69 mach1 351w Roller rocker recommendation

[rindel]

Heads are at machine shop. They will put studs in 7/16 and machine Boss to compensate for guide and nut for $200.

Mike do I need to buy hardened push rods of different length? I am going with endurance series at summit so I could use the guidance.. Also are existing rockers rail type and are new scb3018 rail type?

Sorry for the thousand questions but I am at the point of no return now.

[Mustangmike]

Regarding valve train geometry, below is a excerpt from my 66 project post: YLWHRSE is the author

RE: 66 Mustang Restoration

I sure you are aware but in case not I thought I would share. To check rocker valve train geometry the easiest and quickest way I have found ( and you should check even a stock rebuild ) is to clean the top of the valve with a rag and some brake clean then take a magic marker and color the tip of the valve solid with the marker. Then install the rocker arm ( cleaning the surface that contacts the valve the same way) adjust your rocker arm for zero lash and then rotate the engine over allowing the valve to cycle open and closed. Then remove the rocker arm and inspect the now shiny spot ( should be a straight line roughly ) that should be centered over the center of the valve tip. If the "wear" mark on the tip of the valve is forward or rear of centerline your geometry is out of whack. Just make sure if you have hydraulic lifters that they are pumped up so you dont compress the lifter plunger. There are many variables in the geometry and the effects on it, deck height, cam profile, surfacing heads ect. I would also buy a pushrod checker ( essentially a two piece pushrod that has a threaded piece in the middle to adjust it for length. I built my first one with some all thread a welder and a couple of nuts. While crude it did get the job done. Every cam manufacturer has some tech info on the subject so I recommend checking those sources out it is worth the read. A good machine shop should be able to assist you with advice and if purchasing the pushrods from them may even lend you a pushrod checker, although I am in a small town and on a first name basis with my machinist. That may not work where you are at. Hope this helps.
YLWHRSE

YLWHRSE is right on how to obtain the correct geometry. Here is a picture of my heads after I installed the correct length and "hardened" push rods. I used also used Comp Cam roller tip rockers:

   

The correct length pushrods ended up being about double the price compared to the stock length but having the correct geometry is worth the extra $$

I actually purchased the pushrod tool from Summit Racing for about $20.

[1969_Mach1]

Scorpions SCP3018 are nice rocker arms. That's what I would have selected. The stock 351W rocker arms are rail type. Those Scorpion rocker arms are not rail type, like all other full roller rocker arms. That is why the need for guide plates. You might need longer push rods. I used the same method Mustangmike has in his post to check for proper valve train geometry and change push rod lengths to adjust it as needed. It works well and isn't that difficult.

You will need hardened push rods, regardless of the final length. The guide plates will grind material off a non hardened push rod. I would start with one of your old pushrods to get a baseline length. Then adjust length as needed. You only need to check the length with one valve. all others should match close enough to the one you check. I tried an adjustable push rod like Muistangmike did to obtain the correct length on my 351W, but the adjustable portion of it interfered with the guide plate. So I made an educated guess. Bought a couple different lengths from Summit Racing and returned what I didn't use. Summit Racing has excellent return policies.

$200 sounds like a good price for that machine work. Are they also going to completely rebuild the cylinder heads or just repair them?

Best Regards,
Mike

[rindel]

For $200 they will machine the boss and thread 7/16. Also i had to buy a piston so they will connect the piston to the piston rod.

BTW I learned a lot from this thread. I have some mechanical help from family member who knows 90% of this stuff but I had to research and fill in the remaining 10%.

I'm still on the fence whether to go 1.7 or 1.6. I have no plans to change the cam so would like 1.7 but I don't want to complicate things and have clearance issues.

[1969_Mach1]

Other than the 3 loose press in studs, are those heads in good condition? Have they been rebuild recently? I only ask because they are fairly old cylinder heads and the valve guides and valve springs can be severely worn out.

1.6 vs. 1.7 is a tough decision. My preference is 1.6 and do cam changes. But it's your decision.

Best Regards,
Mike

[rindel]

The heads look pretty good and so do the valves and springs. The pistons are all in good shape except for piston 5 which is the one i had the broken piston ring. That piston had some scuffing but the cylinders were all smooth.

[1969_Mach1]

Okay, sounds good. I wasn't sure if these were severely worn or not. Sounds like your on the right track. Keep us posted, we'll help anyway we can.

Best Regards,
Mike

[rindel]

Mike what diameter do I need on the pushrod?

[1969_Mach1]

The 351W uses a 5/16" diameter pushrod. Get a one piece hardened 5/16" diameter pushrod. Obviously it will be hollow for the oil passage to the rocker arm. I say one piece because there are a couple out there that have the ball ends pressed into the tube. I haven't seen that type for a 351W. But just to let you know about it and avoid it.

When I bought mine, the least expensive were either Summit Racing's house brand or Trick Flow. Name brands like Comp Cams, Crane Cams, etc. can get expensive.

On a different note. Mustangmike's engine looks nice. I apologize and don't like being critical, but in the picture of the valvetrain I don't see a self aligning type rocker arm or guide plate to maintain rocker arm location over the valve tip. It might just be the angle of the picture. I haven't seen a small block Ford use the cylinder head and push rod to maintain alignment. Chevrolet's have done that and occasionally there is an issue. I'd be a little concerned the push rod might grind away the cast iron cylinder head over a long period of time.

Best Regards,
Mike

[Mustangmike]

On a different note. Mustangmike's engine looks nice. I apologize and don't like being critical, but in the picture of the valvetrain I don't see a self aligning type rocker arm or guide plate to maintain rocker arm location over the valve tip. It might just be the angle of the picture. I haven't seen a small block Ford use the cylinder head and push rod to maintain alignment. Chevrolet's have done that and occasionally there is an issue. I'd be a little concerned the push rod might grind away the cast iron cylinder head over a long period of time.

Best Regards,
Mike

Mike...no worries of being critical. The early Ford heads have slotted push rod guides so guide plates are basically not necessary. A matter of fact, when I located these heads they actually had Ford guide plates on them. I ended up listing them on e-bay for someone who may have needed them more than I did. I am unable to confirm or deny if the your assertion about the push rod wearing away the cast iron over time but I don't think it is going to happen in my life time (LOL). Actually, I did not even have the machine shop install hardened seats. Not quite sure if that is necessary either but I would lose more sleep over the heads being damaged that way.