For the bang for buck to get around 375hp sounds like: hydraulic cam 212 or 284 port heads with new stage 1 springs new lifters, pushrods
The best part about the roller cam design is that you can have a race type cam and a street cam in one because the cam is not a compromise the way it was with the regular old cams.[/quote] I'm not sure what you are trying to tell me? Its a race cam that is very reliable with a street grind for its manners?o No:
I am sorry, poor wording... My point is that the advantage of a roller cam is that the profile can be agressive and give good HP like a larger flat tappet cam, while still giving great street freindly low RPM performance. With the typical flat tappet cams it is hard to have your cake and eat it too... A full out race cam in the flat tappet design will give up lots of low RPM power. A full out race cam in the roller design will have better low RPM power. For a mild application like a close to stock cam the advantage for the roller vs flat tappet is less noticable.
Any cam should be at least checked with a degree wheel to be sure it is at least close to where you are aiming to have it set up. It takes a bit of time however why spend $ on head porting etc to miss out on some cheep HP by degreeing the cam. Sounds good to me!:beers2: I suggest getting adjsutable pushrods so you can fine tune each one.... Any time there are valvejobs or other variables changed the pushrod length may need to be fine tuned.
Sooo, I have a question....why all the fuss with adjustable pushrods? Are hydraulic lifter not design to take up the slack/compensate for different valve stem height?
Now that makes more sense and I think my prvious post was on the right track but maybee wording wasn't great. So if i really was looking to make this car more of drag car with some street mixed in the Hydraulic Roller makes a lot of sense and the extra cost is worth it.
degreeing the cam is so very easy , simple and cheap that it should be done regardless.... The adjustable pushrods are soley to take up the difference between either a new cam that was ground to a smaller base circle, decking the block or cutting the heads. In my opinion its just as cheap to have custom larger diameter pushrods made to the right length. The roller rockers while making alot less friction as well as being alot stronger make a wise choice with large lift high stress cam profiles. The roller cam allows a much quicker ramp speed over the flat tappet giving it its better street manners. And the flat tappet cam gives a much truer profile over the hydraulic becuase there is no " shock absorber " effect to the valve train......I run a fairly aggresive flat tappet now and can still drive it on the street but it's defineatly not my daily driver ! I am still not even sure the roller cams for the small block are fully available yet ??
350 roller cams and roller lifters have been available for a while..as for the lil stuff like a cam button and and w/e else may be roller cam specicic...not too sure
I agree this is an option and as you know it is best to measure using adjustable pushrods before you order custom length rods. Without mocking up the engine to find out what you really need for pushrod length there is no way to know what length are required. Another factor is the stock decks of the blocks are rarely square to the pistons so different length pushrods are usually required around the engine. I know you know all this just adding it so others can learn... The roller cams are out there, this spring we should get the numbers on how the roller cam from TA works in an R&D Buick 350 race car without a power adder.
Hydraulic lifters are designed to create "zero lash" in the valve-train, but the problem comes when there are many different sources of variation. - From factory the pushrods are "close enough" to the right length, but not optimized. - Over time as parts wear (cam, lifters, pushrod tips, rockers, shafts, valve stem tips)... Because of this wear it becomes too much to ask for the lifter to take up all the slack. - Many times longer pushrods are required on engines as they get higher in milage. Looking over the receipts for my 76, its first engine work was at 74,000 miles when the valvetrain began to clatter a bit. The lady who owned the car was VERY particular and had longer pushrods installed... Never any issues with the engine after that. So add factors like wear, valve stem heights, etc. it is not hard to see why an adjustable pushrods (or custom length) are a good idea... People tend to spend $ on high end parts and not optimize things like degreeing the cam and optimizing the pushrod length and they miss out on HP and reliablity.
With hydraulics there is a delicate balance between lifter noise, spring pressure and valve float. The factory uses about the lightest springs they could get by with to hold valve float above the 5500-6000 rpm range for long life, but this means keeping the pushrods as short as possible without clatter. That's why it only takes a little wear to get noise. The lifters themselves have nearly a quarter inch of usable travel. That means stock pushrods are usually fine if the head has to be surfaced. But anything else that is changed is likely to cause trouble if pushrod length isn't balanced out. And if you go too deep in the lifter travel it takes more spring pressure to keep the valves from floating. I generally shoot for about .060-.080" of compression in the lifter and that seems to work out pretty well. If you think about it this also explains the noisy operation of Rhodes and other lifters designed to bleed down fast to prevent "pump-up". With those I'd think seriously about adjustable rockers. Now as to the degreeing of the cam. Personally I did not find it to be at all simple or intuitive, so could someone give a quick run-through on the proper way to do that? JB
if a person is not comfortable with degreeing the cam and or does not have the tools then it is a good idea to pay someone to do it or find a friend who can help. Here is some info: http://www.cranecams.com/uploads/instructions/803.pdf
Read what sean posted...thats the ticket for degreeing the camshaft..... As far as ther rhodes lifters, I used them and they suck in my opinion ( just me ). You also have to keep in mind that when you use an aftermarket camshaft ( larger grinds ) you will have rocker arm geometry that will come to play. Thats another reason to use either adjustable or new pushrods of the correct length. Not to steal this thread but ......what roller lifters are available for the small block and why the heck would they make a hydraulic roller cam ???
Looks like that should be helpful, but will require a bit of study. Sean, I was just hoping you could condense it down to the finer points. I know for instance when I degreed my cam in the 340 there was great confusion about how to read the wheel. And it wasn't for lack of reading glasses (I have those), I have a 16" wheel. Anyway, because SBB cams are all "Reduced Base Circle" cams it means any time you increase the lift you reduce the base circle. That means (because the factory used short pushrods to reduce spring pressure) you need longer pushrods with any performance cam. It's an additional expense, but a necessary one. As for the hydraulic rollers, why would you not? The hydraulic element plays the same part as in a flat tappet lifter, it takes up the slack to eliminate valvetrain noise and keep the valve lash at the proper spec. Solid lifters do not allow any more lift or duration, the hydraulic ramp is added to the no-lift area at the toe of the up ramp to take up the lash and a solid lifter cam simply does not have that mini-ramp added. What limits the lift of a hydraulic cam is the lifter's tendency to accumulate oil on the downslope as it's valve spring is fighting to keep it in contact with the cam lobe and engine oil pressure is trying to expand it. At high enough speeds the internal pressure wins out and the lifter pumps up, floating the valves around the base circle, reducing power and limiting rpm. You can run solids on either type if RPMs are your goal but for speeds under about 7 grand the right combination of components allow the use of hydraulics so why would you? JB
don't get me wrong, hydraulics are all useful. But , If your going to use a roller cam which requires roller lifters which will require either adjustable pushrods or new pushrods your more than likely to use roller rockers since your going for the least amount of friction. Saying so why not use a solid tappet to utilize precise tolerances ...which with higher spring rates and rpms hydraulics do tend to create lifter collapse.
You have good points as well! Good discussion on the different types of cams and lifters!! The solid lifter flat tappet you run in your 350 works great! Many people do not take the time to optimize all the factors like you have in your build and it shows! http://s1021.photobucket.com/albums...34/swannymh/?action=view¤t=100_0387.mp4
Ok reading up on degreeing and not sure if I will attempt this by myself but maybe I can find someone locally to help on that front. What if I can't? How much performance could I lose by not degreeing? Sounds like a 9 key timing chainis the way to go if you are degreeing correct? Push rods comments are showing up so seem adjustables are the way to go it seems. When using them how do you know what lentgh is correct? Looking at the cams 212,284,290, could I have valve to piston clearance issues or is that more for the race cams? Thanks for all the help.
