camshaft question (and timing)

[brnwlms]

On my 95 silverado 350 TBI, the lifters are needing to be replaced. I figure since I am in there, I might as well start changing some other things, and in this case, I figure I will put a new camshaft in there also. Has anyone chenged their camshaft and if so, what are some things to expect? I have done work on my cars and truck before, but nothing this in depth so far. I guess I am a little cautious because I have to remove so much other stuff like the radiator, fan, timing chain, and such. Also, with the timing gear, should I replace that since i have it off or should it still be fine? Does anyone have any experience with the gear drive timing setups? What are the pros and cons of it? I am thinking are they worth the extra price for the sound and strength? Also, do they add any more power and how much drag do they have compared to a timing chain setup? Other than the sound, I am dont know much about them. This is the first of a list of planned upgrades. Thanks, Brian

[Tireburner]

Brian,

It's actually pretty easy. It's just time consuming.

I take it you have quite a few miles on your motor if you need to replace the lifters. Older 350's were very hard on cams too, so if you want a little more performance, you can achieve it while you're in there by putting in what used to be designated as an RV cam. It is a real mild grind, but has large performance gains. If you replace the cam, the cam bearings MUST be replaced, this is not fun, nor easy, especially with the motor in the vehicle. Your local parts store, or tool rental store should have the tool to remove/ install new bearings.

Anytime you are that deep in the motor, I highly recommend changing the tiiming chain and tensioner. If the cam and crank gears are made of metal, and don't appear to have the tips of the teeth worn off, they will last another 500,000 miles.

[Crackerman]

first of all, you will only need to replace the cam bearing ONLY if they show copper, are gouged(they micht have a groove in the middle of them for oil) or are excessively polished or unless u want to, (it is a huge job). Second, you are supposed to replace the timing chain and gears together thats why they come as a set and there is NO tensioner on a sb chevy and the set will cost about 19.99 cheap insurance., third, it is a big job you will also need to pull ur balancer(easy to get off hard to put on don't use a hammer,) ur air conditioner condenser will also need to be removed and or moved out of the way(don't vent the freon to the atmosphere, it can land u in jail w/ up to a 10,000 dollar fine) A gear set is fine to time ur cam, although it will make a lot of noise it is not entirely necessary. it is usually recommended for ultra high rpm applications where absolute precision is a must. The rv grind would be a good selection for a truck, more torque and power down low where it is needed, with great drivealbility too. Also your clutch fan might be screw on instead of bolt on and it is usually reverse threaded.If you have any more questions, please post here i will be glad to help out.

[Tireburner]

On the cam bearings:

I was telling him he must replace them if he's replacing the cam. Failure to do so will result in premature bearing/ camshaft wear/failure.

You are correct about no tensioner... sorry for the mis info, too many years and too many different motors.

[0utlaw]

and in addition to above------
Many guys select a cam that is too big just to get that rumpty rump sound. Once you exceed 220 degrees of duration at .050 , you start to get into a rough idle cam. Durations slightly lower than 220 with good lift will help build low end torque. dual pattern cams help purge exhaust gas better. I like to adjust lifters warm and at a slow idle using a stethoscope, one side at a time. After you reach zero clearance on all 12, shut off and tighten all 1/3 turn. I have raced with them set this way and never had a noisy lifter. I have had good luck with Crane, but that's me.
Before you pull it apart, set your damper in the no 1 firing position( rotor pointed at no. 1) mark no.1 on the distributor body and note position of distributor with respect to valve cover or something.. to drop the distributor back in-first turn engine till compression pressure is felt on no1.( use a screw in compression gage if not sure) rotate damper slightly till it is close to your normal timing mark- say 8 degrees btc. Dropping it in may require turning the oil pump shaft with a long screwdriver to get the slot lined up. This will give you a quick fire-up static timing without any problems.
My 350 40 Ford Pickup ran 13.89 at 101 with street tires.
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[0utlaw]

correction to above- after you reach zero clearance on all 8 rockers on one side----
I never could count.
From OUTLAW
On gear drives, I got the noisey one (PETE JACKSON) on my 427. Works well, but the noise will wake up neighbors. It's supposed to sound like a blower but after driving a supercharged car, it's slightly different. To the untrained ear, they will think it's got a blower. If you want a gear drive, go for a "quiet " one which will still make some whining noise. Unless you are going to run it very hard, the chain will do just fine for you. There probably isn't a huge difference between the 2 that you could notice horsepower wise.
Gear drives will stay right on while chains will eventually stretch and cam timing will change. However (I run both types, gear drive and chain type with no major trouble.) My supercharged truck runs a chain and it remains fast after 10,000 miles of occasional hard use. If you choose chain, get a double . Cloyes is a good one. Other name brands too. Do not get a ZOOM $19.95 chain.
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[0utlaw]

IMPORTANT- From the OUTLAW


If your vehicle is going to remain emission compliant (that is with computer and sensors still working), the gear drive may not work for you. The noise of the gear drive may CONFUSE your knock sensor and retard your spark effectively making you less power.
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