Quote:
Originally Posted by Blk91Firebird  not trying to seem like a complete idiot but I have no idea what kind of cam your supposed to use for this kind of set up lol there are a few I know but...
Retro-Fit Hydraulic Roller ?
Hydraulic Flat Tappet ?
Solid/Mechanical Flat Tappet ?
Solid/Mechanical Roller ? |
Some lifters are pumped up by oil, meaning they're hydraulic. The cup the pushrod sits in is pushed up to the correct height by oil pressure. Some are just solid, and the cup the pushrod sits in is physically fixed in its location within the lifter.
Solid lifters are lighter (tehy're not filled with oil) and they're generally for motors taht see very high RPMs as tehy're lighter and just generally work better for that sort of work. They require maintenance though. You'll need to reset valve lash at regular intervals (adjusting the rocker arm height on the stud) whereas hydraulic lifters basically adjust themselves unless there's a problem. Most factory cars and I'd say most hot rods even have hydraulic lifters. They're just a bit more user-friendly, require less maintenance, and work fine for most people.
Now you have to consider roller vs flat tappet. A roller lifter can be hydraulic or solid, and a flat tappet lifter can be either hydraulic or solid. Doesn't matter. A roller lifter can use much more aggressive camshafts and make a lot more power. They are also not as prone to failure. This is what ahs been used since 1988 in most factory sbc's (There are exceptions). They use a roller to ride the cam in the same way your wheels on your car ride on the road.
A flat tappet lifter works a lot differently and the whole lifter must rotate along the axis of the pushrod to stay lubricated and ride the cam lobe as it goes up and down. Modern oils aren't formulated for these types of lifters anymore since they dont make flat tappet lifters in new cars anymore. You'll have to take very special care to make sure a flat tappet cam doesn't grind down a lobe and put metal shavings all through your new motor with special lubes and additives. After break in this is much less critical, but for initial startup it's a very, very big deal.
Roller lifters are for the most part always better, but they cost more money. Flat tappet style cams are fine for most people, just take care in the early stages and you should be fine. Whether or not you go hydrualic or solid depends on what kind of power range you're tryign to hit and how fast you want/need to spin the motor. IF you're gonna keep it under 6,000 RPMs and you dont know the difference between teh cam types yet, I'd say hydraulic is probably the better choice for you. Solid lifters require regular maintenance and tend to only be used in fairly serious builds that are meant to rev a bit higher than most.
If your block can take roller lifters you should use them. If it doesn't take roller lifters, the retrofit rollers will usually work, but they cost a lot more money than regular roller lifters. If your block is a 1973 block, it cant take roller lifters. Your best bet is to go flat tappet unless you've got the money to burn on nicer roller setups.
From 1955 to 1986/1987 GM used either a solid or hydraulic flat tappet in their engines. After that GM moved up to roller cams in thier engine. So you will either need a Retro_fit hydraulic roller or a flat tappet cam. The lifter bores on all of the engines are the size but the newer blocks have taller lifter bores. You can take a roller cam engine and run a flat tappet in it with no problems, but to run a roller in a older engine you have to have lifters with a connecting bar, special lenth push rods and that kind of thing. You can go to a roller in the engine but you will be looking at about $1000 to do it. If you go that way it is best to buy a kit where everything is matched and it is not so confusing that way. 
