The 312 pistons are .050 larger than the 292.  It would be a rare block that couldn't stand that.  Is it worth it?  If you already have the pistons, it's well worth it.  If you have to buy pistons, go to about .030 over 312 to 3.830.  That's what I do in the Hurricane, and supercharge it to sometimes 14 psi in the manifold.  No cylinder wall problems.

John

Thanks, that about what I thought. I do have a new set of 312 pistons with rings so boring would be the only big expense. I guess I'll go with that. 

Next question. Can you use an ounce scale for balancing pistons or is gram that much better? Thanks again. Chuck

The gram scale seems to be industry standard, so it must be better.  Ted will probably delete this message since he is in the balancing business, but what I use is a balance, compare pistons until I find the lightest one, then use that as a standard to lighten the other 7 to.  Do the same to the rods, small ends and total weights determined the same way.  Then I take a sample piston, pin and lock rings, rings, rod, and bearings to my machinist and have him balance the crank.  Saves me a few coins and saves him some time.  Oh yeah, the pin diameters and compression heights are the same for 292 and 312 pistons.

John

A gram scale is used because of the greater resolution.  There's approximately 28.7 grams per ounce so the amount of precision becomes greater with a gram scale versus that of an scale that measures in ounces.

          Does John mean that you think he's unbalanced? He's accused me of that! And it's possible.

                                                           Frank

John

Ssshhhh.  Don't let Ted hear this one.  I have a feeling you are leaning toward making the 312 pistons weigh the same as the 292 pistons and assembling the engine, accepting the "factory balance" as OK.  If this is your plan, I would determine the "average" 292 piston and match the 312 pistons to that one.  I kinda expect Ted to chime in here and tell us how far off factory balance really is.  Hope I didn't hurt him again.

John

The factory balance is like all the other variances within the engine as it falls within a given tolerance when performed at the factory.  Some rotating assemblies would appear to be in the ball park while others are at either end of the spectrum or range.  This is just one of the things within an engine that would explain why identical engines perform completely differently.  Those engines that are at the ends of the balancing specifications or ranges are the ones that ultimately have early wear issues and in worst case scenarios, actually have vibration issues that can be felt in normal driving.  Having an engine or rotating assembly balanced by your local machine shop falls in that blueprinting category where you're striving to get everything just 'right' and much closer than factory tolerance.

If an individual were to merely match balance the stock pistons as well as the small and big end rod weights, then that in itself would be a significant improvement regardless of the where the crankshaft balance originally was.  When making a change in the piston or connecting rod weights, then the crankshaft does need to be rebalanced accordingly.  The crankshaft is the piece of the puzzle that has to be done by some specialized equipment so it's difficult for the average garage guy to do this piece but the rods and pistons are fair game if not going overboard with the lightening process.

I trust this helps to understand more about why to balance.

One day I too will have an engine that will run! Thanks for all the help and advice, Chuck in NH

My car picked up a couple tenths in the quarter when I went from .010 to 0 deck.  I am running lower comperssion heads than you are, but also more boost.  The 113s have the big intake valves and ports, should flow better.

Balancing the rotating assembly is a good idea, as Ted recommended.  I run .020, .016, and .016 ring gaps.  I have seen evidence of the ends butting on the top ring when I tried to run them at .016.  Oil ring gaps are not critical as long as they have enough.  Space the rail gaps 180 degrees apart and they'll do fine.  Did you get your throttle kickdown linkage, carb secondaries,  and fuel pump issues fixed?  I want to see Moonshadow in the 15s this year, or better yet, in the 14s.

John

I thought the G heads were the same basic valve setup as the 113's but a small chamber? Nothing done on  the carb yet. Ted did put in the plastic floats for me last year. That was a big part of it. I find it difficult to understand why the 600CFM manual secondary dosen't work correctly. I have a vacume secondary 600CFM but I'm not sure how to boost reference the secondaries.

I've also wondered if I'm shifting past the power range. I've been going up to 5500-5800 and it could be too much.

I have given a little thought to going to Dearborn in August to the Woodward cruise. It's two weekend before Columbus. I could visit my daughter on the way out and then make a run to "Farmer Johns Racing Emporium" for a few days before the event. If you are willing that is? Chuck

I've been embarrased for too long with how the car runs! It's way too slow for what it has. Could be driver!

You typed ECG for your present heads.  Are they ECZ-G?  If so, the difference between them and the 113 are negligible.  If they are ECG-something, they will have the smaller intake valves.

Come on down after Woodward, no guarantees of making it faster, but we can try.

John

          You're going to have to put a boot around the secondary Vacuum link and then plumb a line to the air horn to make the vacuum work right. The mechanical should work without that, shouldn't need any changes. Might be something wrong. do you have enough fuel and fuel pressure yet?

                                           Frank

     The 570 should work, I think the 390's too small for your motor. The 390 is more of a V-6 or very small V-8 thing anyway.

      Let me think about how to do it, Jerry Ponder showed us how on the Teapots, but that was easier to reference than a 4160 series.

                                                           Frank 

           Wrong side of the diaphragm. The side with the link, that's now open to atmosphere, has to be closed off and referenced to the air horn.

                                               Frank

          The "post" runs through the water jacket on the flat area of the chamber toward the exhaust side. You can feel it by sticking a finger in one of the larger water jacket holes towards the valves. The object was to stregthen the deck in the flat area. Racers used to crack the head there with too much compression. make sense?  

                                     Frank

There is someone in Maine here who does most of the balancing and crank work for all the well known machine shops building engines that race at Oxford Plains speedway, epping and others around this vicinity. He is located in Augusta Maine and I had him balance a steel crank 292, .060 over, forged Ross pistons, mumert 272 cam etc, He is a nice guy that knows his stuff and he balanced everything from the damper to pressure plate. I used a truck flywheel and he lightened it for me and I bought an 11' clutch and pressure plate for a 63 406 setup which bolts to the truck 11" pattern and fits the T10 tranny spline which I will be using. I think He only charged me somewhere under $200 bucks for all this and I watched him do half of it so I know it was done right. 

His name is Jim Fortin (Auto Fabb) is his shop and his number is (207) 623-4154

Just thought I would let you know, Maybe we can hook up at a local show sometime, I usually go the Oxford show shine and drags and a few others in this area.

How many other Y-Blockers do you know in the area? I've often thought about working up a show like the Y-Block Nationals (Columbus,Ohio) for the East coast. Maybe with the All Ford meet at Eping? I'd sure like to see what is lurking in the New England area. Chuck

Oxford plains speedway is on Rt 26 in Oxford Maine, it is about as close to you as it is me. They have drags every friday night where you can bring anything you want. I went last summer to test my car but just spun the tires all the way down the track, its only an 1/8 mile strip and could not get under 15 seconds with the tire spin. I was also beat by a girl in a jeep wagoneer. It was the first time I ever run and wanted to see what the car did stock. 55 Vicky, 272 with B 4bll intake and later distributor. it drew quite a crowd from the oldtime Ford guys. I pitted next to a 52 Dodge pickup and it turned out the guy was A ford man and had a 428 ford in it. The girl I guess races there every week and went to the finals. I only ran the test and tune class so I really wasn't competing against anybody, but it was a lot of fun and I plan on doing it some more this summer as I modify my car.

I am first installing a T10 4 speed, then the 9" rear I got from a 57 edsel, then the motor I am building and see what the differences are each time I make a mod.

As for the show shine and drags it is a big event with 500 or so classics, some just show and shine around the oval track and others drag race their classics all day into the night until there is a winner. It draws many thousands of people.

As for car shows there is one every night of the summer around here with some big ones scattered throughout, some to mention are the Oxford show shine and drags, Twitchells airport in Turner Maine, Lewiston Auburn airport in Auburn Maine. and Owlhead transportation Museum which has an all Ford event which brings some nice cars out of the wood work.

Sorry for getting carried away but PM me and maybe I can send you some schedules.

Looking at the map from you it may be 1.5 to 2 hours but an easy drive, head east on 101 to 95 and up to the Gray exit, it would be at approximate mile 60, used to be exit 11, take a left on 26 and about 15 - 20 miles up is Oxford Plains Speedway on the right, you couldn't miss it.

sorry about that, I looked at my profile and nothing was in there for an address so I will put one in.