on any teen that isnt race bound for power in the 4000-7000 rpm range! Also the compression has to suck! Ill bet my 273 is dam close to that all day with alot cheaper well selected parts (minus the pistons, those were not cheap! Lol.
 
It's a pretty mild build besides the top end bling :)
At first seems disappointing cause of the heads but I bet dead stock 318 heads would make at least 50 hp less.

What's the top end of your engine ??

He did all that to a 318 and cheaped out on the pistons
 
There's a guy named Stan who runs a 318 in a '70 Duster at my local track. NA, all motor. He runs about 6.35 in the 8th mile consistently which means he is putting over 600hp out according to several calculators I've used. I'm pretty sure he built it himself.
 
...and that's with stepped race headers, and no accessories. At least he could write the right checks. Was he happy after your session?
 
degree the cam in right and watch the peak torque drop to 3000rpm and hp will go up a little, cam must be retarded 6 to 8 degs.
 
all in all with a small cam Edelbrocks probably don't do much more than save weight.
..still those numbers are better than a stock early higher compression 340...and i'm
betting that would be fine for a lot guys.
 
Cheaper out on slugs IMO. Even more so with the Edelbrocks on top. I think he should have taken advantage of the aluminum head with a good slug and have grabbed some quench!
The next thing is the cam. It is not taking advantage of the head. Which I do not believe is to much for the 318, but, to much for the 318 as built. Well preped iron would have been better. And cheaper. And 104psi oil pressure! Where is the jaw dropping goggle eyed smiley?!?!?!

Hey RAMM, where is the link to the other engine... If there is one?
 
Quite a list of spendy parts. The rods are not needed and with pressed pins? The heads are overkill unless the pistons are at zero deck. A nicely done set of stock teen heads with bigger valves or a pair of #302's would be great to compare. The rockers are nice but not necessary. The big pressure oil pump isn't needed for a mild street engine as well as the mega dollar pan. It would all work but you could do better with inexpensive stock parts of the right combination. It seems to be a mix-match of pieces.
 
moper said:
...and that's with stepped race headers, and no accessories. At least he could write the right checks. Was he happy after your session?
Click to expand...

Oddly enough he was happy with 300hp-ish. At least its going in a 3600lb F-body with 727, 2.91's--LOL. J.Rob
 
ir3333 said:
all in all with a small cam Edelbrocks probably don't do much more than save weight.
..still those numbers are better than a stock early higher compression 340...and i'm
betting that would be fine for a lot guys.
Click to expand...

Not really, I tested a 340 (344.5) on Monday with stock "X" heads very similar cam same intake and Eddy 600 carb and it made 364 hp and 403 ft/lbs. I was impressed with the torque. J.Rob
 
rumblefish360 said:
Cheaper out on slugs IMO. Even more so with the Edelbrocks on top. I think he should have taken advantage of the aluminum head with a good slug and have grabbed some quench!
The next thing is the cam. It is not taking advantage of the head. Which I do not believe is to much for the 318, but, to much for the 318 as built. Well preped iron would have been better. And cheaper. And 104psi oil pressure! Where is the jaw dropping goggle eyed smiley?!?!?!

Hey RAMM, where is the link to the other engine... If there is one?
Click to expand...

This is where the machine shop really needs to strongly suggest these things. Things like even a KB 318 piston and a more appropriate head. Even if the customer just has to have aluminum heads then at least mill them to suit the build. The cam is an old grind and I personally have never really seen one work all that well. There are MUCH better grinds as we all know. This cam is not all that large and yet only 7.5" vacuum was recorded @ 850-900rpm--unacceptable when evaluating the whole combo. I will say again-The 318 is VERY easy to overcame. J.Rob

p.s. The other one I covered here http://www.forabodiesonly.com/mopar/showthread.php?t=304300
 
BlueDream said:
So, you're telling me that the shiny intake manifold didn't add 40 HP?
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No, you need a fartcan muffler and a Type R sticker to go on the decklid next to the car model name, and a tattoo of Japanese words (that say Stoopid roundeye) on your neck or arms. THEN you'll get that 40 HP. :wack:
 
toolmanmike said:
Quite a list of spendy parts. The rods are not needed and with pressed pins? The heads are overkill unless the pistons are at zero deck. A nicely done set of stock teen heads with bigger valves or a pair of #302's would be great to compare. The rockers are nice but not necessary. The big pressure oil pump isn't needed for a mild street engine as well as the mega dollar pan. It would all work but you could do better with inexpensive stock parts of the right combination. It seems to be a mix-match of pieces.
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Yes the SCAT rods are just their 2-ICR40L-6125P Pro-stock rod which I didn't even know they offered. Agreed on the zero deck statement. This thing will have no trouble on the lowest octane out there. Disagree on the 302's they're crap, I tried them before and never again. The rockers while nice are so over kill and so heavy I bet a stock set of rockers would move peak power from 5500 up to 5800 and unlock about 10 more HP due to their lightweight. I have done this on a big block and even with losing ratio from a 1.6 this is what happened. The oil pump is an easy fix--install a standard volume pump and watch another 7-10 hp show up. Also I believe the customer picked up the heads on E-bag or something and did not allow the shop to check/valvejob or do anything other than bolt the heads on. This is the epitome of a mix-match of parts--hence this thread.

I'm really not trying to be negative or blow my own horn. Really just trying to share what I feel is a disaster of an engine. Reading this thread will hopefully provide others with some additional info when designing their engine.

Keep in mind this is a fresh, professionaly machined engine that really does run great and doesn't leak a drop of anything, so its not like there are other issues at play here. Its just very lacking especially when considering what it must have cost. J.Rob
 
BlueDream said:
So, you're telling me that the shiny intake manifold didn't add 40 HP?
Click to expand...

I know you are being humorous but NO I am not saying that. Surprisingly enough the Eddy RPM Air-Gap is such a good intake even for a 318. The intake and the Pertronix distributor and carb are my favorite parts. J.Rob
 
RAMM said:
Disagree on the 302's they're crap, I tried them before and never again.
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What makes the 302s crap? It was my understanding that smaller intake side increased the airflow speed, and you got better torque as a result. Just the thing I'd want on the street. Is it because they are iron instead of aluminum?

Do these 302s make me look fat? :banghead:
 
Ottmundr said:
What makes the 302s crap? It was my understanding that smaller intake side increased the airflow speed, and you got better torque as a result. Just the thing I'd want on the street. Is it because they are iron instead of aluminum?

Do these 302s make me look fat? :banghead:
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I thought the 302's might be a good idea because of the small combustion chamber. Flat tops and a closed chamber has got to be better than a flat top and open chamber especially if the piston is down from tdc. Am I close? I know the valves aren't huge and the ports small but it's a teen with a small cam. Just my take.
 
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