A Few Camshaft and Related Questions...

    As some of you may know, I'm currently breaking in a motor I built for my Sunbeam Tiger in my HiPo car.


    Part of this little project originally was to give me the opportunity to detail my HiPo motor while it was out of the car. Well... It turns out it needs more than detailing, and the motor is completely disassembled, and ready to go to the machine shop.


    The cam and lifters are HOSED. I plan on putting a Comp Cams Ford 289-302 Nostalgia Plus N+271H Cam, part# 31-670-4 in it, as I did with the motor I built for the Tiger. I REALLY like this cam, and I'm sick of messing with mechanical lifters, quite frankly, so a change is in order.


    This cam is available in a "kit" which I bought for my last motor, that comes with springs, keepers, seals, lifters, and a timing chain. I called the Comp Cams help line with 2 simple questions, which the bonehead who answered the phone (after me being on hold for 20 minutes) couldn't answer. Some of these "experts" amaze me. He knew NOTHING about HiPos. All I got from him was "A 289 is a 289 is a 289." Finally, I just hung up on him, since I know I can get better answers here. Here goes:


    1. Does anyone know of a roller timing chain that has the thinner crank gear to accomodate the HiPo oil slinger? If not, can I turn a roller crank gear down to get the proper clearances for it? I'm tempted to buy a roller set, and just put my hatchet and gears in a box on the shelf.


    2. Comp Cams says you need to change your springs when using this cam. "Mr. Helpful" wasn't able to tell me if the HiPo springs are adequate to use, since "All 289s are the same." I would imagine the stock HiPo springs are more than okay for this application.


    The dollar difference is substantial.


    Any input?

    Getting any imput here is tough as most all these people are purist.I've drag raced for many years and personally love a solid lifter cam.Really I'ld rather have a roller but lets stay some what modest.Once you get a knowledge of the valve adjusting procedure it just another job but you need springs that are compatible with the camshaft your using.There are alot of spring choices today as they make some good ones but to answer your question take your springs and check the spring pressure on each spring and if they are compatible to the pressures needed on cam card go with them if not get new ones.The next question is easy as all you have to do is take the bottom gear in your chain set and mic your hatchet then take the gear to a machine shop and have that number surface ground off back side of gear and your set to go with chain selection!

    Give the machine shop the specs to your camshaft. Have them setup your spring height. If it is not a roller cam and is fairly conservative, you may get away with a single spring setup. After many heat cycles, springs wear out. Most of the heat from you valvetrain come from your springs. That is why it is important that they have a good coat of oil on them for startup as well. Most weekend racers change their springs at least once a season. A decent shop will toss the stamped locks for stronger machined locks as well. The original hipo camshaft does not have the aggressive ramp designs that Competition Cams uses.

    To my knowledge the Roller timing set for the Hipo is no longer produced by anyone.


    Cloyes DID in fact make one in the 70's - with the thinner profile needed for the hatchet weight.


    I have the part number in some notes somewhere, but I think I have posted it here before. I received this info directly from Cloyes - their "TECH" guy was TOPS - he knew exactly what a HiPo was and what was different about it. I looked extensively on-line and contacted several NOS auto parts companies and came up empty handed on the Cloyes roller set.


    You "might" be able to turn down the back of the crank gear and drill it for the hatchet weight on a regular 289 roller set - provided the chain does not hit the weight once installed - tricky, but a good machine shop should be able to do it. Not sure it would be worth the money however.


    Besides if you have your engine balanced you can leave the hatchet off and use the regular 289 roller set no problem.


    The HiPo springs are different than the regular 289, but the advice of letting the machine shop set up your heads and cam is good. Most cam spec sheets will give you the spring rates needed and the machine shop can set this up when they do the heads.

    You cannot use a double roller chain with the hatchet. There simply is not evough room. I have converted several hipos to the true roller chains, but I had to install a slug of mallory metal in the front counterwieght of the crank and not run the hatchet.

Participate now!

Don’t have an account yet? Register yourself now and be a part of our community!

Register Yourself Login