I know alot of people prefer the Isky street/strip cams for Flatheads, but what about the compe***ion only, full race cams that Speedway Motors sells? Any one have any problems with them? How do they run and sound? Thanks, -Dean
hey man, I keep hearing the L100 cam being mentioned as a really good cam. I know of a few people on here who are going to run them but have never experienced one in real life. I have heard the Isky 3/4 cam (Max1?) is a waste of time and the 400jnr is alot better. What about Schneider? Danny
Isky has limited choices for the street and their race cams are ancient designs. Check out Schneider. They list a wide choice on their site plus they have masters for just about anything you could possibly dream up. Remember that any one particular design may not be suitable for all the displacements used in a flatty. Once I went with Schneider I never looked back.
hey 286, for some reason i thought you were a fan of the L100? what schneider cam you running at the moment? best choice for currently stock displacement 8ba? i could talk flathead cam choices all day.... danny
My pop is running an isky 400jr track cam in his 286" 8ba in his AV8. His motor has been fully built, chevy valves, balanced, blueprinted, ported, relieved, bored, stroked, the whole bit. It really sounds bad *** with straight headers! He's running an aluminum flywheel too. It works out great in that light car, but I don't think that cam or the aluminum flywheel would be the choice for a heavier car. My '47 I'm running the 59AB bored .040 with an isky max 1. With headers and duals it sounds great, much better than before I tore it down, but it's a lot healther now too. My motor is much milder but does good in the bigger car. Both cars have high compression heads. Pops motor is around 8.5-9:1 compression I don't remember exactly, my car is 8:1. Pop runs triple 97's hooked progressive, I've got dual 94's hooked straight.
Great post, It seems that most often there are many mistakes made when building flathead fords. The big one's are over camming and over fueling. There is also the most glorified mistake reliving the block. 1st it only helps to promote cracking between the valve's. 2nd it dramaticlly reduces compression. 3rd some folks thought that some where between 46-48 ford used to send them out from the factory this way, yes they did but only to use up old stock, the heads put on those enginge's were out dated and needed to be used. A more practical aproach is to slightly radius the area just after the valve to resemble an airplane wing. Two things happen with this, you will pick up tons of velocity and compession, just the very things needed to make horsepower. I hope this helps out the flathead builders out there.
Ah, the great argument. To relieve or not to relieve. I used to be an armchair proponent of not relieving. Now I think it depends on expectations and how the engine is used. For a street driven engine, it probably doesn't make much difference, so why drop compression for a little more flow? Flow bench work by any number of people indicates that a relief improves flow. According to Joe Abbin, even Mark Kirby of Motor City Flathead no longer advocates the mild relief they once did. As for lost compression, with a relief you can enlarge the opening of the transfer space with less loss of material than you can by taking it out of the head. This, of course, presupposes that the transfer area is in need of enlarging, and in a compe***ion engine, it seems to need it. The other thing to consider is that the intake charge is only one thing that has to go through the transfer space. You also have to get the ignited charge through there to apply pressure to the piston. Even if the intake charge wants to go up, and I think it does, the pressure charge doesn't. A trick several drag racers have used (Whitey McDonald and Rick Schnell a**** them) is to bevel the leading edge of the piston to match the bottom of the relief. They claim this reduces the rocking of the piston, applies a little more force down instead of sideways against the piston, and smoothes the initial flow of the lit charge. I'm sure the argument will go on for decades. I think two things are probably true. One is that you can't tell what effect anything you've done to an engine is having without precise measurement such as a drag strip with an accurate timing system, a dyno, or a flow bench and the readings from them have to account for weather variables and so on. Seat of the pants is too easily influenced by what you want it to be. The other thing is that compe***ion and street engines are two completely different beasts and you need to be very careful when transferring build parameters between them. And finally, the Flathead/Inline Nationals is at Bandimere Speedway is only a week away. After a few days in the pits, I may have changed my mind completely. After all, I've never done the kind of testing that is required either, so all my info is second hand.
The most common mistake made when discussing the building of flatheads is speaking in absolutes! I think you'll get a a little pushback on some of your views - there are dyno tests out there that are starting to disprove the over-carbing theory, for example. It seems our little flathead likes a lot of carb, if the charge can be efficiently maneuvered through the multiple switch-backs of the snaking port. This is only possible with heavily m***aged ports... As for dramatically reducing compression, I think we'll have to figure out how much "dramatically" is - even an aggressive relief of .125" or so, isn't all that much & the flathead Harley racers will argue with you all day long about the benefit of reliefs - they're mandatory for those guys, even done by the factory for the R-model stuff (WR, KR, KHR, etc.). Compression is important, but you've got to fill the chamber effectively too - it's a compromise portion of the engine design/build. I think a lot depends on what your expectations are for any given engine. Your reduced-relief-ish, airplane wing is a very good approach for a street-driven car. For something a bit more all-out & large displacement, you're going to need a bit more room to move the air. Current testing is still largely contradictory & even Abbin is advocating the mild cut, but back cutting the head over & behind the valve now. Personally, I think there's more to the pop-up pistons like Navarro was running - that's the way forward in the Harley arena too. Of course, you can eliminate all this BS & flow restriction by simply bolting a blower on!
hey everyone, speaking of blown flatheads...everyone seen Rad*******s new toy? http://www.jalopyjournal.com/forum/showthread.php?t=56799 Dany
listen to what speedy bill at speedway says and go with the max 1. you'll need a LOT of cubes, low gears and light weight with that 400 jr.
You mentioned sound. If you want a cam with a ragged idle, pick one that has at least a fair amount of duration and a lot of overlap. You ask about how it runs. If best performance it the goal, select a cam that's compatible with your combination of parts and intended use. An excessively radical cam will take more away from performance than one that's too conservative. Generally speaking, radical cams wear stiff out a lot faster, get lower fuel economy, and are less user friendly in everyday use.
Im not going to tell you not to buy an ISKY cam but I would strongly suggest you get a degree wheel and dial indicator and check it when you install it. I had a 1007B ground by them and it wasnt even close to spec. I wonder how many people just put them in and think they are good. You would also do yourself a favor and check out the Ford barn guys for some cam help. Pete, Ol Ron and JWL a****st others, have decades of expierience with these motors. the L100 is supposed to be a great high performance cam the 1007 B is supposedto be a great torque midrange cam.
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