What are the "secret cams"?
The "secret cam swap" for the 96-02 2.4L Twin Cam (LD9) motor was pioneered back in 2001 by a few guys in Winnipeg.
The following is the original post about the "secret cam" swap:
Well, I guess I will let the cat out of the bag now. For over a year now I have been speculating about using Quad4 cams in the LD9 as upgrades. The first idea cam from here -->http://babcox.com/editorial/ar/ar40032.htm
Since the 95 spec cam has the required cam position sensor lobe and the power steering drive, it should work.
Next I found the specs for the Mantapart street cams:
Mantapart Mild Cams Specs
198 degrees @ .050" with .360" lift for the intake
201 degrees @ .050" with .374" lift for the exhaust
What I saw was this:
1995 Cam Specs
200 degrees @ .050" with .360" lift for the intake
200 degrees @ .050" with .360" lift for the exhaust
LD2 (1990+) Cam Specs
200 degrees @ .050" with .375" lift for the intake
200 degrees @ .050" with .375" lift for the exhaust
Note the 95 intake and the LO Exhaust! Pretty darn close eh?
So I was always wanting to try this theory out, but was unable to find the time or courage to do it. That is where my buddies Mark and Colin came in. Mark really wanted to do this, so he went to alot of effort to find the cams. Colin (V6HO) came in and did the install into Mark's car, and it ran great with no codes.
Next up was Aaron's (Pimpin2da4) car the day before he left for the bash. Judging by him being the only NA car in the Quick 8, I think that the cams show what is possible.
I thought it more prudent to share this with everyone so the whole can benefit from the knowledge gained.
Now, everyone wanting to do this, hit up your local junkyard and get tuning!
Here is some more information about the cams required:
Intake cam
The intake cam is from a 1995 (only) 2.3L Quad 4 DOHC engine (LD2). The eighth spot in the VIN must be the letter D. It may be found in the following cars:
1995 Cavalier Z24 (all)
1995 Sunfire GT (all)
1995 Olds Achieva (S Series I & II models)
1995 Buick Skylark (Custom or Limited models)
1995 Pontiac Grand Am (SE and GT models)
If you want to buy it brand new, and can find stock, it's GM part #24574239, and is around $200 USD.
The casting number on the cam is 245/742 (which is the same number found on the 2.4L LD9, but this has 0.360" of lift). The casting number on the cam housing/carrier is 24574057.
Exhaust cam
The exhaust cam is from a 1990-94 (only) 2.3L Quad 4 DOHC engine (LD2). It should be VIN D as well. It may be found in the following cars:
1990, 1991 Buick Skylark (Custom, Gran Sport, Luxury Edition models)
1992-1994 Oldsmobile Achieva (S, SL, SC models)
1990, 1991 Oldsmobile Calais (International, S, SL models)
1990, 1991 Oldsmobile Cutlass Supreme (base models)
1990-1994 Pontiac Grand Am (SE, LE, GT models)
1990, 1991 Pontiac Grand Prix (LE, SE models)
If you want to buy it brand new, it's Melling MC832 from Autozone, or from GM part #22545390 (around $200).
The cam casting numbers are 225/455 (which is the same number as the HO cams, but only has 0.3750" of lift, not 0.410"). The casting number on the cam housing/carrier is 22542963.
Parts needed
If you are going to do this swap, here is the complete list of gaskets required. I bought them not as kits because I didn't want to be left over with gaskets I didn't need. When I compared costs briefly with Nate, it would appear that I didn't spend more than him and may have even saved some money because the kit he got had the head gasket, and I didn't get a head gasket.
YOU DON'T NEED A NEW HEAD GASKET FOR A CAM SWAP!
I also bought a new timing chain cover gasket, but you don't have to. Unless yours is leaking, you can re-use it. If your car is getting old, you may want to change it while you are in there anyway.
Here are the GM part numbers:
24574239 Intake camshaft for LD2 (95-only 2.3DOHC)
22545390 Exhaust cam for LD2 (Pre-95 2.3DOHC)
12355988 - Intake or exhaust cam carrier gaskets (upper and lower)
12363173 - Intake or exhaust cam carrier gaskets (upper and lower)
24575512 - Tensioner. Not required, but if you have timing chain noise..change this. Also, be sure you are familiar with how this part works because it has to be pre-loaded once installed to snug up the timing chain.
24575513 - Tensioner shoe. This will probably break when you remove, so change it anyway.
24575255 - Guide. Not required unless yours are worn.
24575257 - Guide. Same as above.
24575256 - Guide. Same as above.
992704 - Assembly Lube. Good idea to coat the cam lobes and the carriers where the cam contacts with this stuff.
992869 - Oil supplement. The GM manual calls for this stuff when you do the cams.
12360464 - I think this # is the timing chain cover gasket.
245752453 - I think this is the # for the water pump gasket kit. This is only required if you are doing your water pump. I did my water pump and thermostat at the same time as the cams.
Cheap GM parts can be found at: www.GMPartsDirect.com
Thanks to:
- Mike Booth for the original article and figuring all this stuff out
- Colin Bulloch aka v6h.o. for making the first swap happen, and porting Mark B's head
- Mark Bannister for being the first 'guinea pig'
- Aaron aka Pimpin2da4 who proved it to everyone by being the only N/A car in the Quick 8 at the 2002 J-Car Bash
- Mark Pain for the list of gaskets and parts needed, along with GM part numbers
-
http://www.quad4forums.com/forums/showthread.php?t=1763 for Quad 4 info
- ge_forcez22 for re-posting an accurate list of cars the LD2 engines came in
- Mylife75 (ajose) for re-compiling and re-posting it
- Everyone else who kept the threads and information alive over the years
Information on cams compiled, and FAQ entry edited, by John Lenko.
