AGood2.8

I have definate proof that there are two different 3.4 type cam profiles.

In a past post, a few of us were trying to determine if the HT3.4 motor's cam is the sam profile as the '93-'94 Camaro 3.4 cam. This part I unfortunately still do not have an answer-

However, here's what I have confirmed ( the info's been there all along right in front of me but I failed to cross check things:

GM offers the HT3.4 with a low end torque cam with the profile of-

204*i/216*e durations and the lift w/ 1.5 rockers at .427"i/.454"e

Here's the catch- GM offers 2 cams with that exact profile- only difference is the lobe separation. The HT3.4 has a lobe seperation of 107* and the second cam has a separation of 112*

The 107* is better for towing (lowend), the 112* better for racing (mid to topend)


Now from what I have computed, the 107* with that lift and duration will play havoc with the smog sniffer and computer vacuum controls- and combined with 1.6 rockers instead of 1.5's, It will have a tad more lobe overlap and make worse the computer compatability.

So basically I think the 112* cam would be better for computer compatability- but why does Crane cams disput this? (they say its not for computer controled cars) My only thought is they are not wanting to allow the extra duration of fuel intake because I think the overlap is about the same on a lower lift- smaller duration- closer lobeseparation profile that is computer compatible? Go Fu(kin figure(I'm still old school and cant stand computer cars & the bs limitaions that come with!)
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If anyone can find out exactly what the profile of the cams in the 3.4 Camaro's is (including mostly lobe separation) That info would be greatly appreciated (they are computer controlled, of course, so it would be nice to know there fundemental profile.

Thats for any input, Dean

Project: 85 2.8 bird

If I remember correctly, & I don't know where the gmpp catalog is for it has this info, the HT 3.4 cam is the exact same on e in the 3.4 crate motor. Last time I called a dealer, last yeasr actually, that HT 3.4 cam KIT , cam & lifters was $118. might have changed by now. The other cam/cam kit offerd was like $170-$220 or so, had less lift too. & was being discontinued. I'm gonna see if it's on there web site.

Project: 85 2.8 bird

Stock 3.4 Cam specs


GMPP cams for the 2.8-3.4 from www.gmpartsdirect.com :



12353919 Camshaft Kit
All models car and truck Chevrolet V6/60º (2.8L & 3.1L) for off highway use. Smooth idle, daily usage, off road, towing, economy, mild turbo-charged 8.0 - 9.5 to compression ratio, 2200 - 2600 cruising RPM. Basic RPM range 1500 - 4000, 6500 RPM attainable with proper valve springs and lifters. This camshaft kit is designed and manufactured by Crane Camshaft Co.r for GM Service Parts Division. The kit includes (1) camshaft and (12) tappets. The duration at .050 lift (intake/exhaust) is 204º/214º, while the value lift is .420"/.442". Lobe centerline is 112.


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12363220 Camshaft
This performance flat tappet hydraulic camshaft is used in the new 3.4-liter engine conversion package (P/N 12363230) and is also applicable to 2.8-liter and 3.1-liter engines. Designed to increase mid-range torque and horsepower, this camshaft is ideal for daily performance usage. The duration at .050" lift (intake/exhaust) is 204º/216º, while the valve lift is .427"/.454". The basic RPM range is 1500-4500, and the lobe separation is 107º.
Technical Notes: Use with valve spring P/N 12363215 and retainer P/N 12363216.

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12364059 Camshaft Kit
Applicable to all 1980-94 Chevrolet 60º V6 (2.8-liter & 3.1-liter) engines, this performance-oriented camshaft kit is designed to significantly improve mid-range torque and horsepower without sacrificing idle quality. The basic RPM range is 1500-4500 with 6500 RPM attainable using proper valve springs. Cruise RPM is designed for 2200-2600 RPM, and a compression ratio of 8.0-9.5 to 1 is recommended. This kit is not legal for pollution-controlled vehicles. This camshaft kit is designed and manufactured by Crane Camshaft Co.® for GM Service Parts Division. The kit includes (1) camshaft and (12) tappets. The duration at .050 lift (intake/exhaust) is 204º/216º, while the value lift is .427"/.454". Lobe centerline is 112.


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12453171 Camshaft Bearing
This small-block V8 cam bearing provides a wider bearing surface than standard V6/60º bearings. This bearing should be installed in the front and rear bearing housings.
Technical Notes: Check bearing position in block after installation. Oil hole should be located between 4 o'clock and 5 o'clock position when viewed from front of block.

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12453172 Camshaft Bearing
Small-block V8 cam bearing for #2 and 3 bearing housings.
Technical Notes: Check bearing position in block after installation. Oil hole should be located between 4 o'clock and 5 o'clock position when viewed from front of block.

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14031378 High Output Camshaft
This flat tappet hydraulic cam is used in high-performance X-11 and fuel-injected V6/60º engines. It has .394" intake lift and .410" exhaust lift. The intake duration is 2760 at the lash point and 1960 at .050" from the base circle. The exhaust duration is 2930 at the lash point and 2030 at .050" from the base circle.


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17120070 Roller Tappet
These roller tappets are used on late model V6/60º engines for improved performance.
Technical Notes: Must be used with late model cylinder blocks.

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24505674 Camshaft "Roller Lifter Design"
This Gen III Roller lifter design camshaft features 6000 rpm operation (spring installed at 1.66") with a power peak at 5200 rpm. It features a cast iron distributor drive gear for improved durability.
Technical Notes: Requires fabrication to secure anti-rotation bars and installation of thrust control devise.

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Chevrolet V6-60 Degree Camshafts Quick Reference Chart
Part Number 12353919 12364059
Description Camshaft Kit Camshaft Kit
Duration .050 Int: 204
Exh: 214 Int: 204
Exh: 216
Lift Int: .420"
Exh: .442" Int: .427"
Exh: .454"
Lobe Centerline 112 112

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AGood2.8

I owe you a beer!

That solves the puzzle- the 3.4 cams are not the same as the HT3.4's in any way.

HT 3.4 profile : 112 center, 204*i/216*e, .427"i/.454"e, 107*sep
Stock 3.4 cam: 111.5 cent, 195*i/201*e, .394"i/.409"e, 109* sep

I think that HT3.4 replaced with the 112*sep cam and 1.6 rockers is the hot ticket. That will bump up the usable torque rpm range and give good mid to upper end power.

Edit: So GM's 12364059 Camshaft kit is actually Cranes Cam? Interesting. They don't give all the info specs at GM but Cranes website specs are: 112* intake centerline, 204*i/216*e, .427"i/.454"e, 112* lobe sep.

Now everything makes sense- I never new they had two grinds close to the same profile w/ only lobe sep defferences.

Project: 85 2.8 bird

supersix even has some cams, but mainly regrinds. one of the problems 4th gen 3.4s have in cams is the need for a cam position sensor. If you order one of these, & they tell yoou they caint do it because of the sensor, tell them that's ok, you don't need it

AGood2.8

Yes I know the one they are offering has a single pattern 214*duration and .480" lift with 1.5s. I am sure they definately had the computer in mind when they chose that profile, i just dont have any other specs on it than those two.

I do know all about the cam sensor, thank you though.

Project: 85 2.8 bird

I mentioned the sensor for the DIS impaired

Doward

That first one sounds a lot like the Melling MTC-5 I'm going to pick up...

204/214, .420/.443, 107/117 centerline.

(112 lsa)

Doward

I'd just like to point out this cam for a moment. Now, this is almost exactly like the cam I'm going to get. Notice the whole suitable for mild turbo-charged applications? Odd... seems that's what I'm working on. Well dang... can that mean I actually picked out a cam that will work really well with my setup?

Surely not! (sorry guys, if you read my Turbo Chronicles thread, you'll see what this one is all about)

Project: 85 2.8 bird

I thik they put that turbo thing in for the turbo 3.1 grand prixs. It's all good though

AGood2.8

Basically what I am trying to figure out is what way I want to do things- new crate motor or rework a used Camaro 3.4 mill.

I have stock 3.4 heads availible to me that I was debating messing with because I was deciding on picking up a new HT3.4. Figured I could try sosme port work myself on the spare set I have access to and slap them onto the new motor (Supersix heads and new crate motor are getting up there in price when we are talking $ per HP cost.

What I am now figuring is, since the cam in the HT3.4 crate is worthless to me as well as the stock heads it comes with, and I plan to pull the crank and have the dis crank trigger weight machined for better balancing and lightness, Then I might as well pick up a used stock 3.4 and rework it for the price (along with the supersix heads cost). There is just too many worthless parts on the new HT3.4 that I don't intend to use.
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Edit: On a side note, I really don't want to use SuperSix's single pattern cam with the 1.6 aluminum rockers. It will handle the lift, however, 1st- I don't want to breach .500" lift on a daily street car, and secondly- I dont think i'll need the higher intake lift with the 1.8 intake valves they claim to offer to inprove intake flow. My biggest concern however is the valve seat inteference/clearence with 1.8i/1.42e valves (things are tight already with the 1.72i/1.42e seats

Decisions, dicission- Everything has to be married together for and engine to really tick. I'm deciding on my final options before I start purchasing parts- going to have to make a call to supersix on the Valve choice.

confucius101

ok i just read this whole post b/c
i'm still trying to understand this whole
cam lifter rocker thing and now i'm
even more lost then ever......

Dale

iTrader: (12)

Amen

And does the crate cam have a cam trigger on it?? How much will it play games with a ecm??

AGood2.8

Don't know about the Cam sensor, But I do knoe it has a trigger Crankshaft.
Stock 3.4 Camaro engines have both for the DIS from what I understand. Have not ever checked into it further because they are irrelevant to me- sorry.
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confucius101,

The info I posted only pertains to the new HT3.4 GM crate motor which includes GM cam #12363220. There is another cam GM offers (part #12364059) that is different, but doesn't look different at a glance.
The cam lobe grinds are identical on both cams except the HT3.4 cam has the intake and exhaust lobe separation closer @ 107* which give that motor peak torque at a lower rpm (2700). The 2nd cam grind with 112* separation that will raise peak torque rpm's to around 3500 rpms as well as produce slightly more HP for top end use.
I have now been told that these computer control cars require a certain range/amount of valve overlap. What is valve overlap? It is the period of degrees that the exhaust lobe and the intake lobe of a cylinder will be open at the same time- only breifly. The more overlar a cam has, the more low end power it has ( and vica-versa) The more overlap, the more loss of Vacuum which is bad for things like brake boosters and the ECM vacuum controls, Too much vacuum can play havoc on the computer also(thats the part I am just finding out) But can be helped with prom work.

Now the with the 2 cams above, they both have the same lift and duration, so, The 107* sep cam has too much overlap already- combine that with 1.6 rockers and it will close the gap more (rockers extend duration slightly). The 112* sep cam has too little overlap for the computer (without prom correction- This is only estimates, No one I've talked to or anything I have read can completely confirm this) But My calculated guess is that with 1.6 rockers, The overlap will close on that 112* sep cam (with the longer duration from the 1.6 rockers) and give back some of the overlap- Hopefully be perfect for the Computer.

Anyways, I going with the second cam grind w/ 1.6 rocker- And I plan to have a new custom prom burned regardless because I will have too many changes along with 19# injectors, heads, headers, 62mm TB, and hopefully my new ram air design plenium (that plenium part remains to be seen- right now its only a pipe dream, but I WILL attempt it).

Hope this clarifies cam grinds alittle for you,
Dean