1968 Colony Park 482

[6667fan]

Mark, email me your address. I’ll get a spacer headed out. If you don’t end up needing it I’ll get it back later, np.
jwysocki@charter.net

[FirstEliminator]

Assembly has started this evening. The crank is installed in the block and the caps torqued to 105. Cross bolts to 40. I verified the 2-3 mic with a set of standards. It is right on when using the clicker. I measured the #1 rod journal and got 2.1993". Then assembled the #1 rod with new bearings. Also, I had set the dial bore gauge to zero in the mic. Then measured the bearing in the rod. It comes up with .0032 measured 90° from the parting line. Looking in the 1970 Ford Engine manual, it says .0015-.0025 for CJ with .003 max allowed. Rods #2 is .0034 and #3 is .0033.  This is the first time I am using the dial bore gauge and not sure if I am doing it right. But, things are coming up consistently. Remembering I have the Reher-Morrison Championship Engine Building book I found the procedure and I was doing it correctly. Also, I realized I have Chevy rods and RH recommends rod bearing clearance at .003- 004". I am right in spec according to RH. But, this is not a race engine. It's a street engine. So, either this is good and put it together. Or, I might look into some .001 under bearings to get a little closer to the Ford spec. I am leaning towards undersized bearings. 
     Thank you,
         Mark

[blykins]

Mark, for a BBC rod journal size with a good quality rod, I like to see about .0022-.0025" on the rod bearing clearances.  I would throw a set of .001" bearings in there. 

[My427stang]

Mark, for a BBC rod journal size with a good quality rod, I like to see about .0022-.0025" on the rod bearing clearances.  I would throw a set of .001" bearings in there.

Mark, this is very good advice, not that I need to back up Brent, but been flight following this one for a while

You cannot use the Ford spec for the rods as the journal is smaller, and for the street, you don't want a loose rod hammering away, especially since you have been chasing noises in the past.  Even then, that RM spec looks awful loose to me except some very violent applications.......the easy answer is to move the decimal point from your measurement on any bearing in that engine, mains too.  So 2.20 = .022, then if you have to wiggle, a little more clearance is better, third decimal point though, not second.  Exactly what Brent pointed out

Keep in mind, also good math for your mains, not sure where those ended up

[FirstEliminator]

Thanks Brent. Thanks Ross, that is a good rule of thumb on moving the decimal. The 1 under bearing should put me right  where I need to be. 
  I did not measure the mains as those bearings looked good when it was disassembled. Rear main seal and all the cross bolts are in. Am i being lazy and shooting my foot by not checking? Would plastigage be sufficient to check the front bearing?

[blykins]

Thanks Brent. Thanks Ross, that is a good rule of thumb on moving the decimal. The 1 under bearing should put me right  where I need to be. 
  I did not measure the mains as those bearings looked good when it was disassembled. Rear main seal and all the cross bolts are in. Am i being lazy and shooting my foot by not checking? Would plastigage be sufficient to check the front bearing?

I wouldn't trust on plastigage and even though it's a pain in the booty, I'd check the mains.  New bearings can be different than old bearings, surprisingly different.

[Barry_R]

I normally subscribe to the .001" per inch of journal diameter idea for clearance.  I often add a little to rod journals, with a target of perhaps .0025 +/-.0002

I might swing a half shell in there to snug those up - but although its not optimum, a bearing at .0033 aint likely to hurt you.  Odds ar that the mains are fine - but if you pull a cap or two off and take a picture we can get a pretty good idea just how "happy" they are

[blykins]

I normally subscribe to the .001" per inch of journal diameter idea for clearance.  I often add a little to rod journals, with a target of perhaps .0025 +/-.0002

I might swing a half shell in there to snug those up - but although its not optimum, a bearing at .0033 aint likely to hurt you.  Odds ar that the mains are fine - but if you pull a cap or two off and take a picture we can get a pretty good idea just how "happy" they are

Agreed, I run a lot of stock journal rod bearing clearances at .003-.0035" without issue.   

I think if I were wanting to dial this one in though, and had the time to do it, I'd sling some different bearings in.

[FirstEliminator]

A set of 8-7200CH1 are coming over night from Summit with a few other odds and ends I need.  Maybe I will pull the crank as an ounce of prevention is worth a pound of cure.

[FirstEliminator]

I was feeling lazy, but guilted myself into pulling the crank and setting up the bearings in the mains. The oil clearance in the mains is #1 .0013, #2 .0014, #3 .0013, #4 .0014, #5 .0022  I thought about getting a set of 1-under mains to use one for the #5. But, not in stock, I would not see them until February.  The spec in the 1970 Ford manual says allowable for 390, 428CJ is .0008 to .002. Then I noticed for 428 Police the allowable is .0005- .0025.  Again, Reher-Morrison says .003-.004. Also, this is within the "moving the decimal" guideline as the main journal measured 2.7484 and the clearance is .0022.

    The .001 tighter rod bearing will be here tomorrow. Plans for tomorrow night are to get the shortblock together and the heads bolts on.  The intake needs a bit of clean-up, but that will be pretty soon.  Assembly puts the engine in it's most condensed form. Right now there are parts all over one of my trans building benches at work.  Shouldn't be long before this is back in the Colony Park.

     Glad I took time to measure the mains. I feel good about them and it eliminates future questions. 

   Thanks for all the help so far.

[blykins]

Do not assemble that engine with barely over .001” main bearing clearance, and stay away from shop manuals from the 60’s lol....

I aim for main bearing clearances at around .0025-.003, ideally around .0027-.0028.

If you are confident with your measurements, you need to do something about those clearances, either with some “X” Cleveland bearings, some careful crank polishing, or a combo of both.

[Barry_R]

Have to agree - those are the kind of clearances we target on aluminum block engines.  Too snug for iron block stuff.

[My427stang]

Mark, I am with the guys on this.  2 caveats

1 - Are you really sure on your measurements, room temp tools and block etc?  No crud in the bearing tabs, no oil behind the bearings, etc?

2 - The "move the decimal" wasn't a max, it's closer to a minimum.  I'd be looking for .0025 min but might live with #5 if I had a repeatable measurement for a mostly low RPM build.  Old books don't really work, you need some oil for doubling the HP the mains see as well as making room for tolerance stack, slight main misalignment, etc.  .001 just isn't enough for that

I'd be really careful on a remeasure and consider opening things up

[FirstEliminator]

Ugh, pretty soon I am going to need helicolis for these bolt holes.

[My427stang]

Ugh, pretty soon I am going to need helicolis for these bolt holes.

That's funny...