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RyanR 06-20-2013 10:36 AM

Check my valve spring specs for cam break in
 
Hey guys getting ready to install and break in my Lunati Voodoo 268 hydraulic tappet cam and just wanted y'alls opinions on my springs to make sure their not too stiff. I'd hate to wear down a lobe or lifter on break in :( Thanks for your time and help guys.


Spring pressure closed 115 lbs @ 1.800

Spring pressure open** 310 lbs @ 1.225

Coil bind is 1.130

Install height is 1.800

Max valve lift is .575

And here are the cam specs

Advertised Duration (Int/Exh): 268/276Duration @ .050 (Int/Exh): 227/233Gross Valve Lift (Int/Exh): .489/.504LSA/ICL: 110/106Valve Lash (Int/Exh): Hyd/HydRPM Range: 1800-6200

Richiehd 06-20-2013 01:09 PM

Better use some 1.3 rockers or pull all the inner springs. I think you are borderline. What rockers are you using? Rollers? What size studs?

RyanR 06-20-2013 01:28 PM

Man they're just single spring, not dual. And full roller 1.5 magnum rockers on a 3/8 stud. I thought it was gonna be pretty close but dang....

And I dont have any 1.3 rockers... however I do have some stock vortec springs but I'm afraid they'll break at the lift I'm running during break in

MouseFink 06-20-2013 01:37 PM

I broke in a GM Pontiac Ram Air 4 hydraulic flat tappet camshaft with 1970 GM Pontiac Ram Air III dual valve springs. Those springs had 125 lb. seat pressure and 325 lb. open pressure with 1.5:1 rocker arms. I set the lifter preload while the engine was still on the engine stand. After the engine was installed, it started immediately and I took it to 2500 RPM and held it there for 10 minutes. The cam survived the break-in period.

That was about 10 years ago using Crane Cams Moly-Paste #99002-1 on the cam lobes and distributor gear with Valvoline 10W-30 All Season motor oil. The motor oil did not have any more ZDDP 10 years ago than it does today.

RyanR 06-20-2013 01:44 PM

Quote:

Originally Posted by MouseFink (Post 1686930)
I broke in a GM Pontiac Ram Air 4 hydraulic flat tappet camshaft with 1970 GM Pontiac Ram Air III dual valve springs. Those springs had 125 lb. seat pressure and 325 lb. open pressure with 1.5:1 rocker arms. I set the lifter preload while the engine was still on the engine stand. After the engine was installed, it started immediately and I took it to 2500 RPM and held it there for 10 minutes. The cam survived the break-in period.

That was about 10 years ago using Crane Cams Moly-Paste #99002-1 on the cam lobes and distributor gear with Valvoline 10W-30 All Season motor oil. The motor oil did not have any more ZDDP 10 years ago than it does today.

Yeah I intend on running Rotella T for break in and even throw a little zddp additive in it for safe keepings... Rotella T and many of the other hd-fleet oils still have all the good additives in it. :thumbup:

Richiehd 06-20-2013 01:54 PM

Full rollers you might be alright. That .575 lift got my attention though. There will be some other opinions here Im sure. Sort it out and use a quality break in oil such as Brad Penn or Joe Gibbs with the zddp additive. Im not a fan of Rotella, it doesnt have near the zddp you need for brakein, nor is it made for gasoline engines. Again, you will get some different opinions here.

RyanR 06-20-2013 01:59 PM

Quote:

Originally Posted by Richiehd (Post 1686938)
Full rollers you might be alright. That .575 lift got my attention though. There will be some other opinions here Im sure. Sort it out and use a quality break in oil such as Brad Penn or Joe Gibbs with the zddp additive. Im not a fan of Rotella, it doesnt have near the zddp you need for brakein, nor is it made for gasoline engines. Again, you will get some different opinions here.

Man u sure about that? On Bob is the oil guy.com all the VOA's came back with 1300-1400 zinc levels and very high phosphorus levels as well. Main reason I even looked into it is because I live in a very small town and there is not much selection to choose from unfortunately.

ericnova72 06-20-2013 03:03 PM

Quote:

Originally Posted by Richiehd (Post 1686938)
Full rollers you might be alright. That .575 lift got my attention though.

His new springs are good for .575" lift...but his cam is only .504" lift.

I'd check to see if the old vortec sorings will manage the .504" lift without going into coil bind, and use them for the break-in period if they will work. Give the cam every advantage you can during break-in.

RyanR 06-20-2013 03:08 PM

Quote:

Originally Posted by ericnova72 (Post 1686953)
His new springs are good for .575" lift...but his cam is only .504" lift.

I'd check to see if the old vortec sorings will manage the .504" lift without going into coil bind, and use them for the break-in period if they will work. Give the cam every advantage you can during break-in.

Naw, I'm pretty sure the max is .470 on them.... seems like even more risk honestly than using my regular springs

techinspector1 06-20-2013 05:34 PM

This is what I'd do if I just HAD to install a flat tappet cam. Shell out the 40 bucks for these springs, install 'em and run the motor at low r's for the first couple hundred miles. Then, using a spring compressor that works with the heads in place, I'd change out the springs to whatever the cam manufacturer specifies for that particular cam.
Use shop air to hold the valves up on their seats, or feed a length of clothesline rope through the spark plug hole and jam the piston up against the rope to keep the valves on their seats while you change out the springs. Put the light springs in a bucket and label it "Camshaft break-in springs".
Comp Cams 979-16 Valve Springs 1.250" Outer
80 lbs on-seat, 200 lbs at 0.500" lift.
If in doubt, re-read this article. It was written by those of us who have been there, done that many times.
http://www.crankshaftcoalition.com/w...ips_and_tricks

Bottom line Bubba, if you try to break in the cam with 300+ lb springs, you'll be doing it a second time not so far down the road. Suit yourself.:rolleyes:

Richiehd 06-20-2013 07:58 PM

Quote:

Originally Posted by ericnova72 (Post 1686953)
His new springs are good for .575" lift...but his cam is only .504" lift.


DUH, Sorry I read that wrong

MouseFink 06-20-2013 10:39 PM

It is critical that you set the lifter preload and time the engine before you install the engine. You do not want to be cranking on a new engine trying to adjust the valves and timing.

I have only had one camshaft go flat and that was in 1966 and it was because I carelessly got used lifter mixed up. I have never used light valve springs to break in a camshaft but I never used a flat tappet camshaft with more than 125 lb. seat pressure and 325 lb. open pressure. I have never used any special motor oil except Valvoline 10W-30 All Season with Crane Moly paste on the cam and lifters. The engine is primed on the engine stand with a variable speed drill as the crank is slowly rotated by hand.

Make certain the engine will start instantly and you can run it up to 2500 RPM when breaking in a new flat tappet camshaft and lifters. If you try to set the timing, lifter preload or valve lash and monkey with the carburetor adjustments when you are breaking in a new camshaft, you may have the experience of watching your camshaft go flat no matter what trick oil or additives you are using. .

cobalt327 06-21-2013 03:22 AM

The open spring pressure is 310 pounds- but at 0.575" lift. The pressure at close to 0.500 is going to be well under 300 pounds.

I have broken in FT cams w/springs similar to this- but that was then and this is now. I believe if you're careful and follow all the rules, you'll be OK. But then, I won't be repairing it if it goes wrong.

RyanR 06-21-2013 11:10 AM

Quote:

Originally Posted by cobalt327 (Post 1687157)
The open spring pressure is 310 pounds- but at 0.575" lift. The pressure at close to 0.500 is going to be well under 300 pounds.

I have broken in FT cams w/springs similar to this- but that was then and this is now. I believe if you're careful and follow all the rules, you'll be OK. But then, I won't be repairing it if it goes wrong.

So I called my semi local builder that does wonderful head work and he walked me through a formula over the phone to calcuate spring pressure for my setup.

(.505 x 310 = 156.5) + 115 = 271 #'s of spring pressure. He says I'll be fine doing the proper break in steps but absolutely nothing wrong with playing it double safe either. So I guess I need to decide which I'm gonna do. Decisions decisions

techinspector1 06-21-2013 09:09 PM

Quote:

Originally Posted by RyanR (Post 1687223)
He says I'll be fine doing the proper break in steps

Great, then that means that he'll be doing the re-do and paying for the new parts, hey? Yowza, what a great guy!


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