Cam choices

[Boosted_One]

Let's talk cam choices on those AU cams.

 

http://63.251.78.219/Image%20file/camspex.jpg

 

What would set the #4 and #5 cams apart from my say my current 284F?

 

If you can please explain why the valve opening and closing degree oon a particular cam is better than in one aspect than the other cam. Things along those lines.

[Tim_C.]

#4 = .456 Lift

#5 = .474 Lift

 

Cam Timing specs indicate when the valve opens & closes installed straight up. Higher the number, the later it actuates the higher the RPM it is tuned/built for.

That's not for your info Mike, because I'm sure you know that. A small tid-bit of info that I have experienced is the higher you go in cam timing, the doggier it is down low. A big cam with late timing almost always works better when it can be advanced. These are findings from way back when we raced SBC's & Mopars.

I think it would sure answer a lot of questions if someone put the #5 cam in, & used an adjustable cam gear to advance it some. The #4 or 5 cam definitely won't perform very well under 4000 unless it is advanced. Advancing a big number cam will bring it on sooner, & they hold their curve longer than the smaller cam made for the target RPM. Why? I don't know, but that's been my experience.

These guys have an upper RPM figure of 8500 for a 2.6L! I guess these things CAN be made to wing that hi?

I'm not much of an expert per say on cams. I just have a general idea on what will work & what won't in some cases. My grinder has taken a look at a lot of the 2.6L turbo cams available out there, and he says every one he's seen has numbers way bigger than is good for it. The straight durations as big as they are make for a generic grind that loses it's curve before it gets started. According to him, a split figure for intake & exhaust is a must (Split lift & split duration). It will gain more performance with a lot less cam because the split fine tunes the timing, and gives the needed flow when you need it (same thing I guess). All of his 2.6L grinds have split I & E figures. Roller Hydraulic, & Slip Rocker Mechanical, & SR hydraulic.

Tim C.

[TainterRacing]

you can change any of the Cam ## as you want i added more EX druation to mine....

[conquest89]

#4 = .456 Lift

#5 = .474 Lift

 

Cam Timing specs indicate when the valve opens & closes installed straight up. Higher the number, the later it actuates the higher the RPM it is tuned/built for.

That's not for your info Mike, because I'm sure you know that. A small tid-bit of info that I have experienced is the higher you go in cam timing, the doggier it is down low. A big cam with late timing almost always works better when it can be advanced. These are findings from way back when we raced SBC's & Mopars.

I think it would sure answer a lot of questions if someone put the #5 cam in, & used an adjustable cam gear to advance it some. The #4 or 5 cam definitely won't perform very well under 4000 unless it is advanced. Advancing a big number cam will bring it on sooner, & they hold their curve longer than the smaller cam made for the target RPM. Why? I don't know, but that's been my experience.

These guys have an upper RPM figure of 8500 for a 2.6L! I guess these things CAN be made to wing that hi?

I'm not much of an expert per say on cams. I just have a general idea on what will work & what won't in some cases. My grinder has taken a look at a lot of the 2.6L turbo cams available out there, and he says every one he's seen has numbers way bigger than is good for it. The straight durations as big as they are make for a generic grind that loses it's curve before it gets started. According to him, a split figure for intake & exhaust is a must (Split lift & split duration). It will gain more performance with a lot less cam because the split fine tunes the timing, and gives the needed flow when you need it (same thing I guess). All of his 2.6L grinds have split I & E figures. Roller Hydraulic, & Slip Rocker Mechanical, & SR hydraulic.

Tim C.

 

You had a chance to put taht prototype cam in?

[Lidoidol]

Ok, sorry to be jumping in late on this, but who makes these cams and how do I contact them, I have been speaking with my contact at HKS usa about trying to dig up some old HKS cams and have not been paying attention to posts like this so this is new to me, someone help me out

 

Thanks

 

Keith

[Silver_Bullet]

I have a 284 cam in my rebuilt engine, but I don't know who made it.   The shop built it to the spec's given by the previous owner and didn't specify the make of the cam on the build sheet or receipt.  

 

I know this isn't related to this thread, but why not:

 

I have been trying to diagnose my idle "problem", but I am beginning to think the cam is what is causing it to lope between 900 and 1000 rpm's (last night my idle was all over the place, but I discovered the 1g lid I was using had a broken clamp and was letting in unmetered air past the K&N filter at idle!).  All of the sensors are brand new and the TPS and ISC check out fine.  All new vacuum hoses, too.

 

Mike, which cam are you running in your current MPFI setup?

[Tim_C.]

John: I have everything except the rockers. kev is going to send them as soon as he receives my money order. Should have been today, so I'll try to have the swap done by the end of next week?

The numbers look very impressive on the cam. I checked the preload to the rocker you sent me, on a mock/test head set-up I have. It preloads just fine, so that is a good sign. We'll see when we go on the car with it. I will be doing a JV Elim on it too since that is required with the rockers. Also, the HD springs are required, or actually new stock ones will work, but the HD's are cheaper & better. I'm doing valve stem seals too.

My car is running great right now, so it should be a good test for before & after, but I don't have the money for a dyno run. I borrowed my friend's G-Tech, so that's the best I will do for testing. There should be considerable increase, so I'm excited!

Tim C.