This past weekend I did the "secret" cam swap, along with new "complete" timing set, water pump, and other misc. work. I promised several people a how-to review, and sorry to those I promised pics along with this how-to, as I forgot my camera. And to save my butt, this may not be complete, so please do some research before you do this mod, and I assume no responsibility for incomplete information, improper directions, or the like. That being said here it goes:
Review:
There is definitely a shift in the power band and an overall increase in performance.
Low end torque production has died off very slightly, just enough to make it a tad harder to spin the tires but spinning tires is wasted power so it doesn't matter much.
It isn't supposed to change idle but if you have solid mounts it may vibrate a bit more at lower idle r.p.m.s. Upper end power is greatly improved whereas the car began to fall on its face around 5500-5600, it now pulls strong all the way to the automatic's shift point, and the power band is more pronounced though I shall say this, on a stock-ish car, don't expect miracles.
It is a nice support mod in my opinion and I would do it again, just not soon.
Parts list:
(Required) Secret cams, 95 quad 4 vin D 2.3 intake cam with casting number of 245/742 as it has a sensor pad, and power steering hex drive on it, lift being .360", and a duration of 200*.
Now the exhaust cam is from a '90-'94 quad 4 vin D 2.3 liter with lift being .375", a duration of 200*, and the casting numbers are 225/455.
These casting numbers will be marked on the cams.
Unless you pulled them yourself I would recommend using a caliper to the lobes to ensure that you're using the right cams as it is thought the H.O. cams (.410" lift) are too large to fit the stock 2.4 cam towers.
(Recommended) New lifters or the lifters in the correct order from the engines the cams were pulled from.
(Recommended) Both intake and Exhaust cam carrier gaskets (lots of parts stores will call them valve cover gaskets).
(Recommended) Exhaust manifold gasket (metal) along with exhaust flange gasket.
(Recommended) Assembly lube, Oil, filter, and GM Engine Oil Supplement.
(Recommended) Timing cover, housing gaskets, and they are supposedly "reusable" but i wouldn't push it.
(Recommended) Since it is such a pain to do, I would recommend putting in a whole timing set, guides, tensioner, and Water pump and this is to mainly save work later on because they have a tenancy do die early.
(Highly Recommended but not required), a shop manual such as the GM one, Haynes, or Chilton's because I am not covering everything, and am just giving a general over view. And a good set of sockets, ratchets, pulley/ gear puller, 27mm socket, jacks, and jack stands.
Also consider a rubber mallet, air tools, torque wrench, and a good general tool set. A shop is nice in the winter as a buddy of mine let me use his.
The work:
First and foremost, get the car up on jack stands making sure to get it high enough for someone to get under it if needed but only get under if on stands, not on the lift jacks.
And get the front passenger tire off along with removal of the plastic wheel well liners.
Next, remove the exhaust manifold at both the header/ flange, and as a tip there may be a bracket for the manifold so if there is, unhook it first as it is tough to do later, then set the motor at TDC. The service manual will be quite helpful at this stage.
Next again, remove the coolant tank, upper motor mount (support the engine before doing this, consult a guide on what to do), and crank balancer/ pulley.
Supporting the engine can be as simple as using a jack under the oil pan, using plywood to keep the jack from destroying the oil pan.
Now the timing cover must come off along with the removal of the timing chain, setting the crank 90* past TDC, and setting the cam gears as described in the service manual.
Continue to remove everything in the timing housing and begin to remove all the bolts holding the timing housing to the block.
To do this, remove the lower mount bracket to gain access to the oil pan to housing bolts.
Next, you will need to remove the power steering pump, and the block off plate/ lift bracket on the exhaust cam housing.
Now take the intake cam carrier bolts out, remove the carrier while taking care not to drop them or not to spill the lifters out.
Take it apart, remove the old gaskets, cams, lifters, while using the assembly lube on the cam lobe surfaces, the lifters, and the springs.
Now reassemble the cam carriers and torque them to specs as listed in the service manual. The exhaust is the same, just the other side of the motor.
Now with everything finished in the actual swap, this would be a good time to do any other work you have planned such as the water pump replacement. You may consider replacing the thermostat too and now is a good time to think about whether you want to use a 180 degree or 195 degree thermostat.
Now the reassembly begins and goes in this order:
Timing housing, timing set, tensioner, then timing the motor as described in the manual, and installing the chain.
And finally in this step, you would be letting the tensioner out, and turning the motor over by hand several times to ensure it works correctly.
Finally the timing cover, crank pulley, lower/ upper mount, exhaust manifold with the new gaskets, and the coolant tank.
Now if you are confident in your work, do your oil change, add the GM engine oil supplement, and get ready for your test fire.
When test firing, I would only let it run a max of 5 seconds being careful to listen for noises or anything that concerns you while it's running.
If it ran ok and you are again confident in your work, crank it again, let it idle (check manual for any specific cam break-in procedure), and let it warm, the whole time listening, watching all the gages, and lights.
If all is correct then top off all fluids and get ready for the test drive.
During this drive and for a few drives after it, I would be careful not to go W.O.T. for a few days but do go through the everyday motions of driving the car.
After about 250 to 500 or so miles, change the oil, and enjoy the new found power.
It's recommended to change the oil one more time at about 1000 to 1500 mile for extra insurance.
Again I am by no means a master mechanic and would highly recommend researching, finding more experienced help if this is your first time in the motor.
Good luck.
Credits go out to the write-ups on quad4forums.com, jbody.org, to the Haynes manual, and from Misnblu for some info I didn't have or couldn't find.
Bp's97gagt also gets a thanks for being a great seller of the cams to me, and anybody or group I left out.
Finally to my buddy Nathan "Farley" for use of his shop, tools, and help completing this.
Please forgive me for an spelling or grammar errors.
