How difficult is it to change a 318 Poly camshaft??

Jay Gibbs

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My 318 poly 4 barrel swap project is finally about half way through. Engine is stripped down and 2bbl intake and valve covers are off, but I've complicated things a little now. I found a company that custom grinds performance cams for the 318 Poly and I have purchased one, as well as new, slightly stiffer valve springs and lifters which should all arrive in the mail tomorrow. My question is how difficult is it to replace the cam with the engine in the car? I've pulled all front accessories including the radiator (as I found the water pump bearings sound bad so I'm replacing that too)...I'm figuring with everything off now except the engine front cover, this is probably the ideal time to drop the cam in. Having never actually installed one myself before, I am a little concerned that I'm getting in this a little too deep and wonder if I should let a pro install it? How badly could I possibly screw it up??!!...

J.G.
 
First off, drain the coolant and remove the radiator hoses and belts. You will need to pull the valve covers and rocker shafts and distributor. Remove valley cover, the push rods and the valve lifters. (Only models with a free air manifold have a valley cover) Remove the radiator, fuel pump and water pump. Remove the harmonic balancer, you will need a puller tool to do this. Unbolt the cover and loosen the first two oil pan bolts on either side. Remove the cover, being careful not to damage the oil pan in the process. Once the cover is off, line up the timing marks, the crank gear should be at 12 o'clock and the cam gear should be at 6 o'clock, this will simplify cam timing once the new cam is installed. Remove the timing gears and chain, you will want to purchase new timing gears and chain to go with the new cam if you have not already done so. You can now remove the camshaft by pulling it out the front of the engine. On some models you will have to pull the grill to get enough clearance to remove the cam. Once the camshaft is out of the engine, carefully inspect the camshaft bearings for gouges or copper showing, if you find either of these conditions, you will need to install new cam bearings.

Installation of the camshaft is the reverse of the above process, liberally oil the cam journals and camshaft bearings to prevent damage to the cam bearings. Be sure the camshaft gears are properly aligned before reinstalling the the valve gear. Liberally apply the supplied lubricant to the bottom of valve lifters and the camshaft lobes. Before doing this be sure to drain and replace the engine oil and replace the oil filter as some dirt may have been knocked loose as part of the repair process. Be sure to check with the camshaft manufacturer to be sure that the new camshaft will work with the stock rockers and pistons, you don't any clearance issues to ruin your new cam. Also be sure to replace and liberally oil the front seal on the timing cover.. Also liberally oil the harmonic balancer shaft so the seal is not damaged when the balancer is reinstalled.

Dave
 
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To do a proper job of replacing the valve springs, the heads should really come off so that the valves, valve guides and seats can be inspected as part of the upgrade process. If this was my vehicle, I would probably have a valve job done and install the new springs as part of that process. What kind of miles are on this engine?

Dave
 
I'm assuming the engine runs well in it's 2bbl form...
Just stick the springs on there with new valve seals. The cam should be degreed, but this can be a PITA in the car especially if you don't have the stuff and have never done it. So if your expectations are not extracting every ounce of power and economy, you can forgo the degreeing.
 
To do a proper job of replacing the valve springs, the heads should really come off so that the valves, valve guides and seats can be inspected as part of the upgrade process. If this was my vehicle, I would probably have a valve job done and install the new springs as part of that process. What kind of miles are on this engine?

Dave

Thanks Dave...awesome explanation...I really appreciate it! Car and engine just turned 40,000 miles a couple months ago. Camcraftcams suggested I replace the valve springs (slightly stiffer than stock) and new lifters as well which I also purchased. Can't wait to get it all put back together again...

J.G.
 
I'm assuming the engine runs well in it's 2bbl form...
Just stick the springs on there with new valve seals. The cam should be degreed, but this can be a PITA in the car especially if you don't have the stuff and have never done it. So if your expectations are not extracting every ounce of power and economy, you can forgo the degreeing.
I'm assuming the engine runs well in it's 2bbl form...
Just stick the springs on there with new valve seals. The cam should be degreed, but this can be a PITA in the car especially if you don't have the stuff and have never done it. So if your expectations are not extracting every ounce of power and economy, you can forgo the degreeing.

The engine does run well with just 40,000 miles on it, but I'm actually in the middle of installing a 4 barrel setup and stumbled upon the availability of a nice cam for the car and decided to do it now since the engine is all apart anyhow. I figure the combination of adding these parts should perk up the old 318 considerably. I also found out it is relatively easy to swap out the the current 2.93 (8.75) rear carrier and replace it with a more sporting 3.31 or 3.55 to help the off the line performance so that is on the horizon as well...

J.G.
 
The engine does run well with just 40,000 miles on it, but I'm actually in the middle of installing a 4 barrel setup and stumbled upon the availability of a nice cam for the car and decided to do it now since the engine is all apart anyhow. I figure the combination of adding these parts should perk up the old 318 considerably. I also found out it is relatively easy to swap out the the current 2.93 (8.75) rear carrier and replace it with a more sporting 3.31 or 3.55 to help the off the line performance so that is on the horizon as well...

J.G.

As this is a low mileage engine, it is possible to replace valve springs and the sealing "hats" without pulling the heads. To do this, you will need access to a shop rated air compressor (3-5 hp). CAL-VAN, Snap-on and Mac and some other companies make an air chuck that screws into the spark plug hole to which a high pressure air line is attached (120 psi). This forces the piston down and if both valves are in the closed position, they are held closed by the air pressure. A screw type valve spring compressor is then used to compress and remove the valve springs.

Keep in mind that today's no lead fuels are slow death to the unmodified valve systems in these older engines. Stainless valves and iron seats wear out and erode and fairly quickly.

Dave
 
As this is a low mileage engine, it is possible to replace valve springs and the sealing "hats" without pulling the heads. To do this, you will need access to a shop rated air compressor (3-5 hp). CAL-VAN, Snap-on and Mac and some other companies make an air chuck that screws into the spark plug hole to which a high pressure air line is attached (120 psi). This forces the piston down and if both valves are in the closed position, they are held closed by the air pressure. A screw type valve spring compressor is then used to compress and remove the valve springs.

Keep in mind that today's no lead fuels are slow death to the unmodified valve systems in these older engines. Stainless valves and iron seats wear out and erode and fairly quickly.

Dave

Thanks Dave...I did a little research and realized if the springs are out, I might as well replace the stem seals too. Thanks for the compressor advice...I wasn't sure what kind of pressure/hp I needed to hold the valves closed. As for removing the spring keepers, I bought a Lisle 36200 keeper remover/installer...it's not a screw type...will it still work for this application? I figured with unleaded fuels, the non hardened seats will eventually erode...with as little as the car is driven, hopefully it will be some time before this becomes an issue.

J.G.
 
Thanks Dave...I did a little research and realized if the springs are out, I might as well replace the stem seals too. Thanks for the compressor advice...I wasn't sure what kind of pressure/hp I needed to hold the valves closed. As for removing the spring keepers, I bought a Lisle 36200 keeper remover/installer...it's not a screw type...will it still work for this application? I figured with unleaded fuels, the non hardened seats will eventually erode...with as little as the car is driven, hopefully it will be some time before this becomes an issue.

J.G.

Not sure about the Lisle tool number, I think that might be the tool for holding the keepers, you still need a spring compressor to hold the springs compressed and down while the keepers and removed/installed.

Dave
 
What cam did you get, give spec's? To much cam will be a problem with a 2bbl. Food for thought.
40K's not bad, might as well replace timing gear/chain while your in there.
There's a lot more to it then just throwing a cam and expect a Hot Rod that you were expecting. Other then that, take it slow, read a lot, follow directions and you should be good. Good Luck
 
What cam did you get, give spec's? To much cam will be a problem with a 2bbl. Food for thought.
40K's not bad, might as well replace timing gear/chain while your in there.
There's a lot more to it then just throwing a cam and expect a Hot Rod that you were expecting. Other then that, take it slow, read a lot, follow directions and you should be good. Good Luck

Thanks...the cam is part of my upgrade project that started with installing a 600 CFM Edelbrock 4 bbl carb on a factory cast iron manifold. Since I'm going to be in there already, a new timing chain is also part of the project. Cam spec sheet attached...I was looking for best overall performance increase without losing a lot of low end power. Should make the dual exhaust note slightly more aggressive too.

IMG_20180629_182152344.jpg
 
I don't have 318 stock cam spec's available. But looking at those numbers makes me think you bought a smaller cam. For one thing, Mopar durations & lifts are different. You need to STOP immediately and research this out before you go any further! For a stock cam replacement cam wanting a small boost? I would not use this cam for that!
 
Not sure about the Lisle tool number, I think that might be the tool for holding the keepers, you still need a spring compressor to hold the springs compressed and down while the keepers and removed/installed.

Dave

As I saw the Lisle unit demonstrated on YouTube, it is held on top of the assembled spring and rapped with a mallet. As the spring compresses from the mallet blow, the keepers are "sucked" from the top of the spring by magnets in the Lisle unit. To reinstall the keepers, they are inserted in the other end of the Lisle assembly, the unit smacked again and the keepers are reinserted and the spring secured. It's pretty trick looking...
 
I don't have 318 stock cam spec's available. But looking at those numbers makes me think you bought a smaller cam. For one thing, Mopar durations & lifts are different. You need to STOP immediately and research this out before you go any further! For a stock cam replacement cam wanting a small boost? I would not use this cam for that!

I ended up going for this particular grind as I didn't want to give up a tremendous amount of power down low or lose alot of vacuum but wanted to increase power as much across the board as I could while providing a slightly more aggressive idle. This will be for street use only. I was told by the company that made it that it was the grind they used most often for 318 poly street driven cars. There are few places that make cams for the poly and these guys seem pretty familiar with it so I went with their recommendation...

J.G.
 
A little progress update...replacing the cam was easy! Timing chain was very sloppy too so I replaced that as well...nice and snug now. The reassembly has officially begun!

I've run into an issue trying to reinstall the timing cover and hope someone has some advice on this. I'm using a Felpro timing seal set and will now have to strip it all off cause I screwed it up the first time! First, I used permatex high tack to adhere the timing cover gasket to the back of timing cover. I also installed the rubber front pan sealing lip gasket with Permatex ultra black top and bottom and for added security, put a thin coat of it around the coolant passages. So far so good....next I cut the little front pan corner cork gaskets to size and stuck them to the top of the pan with the Permatex- top and bottom.

After all this I tried to install the timing cover itself. It was a little rough initially getting it to clear the rubber oil pan lip without knocking it out of place. Finally got it right and pressed the cover up to the block and started to (try) to get some bolts put in...I couldn't press the cover low enough on top of that fresh thick pan gasket lip to get bolts to thread properly. I tried to install the two bolts that mount "up" through the bottom of the front of the oil pan thinking they would pull the cover down but those were the only bolts I could get to line up and get in. Of course during all this time the Permatex ultra black set up nicely enough that I couldn't move the cover without breaking the seal! I tried using some long philips screwdrivers to slide the cover sideways and up and down but to no avail. I got close to getting a few bolts in but they weren't going in straight enough and I was afraid to crossthread them so I stopped.

Bottom line- what is the easiest way to get this thing lined up properly and bolts threaded before the Permatex sets up??...which bolts do you put in first and in what order to expedite? Part of the problem seems to be that the lower pan lip gasket is new and thick and I can't push down on the timing cover and compress the rubber gasket enough to get the bolts to line up...

ANY suggestions would be appreciated!

Thanks,

J. G.
 
I tried that at the end of my aborted attempt but it was too late and the Permatex had dried too much to move it without breaking the seal...I ordered a new seal kit and will reattempt when it arrives but wanted to know what the correct order of sequence is? Am I using the correct adhesives in the correct places? Surprised me that it set up so quickly... probably didn't help that I'm doing the job in the driveway and it was 95 degree today...
 
I've had a chance to look over my work again without any fear of drying Permatex...it seems that the rubber seal for the front of the pan is too thick. I took out the side corks and even trimmed the outer ends of the rubber seal down and the cover will not go low enough...and yes I've even tried standing on the top of the timing cover to press it down and it won't compress the seal enough! I've taken a picture of the cover installed on the front of the engine (not bolted) and you can clearly see that the crank is much closer to the crank hole towards the bottom than the top...the harmonic balancer clearly will not slide in there properly....now what?...get a new gasket and sand it down so it's thinner??

J. G.

IMG_20180829_140227838.jpg
 
#1 you don't have the timing cover bolts in, #2 do not sand/trim rubber oil pan gasket.

When Dave said loosen front oil pan bolts well it's more like all the oil pan bolt except for the 2 rear ones.

What you want here is to drop the front of the pan 1/2 a inch or so, put the oil pan rubber front gasket & side (tabs) in, gasket goo the corners, then install the timing cover, hand tighten timing cover bolts up making sure it's in 'proper', ie all bolts should screw in by hand tight, then torque it, don't remember if there is any aligning dowel pins on timing cover, but with all the timing cover bolts seated hand tight the timing cover will find it's proper alignment.

Then re-tighten your pan bolts to snug up/crush the front oil pan gasket. This can be all done fairly quick as you don't want the gasket goo to set/harden. Really not that hard, if your really paranoid about oil leaks you can pull the oil pan and replace the whole side gaskets but that's a whole bit of another fun with the engine in the car.

I seem to remember that some timing cover gasket kits came with two front rubber gaskets big/small on some applications, truck pan vs passenger car, GM vs Ford, vs Mopar, can't remember been years, compare what you take out to what is going in, or better yet read the little instruction paper that should be with the gasket set.
Ah scratch that... it's probably in Chinese. :eek:
 
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