Did or will the 200k mile block clean up at .030" over?

Thought most strokers are balanced at 28oz.
Usually 50oz is the option and costs more and has more drag due to the holes drilled out.

Gotta ask...just wondering

Nos681 wrote:

Thought most strokers are balanced at 28oz.
Usually 50oz is the option and costs more and has more drag due to the holes drilled out.

Gotta ask...just wondering

I saw their $250 option for 28oz. Gonna have to call because most of them, if not all, are 28 oz. 

Check out DSS for a bottom end kit too.  They have good prices and great quality stuff.

I would advise against domed pistons.  I'd rather mill the heads than run domes.  They increase compression, but they suck for flame front travel.  If you look at modern engines one of the major areas of improvement in is piston/chamber design.  Even Dodge's Hemi isn't really a true Hemi anymore, because they don't want to have to run a domed piston.  They've clipped the corners of the chamber for quench areas and brought the chamber dome
WAY down to where its by no means truly hemispherical anymore, and still it gets terrible fuel mileage compared to the GM LS or Ford offerings.

Best efficiency is achieved by a dished piston and a near flat chamber.  Not practical with conventional parts, so stick to a flat top and small chamber.  I had no issue getting 10.7:1 with the right gasket, AFR heads, and a flat top piston. 

Watch the low drag rings.  If they need a vacuum pump to seat them properly I'd pass.  The Mahle pistons/rings are a great combo.  I run them in my 383.  I bet the block cleans up just fine at 0.030" over.  Most 5.0s don't show much wear, even at 200k thanks to EFI.  Some guys just say hone it and go, but if you're serious about power and longevity bore it.  You start fresh and ring seal in terms of power is everything. 

The balance is a question, my 331 is a 28oz. imbalance.  Most are from what I've seen.  Internal balance is not worth it.  I'm going to second avoiding a lightweight flywheel.  They are a chore to drive, more so with an aggressive clutch. 

The AFRs I run are also 58cc chambers (these cc'd out at 56ccs BTW).  Zero deck height, a 0.040" thick compressed Cometic MLS gasket, and two valve relief pistons (-6cc) has me at 10.65:1 compression.  Those are 185s, but if you are looking more in the 5,000-5,500 max RPM range you could go with a smaller head like a 165-175.  I plan to spin north of 6,0000. 

Scat parts went into the second motor. They have a good reputation. I would balance it to whatever flywheel and harmonic balancer you have already.

If you have a preference about how the rotating assembly gets balanced, ask the question. Some drill holes in the counter weights. Others turn the counter weights down. I would have the block looked at to make sure it will clean up at .030 before I buy a kit with pistons.

They spec a compression ratio for the piston, but you will need to ask them the combustion chamber size that make that stated CR valid. Compare it to what your looking at. Wallace racing has a good CR calculator where you fill in the values if what they offer doesn’t match what you’re intending to use for heads.


What type of fuel injection system you going to install or am I thinking of a different thread!!!

Good luck with the build.

Take the block to the machine shop before ordering the kit.  Have them tell you if a 0.030" over bore will work.  If it needs more than that the block is junk anyway.  Some can be bored a little more, but the 5.0 is a thin wall casting.  I would not go past 0.030" without having it sonic checked for thickness, and the cost of doing that may make buying another block a better option. 

If you want to mess around with compression ratios just use this calculator:

http://www.csgnetwork.com/compcalc.html

I will caution that you don't want a compressed HG thickness of less than 0.038" if the pistons are at zero deck (flush with the deck surface at TDC).  That's your quench distance and you risk a piston smacking the head at less than 0.038".  BUT, you don't really want a lot more than that either.  Quench creates efficiency, which builds power. 

On the balance I wouldn't go trying to reinvent the wheel.  There's no power in it.  If its designed to balance out at 28 oz. imbalance then run the correct damper/flywheel for it.  Sometimes the manufacturers have moved the counterweights around to improve balance.  The parts are designed to work together at a specific balance.  Trying to change it is going to cost money.  A typical balance job is going to be about $150 without heavy metal or a lot of machining.  Don't let anyone talk you into shaving weight off the flywheel/balancer to achieve some bastard balance number.  That becomes a mess if you ever have to replace either part. 

A final word of caution, I would not have the assembly balanced by the company you buy it from, unless you also buy a damper and flywheel from them.  The machine shops I've used have always wanted the balancer and flywheel I was running to complete the balance job.  I know, all 28 oz. imbalance parts should be the same, but its not worth the risk IMO. 

50vert wrote:

I'm tempted to put a 331 in my original bore 30K engine ... then I can put 327 badges on it like MS's 427 badges. 

That is what I would really like to do, but with 200,000 miles on the engine I imagine the block needs to be bored.

The reason just a hone isn't ideal is that a hone isn't going to true the cylinders.  All it does is smooth out what's already there.  In 200K miles the block has moved around and "seasoned".  That's good; it means its now a stable platform on which to build.  A Corvette restorer and racer I knew growing up used to say using a new block as the basis for an engine wasn't really that great, even aftermarket blocks which were super expensive back then.  Instead, he'd build a mule motor out of a new block and let it season in his tow truck for 50k miles.  By then, under those conditions it had taken a set and was now ready to be machined into a winning engine.

0.020 or 0.030 are both going to require boring.  Honing only removes about 0.005" of material.  You can try to only go 0.020" now in the thoughts that you may get another rebuild out of it, but if it needs another 0.020" at that time its probably going to be junk anyway.  Again, I would ask your machinist what he thinks and go with his recommendation.  I went into my 331 with the same thoughts, and my machinist told me 0.030" over gave me the best possible ring seal with no risk that we didn't cut it enough.  Remember, 0.030" seems like a lot, but you're really only removing 0.015" from the face of the walls. 

As far as decking, you're going to need a mockup to tell how much you need to cut the decks.  A 5.0 usually only needs at most a skim cut to be at zero deck.  SBCs are always like 0.020" down in the hole, but Fords just aren't.

6sally6 is totally right on the dished piston setup, and I was interested in doing it, but couldn't find a head with a small enough chamber to allow it to work with commonly available parts.  Dished pistons are meant for blown engines running 8.5:1 compression  You need a 45cc chamber to make it work with a common 18cc dished piston, and that's still not really ideal, you want a deeper dish and a smaller chamber (like 30-35cc) to really get the most out of it.  I remember an engine Joe Sherman built for Engine Masters years ago, which won, that was like that.  BUT it was Joe Sherman, he had the skills needed to modify the parts and the cash to have the others made.  Dished pistons, welded up and remachined chambers, longer valves, etc.  Super cool, but impractical for guys like us.  Plus, the farther you get away from standard parts the longer the engine is down if anything ever breaks.  Guys who race stuff like this have spares to prevent that.  Most of us are lucky to have enough cash to buy the parts for one engine, let alone a second one.  If an engine so built made another 20HP its in no way worth the tradeoffs.  If you're worried you might need more power gap the top rings a little heavy and spray it.  You'll get another 100-150HP for $650.  I've done this with two engines and have been quite happy with the first one, and expect to be with the second one. 

MS wrote:

I built Warley’s 331 (actually 327, not bored out) using a kit from Jeg’s, very reasonable under $1,000.  I prefer to let a local shop do final balance, so why pay for it with a kit?
I can send you the spreadsheet on his engine if you email me.

Last I heard he was real happy with it. I drove it and it would easily break ‘em loose in second gear.

What pistons did you use?

Please explain your “test” criteria again about the cam selection.

After a conversation with Crane's tech department I went with their cam #449631.  Also on a 112 degree LSA.  Stated operating RPM is 2,500-6,000RPM.  Its got a bit more duration (282/290), lift is .542/.563 with a 1.6:1 rocker.

A little heavier car (Fox body GT) with EFI and all power accessories, AC, manual trans, and 3.73 rear gear.  Target HP is 425-450.  Its also good for a plate nitrous engine, which I may add at some point. 

I'm a big believer in letting the cam company select the cam.  I'm also a big fan of Crane. 

Torque is definitely king on the street, but like most things you can have too much.  Consider that a stroker is already going to make considerably more low end torque than a stock size engine.  The difference between a 289/302 and a 331 is going to be about 50lbs/ft all things being equal.  You then use the cam to determine where you'd like to make that power.

Rear gear ratio is also important.  If you're already running a 3.50ish gearset I would tend to move the torque peak, and therefore HP, up in the RPM range a bit.  Small engines need all that gear.  Big engines not as much, but you can use the gear to get it through the lower RPM where there isn't traction and into the RPM where there is quickly. 

Point is, torque is great, and good street engines need a lot of it, but there's a line where you've turned the accelerator into a tire spin pedal and the car would rather break the tires loose than accelerate.  That kind of power is just as unusable as an engine that makes max power at an RPM it never sees on the street.  So my advice would be consider how the car behaves now under hard acceleration and think about what another 25% does at various conditions.  A little spin where it catches and takes off now probably becomes spinning so hard you have to let off to get it to catch.  A little bark of the tires on a gear change might now push the car sideways. 

Interesting the 86 still came with a fuel pump eccentric, but one that is thinner and not viable as an actual part to run a fuel pump.  I have seen those before, on an 86 5.0 I bought.