I've been compiling a large list of upgrades for the 3.3/3.5/3.8 platform (which you can see here
) and I was hoping I could have some help on the valve train side of things. I'm mainly doing pre-2001 stuff right now, since it's the least documented and what I've been working with on my project engine.
I'm no machinist and have a hard time remembering the measurements off the top of my head, and on top of that, these engines are really well documented to begin with.
I'm curious if these need upgraded anyway but I imagine so with some boost. I'm planning on running upwards of 14lbs of boost on my stock '98 3.8L - Just to see how long the engine can handle it. But in the meantime I want to source a list of parts that are cheap but do the job.
The only documentation I can really find on stock are here:
I've been recommended the following valve springs from multiple sources:
COMP Cams 26995
- These are used as drop in replacements for Chrysler 2.2/2.5 engines. Those same engines use the 3.3/3.8 spring as an upgrade, but use a .050" shim to make up for the height difference. I believe these are the closest to stock I could find.
Crane Valve Springs 99893
- These are supposedly used in the Shelby Can-Am cars, but probably need machining.
COMP Cams Valve Springs 26918
- Another person has said stock 6.1L GEN III HEMI springs might be a good fit. They're a tad bit taller and slightly skinnier, but I can't find any good numbers on them, but these are a drop in replacement.
Stock Intake: http://www.rockauto.com/en/moreinfo....376311&jsn=452
Stock Exhaust: http://www.rockauto.com/en/moreinfo....14403&jsn=1041
So far the only valves I can find that remotely match ours are GEN III HEMI valves.
GEN III Intake: http://www.rockauto.com/en/moreinfo....441242&jsn=559
GEN III Exhaust: http://www.rockauto.com/en/moreinfo....433753&jsn=912
Surprisingly the HEMI exhaust valve is really tiny. It's only .08" larger. But the intake valve is .21" larger which may not fit in the heads, but I'd have to do some measurements to see. The other glaring issue is the over all length differences. The 3.3/3.8 valve lengths are roughly .1" - .2" off, which I imagine would involve longer push rods to compensate.
COMP Cams Steel Valve Spring Retainers 774
- I think these retainers would be a good match with the last two valve springs, and stock keepers (relative to the valve) would work AFAIK
I have no idea where to even start with this, but the only thing I know of which even remotely close is roller rockers for a W2 Mopar head. But I feel like that's way to expensive to bother with. As W2 roller rockers cost more that everything above including the engine put together.
Any advice and ideas would be appreciated!