Engine Power Itch , Experienced Guys Step In

[TOOLOW91]

NIKwoaC I need your cam expertise here as well

everything I had listed below was with a stock crank .


So I have my my old stuff from my motor first off the cam .

Lunati RRN1 218-228 - What do you think about this thing on the street with 3.55 gears (had stock gears when I had the motor in) ?

Pistons and rods . I have Ross racing flat top .030 over pistons and eagle H beam forged 5.400 rods . I want to order a bearing kit and a SCAT stroker crank .

With my old motor I have edlebrock performers with 2.02 valves and springs for the cam I have .

Would this combo work 331 with these heads and cam ? How would drivability be ? Should I sell the cam in favor for let's say a comp xe270?

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[TOOLOW91]

Basically I am trying not to spend money if I have the parts to do it here and only need a crank, machined block . bearings and a balance .


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[reldla1996]

If you get a stroker crank, you will need different pistons that match the stroke on your crank, so you will need new pistons as well.

 

[NIKwoaC]

Quote my post on this so I remember to come back to this later tonight. Leaving work now, no time to think.

 

[TOOLOW91]

Quote my post on this so I remember to come back to this later tonight. Leaving work now, no time to think.

will do thanks pal


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[TOOLOW91]

If you get a stroker crank, you will need different pistons that match the stroke on your crank, so you will need new pistons as well.

even if they were on a 5.400 rod just stock crank it's gonna affect the stroke enough to warrant the piston being changed ?


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[reldla1996]

The stock stroke is 3.00, and the 331 stroke is 3.25, so that means if you use pistons and rods designed for the stock stroke, the pistons will stick out of the block by roughly 0.125" with the 331 crank, which means the pistons must be changed. Sorry.....

 

[TOOLOW91]

hey no need to apologize I am here asking what is and what isn't this way I no what I have and what will be cost effective no need to spend on stuff I have


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[TOOLOW91]

The stock stroke is 3.00, and the 331 stroke is 3.25, so that means if you use pistons and rods designed for the stock stroke, the pistons will stick out of the block by roughly 0.125" with the 331 crank, which means the pistons must be changed. Sorry.....

I just re read this , I thought I explained my motor that I had had a 5.400 rod in it which is a 331 rod . that's why I want to no If it would work unless what you are saying is the skirt and pin placement is diff but I can't see how I always thought it was a .30 over piston and a 5.400 rod and 3.25 crank you would be at 331 specs


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[NIKwoaC]

What reldla1996 is getting at, is what's called piston "compression height". Compression height is the theoretical nominal distance from the center line of the wrist pin to the top of the piston. Ideally, compression height is the distance left after you subtract half of your crank stroke and your rod length from your block's deck height. SO, for a 302 with a 5.4" rod, you've got 1.5" for half of your stroke, plus 5.4= 6.9. Deck height is 8.2, so 8.2-6.9=1.3. So your current pistons are probably around 1.3" compression height (any difference is what's called "deck clearance", so if your pistons are actually 1.280, you've got .020 deck clearance or "they're .020 in the hole".)

A 331 uses a 3.25" crank, so half would be 1.625. 8.2-(1.625+5.4)=1.175, so a 1.3" piston would hang a full 1/8 of an inch outside the block, and smash into your cylinder heads.

If you're worried about budget, just build yourself a nice 331/347 with your current parts and enjoy it for what it is. Down the road, when you're ready to upgrade, look into a custom ground cam, and maybe some intake/cylinder head porting. On that topic, you didn't mention what intake you have. Exhaust?

 

[TOOLOW91]

What reldla1996 is getting at, is what's called piston "compression height". Compression height is the theoretical nominal distance from the center line of the wrist pin to the top of the piston. Ideally, compression height is the distance left after you subtract half of your crank stroke and your rod length from your block's deck height. SO, for a 302 with a 5.4" rod, you've got 1.5" for half of your stroke, plus 5.4= 6.9. Deck height is 8.2, so 8.2-6.9=1.3. So your current pistons are probably around 1.3" compression height (any difference is what's called "deck clearance", so if your pistons are actually 1.280, you've got .020 deck clearance or "they're .020 in the hole".)

A 331 uses a 3.25" crank, so half would be 1.625. 8.2-(1.625+5.4)=1.175, so a 1.3" piston would hang a full 1/8 of an inch outside the block, and smash into your cylinder heads.

If you're worried about budget, just build yourself a nice 331/347 with your current parts and enjoy it for what it is. Down the road, when you're ready to upgrade, look into a custom ground cam, and maybe some intake/cylinder head porting. On that topic, you didn't mention what intake you have. Exhaust?

Nik , I have shortys , x pipe , 2.5 all the way back in 2 chamber flow masters . intake is just a truck exp intake . so I realistically need too pick up another set of pistons . I read about compression height right before you posted thanks dude ... so what would be ideal with it all ? should I dump what I have and start fresh ?


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[NIKwoaC]

You will definitely want a bigger intake if you're going stroker.

 

[TOOLOW91]

You will definitely want a bigger intake if you're going stroker.

Figured , thanks for your help dude


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[TOOLOW91]

NIKwoaC

Brainstorm number 1000000 - What about this cam , 1.6rr with twisted wedge heads on a stock bottom end ? too much duration to even bother or is it worth a shot


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[NIKwoaC]

You could try it. I'd build a bigger engine first, though.

 

[Rick 91GT]

Why do you need a crank? Or think you need a crank? If you currently have a 331 and just need a rebuild all you'll need is proper bearings, rings and some machining.

Did you hurt the current 331?

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[TOOLOW91]

Why do you need a crank? Or think you need a crank? If you currently have a 331 and just need a rebuild all you'll need is proper bearings, rings and some machining.

Did you hurt the current 331?

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Rick the old motor I had was a stock crank , 5.400 rods , and custom Ross pistons and it broke the crank and the first journal a year ago .. i still have the rods and pistons and was trying to get away with a budget build .

The motor I bought was second hand already built and the price I couldn't pass on it but in the long run it bit me ...


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[TOOLOW91]

Motor was

Lunati RRN1 218-228
Edlebrock performers with 1.7rr
gt40 upper and lower with 24s
5.400 eagle rods
Ross pistons
stock crank (was originally told it was eagle lol )
I paid 1500 and leaned a big lesson no more second hand motors


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[Rick 91GT]

So are the pistons like 1.3" CH? Basically it was a long rod 302/306 depending on your bore.

Might be cheaper to just buy a stroker kit or stroker short block depending on exactly what rod it is.

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[TOOLOW91]

So are the pistons like 1.3" CH? Basically it was a long rod 302/306 depending on your bore.

Might be cheaper to just buy a stroker kit or stroker short block depending on exactly what rod it is.

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That's it sir ! 1.3 so useless to do anything with , block was garbage so it's gone , I was basically trying to see if. anything I had was worth while or Shojld I just start fresh


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