3900 turbo with cam from Youtube

[merlot566jka]

So the owner of the video said he got a cam from comp and it was from a 2001 3400 in comps catalog… but he had a custom cam and he would share the details here.

So… I am here, care to share how ya got that cam and what the specs were?


Oh and its been probably 15-20 years since I have posted here. Been a loooong time.

[Shaun41178(2)]

In this video, I share my cam card. It shows the part number as well as the grind numbers.

https://youtu.be/K1nybJ9krbU?si=qEemNTbl4UlcgZCb

You have to choose the grind numbers based on a sbc since the journals and lobes of the older 3400s share the sizes as a sbc. There are a decent amount of grinds for intake and exhaust to choose from mild to wild

I can help you select a grind if you have trouble figuring out how to read the catalog. Download the comp cam master lobe profile catalog. Google search will have it.

Once you have the grinds selected, you chose your lobe separation angle, and then a simple call to the comp sales team and you can order it. Should be done in 2 weeks or so.

If you want more details or specifics lmk

[merlot566jka]

Ive got dynosim6 and have been playing around with different cams. Found a few lobe profiles I wanted to try out, and was working with WOT-tech to chose a cam. He was slightly biased towards using one of the cams he developed despite my simulations being drastically different.

And to add, I dont understand why new pushrods are needed when the base circle hasnt changed, or why I need to cut down the spring pockets if the springs have a coil bind at 1.15 and install height is 1.74… if I math correctly, thats still .590 of lift before bind. And with a cam that has .540-.570 lift, whats the reason behind machining?

Regardless, I am eager to find the price of a comp cam from they themselves, because $540 for a cam or over $900 for cam, springs, and pushrods seems a bit steep. But I havent bought a cam in 10 years or so, maybe I am out of touch.

At any rate, thanks for the info. Your cam is similar to what I have designed in the sim and I think its a good way to go. Have you dynoed with that cam yet? I am interested in the torque numbers below 3000rpm. My goal is more along the lines of streetable than high hp.

[ericjon262]

the valvetrain is non adjustable, you are correct that you shouldn't need new pushrods if the base circle is unchanged, but the only way to know for sure is to measure. typically, you need to pushrods for proper lifter preload.

Side note, it's often said "you need different pushrods to correct valvetrain geometry" technically, this isn't accurate, unless the pushrods are grossly wrong, you're not correcting geometry with them, you're correcting lifter preload. the only ways to change valvetrain geometry are to change to some kind of stud mounted rocker, or to shim(or mill) the stock pedestals, it gets pretty tricky doing either of those, when the stock pedestals and rocker geometry seems to work OK.

[merlot566jka]

Shaun,
I am going turbo as well, gt3582r. I already have a 65mm tb and adaptor. Thanks though!
We could figure out your torque numbers, its just some math! HP×5252÷RPM.

Eric,
Perhaps the lifter pre-load is why they require new pushrods… but back to the same question… how would it be different than OEM if the base circle didnt change? Is the OEM preload not correct? Do the lifters wear so much that we need to adjust preload with wear?

Thanks guys!

[ericjon262]

Eric,
Perhaps the lifter pre-load is why they require new pushrods… but back to the same question… how would it be different than OEM if the base circle didnt change? Is the OEM preload not correct? Do the lifters wear so much that we need to adjust preload with wear?

Thanks guys!

That assumes the cam is ground on the same base circle as stock, which you won't know until you have the cam in your hands.

[SappySE107]

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[ericjon262]

I have dynod with this cam but it was with a turbo so my low end tq numbers aren't gonna be what they would be n/a plus the Dyno was picking up interference so the tq readings weren't accurate, so my graph displayed mph. So since the Dyno was in mph I have no idea what my tq.numbers were.

Torque readings weren't accurate?! What do you think HP is based on? Normally you do MPH because the pickup for RPM isn't working. If torque isn't working, you have nothing.

I didn't read that post, that's hilarious!

[SappySE107]

.

[ericjon262]

John at Comp just quoted me $542, also no cores, whoever Shawn is talking to either isn't comp, or is someone who knows something John doesn't.

[SappySE107]

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[The Dark Side of Will]

Took the trash out.

[Shaun41178(2)]

Call comp. They will regrind your stock camshaft.

[SappySE107]

.

[The Dark Side of Will]

I took some more trash out.

Regrinding a hollow tube camshaft is not the smartest move.

I'm curious about why this would be.

[Shaun41178(2)]

Shaun,
I am going turbo as well, gt3582r. I already have a 65mm tb and adaptor. Thanks though!
We could figure out your torque numbers, its just some math! HP×5252÷RPM.

Eric,
Perhaps the lifter pre-load is why they require new pushrods… but back to the same question… how would it be different than OEM if the base circle didnt change? Is the OEM preload not correct? Do the lifters wear so much that we need to adjust preload with wear?

Thanks guys!

Since you're going turbo, if cams aren't available when it's time to assemble, then I'd just use a stock cam. I used a stock cam before and still made good power. Power falls off around 5400 rpm, but you'll still make overall good power even on just 7 lbs.

Not sure.what your HP goals are?

[SappySE107]

.

[SappySE107]

I have dynod with this cam but it was with a turbo so my low end tq numbers aren't gonna be what they would be n/a plus the Dyno was picking up interference so the tq readings weren't accurate, so my graph displayed mph. So since the Dyno was in mph I have no idea what my tq.numbers were.

Torque readings weren't accurate?! What do you think HP is based on? Normally you do MPH because the pickup for RPM isn't working. If torque isn't working, you have nothing.

I didn't read that post, that's hilarious!

It was deleted along with everything else shaun said so that no one will judge him for who he is.

[The Dark Side of Will]

I have dynod with this cam but it was with a turbo so my low end tq numbers aren't gonna be what they would be n/a plus the Dyno was picking up interference so the tq readings weren't accurate, so my graph displayed mph. So since the Dyno was in mph I have no idea what my tq.numbers were.

Torque readings weren't accurate?! What do you think HP is based on? Normally you do MPH because the pickup for RPM isn't working. If torque isn't working, you have nothing.

I didn't read that post, that's hilarious!

It was deleted along with everything else shaun said so that no one will judge him for who he is.

I'm trying to keep this forum technical instead of just being a big collection of arguments. You know where the arguments go.

[jdv]

Do the have a time frame when they might make more cam blanks?