I want to stick with the stock long block so no cam or heads at this time.

I recently installed a set of Kooks long tube headers and cats. Once the rockers are on I'll have my guy check the tune.

So, I went with Comp Cams Pro Magnum roller rockers and Lunati springs/retainers/locks/seals. This should be a decent compliment to the new headers.

I was at 378 rwhp with JBA shorties and cats prior to the Kooks and upcoming 1.8 rockers. Would be nice to hit 400 rwhp but we will see.

This particular combo of rockers and springs is a proven formula by another GTO friend. I'll post more as I make progress.

 

Good rocker arm .... adjustable or non adjustable.

 

expect about 8-10rwhp out of them

 

Good golly that stuff was filthy. I just got done washing off all the springs, retainers, locks, spring plates and rockers. I know they are coated with something from the factory to keep things from rusting, but I also got off a lot of grit and metal shards. One metal shard in with the locks was about half the size of one of the locks. It wasn't really attached to anything, but sheesh. I soaked the springs and spring parts (except the seals) in denatured alcohol and wiped them all down. I got off a lot of dark brown residue. I then bagged them and poured a lot of motor oil in and marinated everything really well to get everything coated. For the rockers, I washed them in lacquer thinner per Comp's instructions. Lots of grit and metal shavings there too. Again, marinated in motor oil in a ziploc baggie. I'll soak them in a pool of oil before installing them per instructions.

Instructions say the warranty is void on the rockers unless they are installed with new pushrods. Not sure about that. I'll measure for pushrod length and replace if necessary, but if the stock pushrods look okay I plan to reuse them. If I do have to change them, should I shoot for .080 wall pushrods? Are the larger diameter pushrods necessary for this upgrade?

 

Not sure if that was a question or a statement. But what I got are non-adjustable.

 

With Smokey you can't really tell.....

 

Rich,

Short answer, yes get larger diameter pushrods. Your spring pressure will increase due to increased lift. And the load on the pushrods will increase further, because the ratio will multiply the higher spring pressure to an even more-higher number.

 

Use a 7/16 stud and not the tiny 8mm thats normally used. Its a trick that my buddie told me about.

 

Yeah... no.

 

Nothing wrong with the 8mm bolts, the GM bolt down trunnion design does a great job at reducing bolt side load and movement compared to a true stud mount like in an SBC.
I use the 1.8 non-adjustable, been through 3 Drag Weeks and many TNT passes.
This is at .670 lift, 7800 rpm shift 7500 trap. They are used with BTR springs, Comp short travel lifters, preload is set at .010-.015 cold on an aluminum block with Manton custom length 11/32 pushrods. Rockers are still in great shape and going back in the freshened motor this week.

 

Okay, started in on the project. Good news and bad news. Need to make some decisions too.



Good news.

I got the coils, plugs and wires off. I pulled one valve cover and checked the pushrod length. At zero lash, the pushrod is about 7.360 long. So, since stock lifters want .050-.100 preload the stockers should still work should I decide to reuse them. I just need to decide if I want to upgrade the pushrods anyway and 7.400 length would still be appropriate. I need to double check the roller tip wipe pattern yet which might factor in.



One oddity I noticed while doing this checking. For example, I got the #1 cylinder intake on the base circle (when the exhaust is just starting to open). I removed the rocker and did my checking, no problems. So that I could move on to the exhaust side (need to see the intake just begin to close to know exhaust is on the base circle) I reinstalled the stock rocker. As I snugged it down, I noticed the rocker began to open the valve just a bit as I snugged down the rocker. I did NOT see the valve close as I took off the rocker, so did the lifter "pump up" while I had the rocker off? I noticed the exact same thing happen on the exhaust side when I put that rocker back on after checking. Why wouldn't the pushrod simply push into the lifter preload instead of moving the valve as I snugged down the rocker?

Bad news.

As I was trying to find the correct sized socket to put on the crank bolt to be able to turn over the engine, I found that the crank bolt was loose! I could turn it about 3/4ths of a turn before it was more than finger tight. Whoa! That was a problem not far from being very serious. Since these bolts are torque to yield I will definitely have to replace it. At least I found this out before disaster struck.

 

I got a set of those rockers a few years ago. Still have no visible wear. The only thing that bothers me about them is they have a fair amount of side to side play compared to the stock ones, I don't know whether that matters at all.

Also, with the stock diameter pushrods, and the 1.8 ratio, it looked like some rods were touching the sides of the holes, so when I had the heads off I enlarged the holes by about 1mm (to 12mm).

For bolts, the stock bolts are better than those ones with the round heads, which round out too easily (as I found out). Also, a 6 pt 5/16 socket fits slightly better (on the stock bolts) than an 8mm one, so less chance of rounding off the head.

 

Had a little time today and tested the rocker wipe pattern. Right in the friggin' middle! I've decided to buy a set of 7.400 chromoly pushrods just to play it safe.

I guess I can't go to larger diameter pushrods on unmodified stock heads. So, what IS the stock diameter so I don't get the wrong type?

 

In4results!


I had no issues with 1.8s and stock pushrods.

 

Any idea if stock pushrods are chromoly or just regular steel? The few I've had out look just fine, no wear just a polish at either end.

Are stock pushrods 5/16" in diameter?

Good Comp Cams Magnum 7.400 chromoly 5/16" pushrods with .080 walls are only $112.

 

Got all the old rockers off. The stock pushrods look fantastic. Next up is to replace the springs. That ought to be fun.

Today I also rebuilt the valve covers. To accommodate the spacers you have to install new bolts and spacers. A bit more of a chore than it seems like it should be.

 

Stock pushrods are smaller than 5/16. I want to say 7mm

 

I got the right bank of valve springs installed without any problems. The air hose thing was being a useless PITA so I just went back to the tried and true rope method. Soaking the rockers in oil now, hope to have the springs done in the next few days and then I can get the rockers on too. Haven't made up my mind about new pushrods. The stockers look fantastic.

 

I decided to go with new pushrods too. I ordered the Comp Cams Magnum pushrods last night.

 

You choose wisely.

A small expense to ensure that you get things 'right'!

KW