Valve Spring Help

[David]

I'm looking at the Hughes whiplash cam for my 318 (the specs are below) My question is will the stock valve springs work? If not can I just get upgraded springs or will I need a valve spring kit. I've never messed with valve springs so it'll be a new experience for me

Intake Valve Lift 1.5 .485"
Exhaust Valve Lift 1.5 .518"

Intake Valve Lift 1.6 .517"
Exhaust Valve Lift 1.6 .552"

Intake Duration at .050" 213°
Exhaust Duration at .050" 226°

Lobe Separation Angle 109º

Intake Opening at .050" .5° BTC
Exhaust Opening at .050" 45° BBC

Intake Closing at .050" 32.5° ABC
Exhaust Closing at .050" 1° ATC

 

[Cranky]

NO on the stock springs. The cam manufacturer should have a recommendation for springs....

 

[David]

Thanks Cranky. I called Hughes and they said stock valve springs would work if they are in good shape. I just wanted to double check so looks like I will be buying new springs.

 

[Coronet 500]

Check the spring retainer to valve guide distance, if they are stock they may not allow that much lift. More than .450" and 318 heads get tight.

 

[67 B-body]

Thanks Cranky. I called Hughes and they said stock valve springs would work if they are in good shape. I just wanted to double check so looks like I will be buying new springs.

Hard to believe they would begin to suggest stock 318 springs will be sufficient for over .500" lift!:eusa_doh:
I wouldn't recommend this....
MHO.

 

[David]

Yeah I was surprised. I'm not going to risk it I'm going to buy the recommended springs. Now I've never done valvetrain work before. Should I buy new locks, retainers with the springs? Also can the springs be swapped with the heads on the motor?

 

[Coronet 500]

I would get manufacturers recommended retainers and locks.

Yes, on the compression stroke with piston BTDC feed in a lenght of vacum hose through the plug hole leave some hanging out for removal. Bring the piston up and hold the valves, change springs, lower piston and pull hose out. Some use a fitting and compressed air, if you do it this way with the piston up hold the crank as the air could push the piston down real fast and get dangerous.

 

[David]

Thanks Coronet 500. I'll try and get some pics up after i'm done with the swap

 

[Meep-Meep]

I'll agree that seems like a lot of cam for a stock spring. I wouldn't do it. Definitely check all clearances as suggested! The intake closing point vs. compression will make or break the combo. Make sure you have enough compression to run that thing or you will be sorry. Actually, looking again at the intake closing it may be OK. Seems like a lot of lift for stock ports though and it's probably not a smooth profile cam either. Smooth as in valve train dynamics not the way it runs. It will be interesting to know how it does.

 

[Cranky]

A buddy and I stuck in a .480 lift cam in a teen and used the 933 Mopar spring and heavy duty MP rocker arms and we run it 6200 rpm. Can't remember off hand but I think the 933 are only good up to 510 lift....the stock teen springs are barely good enough to go over the stock lift especially if they are older. Maybe Hughs knows something that we don't but imo, if they want to run a stock 318 spring on a cam that size, I say let them go for it.

 

[David]

I'm going to order the springs that Hughes recommends with the cam. Meep this is what they advertise on their site "No machine work, leave the heads on, raises cylinder pressure. Ground on true .904" cam lobes. This gives you max area under the curve. Has low lift to clear guides. These HMC cams have bad-to-the-bone idle, very quick stop light to stoplight acceleration! Idles like a funny car but smooths out above 1600-1800 RPM.These cams are designed to drive better than the sound would imply. These are killer cruising cams made for low compression (8:1-8.75:1) engines and are designed so the cylinder pressure will not be reduced (Torque Killer!) like other cams of this size or type." So I'm interested to see how it performs as well.

 

[Meep-Meep]

.485" / .518" on a hydraulic is low lift?? Not exactly. Looking at the description it does sound like they cover all of my concerns - the main one being the cyl pressure killer. Before you tear your old cam out do a blow check with a gauge and record the numbers. Then repeat that with the new cam. Would be interesting to see how much was lost if any.

 

[David]

Alright think I can manage that. Just waitin on the valve springs to show up now.