Overheating Very Quickly

having a hard time getting to zero lash. Once I feel the pushrod start to drag I cant tighten more than an 1/8 turn. Screw bottoms out. Do I need to use a bigger wrench? im just using an allen wrench.

I don't know the brand but they look common. The most I could get was almost a half turn after what I think was 0 lash. I'm not sure how obvious the drag should be this is my first time being in a motor unsupervised. Since these rockers don't have a lock down adjuster it would make sense that they would be pretty tight. I think I could get them tighter if I used an actual socket wrench not sure. As you will see in the pics below its pretty on center with that 1/4 turn of lash. Also is that long Bar that connects the two rockers a shim?

Went to the local speed shop today and they told me the valve springs on that are probably too stiff to use a a rod length tool. He offered to loan me a couple sizes if I bring one of mine in to reference. This will also inform the new rocker decision since these arent stamped with any ratio. He said they look like cheap chinese ones from Proform or something.

Does the fact that these are hydraulic lifters make any difference?

Anyone have ideas?

These do not have any sort of locking nut built in. They are going in the trash. Bought a size up and size under pushrod and going with scorpion 1.6 rockers. Hopefully 1.6 is right because these junky rockers dont have any sort of label. My guess is the pushrods are fine but the rockers Im using are made to go with a 1/4 turn of lash. No matter since they are all screwed anyway. Held a scorpion rocker in my hand and it weighed about a 1/4 of the ones I have and had no side-play. Cant believe how much of a difference they felt like.

If I'm able to set lash better with a size-up on the pushrod I will go with those. SHould I have the new rockers in to measure that? The local speed shop said to make sure pushrods are long enough before ordering the new rockers.

stang89bidges said:

Oh crap, you were using the old rockers? Glad you couldn't get them to set right then lol.

Those new rockers at 1.6 should be fine. You will want to check P2V! And then study up on valvetrain geometry. Switching rockers could make a huge difference. Could be such a big difference they don't work with current setup. That's worse case scenario though. I forget, stock cam or aftermarket?

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I was only using them to check the pushrod length and try to figure out what went wrong. No way was I gonna fire it with those. I'm pretty sure these are what caused the cylinder scratches. The PO finally contacted me and found out that these were indeed proform 1.6 rockers. Stay the heck away from these!. Assuming I find the right pushrod length to get preload correct will I still need to pull the head and check p2v?

I plan on using the clay method to check the p2v. Is this accurate enought? I'll also need a nice digital caliper gauge. Any recco's for a good inexpensive one?

Picked up a pair of Calipers from Amazon. Hopefully will be able to measure p2v today or tomorrow. I have one other concern I forgot about:

When I was turning the crank to check pushrod length I noticed a spot where the crank got a little difficult to turn. It was always followed up by a vacuuming type sound so I dont know if I'm fighting compression despite their being no plugs or if I have a crank problem. I suppose I should pull both heads off and double check but that would mean an extra $40 headgasket set for a potentially useless longblock. This has been a very stressful project so far gents :/ If the crank turns out to be bad she will be towed to my house to sit until I have the money to rent a garage. My friend has run out of patience for me using his place...

stang89bidges said:

I think your just seeing compression. All the plugs were out? You should have that compression on all 8 cylinders when turning the motor over. The vacuum sound is normal. Maybe someone else can comment on how it happens with the plugs out but I'm guessing your still building compression in the cylinders or something.

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Yea all the plugs were out and it wasnt super difficult just took more effort. This is all pretty new to me so Im not sure what Im supposed to feel. The only concern I have is maybe the lack of lubrication from having coolant in the oil could have caused a spun bearing. or maybe the overheating caused a crank issue. Im just going to stop worrying about it. Worst case is I put it back together and find I need a new shortblock. If thats the case I still have a great set of heads, turbo, and valvetrain and 302 blocks arent hard to find.

Okay went in with the two pushrod sizes the speedshop gave me to try. One was a size under (6.200) one was a size up (6.250). I was testing to see if I could set the rocker nut down to between 18-21 ft. lb. of torque at less than a 1/2 turn but more than 1/4 (is this correct?)

With the size up pushrod I got to about 18 ft. lb. at more than 3/4 of a turn... hmmm. With the original size pushrod I had I was able to get it set between 1/2 and 3/4... uhmm. Finally, with the size under (6.2) I was able to set preload to 18 ft. lb. at just under 1/2 a turn.

My confusion is that my original problem was that I couldn't get the rocker nut to tighten down at anything more than a 1/4 turn at best. There are a few possibilities here:

1. I could have accidentally set the screw on the rounded side of the rocker instead of the flat side. This would cause the screw to be just up enough to cause the screw to tighten way before bottoming out. This isn't super likely because I took the rocker off and put it on several times and tried 2 other rockers.

2. My test yesterday was not done at the base circle of the camshaft. I recently learned about how to make sure this happens by watching for the exhaust lifter to start to rise when adjusting the preload on the intake. I was pretty sure I had left the intake lifter at the base circle last time so I didn't bother to check it... but I've been mistaken before.

Number two is far more likely. If say the lifter was beginning to rise that would cause the rocker's zero lash to be off and the lash would be loose once the lifter reached the actual base circle of the camshaft correct? Would this not also cause the pushrod to act like a long

er version of itself? Can anyone think of a way that this would cause me to want to use an undersized pushrod? As far as I understood it, the pushrod length was likely too small before because it was impossible to set preload at over a 1/4 turn. Now the same pushrod tightens at close to a full turn.

Either way I am going to perform the test again at lunch and make sure im at the base circle of the camshaft. I will also double check the rocker is centered on the valvestem using the marker trick once more. Sorry of the long-winded response. Just wanting to learn more. (BTW this test was done with the original rockers. Holding off on ordering new ones until I verify pushrod length but will likely be going with scorpions that are adjustable.)

Bingo! Not sure exactly how far into the ramp the lifter was but it was definitely not at the base circle. I put the lifter down to the base circle and then set about retesting the pushrod lengths. Starting with the original pushrod I set the rocker to 0 lash and at about a quarter turn from there the rocker got tight by hand. Using a torque wrench I believe it got to abouot 20 ft. lb. at close to 3/4 turn. I had marked the end of the valve stem and when I pulled the rocker off this is what the centerline looked like:

After that I went to the Shorter 6.200 inch pushrod. This would not even let me get down to zero lash. Threw that one in the spare part bin.
Finally, I installed teh size up pushrod (6.250) This one was hand tight at 1/4 turn and reached 18ft. lb. at a little over 1/2 a turn. Here is the valvestem:


Not a huge difference overall. Now I'd like to have that rocker reach 20 ft. lb. more between 1/4 and 1/2 turn as I understand it but am afraid that going any longer on the pushrod will push the centerline too far inboard. Im trying to decide between going with the 6.250 or one size up.

In order to finish the car before I get kicked out of this garage I need to put in the part order before 5 today. I will have to take a risk on the pushrod length so if anyone has any suggestion on the sizing let me know. Even if the 6.250 is still too short, Im guessing that since the new lifters will have a lockdown nut and is basically more adjustable this wont be quite as critical. At least I know it is close to center of the valvestem and I will be able to set preload within a whole turn. Am I correct in my assumptions here?

mikestang63 said:

That is what shims are for. Go back and read my posts.

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Ah yes! I reread and as I understand the shim will move the rocker tip out? So would it be better to have a pushrod slightly too long and then shim as needed to bring the rocker tip to the center of the valvestem? Or should I stick with the 6.250 (which I believe is stock length) and use the shim to bring the preload within spec?