shawn
So, why is this cam highly recommended? What are good applications for this cam? I am about to order an Edel Performer cam, but I read on this board teh Summit one is very good. This will be going on a 304 on my CJ, so idle torque is crutial. The summit cam says it's for 1500-4500rpms, so is it not good off idle cam? Would the Edel cam be better? I've got the Edel intake on right now, and just got in the new Edel Classic Valve Covers so I figure I'll just through a cam in while I'm at it. Thanks for any advice.
jeepsr4ever
The edelbrock performer camshaft is dyno'ed around the 304CID so I would try that if your looking for the low to mid range.
tarior
Summit cam velly, velly bad. Had two in a row go flat, ruined a new motor :(: Buy Comp or Crane!
shawn
After some research, I here (through the grape-vine) that Edel cams are actually Clevite cams. So I start looking at the specs of the Clevite cam, the RV cam 77 is in fact the exact same as the Edel 2123. Hmmm. And it's a lot less $$$$.
JMSII
I have had GREAT luck with Reed cams...they have been doing great AMC cams for quite some time! I had the edelbrock performer and was not pleased with the low end torque. Just my two-cent's worth! :t:
SwampRat
To whomever said they had two summit cams go flat, no offense, but more than likely this was your fault. You are correct, the summit cams won't be as precise as something from a major manufacturer, but if you ruined two cams sucessfully I heavily doubt it was their machining.
The truth about the clevite, edelbrock, melling, and speed pro ect grinds is that they are all from a placed called CMC in Michigan. So that's why whoever found some identical grinds in a couple different catalogs.
The summit cams are good for a low performance engine, and they will make good average power for the money, but they won't have nearly the ramp speed as some of the new stuff out there. But like I said, they will make great average torque for a street car.
I will be glad to make a reccommendation to the first poster here with some more vehicle and engine specs.
donwag
Okay, Swamprat, I will bite.
401 .30 over
Stock cast pistons
Edelbrock heads (flow slightly better than stock, some porting, 2.02 and 1.6 valves, 54cc)
Edelbrock performer intake, 650 to 670 cfm carb
Compression ratio will be approximately 9.24
Stock 727 with Transgo shift kit
Daily driver with occasional leadfoot just to show the bowties their place.
What is your recommendaton?
jeepsr4ever
comp cams 26oH
donwag
How about CC XE256H? This is the cam I have tentatively picked.
I will check the specs on the 260. Thanks.
pablorg
donwag wroteOkay, Swamprat, I will bite.
401 .30 over
Stock cast pistons
Edelbrock heads (flow slightly better than stock, some porting, 2.02 and 1.6 valves, 54cc)
Edelbrock performer intake, 650 to 670 cfm carb
Compression ratio will be approximately 9.24
Stock 727 with Transgo shift kit
Daily driver with occasional leadfoot just to show the bowties their place.
What is your recommendaton?
The Edelbrock Heads flow only SLIGHTLY better than stock?? I am about to finish installing them but I hoped for a huge improvement over stock, to justify the ~$1500 investment........
SwampRat
I've seen highly reworked #291 AMC heads flow about 270 CFM @.700 on the intake side with a 2.08" valve, granted it was on a bore of something like 4.2"-4.25". The edelbrock heads with a smaller valve (and guessing smaller intake runner volume) flow 250+ CFM with a similiar bore size @.500" lift, and I'm guessing have quite a bit of potential as well, but even if they really are maxed out at 270 CFM (which I doubt, and am unsure of), it will probably be at a little more usable lift for a budget engine.
As far as cam goes your compression is your main limiting factor, for a street car with a tight converter and especially a 3 speed the cam timing I was taught to put with this is on a very wide LCA (preferrably 114 LCA) So a profile needs a lot of compression since it has a later closing than a similiar grind on, let's say a 110 LCA. I strongly believe that a 110 LCA cam has it uses, with a 3000-4000 converter, but otherwise the profile's LCA should stay wide to make as much average torque as possible, this type of cam profiling also likes a little bit of nitrous and the tall gears associated with a street ride. Giving a general reccommendation it looks like about 215-220* of duration @.050 on a 112-114 LCA. For some reason a lot of major manufacturer's grinds for AMC's seem to be on 106-108 LCA's (maybe keeping the smaller engines in mind). But crane should have a decent amount of cams to pick from like this, but the best ramp is gonna be found from a custom grind, but for a street ride I understand wanting to stick with a off the shelf grind, so take a look at em at some place like www.summitracing.com
tarior
SwampRat wroteTo whomever said they had two summit cams go flat, no offense, but more than likely this was your fault. You are correct, the summit cams won't be as precise as something from a major manufacturer, but if you ruined two cams sucessfully I heavily doubt it was their machining.
No, I followed the instructions to the letter when I installed them. I had several engine builds under my belt (including a couple AMC's) , and I knew what I was doing. I didn't do anything different when I put the Crane cam in, and guess what?, no problems, even with the double springs installed.
My personal feeling isn't that the Summit cams are not machined correctly, but I tend to think that the QC in the heat treating of the lobes is lacking.
BTW, you should probably get to know a guy before you tell him he is f@#king up :mrgreen:
jeepsr4ever
Their are only 3 (IRRC) camshaft casting houses in the US and just a couple dozen cam grinders. The majority of the isues you will see in camshafts has to do with the quality of the lifters. After Johnson lifter was bought out and taken over the quality of lifter went WAY down and I do not believe that a single hydralic lifter is made stateside anymore.
SwampRat
There is no reason why two new camshafts would go flat and it was completely the manufacturer's fault, if the odds were that great that if you bought a summit cam and it ruined itself, they still wouldn't be selling cams. Did you use brand new lifters on your brand new cam? Did you break in the cam with light valve springs and low ratio rockers? Did you use oil with zinc or a break in oil additive? Did you drain the oil while it was hot after the break-in and inspect the filter? Did you vary the RPM's between 2000-3000 for twenty minutes? Did the engine start IMMEDIATELY when the starter was hit? And last but not last least, if you think you did all of these correctly, the block's factory machining may be off, I've seen this problem in big block chevys and the such were a engine keeps eating a lobe, just a case where the "perpendicularity" is "off."
I said no offense to my comments for a reason, don't take any offense from them. I'm sure thousands of people, even who have built engines loose flat tappets cams each year. Just because you built a engine and it turned out fine doesn't mean that the next might ruin a lobe, it's tricky business with flat tappet cams, but I still like for them for cost reasons with small profiles. I just recently received my monthly "Power and Performance" article from Comp Cams and the first article in it was in regards to breaking in flat tappet cams. So obviously it is still a problem.
tarior
MC makes a good point about lifters, I didn't use Summit lifters when I installed the Crane, that may have been the difference.
As far as being offended, I'm over it 8)
SwampRat
Comp Cams claims all of their lifters are made in the US...
jeepsr4ever
Made and assembed can be one in the same sales jargon. I cant say for sure, only speculate but the rumors are no more state side hydralic lifters.
tarior
I was just about to ask: where do ya' suppose Comp and Crane source their lifters from? What about Rhoads lifters? I think I may have to start a new thread about Rhoads, I'm kinda curious.
SwampRat
Variable Duration lifters are a touchy subject. There is a certain "sweet spot" where they actually have a purpose, and in other areas they aren't worth it. With durations less than 210@.050 the duration is already small enough (and the engine already "smooth" enough) and will not make much difference, and with durations over 230@.050 the duration "cut-out" by the lifter starts getting small compared to the total duration (seat duration) and once again the "gains" become less noticeable. Companies like rhoads advertise a drop in seat duration of 10*, I have a hard time believing this and have seen quotes from much more informed people than myself say 4-6*
Rhoads also introduce a whole set of valvetrain problems as well. They are more apt to "collapse" under high spring loads because that is basically what a fast-bleed down lifter does! It cuts duration off of the closing edge of the lobe, and supposedly different cams with different closing ramps can be effected by these kind of lifters differently (if that makes any sense)(and even though this is also hard to verify).
There are also wives tales out there saying that you need such and such oil pressure for them to work right, and if they aren't clattering then they aren't working. I can't verify any of these claims myself, but they seem like a little bit of a farse.
If you open up the pages of "How to build and modify small block chevrolet V8 Camshafts and Valvetrain" by David Vizard you will also find a detailed explanation of how fast-bleed down lifters effect cam timing and require a re-adjustment of cam timing (adv./ret.) to compensate. In this book you will also find quite a bit of info on them, including some of his testing on certain lifter's bleed down rates, but this book was published going on 15 years ago, and these tests may be somewhat "void."
All in all, they may have some purpose, they may not. This subject maybe even more than others is something that maybe should be tried yourself. But I kinda think that annular boosters and vacuum advances may be better camshaft "tamers" in some situations, especially maybe durations more than 230@.050, and once durations start getting that high extra compression with something such as water injection to keep it tame under pump fuel also seems to have some merit.
Hope this answers some of your questions.
tarior
Well, actually, my question bout Rhoads had to with their quality, as they claim to be entirely U.S. made. As it happens, my present motor project and the next one I have on deck use cams that fall right in that 210-230 degree (@.050) range. In fact, that's just about where the majority of "street" cams fall.
Back to my original query, how are the Rhoads for quality, are they actually made in the US?
In my present motor project, which is 90% assembled, I'm using a Comp 268H and I'm using Comp lifters. The engine I have on deck will use a Crane cam 214/224 @ .050" .488/.498 lift, I have run this cam before with regular lifters (in the motor that had the two Summit cams go flat), and it was weak below 2500 rpm, then came on VERY strong up to about 6000 rpm. I would like to use Rhoads lifters if they will shift the power band down 500-700 rpm. Have you had much experience with them? I don't really want to mess around with the cam timing if I can avoid it. Oh, yeah both of these engines are 360's.[/u]
