stock head cc 1984 318 M body 2bbl

Engines, Exhaust and Fuel Systems

  1. 84Furyus

    84Furyus Well-Known Member

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    Looking for info. I have an 84 Fury 318 2bbl and was trying to find out what the combination chamber cc is on stock heads.
     
  2. Aspen500

    Aspen500 Well-Known Member

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    It should be 63-65 cc's. It will vary a bit due to production tolerance. I believe the official size is 65cc.
     
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  3. SixBanger

    SixBanger Well-Known Member

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    I would say that the combustion chamber for a 318 1984 with an CR of 8.6:1 (2) would be around 68 - 72cc (3).

    85.5 Cc calculated total. With the volume of deck height-piston ( .056'' (1)) for 11 cc. Gasket ( .033" (1)) 6.5 cc. The resulting volume in the cylinder head would be in the direction of 68 cc.

    Cr=(Vh+Vc)/Vc = (651cc+85.5)/85.5 = 8.6 ish.

    Vh volume only one cylinder and Vc total compressed volume

    318 Engine Specifications (1)
    318 Are my pistons too deep in the hole............... - Moparchat - Home of MOPAR enthusiasts worldwide! (2)
    http://www.darkside.ca/node/131 (3)
     
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  4. SixBanger

    SixBanger Well-Known Member

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    I did not see that aspen had already responded.
     
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  5. SixBanger

    SixBanger Well-Known Member

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    Funny. I used the darkside website once as a source for a thesis. Nowhere could we get concrete data from the 8-71 and 16-71 superchargers. The name, darkside, does not come across as scientific. But the production tolerance also varies considerably with these products.
     
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  6. 84Furyus

    84Furyus Well-Known Member

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    My googling around has left me thinking that you could RIP open 3x 318 engines all "the same" and have 3 radically different compression ratios.
    I've seen piston can be 0.2 to 0.8 below deck at tdc and where there's as much as 8cc difference in combustion chambers on the same heads.
    Only thing I see that seems to stay is that most everything says flat top with 4 valve reliefs
     
  7. XfbodyX

    XfbodyX Well-Known Member

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    I have some nos mopar heads in these years and a good round figure is 68-69-70. If you were use after market nail head valves you could get 2ccs back.

    There are several different compression heights on the in the hole 318 pistons so thats why you get your wide range, there low comp then there is the stupid low comp.

    There are flat top teener pistons (the super low comp) and then the 4 valve relief.

    1.672 and 1.739 is two comp heights that are Flat and 1.759 with the reliefs.

    A zero deck piston they sell would be 1.81 and still might be .010 in the hole.

    What are you actually trying to do? Ive tons of new 318 parts, pistons, rods, cams, machined dippy roller block, ect... alot of roller parts id love to dump some of it.
     
    Last edited: Dec 30, 2018
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  8. 84Furyus

    84Furyus Well-Known Member

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    I'm trying to plan my engine hop up and was trying to figure out what I'm starting with.
    There's the possibility I may toss a turbo on it down the road so I'm not trying to get high compression.
    I'm thinking about trying to locate 308 casting heads and using a "RV" cam (basically the same as a performer) I already have an aluminum 4bbl intake, 1406 carb, new dizzy and coil setting on my shelf. Depending on final compression that should be 300hp +/-.
    Honestly I'd love to get my hands on more parts but around here most guys wont let go of their stash and those that will think a factory intake is worth $100-$200
     
  9. XfbodyX

    XfbodyX Well-Known Member

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    Ive some nice low comp 1.76 comp height .030 forged pistons that would be great for a turbo or spray.

    Another option is if your limited to a oem compression height piston, a good cheat is a offset ground crank 3.450 or 3.455 which puts a smog piston at zero deck but ya gotta watch cam lift.

    Ive also a few oem 4 bbl intakes I cant give away.

    If youd like to step up to a dippy like roller motor ive a machined block, new mopar heads that I cant seem to give them away either.

    Look at page 5 and 6 here. 350 Hp 318?

    Here is the machined roller block ready to build and brand new mopar heads.... Ive new mopar roller lifters, spyders, dog bones,... Id dump all for $500 or better and just the bore, hone and hot tank was close to $300.

    1.JPG

    2.JPG
     
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  10. XfbodyX

    XfbodyX Well-Known Member

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    What ever you do look on ebay for the type of cam you mentioned, there is one seller who has great deals on cam, lifter and springs and they are elgin products.

    If you look at the elgin master list some of the good cams are on amazon for under $75.

    Elgin makes good parts for what were doing.
     
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  11. 84Furyus

    84Furyus Well-Known Member

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    Thanks. I'm trying to be very budget minded on this as I've way over spent in the past and also built engines that were not as street friendly as they needed to be.

    My little 318 runs great but has a serious lack of power (130hp I think it was rated whis is the same as the 2.2L in the Cavalier I was driving for a while) and being one with a hotrod devil on my shoulder i need my car to scoot.
    Hoping to get right around 300hp (that's a power level i know works great in this size of car for my liking) and still keep it a very street friendly setup.

    I did find the cam grind i want with lifters & valve springs for $155 shipped
     
  12. XfbodyX

    XfbodyX Well-Known Member

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    The Mr Gasket .028-s are about as budget friendly as they come for the think head gaskets.

    1121G
     
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  13. 84Furyus

    84Furyus Well-Known Member

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    I was looking at those yesterday.

    I was trying to figure out what my compression would be like with stock pistons, thin head gaskets and the 308 casting heads.
     
  14. XfbodyX

    XfbodyX Well-Known Member

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    Use the wallace calculators to get your comp and figure both static and dynamic as you should have your cam events.

    At the price you listed id think you got the elgin type parts kit or maybe enginequest, but id hope elgin over EQ.

    But you should be able to find your cam events on here if its a elgin https://www.carid.com/images/elgin/items/pdf/elgin-product-catalog.pdf
     
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  15. 84Furyus

    84Furyus Well-Known Member

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    Was using a calculator but with such up in the air specs it's hard to calculate the compression. Iirc the range was anywhere from 7.6:1 up to 8.4:1
     
  16. Oldiron440

    Oldiron440 Well-Known Member

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    You guys get up early!:)
     
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  17. 84Furyus

    84Furyus Well-Known Member

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    3 days a week I'm up way too early but the rest of the week not so much.
     
  18. Aspen500

    Aspen500 Well-Known Member

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    I quoted the "official" head cc spec. As mentioned, a stock head could vary by quite a bit due to production tolerance, how far the valves sit down in the seats, etc.
    I get up by 5am every morning, no matter what the day. Not by choice, I just wake up no matter what. Downside is, I have a hard time staying awake past 9pm, or past 6pm this time of year, when it's pitch black by 4:30pm.
     
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  19. 84Furyus

    84Furyus Well-Known Member

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    You have any idea the official cc on 308 casting heads?
     
  20. Opticon77

    Opticon77 Well-Known Member

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    Note: If you are actually serious about a turbo you are going to want to think about how you intend to fuel it now. AND the pistons you're sticking in it.

    Scenario 1: MPFI with forged pistons and ethanol blends? You'll have enough accuracy and resistance to preignition for decent boost levels near 10:1 base compression. Expensive.

    Scenario 2: A sloppy blow thru carb and stockish hypereutectic pistons on clear gasoline? Better just throw on some 360 heads, tank your base compression, run it rich, and use a good intercooler for insurance. Cheap... at least until you melt the pistons a few times.
     
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