318 questions
 

Hello, i have a 318 magnum year 1993 derivation Grand Cherokee, i installed a kit stroker 390 JMS racing engines, heads original unmodified, camschaft Comp 20-745-9 http://www.summitracing.com/parts/CCA-20-745-9 , Summitracing tells me to mount this type of valve springs http://www.summitracing.com/parts/DCC-5249464 , what valve springs retainers should I use?
the original ones are no good, they are small ....
you think I should change also rocker arms and pushrods?
I do not have much experience with these engines, for me it's just a hobby
I live in Italy where no one can help me ... I hope I explained myself because I use a translator

Thanks to everyone for the help

Fabio -

With that kind pf a rebuild, you're probably better off with a whole new valve train. Not even sure you can use your old push rods with the roller tappets (lifters).

Yes you might want to have the valves looked at while you're at it.

Been w hile since I/ve done this, but when I was doing that kind of a build, I used to like getting everything from the same manufacturer, if possible.

Archer

You explained yourself just fine.

Ive installed that cam a couple times. You need a valve spring and retainer from www.hughesengines.com Part number is 1110. You also need the retainer they sell for that spring. They will ship to you. PM me if you cant figure it out and I'll list it out for you. There are several other items you can use but I assume shipping is gonna be costly so prob best with one vendor.

The stock valve train is fine for that stick. Base circle change did not necessitate pushrod change but I would still measure. Remember to torque to 22 ft pound on cam base circle. It is not a 1/4 turn chevy set up.

Not sure what its going in but that cam in a 390 is going to peak under 4500 rpm. It will make GREAT torque. If it is fuel injected it will need to be tuned.

Hi guys i'm Fabio's buddy, just trying to help him about the issues is having becasue of a not very skilled mechanic, he's kinda sick and tired to waste money and time in it and still get the same problems...

The problem is fairly simple but we need to get informations and find the matching components for the valvetrain.

Well, we have stock valvetrain except the valvesprings and custom billet retainers wich are wider compared to the stock ones, and becasue of the bigger diameter they have (i guess), the rockers are not working on the valve stem but they're hitting ob the retainer itself causing the premature wear of the keepers (of course they last kinda 5 minutes) and later than that engine begins to loose one cylinder than two and so on, this happens just on the intake valves, exhaust seem to be ok.
I'm wondering if roller rockers wich are narrower compared to the stock ones because of the tiny bearing and their shape would be a goo idea and probably we will get more gap so they will not hit on the retainers like the old ones.
Any help will be apprecciate, thank you in advance.

Paolo.

Paulo,

You can use an off the shelf triple or double retainer on the springs since the MAX you can go spring wise is 1.44 or you are going to hit the head bolt.

Remember the lock fits the valve stem and OEM ones you had with the heads hold just fine up to 500 HP.

You can use a 2.2L dodge OEM retainer or something from Comp or Howards but it needs to fit the spring. If you tell me what spring you are using I can help you track down a part.

The lock you have must have a .05 or .10 plus key and the outside retainer is hitting.

You can use an 5/16 to 3/8 ARP stud with a gen 1 chevy 1.6 roller but you need guide plates. I believe they are from an Oldsmobile. This does work but geometry is not perfect. Acceptable by most but NOT perfect.

The old vendor I know of who makes a roller specifically for those heads is Harland Sharp.

Let us know what you have and we'll get you set up.