SOHC build questions

[338Raptor]

I have some SOHC specific questions I’m hoping someone can help me with.

1. Since the spark plug tube acts as a plug gasket, should the spark plug gasket be removed?

2. How long do the spark plug tubes last before the plug seal area gets smashed flat making it no longer seal properly?

3. Do you guys index your spark plugs?  If so, how do you position them?  Have you ever tested the power gain of indexing them vs not indexing them?

4. Jay- Will the OE valve lash caps work with the FE-Power double rocker rocker arms? Or are the OE caps impossible to find?

5. Drive Chain adjustment: Does everyone use the .005” right cam sprocket retaining bolt deflection method to properly tension the chain adjuster, or is there a better method?  Does anyone use a different deflection value with Billet cams?

6. Intake valve to cylinder wall clearance:  Is it a good idea from a performance standpoint to relieve (grind) the top of each cylinder wall directly below the intake valve? This would unshroud the valve at low lift increasing air flow as the valve is opening. I know Cobracammer-Jason had to do this due to his intake valve actually contacting the cylinder wall. He relieved a very large area (like 1/4 the circumference) but the grinding he did wasn’t enough to unshroud the valve. I’m considering an area approx 1” wide directly adjacent to the intake valve and carrying it down into the bore to approx 1/4” above the top ring at TDC. I would grind it back to the head gasket.

7. Do you install oil restrictor orifices in the deck to restrict oil to the rockers/cams etc, or does a cammer need full oil flow?

[ToddK]

With a lack of responses from anyone with more cammer experience than me, I might as well jump in with my take on a couple of your questions. My knowledge comes from building my iron headed cammer, and that was from information I gained from either the Ford manual, or from Jay’s posts.

1. I removed the gaskets from the spark plugs, since like you, I assumed that the copper tubes would act as a gasket. So far, I have not had any problems with this.

4. The factory lash caps will work, but good luck finding a set. Plus they were for the 3/8” stem valves. I’ve changed my valves to 11/32” stem valves, so I had to source a whole new set of lash caps to suit.

5. I have not used the cam sprocket deflection method, I have just adjusted the tensioner bolt to 125”/pounds torque. Again, so far, the chain tension seems to be holding okay.

7. I did not restrict the oil flow to the heads, my thoughts are that the valve train needs as much lubrication as it can get. I also use the mod that Jay posted, taking a restricted feed from the front head oil passage to drip feed oil onto the tensioner and idler gear bearings.

[jayb]

I have some SOHC specific questions I’m hoping someone can help me with.

1. Since the spark plug tube acts as a plug gasket, should the spark plug gasket be removed?

2. How long do the spark plug tubes last before the plug seal area gets smashed flat making it no longer seal properly?

3. Do you guys index your spark plugs?  If so, how do you position them?  Have you ever tested the power gain of indexing them vs not indexing them?

4. Jay- Will the OE valve lash caps work with the FE-Power double rocker rocker arms? Or are the OE caps impossible to find?

5. Drive Chain adjustment: Does everyone use the .005” right cam sprocket retaining bolt deflection method to properly tension the chain adjuster, or is there a better method?  Does anyone use a different deflection value with Billet cams?

6. Intake valve to cylinder wall clearance:  Is it a good idea from a performance standpoint to relieve (grind) the top of each cylinder wall directly below the intake valve? This would unshroud the valve at low lift increasing air flow as the valve is opening. I know Cobracammer-Jason had to do this due to his intake valve actually contacting the cylinder wall. He relieved a very large area (like 1/4 the circumference) but the grinding he did wasn’t enough to unshroud the valve. I’m considering an area approx 1” wide directly adjacent to the intake valve and carrying it down into the bore to approx 1/4” above the top ring at TDC. I would grind it back to the head gasket.

7. Do you install oil restrictor orifices in the deck to restrict oil to the rockers/cams etc, or does a cammer need full oil flow?

1 - Yes
2 - I've never had a set wear out
3 - No
4 - Any lash cap that fits the valve will work, but they will have to be ground or shimmed  to set the lash.  The non-adjustable sets I've done so far have needed somewhere in the neighborhood of 0.006" to 0.0016" shims between the valve stem and the lash cap.  But of course this will vary with the length of the valve and the valve job.
5 - I've used an inch pound torque wrench to set the chain tension.  Used to use about 60 inch pounds, but more recently have gone up to 110 inch pounds.  Haven't had a problem with either setting, but it is important to recognize that with aluminum heads and/or block, the engine needs to be completely warmed up before you make that setting.  Otherwise, the growth of the block and heads will make the chain even tighter.  I usually start the engine with about 30-40 inch pounds on the tensioner bolt, and then re-adjust after the engine is completely warmed up.  Also, it is important to set the chain tension with the force off the rocker arms.  Slide the 1,2,3,6,7,and 8 rockers away from the valves, and then turn the engine until 4 and 5 rockers have lash.  This way the force of the cam against the rockers is not adding to or subtracting from the tension on the chain.
6 - I would only grind the tops of the cylinders if it was necessary for clearance.
7 - No restrictors

[338Raptor]

Excellent info.  That’s exactly what I needed to know.  Thanks.