The Ford Barn

hemiphil · 02-02-2013, 07:17 PM

Hey Guys,
I got the old Model a engine out of the car and I'm getting ready to install a nice simmons super power head and I gess I should check the main journal clearence. What is the recommendation? I also notice that the valves seem to to be loose in the guides. Whats involve in changing the guids?

Thanks,

Joe K · 02-02-2013, 07:38 PM

Journals should run in the 1 to 1.5 clearance. Up to 3 is allowed. Well, keep that center main tighter if you can.

You can still find "plastigauge" at various auto supply houses, but I find I can do it by "feel" just as accurately when the engine is upside down in a stand. Keep removing shims (or God forbid shave the caps) until it gets "tight" and then put a thin shim (or paper) to first one side or the other (or both)

This really the sort of job best done with the engine out of the car. It's not that hard to remove.

As to valve guides, they're available and not too expensive. But if you're doing the guides maybe do the valves as well? (They're worn after all) And if doing the valves then why not the...well, you see the problem here. This a sort of thing that "snowballs."

Keep your valves numbered so they can be returned to the same holes. Remove the springs/keepers with a spring compressor. Using the open valve stem as a guide, apply the valve guide removal tool and give it a sharp rap with the hammer. You can use a screwdriver for this but you run the risk of chipping the tops of the guides or marking/galling/breaking the valve stem.

With everything apart you'll want to carbon clean things up and maybe grind in the valves a touch? At least to establish "seal" if at all suspect? Oh yeah, any cylinder carbon. (head off)

With the guides out, you can put in new guides from the valve chamber without disrupting the lifters if they're adjustable. I.e. this a warning not to mess with these unless your feeler gauge shows the clearance to be incorrect. Solid lifters you're pretty much stuck unless you dare touch up the ends of the valves CAREFULLY to restore the normal clearance. (Don't overshoot in grinding or you'll be back at grinding that valve seat to try to decrease clearance.)

Assembly is basically the reverse of dis-assembly from here on.

Wot compression ratio is that Simmons?

Joe K

AL in NY · 02-02-2013, 07:55 PM

Here is a procedure I got off this site for adjusting crankshaft/babbit clearance.

1. Pull a crank journal and remove a shim layer from a shim on one side of the journal.
2. Reinstall journal and torque down. Turn the engine with the hand crank.
3. If engine turns normally, pull the same crank journal again and removal a shim layer from the other side of the journal.
4. Reinstall and torque down. Turn engine with hand crank.
5. If engine turns normally again, repeat the process one side at a time and back and forth until you cann't turn the engine.
6. When you reach a step where the engine doesn't turn with the hand crank, reinstall the shim layer you last removed.
6. Torque that journal down and move on to journals 2 and 3.

hemiphil · 02-02-2013, 10:46 PM

I check the clearance and its around .002 so it should be good. As for the valve I will need to change the guides.

Thanks for the info!

glenn in camino · 02-03-2013, 03:11 PM

Sponsored Links (Register now to hide all advertisements)

The old ring order is oil rings and expander at the bottom, middle compression ring with beveled side DOWN, top compression ring square with no bevel. The instructions say, beveled rings must be installed with the beveled side toward the top of the piston. My new rings, from Brattons, don't look like the picture in Les Andrew's book. The beveled rings are beveled on the inside edge. I guess I'll follow the instructions and install the middel rings with the beveled side UP, toward the top of the pistons. The engine was rebuilt by a machine shop back in the early 70s. If the bevel is on the inside edge, What does it do?

02-02-2013, 07:17 PM	#1
hemiphil Junior Member Join Date: Nov 2011 Location: dieppe canada Posts: 19	model a crank clearance Hey Guys, I got the old Model a engine out of the car and I'm getting ready to install a nice simmons super power head and I gess I should check the main journal clearence. What is the recommendation? I also notice that the valves seem to to be loose in the guides. Whats involve in changing the guids? Thanks,

02-02-2013, 07:38 PM	#2
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: model a crank clearance Journals should run in the 1 to 1.5 clearance. Up to 3 is allowed. Well, keep that center main tighter if you can. You can still find "plastigauge" at various auto supply houses, but I find I can do it by "feel" just as accurately when the engine is upside down in a stand. Keep removing shims (or God forbid shave the caps) until it gets "tight" and then put a thin shim (or paper) to first one side or the other (or both) This really the sort of job best done with the engine out of the car. It's not that hard to remove. As to valve guides, they're available and not too expensive. But if you're doing the guides maybe do the valves as well? (They're worn after all) And if doing the valves then why not the...well, you see the problem here. This a sort of thing that "snowballs." Keep your valves numbered so they can be returned to the same holes. Remove the springs/keepers with a spring compressor. Using the open valve stem as a guide, apply the valve guide removal tool and give it a sharp rap with the hammer. You can use a screwdriver for this but you run the risk of chipping the tops of the guides or marking/galling/breaking the valve stem. With everything apart you'll want to carbon clean things up and maybe grind in the valves a touch? At least to establish "seal" if at all suspect? Oh yeah, any cylinder carbon. (head off) With the guides out, you can put in new guides from the valve chamber without disrupting the lifters if they're adjustable. I.e. this a warning not to mess with these unless your feeler gauge shows the clearance to be incorrect. Solid lifters you're pretty much stuck unless you dare touch up the ends of the valves CAREFULLY to restore the normal clearance. (Don't overshoot in grinding or you'll be back at grinding that valve seat to try to decrease clearance.) Assembly is basically the reverse of dis-assembly from here on. Wot compression ratio is that Simmons? Joe K

02-02-2013, 07:55 PM	#3
AL in NY Senior Member Join Date: May 2010 Location: Southern Upstate New York Posts: 1,160	Re: model a crank clearance Here is a procedure I got off this site for adjusting crankshaft/babbit clearance. 1. Pull a crank journal and remove a shim layer from a shim on one side of the journal. 2. Reinstall journal and torque down. Turn the engine with the hand crank. 3. If engine turns normally, pull the same crank journal again and removal a shim layer from the other side of the journal. 4. Reinstall and torque down. Turn engine with hand crank. 5. If engine turns normally again, repeat the process one side at a time and back and forth until you cann't turn the engine. 6. When you reach a step where the engine doesn't turn with the hand crank, reinstall the shim layer you last removed. 6. Torque that journal down and move on to journals 2 and 3. __________________ AL in NY

02-02-2013, 10:46 PM	#4
hemiphil Junior Member Join Date: Nov 2011 Location: dieppe canada Posts: 19	Re: model a crank clearance I check the clearance and its around .002 so it should be good. As for the valve I will need to change the guides. Thanks for the info!

02-03-2013, 03:11 PM	#5
glenn in camino Senior Member Join Date: May 2010 Location: Camino, CA. Posts: 3,086	Piston rings Sponsored Links (Register now to hide all advertisements) The old ring order is oil rings and expander at the bottom, middle compression ring with beveled side DOWN, top compression ring square with no bevel. The instructions say, beveled rings must be installed with the beveled side toward the top of the piston. My new rings, from Brattons, don't look like the picture in Les Andrew's book. The beveled rings are beveled on the inside edge. I guess I'll follow the instructions and install the middel rings with the beveled side UP, toward the top of the pistons. The engine was rebuilt by a machine shop back in the early 70s. If the bevel is on the inside edge, What does it do?