Valve springs...

[bzdel2441]

What happens if you put better valve springs on an almost stock 4.0? I have a very mild crane cam and ported and polished headand stock valves. I have talked to people and they told me because my cam is so mild I dont need aftermarket valve springs but I can get a set of Crane springs for really cheap from a friend. Would there any downsides to doing this? And would I need new retainers and stuff that goes along with that....

Thanks
Chris

 

[FUNKYTEE5]

What happens if you put better valve springs on an almost stock 4.0? I have a very mild crane cam and ported and polished headand stock valves. I have talked to people and they told me because my cam is so mild I dont need aftermarket valve springs but I can get a set of Crane springs for really cheap from a friend. Would there any downsides to doing this? And would I need new retainers and stuff that goes along with that....

Thanks
Chris

Probably not much will change unless you are experiencing valve float issues. What kind of lift are you running? As with the crane springs, I doubt they'll fit the stock retainers. Usually you've got to swap everything (springs, locks, retainers) to get things to work together.

FUNKYTEE5

 

[5-90]

Not much, unless you plan on changing the camshaft as well. You may accelerate camshaft wear slightly by increasing the friction against the lobe (but probably not much, unless you're going to get silly with spring tension.)

The main reason for changing valve springs (apart from breakage) is because you're either changing to a much more aggerssive cam or because you're winding up the engine so much that your valves are starting to float at high rpm. If everything is already up to scratch, there's not much point in doing the job.

However, there's nothing saying you can't use them in a stroker later when you put in that more aggressive camshaft. Or, if the price is right, offer them up here and someone else will have use for them with their stroker (or mine, when I start building it...)

5-90

 

[Dr. Dyno]

What happens if you put better valve springs on an almost stock 4.0? I have a very mild crane cam and ported and polished head and stock valves. I have talked to people and they told me because my cam is so mild I dont need aftermarket valve springs but I can get a set of Crane springs for really cheap from a friend. Would there any downsides to doing this? And would I need new retainers and stuff that goes along with that....

Thanks
Chris

If the cam is mild (I guess you're using the Crane 750501), you can keep the stock springs/retainers/locks.
The Crane springs may be cheap but they're larger in diameter than the stock springs, so you'd also need to buy Crane retainers and locks. The Crane springs also install at a 1.70" installed height rather than 1.64" for the stock (or Mopar) springs, so you would need to have 0.060" machined from the spring seats on the head. This adds to the cost as well as being an inconvenience.
For a 4.0 (or stroker) with a more aggressive cam, the Mopar Performance 5249464 springs (rated to 0.525" lift) are the way to go. These require MP spring retainers and valve locks.