Overheating Very Quickly

mikestang63 · Jul 14, 2015

You want the proper sized pushrod for geometry and them shim to achieve the proper preload.

m3x1c0 · Jul 15, 2015

Ok I think I got it then! The .6250 Looks like it has the correct geometry so I'm going to get a set of those, 1.6 scorpion adjustable rockers, and a set of shims. Got my digital caliper in the mail yesterday and will be measuring the p2v tonight. Wont I also need to know the cam's lift to figure out how close the valve will be to the piston at full lift? How can I find that without knowing the cam specs? Maybe a dial gauge to the pushrod?

mikestang63 · Jul 15, 2015

m3x1c0 said:
Ok I think I got it then! The .6250 Looks like it has the correct geometry so I'm going to get a set of those, 1.6 scorpion adjustable rockers, and a set of shims. Got my digital caliper in the mail yesterday and will be measuring the p2v tonight. Wont I also need to know the cam's lift to figure out how close the valve will be to the piston at full lift? How can I find that without knowing the cam specs? Maybe a dial gauge to the pushrod?

Dude you are way overthinking this.

Base circle of cam, 20ft lbs and 1/2 to 3/4 turn. Use the shims to obtain the preload.

stang89bidges · Jul 15, 2015

If your using those old rockers to do all this measuring your going to have to turn around and do it all again when you purchase the new scorpions. They might require different size pushrods than what you have found. Geometry will be different.

My advise would be get those scorpions in first. Then check geometry and P2V clearance. Everything else will just be adjustments but you need those new rockers before you know what size pushrods and shims and setting lash and etc etc etc.

m3x1c0 · Jul 15, 2015

was getting ready to check p2v according to these instructions: View: https://www.youtube.com/watch?v=Y66lvdHbm60

they say I'll need solid lifters... son of a...

stang89bidges · Jul 15, 2015

I've seen this one before, should work fine. GL.

m3x1c0 · Jul 16, 2015

stang89bidges said:
I've seen this one before, should work fine. GL.

but i will need solid lifters?

stang89bidges · Jul 16, 2015

You should, but I didn't use them. I just made sure the putty was thicker than they said it needed to be. Know what I mean?

m3x1c0 · Jul 20, 2015

rocker suggestions. Apparrently pedestal mount rockers that are adjustable are extremely rare. I was just gonna go with scorpions

stang89bidges · Jul 20, 2015

Scorpion, ford racing, crane all make em.

m3x1c0 · Jul 25, 2015

what preload should I look for? im getting 3/4 with a pushrod length of 6.250 is this ok? should I increase my lengh to get 1/2 or less?

m3x1c0 · Jul 25, 2015

Ok actually check this out. With a pushrod checking tool set to 6.300 this rocker tightens to 20 ft. Lb. in 1 and 1/4 turns. This mark is nice and thin and just a hair inboard of the center of the stem:

The 6.250 that was already on the car was at 20 ft lb at around 3/4 turn and the mark was center but very wide:

I'm thinking the first length pushrod is correct but both preloads are way more than 1/2 turn preload that I was told to look for. Should I shim them or just ignore the preload and go by torque spec?

m3x1c0 · Jul 25, 2015

with the 6.300 pushrod on the exhaust side I measured the p2v. I saw a .085 at the smallest bit of clay which is too close for comfort on the exhaust side I believe. I think I will just run the 6.250 and shim it until preload is below 3/4 turn.

stang89bidges · Jul 25, 2015

Read this first. Engine Tech: Understanding Valvetrain Geometry and Getting It Right! - EngineLabs

You want good geometry, that roller on valve tip mark is only half the battle.

You should always follow the rocker torque specs too. Normally you want around 1/2 to 3/4 of a turn after you get zero lash set. But with pedestal mount you could be a little more of a turn.

Shims should be used to correct geometry, not how many turns on the wrench to get tight.

Geometry, geometry, geometry.

My new song I sing to my kids at night lol:

Heads connected to the.... valves and, valves connected to the.... pushrods and, pushrods connected to the.... lifters and, lifters connected to the.... camshaft.

stang89bidges · Jul 26, 2015

m3x1c0 said:
with the 6.300 pushrod on the exhaust side I measured the p2v. I saw a .085 at the smallest bit of clay which is too close for comfort on the exhaust side I believe. I think I will just run the 6.250 and shim it until preload is below 3/4 turn.

P2V is a big deal, how is the geometry looking with the 6.250 pushrods?

I can't imagine your too far off.

How are those scorpions looking too? Pictures?

m3x1c0 · Jul 27, 2015

I must have done the marker test about 20 times. Other than that one time I posted above I could not discern a huge difference between the two. I think maybe the marker is drying too fast and screwing up my readings. Gonna try a dry erase next. Generally with eother size my mark is kind of wide but always in the middle. The difference is in how many turns it takes to get to 20 ft. Lb.

m3x1c0 · Jul 27, 2015

I'm concerned because SOMETHING caused those rockers to break. Every other one has a crack or chunk missing and this is on stock pushrods. I'm gonna upgrade to hardened comps and only have one chance to do it right

stang89bidges · Jul 27, 2015

I would blame cheap rockers (or a bad batch from factory at least). Dry erase is the way to go. But bad geometry will cause that most certainly. Bad geo will cause extra stress in the valvetrain and lead to premature wear/breaks.

stang89bidges · Jul 27, 2015

Which is why it's more important to get it right over the roller rocker position on the valves. But a true correct geo will get you damn close to centering the roller on valves.

stang89bidges · Jul 31, 2015

Get it back together yet?

Overheating Very Quickly

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