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Discussion Starter · #1 · (Edited)
Camshaft blanks group buy - the wait is over

As many of you know there are no commercially available camshafts for the 4200, the main reason is GM never released cam blanks with round lobes to allow performance cams to be made.

Last year I designed and had a limited number (3 sets) of camshaft blanks made, 2 of the 3 sets were turned into camshafts and installed into 4200 engines.

Shown below is what the prototype cam blanks looked like after copper plating shown beside a set of stock 2006 cams ( needed for the grind process).

By efi_diy, shot with DMC-LZ2 at 2008-01-16


Comp Cams ground this set of cams using the prototype blanks shown above:

exhaust cam shown


By efi_diy, shot with u710,S710 at 2008-09-18

The new cam blanks will be CNC machined from 8620 billet steel. They need to made into camshafts by a camshaft manufacture - we recommend Comp Cams.

I have attached a CAD model dump of the intake and exhaust cams. The exhaust cam has the variable valve timing passages machined in. Both cams have a hex machined to allow easy rotation during installation and alignment flats like the OEM cams.

I am opening a group buy for cam blanks today that will remain open for 4 weeks. To make this affordable as possible and to cover setup/programming charges we need a minimum of 10 people to commit. If we do not get 10 people then your money will be returned.

So the cost for 1 set of cam blanks with un-ground cam lobes (one intake cam blank and 1 exhaust cam blank) not including shipping with 10 people participating is:

US$ 570.00

Payment is by US$ money order cashable outside the USA. I asking for 100% payment less shipping up front to ensure no one backs out and leaves the others in a lurch.

Your money orders will not be cashed until we have enough people to proceed. They will be held in a safety deposit box until they are cashed.

Included with your cam blanks will be a contact at Comp cams for you to arrange to have your blanks turned into finished camshafts. The cost of finishing the cams is above and beyond the cost of the blanks. Comp is charging US$250 per camshaft for custom grinds. I am working with them to see if we can get a group price.


Within 2 weeks I will have a web page up to support the buy.

If you decide to participate PM for details where to send payment. Also please add your name on this forum.

Thanks

Marc

PS: if we get 20 people to commit there is a significant cost savings! The cost drops to US$400/set. For a comparison a set of cams for the Ford SOHC mod motor is close to $700 for a commercially available pair of cams. So for a full custom set $900 is not far off.
 

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Northwest Chapter
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OK guys, honestly this is going to be the next power adder we have for our trucks. The 02-05 guy can adjust the P10 for the added airflow and change the spark tables, so this is something that CAN be done in terms of performance. All you guys wanting turbos and superchargers, this is the thing you WANT NOW for that power boost. Yes its not the 100+ hp/tq a turbo gets you, but its honest driveable power that can be tune on an 02-05. If I had the 1000 bucks and knew I was keeping my 02 I6 Id be all over this, unfortunately my 02 will be sold by Christmas probably and Im going to invest my money into my SS.

If anyone has questions about this, please PM me or efi-diy (Marc). He worked his ass off getting this deal set up, everyone always screams the I6 has no aftermarket, well here's your chance to have one of the first cam'ed I6s out there.
 

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If there are 20 people (and a $400 pricetag)...

Then count me in.

  1. MikeyDizzle


Now all we need is to get that damn header group buy going....
 

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2003 gmc envoy_sle
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man ive been waiting for you to do this a while, but i dont want to spend the money on it at the moment. I will be interested in it sometime next year though
 

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2002 chevy
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i would love to purchase unless the values and springs are included...dont want to go through the hassle of finding the values and springs.
 

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Discussion Starter · #7 · (Edited)
Some one asked what grinds are available .....

This is a list of lobe profiles that Comp has to offer for the 4200.
http://img257.imageshack.us/img257/6241/compcamslobecatatlas.pdf


If you have an early head ('02-'05) the biggest cam lobe that would be streetable is
intake exhaust
lobe # adv dur [email protected] lobe lift lobe # adv dur [email protected] lobe lift
8754 240 198 0.251” 8755 244 200 0.248

If you have an late head ('06 to '09) the biggest cam lobe that would be streetable is
intake exhaust
lobe # adv dur [email protected] lobe lift lobe # adv dur [email protected] lobe lift

8758 258 210 0.251'' 8759 256 212 0.248”
And I'd even consider the next smaller cam than this one.

Remember that the factory cams are really small in duration under 170* @ 0.050"

So even these lobe are adding 30* duration which is significant. The up side is you should be able to run the stock springs and valve length. The cam follower ratio is close to 1.68. So multiply this # by the lobe lift to get valve lift. This give an intake lift of 0.421" and exhaust lift of 0.416" Stock lift is like 0.370.

More cam than this and the head becomes the limiting factor in particular the early head. Don't get caught in the trap of "Oh I'll get the biggest one on the page".

One lesson I've learned is with the 4 valve/cylinder head we don't need monster cams to make good streetable power.
 

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Discussion Starter · #15 ·
To put a late head on an early motor you need:

head bolts
head gasket
valve cover
ignition coils
Valve cover ground strap
exhaust manifold
exhaust manifold gasket
 

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2005 gmc envoy_sle_xuv
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it would just be so much easier to get your model head and do a job to it lol, and probably for cheaper too! $60 on car-part you really can't go wrong. After the port and everything and time to swap heads and cams and everything it should only take a weekend, most likely less of work if you know what you're doing...
 

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2005 chevy trailblazer_ls
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Im really want to do this like bad but i probably wont have the money til next summer. If anything i would throw money towards the cams first cause its a group buy then save money for the head work and headers that are now available. Then of coarse i would need a good tune to top it all off. Could PCMforLess do a good job without having my truck to see the effects? Either way i just hit a deer and that alone cost me 3700 so i could have done all this this summer but instead i spent my extra cash on a stupid deer :(
 
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