Would a Edelbrock "Sure Seat" valve spring work on Vortec Heads without any machine work? I've heard that the LT4 springs work on this head without any machine work, but I allready have the Edelbrock springs.

I tried installing a spring, and the inner coil on the spring catches the base of the valve guide before the outside spring touches the bottom.
I placed the spring on a 882 head and it went on without any interference.

What should i do, can i use the springs, or get the heads machined, or buy the LT4 springs?
Thanks for any help, its greatly appriciated.

 

What springs does your cam mfr recommend for the cam you're using?

 

The thing about Vortec heads is not the diameter of the guide boss. Well it IS, but there are several springs on the market that can be used. THe big thing is the height if the guide boss itself. It needs to be cut down a tad in order for anything that even resembles a "performance" cam. At normal installed heights, the guide boss creates boss-to-retainer clearance at around .480" lift, IIRC. So while you may be abled to find a spring that can slip around the guide boss, that doesnt eliminate the fact that the boss itself might need to me cut down.

That and the fact that i woule avoid edelbrock springs. Comp, Lunati, Crane, and Isky all offer valve springs that would work.

Along with RB's question, what cam are you using?

 

The Cam I'm using is the Edelbrock RPM cam. They say that they will only warrenty the cam if you use the "sure seat" valve springs. I'm using 1.5 ratio rockers, so max lift is .510".
I've heard that the LT4 springs are good too .525 lift on vortec heads without any revisions. I was just hoping that maybe the "sure seat" springs would be similar.

 

Probably doesn't matter very much what springs you use.... it won't be in there long.... you'll hate it. If it eats itself and has to come out, you'll probably be grateful. It is a POS. Can't think of very many others that would be worse. That's gotta be about the least power you can get while still paying that much gas mileage and driveability penalty.

Catch me on a bad day and I'll tell you how I really feel about it.

 

Is it really that bad of a cam?
What do you recommend? The motor is a 0.040" over 350 with a 3.75" stroke. vortec heads, roller 1.5:1 rockers, edelbrock rpm intake, 750 performer carb, msd 6al, accel coil, 1 5/8" headers with cutout. only accessories are water pump and alternator.
oh, compression is 9.0:1. I want to eventually run a single turbo, but was planning on a cam change anyways when that time comes.

 

No it's really not that bad....

It's worse.

It's one of those old design ones with long, slow, lazy ramps; doesn't open the valves quickly, doesn't keep them near full open very long, etc. Just not a very good design by modern standards. It's a great cam for someone with a street rod that wants alot of "lope" but doesn't need or even want it to be fast, and doesn't care how much gas it uses because it runs for less than an hour a year.

Look at the Comp XE cams, or similar ones from Crane, Lunati, etc. with fast opening rates, as little difference as possible between "advertised" and .050" durations, etc. (be careful of how they measure their "advertised" duration though... at what lobe lift or whatever). Unless you've had the valve guides machined down, which it sounds like you haven't, DO NOT exceed .480" of valve lift no matter what springs you use; somewhere around there is where the bottom of the retainer will smack into the top of the guide at full lift, and you'll be wondering why you have valve train noise, bent push rods, flat cam lobes, etc.

Also, pick a cam with a substantially larger exhaust lobe; those heads have great intake flow but typical poor exhaust flow, and so need a cam that helps the exhaust side out a little bit.

The one that would probably work best with that low compresion is the XE262; or a similar high "intensity" grind from one of the other major cam mfrs with about 218-220° intake duration and 225° exhausat duration.

 

Thanks for all the help and advice, its really appriciated.

I just have one more question, is the fast opening rate hard on the lifters? I want to stay with a hydraulic lifter (roller is out of budget), but want virtually no maintenece.

Thanks again for all the help.

 

Not at the level of the XE262. It's a hydraulic cam, so it uses regular hydraulic lifters. Lifters aren't the thing that gets stressed the most anyway; it's rocker arms.

 

Whatever cam you do end up going with, whether it be staying with the RPM (i dont see why, though) or going with the 262, per RB's suggestion, either way, before finally turning it on, check the clearance if you dont mill the guide bosses. .480" may be the generally accepted value for max lift before guide boss to retainer clearance, however, i have heard issues of a little less. When i dummied up my vortecs before milling the guide boss, i ended up with a bit less than .480, after the .060" or so of clearance space. You will want to check all 16 springs for clearance. Even one spring that doesnt clear can make for a very bad day.

What rocker arms are you using?

 

The rocker arms came with the car, not sure what brand, but they are aluminum, and have a roller fulcrum with a roller tip. I think the ratio is 1.5:1.
I was just reading the power-adders>turbos>cam selection thread, and I'm still kinda confused on whether the XE262 cam would be decent or not (when the car is eventually turbocharged). It has a 114 LSA, which apparently is good, but several people supported the idea of having more intake duration than exaust. (XE262 cam: 218/224 @0.05, 0.464/0.470", 114 LSA)
Would the increased duration on the exaust still be good with the vortecs when in a turbocharged situation instead of NA?

If I could get away with not changing the cam when the car is turbocharged, I'd be very happy.

Thanks again,
Skyler

 

Aluminum rockers have a low fatigue resistance strength compared to the steel versions offered by Comp. Keep an eye on those.

With Vortec heads, with or without the power adder, you do not want to do anything to hinder the exhaust flow. Keep in mind these are factory castings. Because of that, they have the typical SBC exhaust ports - crappy flow. Just because you add a power adder, doesnt mean the exhaust flow changes. You still want the dual pattern in favor of the exhaust flow. The thing about power adder cams, or cams that are more benificial to power adders, are the lessened valve overlap, or the period that both the intake and exhaust valves are open. The less valve overlap you run, the happier the power adders are.

The cam you posted is the Xe262 EFI version. The cam RB suggested is also the 262 cam, however, it is the carb version. The only real difference in the 2 is the LSA.

If you truly are going to turbo charge the engine, get a turbo cam from Comp. if you truly are going to be picky, get a turbo-designated cam from Comp. If you want the most from a Turbo, get a Turbo-designated cam from Comp. 12-400-4 is a turbo cam.

 

It's basically impossible to pick a good cam grind for both N/A and boost. The requirements they impose on cam selection are vastly different.

That said, if you think you're going to be willing to pony up $$$$ by the wheelbarrow full sometime in the great nebulous future to turbocharge the car, a $100 cam isn't going to matter too much in the grand scheme of things. You'll probably spend more in gasoline in the meantime, with a mis-matched cam, than a new cam of the appropriate properties for the motor's next iteration anyway. And I guarantee you, that RPM cam isn't going to be too turbo-friendly, either.

I'd recommend getting the right cam for what you're building now, now; and when it comes time to build something else, get the right cam for that, then.

 

Thanks for all the help and advice!
Skyler