454 BBC .040 over Hydraulic Roller from Lunati .510/.510
Dur @.050 is 234/234
My first roller rocker cam setup
Hopefully going to try and this next week.

What tricks or techniques are used to set the pushrod length. In the past when I did flat tappet cams I have a set of Hydraulic lifters modified to establish Pushrod length. Well now I'm trying to figure how I'm going to do this with Roller Lifters to prevent them from collapsing when trying to establish the correct Pushrod length. I don't mind buying 1 set of roller lifters to modify, but I don't know if there is a industry standard for overall height and/or internal travel of the plunger on Roller lifters.

Thanks

 

Rookie reply: Can you submerge the new lifters in oil and manually pump up the lifters--that way you don't have to worry about bending valves or pushrods.....then install them and set the rocker arm tension using the instructions found in this forum.

 

Remove the valve springs from 1 intake and 1 exhaust valve. Install a test spring in place of the "real" valve springs. The test spring is softer than the plunger spring in the hydraulic roller lifter, and will allow full range movement of the valve while using the actual roller lifter on the cam.

Lars

 

Thankyou; the US Mail Man did deliver my valve test springs this morning, they are very weak, that was was gonna be my plan A. Like I mentioned this is my first roller cam so I'm learning. Okay great; if this is one of the better ways to do it I guess I'm not going to have a problem.

Again thanks

 

Hey HI.. pumping up the lifters I don't think will work correctly. They'll just bleed down with standard valve spring pressure and give me a false length,
I maybe wrong. This is my first time working with aftermarket heads and a Roller Hydraulic cam. The only way I can see to do it is with a Valve Checking Spring an the Adjustable Pushrod. I'm sure there's other ways but I not familiar with them yet.

Regards

 

I am in the same boat as you. Just received my AFR 180 65CC heads and Howards retro roller cam-have not tackled the project yet BUT have read a ton and spoke with Howards about determining pushrod length.

Cam is .510/.525, 219/225 duration @.050, and LSA 110. Stock L-82 bottom end with 66,000 miles on the engine.

I am not an expert and this is my first attempt at a roller cam. Here's is what I have found so far:

Option 1: Valve lift Checker springs-as you seem to be pursing. Not interested in dismantling the springs in the head,
Option 2: Using a solid lifter that will not compress when using a pushrod checker tool-Don't have this option available either.
Option 3: Spoke to the Howards tech and he explained the following:

Since I could and don't want to do options 1/2, he suggested that using a pushrod length checking tool-I am using Comp Cams which can be extended from 6.8-7.8 with each turn of the pushrod moving the length .050. I am planning to turn the engine until the timing chain marks are both at 12-number 1 cylinder TDC. Install the pushrod checker on the exhaust or intake valve when the cam is on it base circle. Adjust the pushrod length so that as the value goes from base circle to mid lift to max lift, the rocker ball travels from the top 1/3 of the valve stem (towards the intake) to center of the valve stem at mid lift and towards the latter 1/3 of the valve stem (towards the exhaust manifold side) at max lift. Do this procedure for both intake and exhaust valves (just 1 cylinder) and you are good to go ordering the proper length pushrod. Interestingly I called looking for roller lifter preload height and he told he that it is a range from .020 to .060 for their lifters and wanted to know why I wanted that measurement. I explained the issue with solid versus hydraulic lifters and the change with oil in them. He explained that lifter pre load (He suggested I add .040/.050 to my final measurement) but that value is a very small part of that total equation effecting a couple of hundred RPM at the top end.

Any thoughts?

 

http://forum.grumpysperformance.com/...php?f=52&t=181

 

HI......... I'm with you on bringing the cam sprocket dot straight up at 12 o'clock for number 1 at top dead center, but I don't think your gonna be on the base circle with the fast ramps on these Roller Cams. Also the lifter plunger will compress, and I think your gonna get a false reading. I'm thinking right now that the lifter preload will be a strong factor in calculating the initial Pushrod length. Once the Pushrod length is established the preload value whether a 1/2 turn 5/8 or 3/4 turn becomes subjective as to what you want set it at.

Right now; as previously mentioned the only way I can see to do this is with those super light "valve checking springs", make sure the lifter plunger does not compress and establish your Pushrod length.

I may be over thinking this, and a little knowledge can be a dangerous thing, so I guess it's time for my disclaimer of; "I reserve the right to be wrong, LOL.

This is my first Roller cam and after market Head's combo and I only what to do this setup once. 6-8 weeks from now I want to be driving my car.

I'm open to any techniques. Just trying to understand this better.

Regards

 

Do yourself a favor and use Lars' method. It's very easy to do and will produce the best accuracy.

 

With roller rockers, you DON'T want the roller to be running off the tip of the valve stem at either full lift or full closed. That's where checking the geometry comes in. Follow the steps, mark the end of the valve and turn the engine. Get the roller on the center and measure the length of the pushrod. Grumpy's Performance post covers it

 

Your comments are pretty much what the Howards cam technician told me on the phone. The most important aspect of this procedure is making sure that the roller ball starts at the top part of the valve stem when the valve is closed, moves to the center of the valve stem at mid lift and ends at the outer end of the valve stem at max lift-its an arc. The soft Valve checker springs or a solid lifter account for the pre load height of the roller lifter with no oil in the lifter without the engine running. The preload lifter height according to Howards (and comp cams and Cranes websites) can be between .020 and .060 inches. The Howards tech told me that adding .040/.050 to the checked pushrod length would be sufficient, especially in an engine that is not go to rev past 5,500 RPM. Knowing what I know about the Gen 1 SBC after all these years, I have to agree with the tech (who told me that he does this procedure all day long) that theses engines do have some latitude in tolerances and are not a LS7, highly stressed motor, hand built.-my comment, not his. I have to believe that when my L-82 rolled off the assembly line in 1977 (year it was built, Oct 1977) with factory stamped steel rockers and questionable cam materials (no degreeing of cams either), that a tolerance of .050-.10 is easily within the realm of error for these engines.

The solid lifter method or the soft valve spring checking method accounts for the preload range of the hydraulic lifter of .020-.060, other than that issue, using the pushrod checking length tool without soft springs/solid lifter should be ok. I will see. If it does not produce acceptable results, I will go the soft spring route.

Since the "standard" roller cam lifter length is about 7.3 inches, I plan on starting there and probably going shorter in the .050 increments of the comp cams checking tool until I achieve the correct "arc" of the roller tipped rocker travel. I am going to be using AFR heads with a Felpro 1094 .015 gasket so I think I probably will be going shorter, but we will see. Let's assume that I find I need a pushrod of 7.150, as an example, I will add .050 inches to that length to account for the lifter preload:

7.150 (measured length) + .050 (pre load height apprx from Howards)= 7.2 inch pushrod.

Let's assume that the preload value is actually .030, not the .050 that I will be using. How does that change the outcome?:

7.150 + .030=7.18 inch pushrod. I would not be ordering a custom length pushrod, either way, and would still order the 7.2 inch pushrod. See where this is going?

That's the plan-subject to change.

 

This knowledge is priceless. I have maybe 10hrs over the last 2 days reading it all. Had to stop for today, my eyes are bleeding.

But... Monday morning I think I can finish.

Regards