Need help choosing camshaft and head rebuild options!

[jayson427]

So my adjustable cam gear slipped about a month ago. Just heard back from my shop and they said I only bent 3 exhaust valves and one intake. I thought I had ferra valves but they say it's stamped with stx on it which I have no clue. Also they say I need new camshafts because the lobes are worn down (they think the hardening process was bad and think it's manufacturer defects) and won't hold the valves open properly. I have crower stage 2 camshafts currently and my warranty is void since it's been about 2 years since I bought them. The whole motor has about 7k on it.

I'm stuck on what other cams I should get to replace them if I should go bigger or not? I will eventually have a 20g turbo set up on my 10.5 compression motor. Also they asked if I wanted to replace the valve seals? I told them if they have to disassemble the head I want to port out the exhaust side of the head since I only ported the intake side. I'm really undecided on what to do guys and need your input! Thanks.

 

[92AWDHX40]

Replace the valve stems, its part of a rebuild and cheap insurance.

 

[jayson427]

Yeah I figured I would replace the valve stem seals but I'm really not sure about my other questions. I'm thinking about going with crower 2 3/4 race cam. I'm just not sure if it's the best choice for my set up and they are about $450.

 

[russell3123]

What valve springs do you plan on using?

 

[jayson427]

I already have crower spring and retainers. I'm just at a loss with the lobes having unusual wear so I'm not sure if I should get another set of crower camshafts or not. Pretty sure I want to go bigger I just don't know what's best for my set up.

 

[BogusSVO]

First thing to find out what caused the wear. Can you get some pics of the cam lobes?

Have you even called Crower and ask if they can help you out?

Also post some pics of the "STX" valves, I have not heard of that brand, mark. Maybe a look see will tell what kind of valves they are.

Also bending 3 valves is a bit odd, most the time they bend in pairs.

What are the specs on the cams you have now?

How much boost do you plan out of the 20g?

 

[jayson427]

So here's the pics my shop sent me.

 

[BogusSVO]

I was expecting a round lobe from what you were saying.

Get a hold of John at Delta cams, he can fix that, or weld and regrind them into lager cams if you have the specs you want.

 

[jayson427]

I'm not sure what to do the shop is saying I need a new set.

Wish I could get pics of the valves but the head is at a machine shop.

I will try and call crower tomorrow and see what they say.

I will probably run around 15-20psi max I'm thinking. So I'm not sure what cam profile would be best for that on 10.5 compression. My current cams are crower stage 2 turbo grind which I don't know the specs of hand.

Now if I bought a different brand of cams would it Still hold a warranty if I don't run a certain spring and retainer?

These are the cams I was looking into.

http://www.crower.com/index.php/cam...pse-non-factory-turbo-camshaft-pair-4663.html

 

[BogusSVO]

Warranty...No... why? .... Because racecar.

Have you ever read the warranty on cams, pistons or any non stock engine part?

You must be logged in to view this image or video.

There are so many ways for them to get out of it.

Your stage 2 cams would fall under a "competition" part (it doesn't have a CARB Number)

So unless it it just wrong out the box, it is yours.

The pitting in your cam could be from improper hardening from the factory, but it could also be from weak or improperly installed valve springs allowing the follower to clatter against cam causing the harden surface to chip and flake.


Just because you bought the recommended valve springs and retainers, that does not mean that the springs were installed at the proper installed height to get the recommended spring pressures.

Now if the cam company wants to do something, they will.

So basically, Just forget about any warranty.


Now that is out the way....

You can run what cams you want on what springs you want , as long as it is set up properly.

Dollars to doughnuts, your head was not set up, just assembled.

I doubt you know what your seat pressure is. You may know what it is supposed to be. But not what the real life spring pressures are on your head.

About like saying you have a 10.5:1 CR

Installed 10.5:1 CR pistons, so that's what you have, No that is only one part of the equation.

If the head was milled, or the block was milled, that can raise the compression.

A thicker HG can lower it

Porting the combustion chamber can lower it

Factory cast heads are seldom what they are supposed to be.

About anyone can assemble an engine, but they do not go into the details that a builder will.

Now that I have vented, lets gather up the info and see what will best help your build.

 

[BogusSVO]

I just checked out the cams you link. They seem off for what you are building.

You may want to think of a set of custom ground cams and not a set of off the shelf one size fits all.

 

[jayson427]

You're definitely right on alot of things. I just brought parts to a machine shop that I researched on and had them assemble it.

I have 225psi in each cylinder from the last compression check I did not to long ago. I see what your getting at, my car is at a good dsm shop but they know more about 4g63 then my car. I see alot of guys posting 272/264 and what not. Is there any numbers you would recommend to be in the ballpark of? I know it's not easy to suggest something on a head your not building since there's alot of factors that you said that come in to play. Anything will help tho. Appreciate the replies thanks.

 

[jayson427]

So I've searched all over the place and still not sure what to get for cams. There's not much feed back on cams for the 420a. There are a few options but no reviews or real good insight. Anyone on here can put me in the right direction? If not I might just buy the same cams I Already have which I don't want that really.