302 rebuild kit question

Discussion in 'Technical' started by bryson123, Jul 11, 2018.

  1. jasonwthompson

    jasonwthompson Member

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    I don't know what type of pistons you are using but with my flat tops and milled (58cc) 351W heads I have around 10:1 compression. I also use 1.7 roller tip rockers without issues, but you should measure your valve to piston clearance with the cam timing setup the way you are going to run it.
     
  2. bryson123

    bryson123 Member

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    Thanks for the info I have come to the conclusion I am going to be tossing my gasket and investing in a thinner gasket to raise compression. As for the rest of my build I wish I would have gotten different pistons so wouldn’t have to do so much work to raise conpression but it has already been balance etc but it is my first build so I am happy with it!! Everyone has been very helpful and at this point i feel it is all about trying to get more compression with this motor. If I were to mill heads down to 54cc and run a thinner gasket I think that will help a lot and maybe 1.7 rockers if able to.

    Another question of mine was since this motor won’t make as much horsepower as I wanted it to what would be another way to try to gain some lost power back through the drive Train? Also I have yet to get a transmission as the one I had lined up was a flop.

    I am going with the t5 I have the 28oz flywheel I was reading back and seeing people mention about swapping gears in the rear ended is the 3.55 the most common what is best for 0-60 but still maintaining ability to drive on highway nothing crazy!
     
  3. Hotrock

    Hotrock MCCI Member Supporting Member

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    What level of horsepower are you hoping for from this engine?

    Cam, heads and intake (CHI) are the key to any engine build. Since this thread has meandered through a list of parts as long as my arm, I can't determine which new or used parts you actually possess and those you chose not to purchase.

    Give us a list of all engine assembly parts you in fact have in your possession to include the block and it's components along with it's state of assembly plus CHI.

    Perhaps all is not lost if we can determine the level of performance you wish to achieve.

    BTW I run a 3.80 gear on the street and at the track. 3K rpm at 62 mph with a 27 inch tall tire.
     
    Last edited: Jan 10, 2019
  4. groberts101

    groberts101 Member Supporting Member

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    My meandering thoughts.

    T5 makes 3.73's seem tame on the highway.. some racier guys go even steeper than that. Tons of final drive ratio calculators on line to help you choose where you want to end up. 2,500 rpm or below at 60-70mph is pretty tame for most gearheads.

    Harder to build compression on littler motors due to less swept cylinder volume. Combustion space needs to be fairly small to hit 10.5 or better. With your pistons and the deck height likely set below 0 in current configuration a thinner cometic mls head gasket($$$) MIGHT get you just past 10:1 but you'll likely need their thinnest .027" version to be worth all the hubbub. The motor will run better, more responsive and more torque everywhere, BUT nothing drastic by anyones standards.. maybe 5-6 ft/lb average gains. Nice thing about the cometics is they are shim style gaskets that are reusable and rarely lose their crush height compared to composites.

    1.7 rockers will almost always help an undervalved/undercammed engine but geometry and pushrod clearance need to be double checked. Just be aware that as you increase ratio/rocker arc lenghts guide wear will increase due to more side valve tip/stem loading. Also keep in mind thinner head gaskets(along with head milling) combined with more lift will reduce piston to valve clearance and need to be verified. Seems doubtful you'll have clearance issues with those pistons deeper valve reliefs and a milder(by todays standards) flat tappet cam. Flat tappets have much lazier lobes than a similar(@.050") roller lobe would relay to the valves movement.

    Well back to work.. hope that helps.
     
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  5. Hotrock

    Hotrock MCCI Member Supporting Member

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    Good direction. No meandering in your post, straight and to the point!
     
  6. bryson123

    bryson123 Member

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    Yes, defiantly has been kind of a search for me on the parts I bought the how to rebuild small block ford book an trying to go by it and utilize its knowledge also. My goal would be 350rwhp but that’s a goal haha

    As for the parts I currently have:
    - 302 block bored 20 over Line bored and has factory deck height
    - factory rotating assembly balanced
    - factory connecting rods resized with arp bolts
    - arp main cap bolts
    - scratches my first set of bearings cause of the issue of not proper fitment and invested in some clevites
    - https://www.ebay.com/itm/Ford-SBF-V...sid=p2349624.m43663.l10137#vi__app-cvip-panel. ( this is the cam and lifters package separate from the rebuild kit I bought)
    - 28oz flywheel (pioneer fw-163)
    - Edelbrock Performer rpm heads (currently at machine shop Getting a valve job and new springs) have not been milled yet but soon.
    - ford racing 1.6 roller rockers
    - mellings high flow oil pump w/ arp oil pump shaft
    - stock oil pan
    - new timing cover have arp bolts for that Aswell cause old ones corroded
    - msd 8352 distributor and msd 6al controller with the msd spark plug wires
    - Hooker heads recently purchased
    - factory harmonic balancer
    - arp motor mount bolts

    Parts still needed
    - carb
    -Intake
    -Pushrods
    - waterpump
    - fuel pump
    Transmission

    The car itself
    -1972 maverick grabbed original motor clean California title no wrecks just alittle rust issues
    - covered to 4piston front disc brakes
    - magnum 500 wheels with new Dunlop tires
    - already has the clutch conversion done to it
    - new interior besides headliner
    - have 4 doors all with the glass and 2 front valences and a bouncy of other extras.
    It is torn down at the moment ready for body work and alittle primer.
     
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  7. Hotrock

    Hotrock MCCI Member Supporting Member

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    Who will be doing the final assembly of your engine?

    Your well detailed list of parts :thumbs2:, is not clear as to piston choice.

    As has been posted before, those big valve RPM heads will require pistons with proper valve reliefs, especially if you plan to mill the heads and possibly install 1.7 rocker arms.

    My choice of intake would be either a Weiand Stealth, Edelbrock RPM or Air Gap. I'm partial to the Weiand but any of the three will perform well.

    Your cam is not a very radical grind with low lift. 1.7 rockers would increase the lift value.

    As for carburetor, I run a 750 Speed Demon. From my experience and with my set-up which is close to yours, a 650 or 750 cfm carb will perform equally well. I've run both.

    I would guess your engine once completed, will deliver 350-360 hp at the flywheel.
     
  8. bryson123

    bryson123 Member

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    Thank you i am going to be doing the final assembly the whole goal of this build was to gain experience and try and do as much as possible so besides the machine shop doing the machine work I’ve done everything else. The pistons are https://www.summitracing.com/parts/slp-h273cp20 they came in the rebuild kit. Honestly the rebuild kit was a waste of money cause I’ve ended up pretty much scrapping a lot of it... ya I was leaning towards the weiand stealth intake with a Holley 650 and maybe a carb spacer or something. The transmission I have is going to be rebuilt so it will be a totally fresh setup.
     
  9. baddad457

    baddad457 Member

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    You're getting yourself mixed up here in thinking the comp ratio is going to be too low. Add 1.605 to 1.5 and 5.095 and you're at 8.2, which would put the piston tops .006 down the hole at TDC. I did the math and you're at 10.2 to 1 here with a 58 cc head and .043" gasket (Felpro 9333) Even with a 64 cc head, you're at 9.3 to 1. You run the risk with thin gaskets of losing their seal when you over heat it with aluminum heads on an iron block. Been there-done that.
     
  10. groberts101

    groberts101 Member Supporting Member

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    Those numbers are wrong and waaayyy optimistic. 4.020" bore.. 5.090" rod or likely couple thou shorter after resizing.. realistically an 8.205"ish deck height unless it was specifically squared or nipped to an exact 8.2" number.. squeezed into a 58cc chamber sealed by a 4.100" bore gasket then mixed with 8cc valve relief pistons?.. does not a 10 to 1 motor make.

    And you've obviously never used $200 stainless shim style gaskets before. This little puny cylinder pressure motor would break something well before it would even come close to hurting a gasket like that. MLS's take way more pressure than any cheap composite style gasket felpro or otherwise ever will. Which is of course why they are being utilized by racers spending the extra ching in the first place. No fire rings to fail either.

    PS. google.. diamond racing pistons compression calculator.. to have your eyes opened to the more realistic spec's based on added piston and gasket crevice volumes. Wallace racing calc's is another simpler one that still paints the truer picture.

    EDIT: http://www.diamondracing.net/tools/

    http://www.wallaceracing.com/cr_test2.php

    If the heads haven't been nipped yet I'd shoot for closer to 54 cc's(just be aware that you'll likely need shorter pushrods, maybe .050-.100" shorter, to compensate for all this lowering/shrinking of the combustion space). Assuming the piston is down the bore by around .010", a 4.030" bore gasket .027" thick will net you pretty near 10:1 SCR. The thinner smaller bore cometic gasket alone will save you 5cc's alone compared to a 4.100" bore .043" thick deal.. which equates to around 1/2 point of compression. Killing off all that excess crevice volume will also make the engine more octane tolerant and aid tuning potential.

    And I have a couple questions which should help clarify PTV clearance and final compression spec's. What size intake valve in the Edelbrock heads.. 1.90 or 2.02? And how far down the hole is the piston @TDC?
     
    Last edited: Jan 12, 2019 at 8:29 AM
  11. bryson123

    bryson123 Member

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    Those are two very good questions when I measured the pistons were .006 down in the bore measured that once fully assembled. As for the intake valve They are the 2.02 when I measured but also one thing is that I just ordered a new micrometer because the one I have seemed to do some funky things on another project so this will all be re measured when it comes. I have yet to order the pushrods cause I was gonna wait till I get them back from the machine shop then get one of those pushrod measuring tools to check for final length. They have not been milled down yet should be sometime next week. As for the thinner gasket as long as I am good with ptv clearence I would invest in one because I feel that would really help in my situation
     
  12. baddad457

    baddad457 Member

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    As for me needing to recheck my math, the OP came up with the exact .006" clearance I mentioned. So, Looks like you're off base here.
     
  13. baddad457

    baddad457 Member

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    If you're going to go forward with thin steel shim gaskets, be very careful when the operating temps climb up above 230* after you get it running. And in milling those heads be aware that you may need to open up the intake bolt holes afterwards to get the intake to fit as milling too much moves the intake bolts between one head and the other closer towards each other. This doesn't affect all intakes, but can happen. I milled my Canfields .060 for a 302 build and had to open up the holes on a Vic Jr to get it to fit, but when I put these heads on my 331, the repop 3x2 intake I went with worked fine as is. But I also used Felpro 9333's on the 331 instead of their thinner Print-O Seal head gaskets on the 302. Those thinner gaskets didn't respond well to overheating, that's why I used the 9333's on the 331. The copper coated 9333's are tough as nails when it comes to overheating, I've accidentally had the temps up in the 250-260* range more than a few times on the 331 before turning the fan on.
     
  14. bryson123

    bryson123 Member

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    as i said though i will double check those numbers because of micrometer. I am going to post a thread for my restoration on my car because i feel this thread has gotten rather long but extremely helpful cant thank everyone enough for the help.
     
  15. groberts101

    groberts101 Member Supporting Member

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    The 302 rod length is and always has been 5.090". Just moving geometry numbers around will only confuse matters and lead away from the main points needing to be made here. Let's do a visual to avoid further misinformation. Here's a fun visual tool giving slightly optimistic results due to non-inputed uncalculated true crevice volumes.

    https://www.eaglerod.com/

    Incorrect-ed numbers

    Ford 302.JPG

    Corrected and more likely scenario

    Ford 302 2.JPG

    My preference(notice the slightly thicker .030" gaskets.. https://www.summitracing.com/parts/cgt-c5511-030/overview/make/ford.. to keep the piston to head clearance in check @.036")

    Ford 302 3.JPG

    MLS style gaskets exceed composite gasket performance in every way EXCEPT cold sealing(hence the Viton coated embossments) but ESPECIALLY in hot sealing characteristics. Better long term sealing and bore stability, less head lifting and gasket failures, especially between the center cylinders. All well known and proven stuff.

    And good catch to baddad for mentioning the manifold riding higher on the heads as they move closer together during milling and shortening the gasket. Pretty trivial and easy mod to do but still one more thing to consider. IMO, those ying/yang pistons with their redundant valve relief design kinda screwed you on compression from the get-go. One of the main disadvantages of offset wrist pin entry level shelf pistons. Then installing .006" down in the hole just added more insult to injury on a relatively small 304" motor like this. Like I said before.. it is considerably more difficult to build compression on the little Fords.

    So now you get to decide how badly and to what end are you willing to spend to get the compression back up so that longer lazier cam doesn't become a complete and utter turd below about 2,200 rpm. The powerband will be narrower and the pedal will feel softer and less responsive down low. Sure it'll sound the part but sharper drivers in 6 speed automatic Honda Accords will hand you your ass if you don't run enough rear gear and/or learn how to slip a clutch to stay up on the cam and carb's boosters. Figuratively of course, lol. Sure these cars are on the lighter side but compression helps everything on a lower torque moderately cammed motor like this one.

    Here's my cars "mule motor" spec's which is intended to run 50/50 mixes of premium/E85 fuel blends. Would have gone higher but the 5cc valve reliefs are killing it. The most effective work around to increase compression much faster and cheaper is to just build a stroker in the first place but we all gotta start somewhere. LOL

    My Ford 302.JPG
     
    Last edited: Jan 12, 2019 at 3:49 PM

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