Backyard shadetree cam swap pointers!

I'll level with ya...I'm a low buck Hack, if you haven't figured that out from my previous posts! I like to build cars with used engines benefiting from a few bolt-ons and then tune the combination to run it's best! Many times I find myself swapping in new cams with the engine still in the car and the veteran of many miles!

I won't go into the boring step-by-step process of getting to the old cam to remove it...you can figure that out pretty easily yourself, right? I just want to pass along a couple tricks I've learned along the way to help make your backyard cam swap go a little easier!

Once you get the timing cover off, note the position of the marks on the stock timing gears. Most often, they are installed touching each other (mark on cam sprocket lines up above mark on crank sprocket). Just remember how it goes when it comes time to put the new chain on!

Now, lifters can be a bugger after they've been in the car a while! Don't kill yourself trying to yank them up out of the bores...work smarter, not harder! Pull all of the lifters up unti they stick in their bores pretty good. Then, bolt the cam sprocket back onto the cam (minus chain!) to help you slide the cam out without nicking the cam bearings. The gear gives you a little more leverage and control. Go slowly, and ease the old cam out.

Now, take a long piece of poster board then cut and roll it as shown in my crude drawing. Insert it into the cam bore and ease it all the way to the back of the engine where the cam went. Now, rotate it so that all of the lifters on one bank line up with the slot in the poster board.

Carefully push the lifters down through the bores one at a time. They will drop into the poster board, and you can fetch them out one by one with a long magnetic recovery tool. When you get the last lifter out on one bank, rotate the poster board to line the slot up with the other bank and repeat the process. Easy as hell and the poster board will only set you back about 49 cents!

<img src=http://www.imagestation.com/picture/sraid80/paadfb2afc56fd6ea5426ac535d88ed9f/fb078040.jpg>

(You could make something a little more permanent out of thin sheet metal or maybe PVC tubing, but I just make up a quick trough out of poster board and pitch it after each job!)

The rest of the cam swap goes fairly smooth. Make sure you lube the heck out of your new cam and use new lifters! Bolt the cam sprocket onto the new cam to help you carefully guide it back into the engine. Again, go slowly and watch out for the cam bearings! The new lifters will push right down into the bores...the old ones only stick because they flatten out slightly and/or develop a little varnish around the base below the lifter bores. They make a tool to help extrxct stuck lifters, but I'm a cheap old buzzard who just has to do it the low buck way!

On engines with adjustable rocker arms and hydraulic lifters, I position the engine so that both valves on a given cylinder are closed, and then tighten the rocker arms on those two valves until I can just barely grab the pushrod and spin it with my thumb and forefinger. Go through and do each cylinder this way. This will get you in the ballpark.

After you button the engine up, remember to break the cam in correctly. The cam will probably come with recommendations for doing this, but I always fire the engine then quickly get it up to about 1800 rpm or so. (Turn the idle speed screw in to get it up there). Over about a 20-30 minute period, I gently ease the throttle up and back, gradually running the motor up to about 2800 rpm, then back down to 1800. Watch for fluid leaks and have someone keep an eye on temperature and oil pressure readings if you can. Shut the engine down if you encounter any problems, and continue the break-in process once the problem is solved. After the 30 minutes or so, adjust the engine back down to normal hot idle and shut it off.

At this point, I drain out the fresh oil and change it right away. Then, you can start the car up and begin to set your timing, fuel mixture, etc, etc.

Also, I like to double check the rocker arm adjustments (if applicable) at this time. Take off one valve cover and set it back on the engine while you start it and get it to a slow idle. (This should be done with the engine at operating temp). Take the loose valve cover off and set it aside. If any rockers are making noise, tighten them just till they stop. Now, start at the front rocker and loosen the nut until you hear it clacking. Then, tighten it till the noise stops, then give it an extra 1/4 to 1/2 turn. Do this on down the line and shut the engine off. Loosen the other valve cover and repeat the process. This method gets a little oil on ya, but I like doing it this way 'cause then I KNOW it's right!

Some engines, like small block Mopars, use non-adjustable shaft-mounted rocker arms that are just torqued to spec. Others use non-adjustable pedestal mounted rockers done the same way. You should be okay with these engines using mild street cams, but anything more aggressive may require adjustable pushrods or other means to get the pre-load right.

Always use a good cam lube on new cams and lifters. I like the stuff from Crane, and most aftermarket cams I buy come from Crane, so I always have some around!

So, now you've found a low buck 70s smogger motor and swapped out the stock cam! See that? Well on our way to low buck street performance already!

 

Cool idea with the poster board. Thanks for sharing.