Intake valve to cylinder wall clearance method?

[69427]

I want to do some measurements to make sure I've got sufficient clearance (whatever that number is) between the intake valve and the top of the bore. The intake valves are 2.25". The current engine in the car has 2.19 intakes, but I put that engine together about 10 years ago, and didn't think about measuring that clearance parameter at the time.
Given that the valves are tilted in a BB head, what's a good method to do this? Also, how much does the valve diameter grow as it hits operating temperature? I can check the valve material and look up its expansion specs, but I don't know what is a realistic temperature to use for the calculation.

Thoughts and advice?

thanks,
Mike

 

[TimAT]

SOme heads have 2.30 valves and I've never seen anything about them hitting the wall. I'm thinking that with bore sizes at 4.00 and above it's not an issue.

That would be another set the head on with no bolts and drop a valve. If it falls into the cylinder, no hit. If it drops a little bit and stops, that's a bad thing.

 

[69427]

Valve to piston clearance testing at the moment

Well, I put some modeling clay on a piston, and then just pushed an intake valve down into it to get an impression. It looks like I'm squeezing by on radial clearance (valve edge to piston valve relief) in this quick test, but I'm trying to get things ready to try it again with the cam in. Right now I can't get the damn damper off the old engine (which stops progress on a lot of fronts). I've cranked down on the puller, but I don't seem to be making much progress. What annoys me is I can still see the antisieze in the parting line between the damper and the crank, so nothing should be seized together.
So, any advice this evening before I go try again tomorrow?

thanks,
Mike

 

[69427]

Some positive progress, and some retreat. After a boatload of work, I finally got the damn harmonic damper off the old engine. Don't know why it was such a tight SOB, but I'm glad it's off. This lets me start taking the cam and sprocket stuff out. In addition to transplanting the cam into the new engine, I need to get the cam sprocket machined a bit on the back side to allow clearance for the (block protector) roller bearings.
I'm not totally comfortable with the piston to valve clearance I've got with the 2.25" intakes. The clearance pocket in the dome is just a bit too tight on the outer edge near the cylinder wall. So, I'm going to put these heads back in the box, and transplant the heads off the old engine. The 2.19" valves in the old heads should give me enough radial clearance to let me sleep at night. I'll either sell the (new) 2.25" heads, or see if they'll fit on the old engine. The old engine has about a point lower compression, so there might be a bit more clearance for these valves.
Another item I'm trying to decide what to do concerns the lifters. I'm reusing the cam, but I don't know if the minute difference in the machining (angle) of the lifter bores will cause issues with the wear patterns on the cam and lifters. The setup is a Crane cam and lifters, and ordinarily I'd just give their Tech line a call and ask about this issue, but I guess that's not an option anymore. Well, I guess I've still got some time yet to figure out what I'm going to do with this. My default option is to just pony up for some new lifters, and hopefully mixing cam and lifter brands will not be an problem.

 

[mrvette]

:shocking: You all going to get a kick outta this shit.....back some 35? years ago before I knew any better..... I took a cam/lifters outta a '67 goat, and put them into a Lemans with 350 engine....never kept the lifters in order at all....

stuck a chain on it, and guess what?? with the '67 400 heads also on that short block, it ran another 200k miles....true story....

so go figger, at about the 300k mark the oil pump ran up the red flag and said nevermore...car did another bunch of miles in city traffic with the red flag flying, :shocking::ill::beer:

 

[JAKE]

Back in the day (and since I'm 65 that was a LOT of days ago) when I was playing with BBs I use to install a cylinder head with a couple of head bolts. Then flip the engine upside down on the stand and measure from the oil pan end. Light springs made it easy.

Another thing I use to routinely do is increase the valve relief bevels in the block. My thinking was to help unshroud the valves a bit more.

Anyway, I know this is a day late and a dollar short, nevertheless . . .

Jake