1968 Colony Park 482

[My427stang]

   Off an on for about a decade,  I've been wanting to buy a dial bore gauge. Maybe now is the time. As far as dial bore gauges, is everyone dead set on a .0001" increment or is .0005" usable for this application?

   Just thinking of options, lets say the pistons are too loose in the bore. What is the course of action? Go up to the next bore size? What is the next bore size from 4.250? Or is there such a thing as pistons available in 4.250+.001 over size?

  Tomorrow after work I will get this engine the rest of the way apart. Also I will see if my big micrometer set has standards with it.  If not, MSC deliveries come next day.

If the pistons are loose, you can buy custom pistons in any size you want.  The fix depends on the issue, if the bore is crooked, hone with a deck plate and buy pistons to match.  IRacetec, Diamond, they can get you exactly what you need.   For instance, the Diamonds in my Mustang are .047 over. 

Just a little CnC programming nowadays, and yes, even in .001 increments, but be sure you know what that bore does loaded, because it does change

A good inexpensive bore gauge like the Fowler at .0005 will work fine.  They can be a little clumsy, but once you get the hang of it, they are very repeatable.

[My427stang]

http://www.us.mahle.com/media/usa/motorsports/fe-inverted-dome-web.jpg

    Why is it the 482 piston #930264550 calls for .0041-.0049 when the other pistons call for .0025-.0033.
 

Bigger slug must grow a bit more. .004 is still pretty tight

[FirstEliminator]

Hey Ross,
      Still coming to Massachusetts?

[blykins]

In one of your other posts, didn't you say you could slip a .006" feeler gauge in between a skirt and a cylinder?

I have ran 4.375-4.400" 4032 pistons at .003-.0035" clearance, so I don't think it's a size issue, unless Mahle mislabeled the material in their chart.

Pistons are made for the bore size, with the clearance built in.   Have you did a quick check on the bore yet?  Calipers aren't the best tool for that either, but you could get an idea if the bore is way big.

[My427stang]

Hey Ross,
      Still coming to Massachusetts?

Maybe in the spring, had a funeral planned that pushed off until then.  When I do, I will give you a yell, would love to see what is inside your engine, but timing likely won't work out if you are jumping in over the winter

[6667fan]

Mark, I did not take a look at Mahle's piston line but the material in the other ones you referenced may be a different alloy with different expansion values?

Keep attacking, April's coming.

JB

[FirstEliminator]

Found a nice dial bore gauge on ebay and won the auction. It does measure to tenths---.0001. Plus, a set of standards to verify my mics is on the way from MSC.  Hopefully within a week I should know exact measurements.

[FirstEliminator]

Of all the engines I've put together, I can't say I remember seeing rod bearings offset with a step. The step doesn't appear to be touching the crank journal radius or protruding on the rod side either. So it's probably a non-issue.  The bearing surface probably is. Until the bore gauges arrive, I can't get an accurate measurement on the bearing I.D. I've used a telescoping gauge on other ID, but feel the bearing material is too soft and telescoping gauges aren't repetitively accurate below a couple thousands. Several attempts with the T gauge seems to average out to about .003, which is the upper limit in my Ford service manual. Plus the way the rod bearings look and the one I bolted on the crank seem loose on the journal. It seems like the noise is predominantly loose rid bearings. More and accurate measuring will further reveal deficiencies.
 https://youtu.be/-nVNCAiA-Qs

[Barry_R]

What rod bearings are those?  Should be a part number stamped on back.  That step is usually because they used two "uppers" or "lowers" in a rod assembly - a significant error, and one that's easy to make.  If it does not touch the crank it won't really hurt anything, as you surmised.  But in my experience they do touch the crank journal radius fairly often if installed wrong.

[FirstEliminator]

Thanks Barry.  1-4 were all lowers and 5-8 were all uppers.   Is it possible this would cause noise or accelerated wear that then caused noise the noise in the video?

   

[blykins]

Stock Ford bearings don't have uppers/lowers, but most of the BBC/performance bearings will be labeled U/L. 

Even when I know I have the uppers/lowers in the right spots, I always set a rod or a cap on the crank (and also check the crank in the mains with the caps off) and make sure the radius on the crank clears the bearing.  Even if a bearing touches just a little bit, it will get hot and can push bearing material into the center of the bearing. 

In your picture, the bearing half is sticking out past the chamfer in the rod.  Quite possible it was rubbing real hard. 

Did that bearing pair spin?  It doesn't look like the bearing half joints line up with the parting line on the cap/rod.

[FirstEliminator]

Hi Brent,
   None of the bearings were spun except the ones that few across the shop in a perfect spiral like from Joe Namath about 5 minutes ago.

   Kidding.

  None of the bearings spun. Not exactly sure where the parting line ended up without reassembling a cap.

     Well, it's good to find something. 

  thank you.

[FirstEliminator]

One of the dial bore gauges arrived Saturday. I went over to the shop and fooled around with it a bit. The head was not bolted on and neither was a torque plate. The bores were oval by about .001--.0015.  i'd suspect a torque plate was used during machining which is why the bore has moved a bit. It's an eye opener using a bore gauge, as it's hard to imagine a big block of cast iron can flex at all

[FirstEliminator]

Today I ordered the parts necessary to reassemble the 482. I should have it back together sometime in the next decade......hopefully the first half.

[Towd56]

Hope to see it at the reunion Mark.