Daniel,

What you have there is a guide insert, not a liner. You are OK.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Tim,



I hope they are not liners, since the top half of the original guide boss is trimmed off. Wall thickness: .0785" (OD .500").



If I use some force to push the hole gauge into the guide, and really clamp down on the valve stem with the caliper, then I've got .0025" max. exhaust clearance. Guess I'll be alright.

6 VOLTS/POS. GRD. NW INDIANA

Just goes to show, not matter what the shop's reputation is, it is a good idea to re-check their work if you have the equipment and ability.  If the work is sub-standard, you avert a possible disaster, if everything is as it should be, you can pat yourself on the back for choosing the right shop.

John

John - "The Hoosier Hurricane"

Dan,

Since I didnt have any clay and town is a long way off, I went out today with the intent of checking valve clearance as you suggest.  There was more than enough room on the exhaust side.  The intake valve not so.  It bottomed on the piston top approx. 1 degree BTDC.  The larger 1.92 intake was the difference.  I put on a rebuilt C1TE head and the clearance was more than good on intake and exhaust.  So maybe retarding the 4 degree advanced cam will be the ticket. 

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

I was wondering because we have a competitor  down the street that has nothing but worn-out equipment, I have seen the work that comes from that shop, and he has got all the Hot-Rod Chebie guys in town convinced that He builds top notch race engines. I'm not worried about the work not coming here, I've got more than enough to do, but I have had to redo some stuff that came from that shop and it is amazing what they turn out.

Did your first job have bronze guides or liners? Liners are a hack way to go, they tend to slip. And Yes, you can stick a bronze guide if too tight.

As for the valve clearance, I would agree with Ted, you want to check it timed the way  it's going to run. I don't care for WD40 though. I like Breakaway.   easier isn't always better.

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Tim,



Some seats were too deep, and most were cocked enough to warrant replacing all and starting fresh.



Funny thing, I checked with a cheap hole gauge and digital caliper to re-measure guide clearance. Though they said that the bronze inserts had been honed out wider, I'll be damned if I can detect it. While a half thousandth increase COULD be hard to nail down with my tools (.0015"-.0020" range), I'm starting to wonder if maybe the inserts were pre-sized, and the alloy is just too hard and elastic to hone much? Or, is it another case of being led down the proverbial "garden path" by machinists who think they know better than their customers? When I mentioned my fear of exhaust valve seizure during cam/engine break-in/overheating, he flippantly commented..."not with bronze guides".



P.S. Instead of clay, wouldn't it be easier to just install a few weak springs and measure the piston-valve clearance at various points of crank degree by pushing on the valves with a dial indicator? You could check after final assembly and merely reinstall the springs with air pressure.

Or, if both heads AND deck were level, and acceptable clearance was similar to gasket thickness, would you need to torque the heads to check clearance?

6 VOLTS/POS. GRD. NW INDIANA

Hey Dan, I have another check to make too (like in valve clearance)!

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

John is absolutely right in that valve to piston clearances must be checked with the timing chain installed and preferably with the camshaft degreed in.  If the camshaft is being advanced, then the intake valve will be closer to the piston and likewise, if the camshaft is being retarded, the exhaust valve will be moved closer to the piston.  For the amount one valve moves closer to the piston, then the other valve will move a like amount away from the piston.  Rule of thumb for a flat tappet camshaft is for each 4° the camshaft is advanced or retarded, the valves will move 0.025” closer and away from the pistons depending upon if advancing or retarding the cam.  But as John mentions, the camshaft profile itself will vary this value so it’s always recommended to do a physical check.  The clay method is reasonably foolproof but be sure to spray some WD40 or other lubricant on the clay so the clay itself does not stick to the valves.

Lorena, Texas (South of Waco)

Daniel,

Just wondering what was "poor" about the first install on your seats, off center, too deep, or just bad seats?

   God Bless.   Tim                           http://yblockguy.com/

350ci Y-Block FED "Elwood", 301ci Y-Block Unibody LSR "Jake", 312ci Y-Block '58 F-100, 338ci Y-Block powered Model A Tudor

tim@yblockguy.com  Visalia, California    Just west of the Sequoias

Actually you should check, using the above method, for several degrees of crank rotation, with the timing chain on and in time.  Just after TDC, the exhaust valve on some performance cammed engines accelerates faster than the piston at TDC and can actually "catch up" with it just aqfter TDC.  Minimum clearance is not necessarily at TDC is what I'm trying to say.  The clay method will compensate for this since you turn the engine to get impressions from both valves.

John in Selma, IN

John - "The Hoosier Hurricane"