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Grain bin find "hopped up" 312

Posted By OlWeldinrig 8 Years Ago
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charliemccraney
Posted 8 Years Ago
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Maybe you can sell it or work out a trade.
It will be beyond too big for your truck if you plan to use it as a truck.
You can probably make it move your car or truck, but it won't be fun at all for street use.  Even if you could tolerate the idle and the lower rpm mannerisms, the rest of the car will not be up to the task.  If you don't have money for a cam, then you don't have the near the money to make that work.
It is a bad call if you use that in a street vehicle.



Lawrenceville, GA
Oldmics
Posted 8 Years Ago
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QUOTE
"The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked"
________________________________________________________________________________________________________

If the first two lobes were used for the measurements - then what was measured was exhaust #5 and exhaust #1.

Cant get the correct event values from that measurment position.

If that actual lift is correct (I would get out the calipers) that is a HUGE bumpstick !

Oldmics


Small block
Posted 8 Years Ago
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Oldmics (4/6/2016)

QUOTE
"The front two lobes were cleaned,I hadn't planned on goin into town so it wasn't spotless as I would have liked"
________________________________________________________________________________________________________

If the first two lobes were used for the measurements - then what was measured was exhaust #5 and exhaust #1.

Cant get the correct event values from that measurment position.

If that actual lift is correct (I would get out the calipers) that is a HUGE bumpstick !

Oldmics



Have it reground   there  are  plenty of  shops that will re do  it to your specs, About  Dean Moon He was the Guy that Shelby teamed up with to do the race engines for his Cobras!
The first cobra was  built in Deans shop!
Ted
Posted 8 Years Ago
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I agree with John in that if only the front two lobes on the camshaft were cleaned, then it sounds like only two exhaust lobes were checked.  If you do stick that camshaft back in the engine, then you can reverse engineer the actual specs yourself with a dial indicator and degree wheel.  If you send me the camshaft and simply pay the shipping both ways, I’ll check the camshaft for you.  I’m curious to the specs on that camshaft myself.
 
Grinding on the combustion chambers for the amount needed to reduce the compression ratio a significant amount is not recommended.  The heads are already prone to cracking in certain areas and grinding on the combustion chambers could just bring that to the forefront especially if your heads are the ‘unposted’ variety.
 
Composition head gaskets in lieu of steel shim head gaskets will reduce the compression ratio approximately 0.7:1 which helps a bunch.  Some rough math on a +060 312 with 10cc domes and 69 cc heads has the static compression ratio at 11.27:1.  The dynamic compression ratio with a 284° duration camshaft would be in the neighborhood of 9.24:1.  Adding the composition gaskets has the SCR at 10.56:1 and the DCR at 8.67:1.  That DCR value is still too high for premium pump gas and needs to be 8:1 or less to be safe.  Assuming the domes are 10cc, then removing 7 cc of dome would have the SCR at 9.68:1 and the DCR at 7.96:1 which would be streetable.  The simplest way to remove a known amount of dome volume is to do it by weight.  Each 2.7 grams removed from the piston tops would be 1 cc.

Lorena, Texas (South of Waco)


OlWeldinrig
Posted 8 Years Ago
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 Ted,I am sure he did the right lobes,I meant front ex/in.He said it was a single pattern cam and to tell you the truth I didn't see exactly what lobes he did his assembly room was jammed right full of engines in assembly stages and I didn't want to wander all the in being half dirty.I do fully trust him,best around here and many from out of province use him as well.
    I probably could send you the cam for further diagnosis.There is a couple very tiny pits on closing side of very back lobe that maybe I should think about and a second opinion would be apreciated.
    On the head chamber work,I was thinking mainly about some radius work across the square side opposite spark plug and the couple "bumps" either side of spark plug where the c1,c2 etc don't have them,I am betting they are solid cast in behind this.A guy could grind that area straight across possibly(spark plug side).Even polishing chamber will drop a little. I have a badly pitted G head I can grind and play with and cc to see what I can get away with.Possibly drill holes to see how much metal I have in these areas.When a 2.02 valve is used some unshrouding is needed correct?This is why I was thinking about possible chamber work.There is bound to be improvements from this.Or I could be totally wrong,thats why I am asking....
    Thanks Dave
OlWeldinrig
Posted 8 Years Ago
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  I understand what you are saying Charlie,Way to big for what I am needing.I feel like I have to at least try  run this cam.I have almost next to nothing invested in this and it literally fell into my lap.I have a couple fairly light projects it may work ok in.Probably the smartest thing to do is order some flat tops and a smaller cam but I better give this a try first...Just because.
    Dave
charliemccraney (4/6/2016)
Maybe you can sell it or work out a trade.
It will be beyond too big for your truck if you plan to use it as a truck.
You can probably make it move your car or truck, but it won't be fun at all for street use.  Even if you could tolerate the idle and the lower rpm mannerisms, the rest of the car will not be up to the task.  If you don't have money for a cam, then you don't have the near the money to make that work.
It is a bad call if you use that in a street vehicle.


OlWeldinrig
Posted 8 Years Ago
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PF Arcand (4/5/2016)
Looks like hi comp pistons alright. Before you spend money on the block, clean it up well & check for cracks, especially in the mains area. Over tightening the main bolts on 312s led to disasters sometimes.. Good luck.   


It is a Canadian block,a heavier breed,visually everything is fine but might check it out.Also rear main bolt holes are same depth and threaded to bottom.I believe that's a Canadian block only aspect.


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