Torque and Clearance Specs.

[mammyjammer]

I had a  machine shop with a good reputation do the heads and build a short block for me. I put the heads and accessories on it and dropped it in my 58 Fairlane. Took a while to get it sorted out, but I got it running pretty darn good and then....it dropped a valve!! I'm guessing a keeper came off, but it does not matter as the machine shop that did the initial work closed.
A damn shame as I'm pretty sure he would have made good on my damaged engine.
Tore up one combustion chamber, bent two rods,windowed a cylinder and exploded the piston, which of course put debris in the oil and took out a laundry list of other items.
Block is sleeved, machine work is done and I think I will tackle the re assembly myself this time.
Engine is .030 over 428 10.5 to 1 , C6aer heads with C J valves, COMP Cams Dual Energy  Advertised Duration 275/285, Lift .515/.541.
Nothing radical for this group, but it is the closest thing to a race engine I have ever assembled..
I ground all the casting flash off the block, chamfered the oil holes on the crank and block, did some clean up on the
oil filter adaptor boss,threaded the oil galley plugs  and cleaned up the oil drain back holes.
 Finally the question:
For an engine like this, should I just use stock clearance and torque specs.? I have a 76 Ford truck factory manual for reference.
Any need to deviate from stock assembly procedures in the Factory manual?

[jayb]

That engine isn't radical enough to require deviation from stock clearances, in my opinion.  I'd go along with what's in the shop manual.  Good luck on the rebuild.

Not to open up old wounds, but you really should try to figure out why you dropped a valve.  Unless the keepers were the wrong ones, I doubt that they were the problem.  Do you have hydraulic lifters in the engine?  Do you have a rev limiter?  Dropped valves are almost always caused by piston to valve contact...

[mammyjammer]

Hyd lifters and  no rev limiter
I will triple check piston to valve clearance before I do anything else
You check that without the head gaskets in place?

[jayb]

No, I would definitely have the head gaskets in place when checking p-v clearance.  Make sure you use a checker spring in place of the regular valve spring or you will just compress the hydraulic lifter when you turn the engine.  Or better yet use a solid lifter in place of the hydraulic when checking.

Even if you have good piston to valve clearance, you can still get contact if the valve spring loses control of the valve or the hydraulic lifter pumps up.  At higher engines speeds hydraulic lifters have a tendency to do that.  I've seen them pump up and pop the wire retaining clips out of the top of the hydraulic lifter, and then nothing is keeping the plunger from coming way up higher than its supposed to.  In a case like that the valve could be hanging open .200" or .300" more than it should be at any point, the valve will hit the piston, the locks will pop out of the retainer, and the valve will drop.  Or, if the engine revs higher than the spring can control it, the valve will be bouncing around on the seat in the head and the same kind of thing can happen.  Ask me how I know all this 

With hydraulic lifters anytime you are past 5500 RPM you are in dangerous territory, IMO.  With the right springs and dyno or spintron testing to confirm the combination, you can go higher in engine speeds with hydraulic lifters, but its risky.  Your combination probably peaks in HP around 5000-5300 RPM, so I think a rev limiter set at 5500 or so would be a good investment.

[mammyjammer]

I had no idea lifters have the potential to fly apart!! I will put a checker spring, a solid lifter and a rev limiter on my shopping list.
How much piston to valve clearance do you like to see?

[jayb]

0.080" on the intake and 0.100" on the exhaust is pretty standard for p-v clearance.  You will probably have a lot more than that, but again if the lifters pump up or the valvespring loses control of the valve, that clearance can rapidly evaporate.

[ScotiaFE]

Sticky valve guides will also hang a valve open.
And kAPOW.

[My427stang]

I doubt you will have any issues with valve clearance with that combo.  However, check coil bind and retainer/seal/guide stack.  Even a stock Ford with stock springs can handle up to about .525, but your exhaust lift is right on the edge of things hitting a stock guide and valve seal.  Aftermarket retainers will help, aftermarket springs probably wont coil bind, but don't forget to see how close things are without the spring on the valve. 

[mammyjammer]

I have aftermarket retainers and springs. I will check guide and seal clearance.
How can I identify if I have  "Stock"  or  aftermarket guides?

[blykins]

What Ross is saying is that the stock guides are usually a lot taller than they would be if we put in new guides or if we had them machined down for clearance.  Doesn't really matter if they've been replaced or not, as long as you have sufficient retainer to guide/valve seal clearance.  If you have a set of checking springs, it's easiest to use them to see what everything looks like as you roll the engine over.  If not, you can sometimes get lucky and peer through the coils on the springs and see what it looks like.

Curious, what does the factory manual say to put the clearances at?

[mammyjammer]

...a a question on this forum I know the answer to!
Per the 76 Ford Truck factory manual:
Rod Bearings   0.0008-0.0015 desired 0 .0008-0025 allowable
Main Bearings  0.0005-0.0015 desired 0.0005-0.0025 allowable
Crankshaft end play 0.004-0.010


As far as the valve train goes..it sounds like if the retainers don't  hit the guides or the seals,I should be in good shape.
I will check piston to valve clearance again to make sure.

[blykins]

Aim for the high side of those specs and you'll be fine.  My stockish stuff gets .0025" rods and .0025-.003 mains.

Manuals like that show what can happen when you stack tolerances....you wouldn't want .0008" bearing clearances.  :-)

[bn69stang]

If you have adjustable valvetrain can you control lifter pump up better than non- adjustable  ?

[jayb]

Yes you can, by minimizing the pre-load on the lifter.   Maybe go a half turn on the pre-load.  This limits the amount that the lifter can pump up, assuming that you don't run it so hard that the spring clips pop out of the top of the lifter; if that happens there's nothing holding the plunger in the lifter body.  After I had that happen on a couple of engines I got in the habit of replacing those flimsy spring clips with normal C-clips, but its probably better just to limit the engine RPM.

[blykins]

How many times have you had that happen Jay?  That would get under my skin real quick....