Over-Camming an engine, now time to select different cam....input appreciated

[billyrb]

Well, I finally have come to another realization. I chose the wrong cam. I selected a PAW cam that I thought would be a great, powerful camshaft. Well, it is. But not anywhere NEAR the RPM range I need. It is incredibly strong from about 3,000 to 6,000 rpm. But, anything below that, it is a broke-leg dog. The specs are:
Lift:
intake @ cam: 2947
exhaust @ cam: 3100
intake @ valve: 472
exhaust @ valve: 496
Rocker arm ratio: 1.6

Cam timing:
intake .050
opens intake @ 0 degrees btdc
opens exhaust @ 49 degrees btdc
closes intake @ 34 degrees btdc
closes exhaust @ 5 degrees btdc

Max lift:
intake @ 107 degrees atdc
exhaust @ 117 degrees btdc

Duration:
intake: 214 degrees
exhaust: 224 degrees

The idle of this thing sounds like 4 pissed-off Harley-Davidson's. Vacuum is erradic as all get out. The only time it runs well is when going over 40mph.

So, now the new dilema. Which cam to replace it with. I have researched several older posts, where people recommend the Crane-Cam 260H. What I am wondering is what everyone thinks would be a good cam for my engine, and WHY.

Here is what I have:
Rebuilt 360 (standard, no bore)
head job
new springs
new hydraulic lifters
oil-mod
D.U.I. HEI Ignition
Edelbrock 3731 EGR Intake
Edelbrock 1406 600cfm carb

Here is what I use it for:
Daily driving
light-duty off-roading once/twice a month.

Here is what I want:
1. Reliability
2. Decent gas mileage
3. Smoother idle than what I have
4. great torque at low-mid range
5. good vacuum

Please post what you think would be best and why. Also, for those that have time to kill, compare it to my current cam and tell me the differences (still a bit of a novice at cam info / selection). Thanks!

[River Beast]

I did the same thing you did a while back.. and still run the same cam... which I will change....

Get up with Kris Thokle ( member) he has a GREAT custom cam from Ingle. Only ran about $160.

He has got the same drivetrain as RBY and also 3.31's and 33x12.50's...

Pound for pound, he has MUCH more bottom end and 'oomph' off the line than RBY with a stock 360. His cam is smog legal for CA as well.. which is a BIG PLUS for the CA guys... very smooth and well worth the time and money...

give him a shout for the specs.. he has 'em... I did and lost them....

[Lindel]

Ryan, I'm not knocking the Ingle cam at all, Ingle has a very good reputation, and the price isn't at all out of line.

Take a look at the Summit SUM-K8600 model, and compare the numbers. My only complaint with it (and not the cam's fault at all), is that you need to install it "straight up". In other words, don't advance the cam during the install, you'll lose a little torque off the bottom that way. I haven't tried retarding the cam, but I know for a fact that installing the cam in the stock configuration will give you a definite "seat of the pant's" boost, off idle.

The price of the cam is less than $100, including the lifters, and a roller timing set (the old "while you're in the area" syndrome) is only about $45. (This is also a Summit part)

[billyrb]

Guys, thanks for the responses. Originally, I was going to go with the Summit Cam. Then my opinions got the better half of me. I always thought it would be neat to have a cam that bumped like mad at a stop light. Well, now that I have that (and every filling in my mouth shaking loose), I would much rather have a smoother idle & more low-end power. This thing is near 5k lbs, and shouldn't be used at higher speeds. I'll check the Isky cam and see what the specs are. Also, I'll contact Summit about their k8600 cam.

[billyrb]

Lindel, I just checked another post of yours....you stated the Summit K8600 cam info, and it looks to be the same specs as my current cam....is that true? If so, then there must be something wrong with how my cam was installed.......verify the numbers for me?

[Lindel]

I didn't pay that close attention to the numbers, I'll admit. Summit's cam is made by the same company that PAW get's their cam's from. It's possible that you installed it advanced, because I have the same problem with mine. I advanced mine by about 4 degrees of cam timing, and then used the stock ignition timing. It idled ok, but had lousy bottom end.

In the 87 GW that I used to have, I installed the same cam straight up, and the low end had lots of power. I wonder if you have a mislabeled cam??

[River Beast]

PLEASE get the numbers from Kris FIRST!!!! The specs will show you how different these cams are for top and bottom end...

I am not knocking the 'off the shelf' cams from Summit or any other company.. but the numbers will show you why the cams act the way they do... I am no expert on cams.. but Kris and I talked for some length of time... he has done his research....

YOOHOOO!!!! KRIS!?!?!?!?! COME IN KRIS!?!?!?

I'll give him a call later on and tell him about this post... he'll chime in.... jsut be patient... its early yet... ;)

[88GW]

Crane truck cam, I believe its the H260-2. Thats what I run in a freshly rebuilt 360. Plenty of low end and runs great. I overcammed too before the engine rebuild with a .488 lift cam and it sucked at low end.

[kreb]

billyrb

the summit cam and the super stock industries cam (which i believe is the one you have) are on in the same. I called summit to order the 8600 but they were on back order. another board member told me the two cams were the same. i called PAW and gave them the 8600 specs and they said the super stock matched the same exactly. that is what i bought and have used in my new engine. i am pleased with it.

benjamin

[billyrb]

Ok, then the problem must not be my cam. The problem must have been with the install. My conditions are:

1. Idle is completely fubar. It sounds like I have one heck of a HUGE cam
2. Low-end power sucks
3. If I sit at idle for more than a few seconds, I get blue smoke out the exhaust.
4. Stumbles through accelleration until I get around 2,500 to 3,000rpm
5. sounds like occassional misfires at idle

Would these things be related to an improperly installed cam (ie: retarded or advanced too far)?

How can I tell?

[Lindel]

Another possibility would be the ignition timing. What is your's set at? If the dist is one tooth off, it's about a 7 degree mistake.

Check that first, timing should be in the 8 to 10 degree before top dead center neighborhood. If the cam is advanced some, this will agrivate the other problem.

[billyrb]

I might be a tooth or so off. Heck, wouldn't surprise me at this point. I think over Christmas I will reset timing & check everything out.

[Smooshy]

I am running a comp 268H wich I think is similar to yours. Its a little weak right off idle, but nothing like you described.

[AMX factor]

I run the Comp Cams 260H with Edel Performer intake and carb. Runs pretty good for being basically stock on everything else. I have power when needed. Could use a bit more power(ex-drag racer) but I didn't wanna blow a motor. My next build will probably be with a Comp Cams 268H or 270M

[billyrb]

I'm getting the impression that the younger guy who did my shortblock didn't do things all too well. I will probably tear it down soon and start fresh. Get the engine at 0 degrees TDC #1. Yank the cam & reinstall straight up. Reinstall the timing gears / chain. Yank & reinstall the dizzy with the rotor pointing at #1. Crank it and check everything. Then, reset the timing to DUI's specs. I am thinking I might get one heck of a difference......

[fsj1978]

I don't claim to be any super genous(especially at spelling!!!) when it comes to engines but didn't the "blue smoke when idling for more than 30 seconds" set off alarms in anybody else's head???? I'd be looking for a MAJOR intake manifold gasket leak that's sucking in engine oil........

[Kris]

All right already... !
I'm here.... !
;)
Ryan, just sent you an e-mail.
And since I didnt check here first, I cant reply to this in the depth that I did in the mail, Ive got typers cramp...
The cam has been great. Its everything I could have asked for in a cam for a street driven, occasionally off-roaded, 4500+lb. Wagoneer.
Paul is running this cam in his 401. We are putting it in MikeB's 401, I will put it in my 401 when I get to it.
But...
Although I can pass tailpipe smog on the Dyno here in Kalifornia, it is not a "smog legal" cam. Im on the high side of the allowable emissions, but can get it to pass by retarding the ignition a few degrees.

Overcaming has more to do with duration and lobe center than with lift.
Mine has .489/.501 lift, but only 209/214 duration (@.050"). Lobe center is 112*.
Increased duration and overlap makes for a crappy low end cam. RPM's need to get up before the cam can breathe properly with increased overlap.

On the smoke...
Yes I did notice that in the post.
My first guess was damaging an intake valve seal in the assembly process. Blue smoke is oil...
:D
kris.

[billyrb]

The blue smoke IS oil. But, it isn't a result of a damages valvetrain. I had this problem since I rebuilt the engine. Then, once I got fed up with it, I removed the heads and took them to a trusted machine shop. The guy said they were ever-so-slightly out of spec, but he re-did the head job and fixed the problem.

Something about the intake: it's an Aluminum Edelbrock 3731. But, for the rebuild, I installed an oil-bypass tube in the valley. As of this, the metal cover / shield on the underside of the intake had to be removed. Now that I think about it, I wonder if this could be the problem for the smoke and the warm off-idle stumble I am experiencing......

[billyrb]

I spoke with an Edelbrock rep about removing the heat-shield from the intake. He says that at idle, it can suck hot oil into the intake, which could cause this problem. He is doing a little more research about it, and said he'd get back to me. So, I may have another tear-down in my immediate future. Great. I love doing that. No. Really. I do. Oh yeah. It's like a root canal. so. much. fun.

[KYJ10]

Ryan, you know my thoughts on the Summit Cams. Both of my 8600's went south. The amchine shop put a different mfg, and all is good. It has slightly lower #'s. 204-214 duration. It has a ton of low end. I think it's made by melling or billing, something like that. Ask a machine shop about this cam. Its called a torquer cam he said. They only showed one in their book. I can get you the exact mfg name and part # if you like? Dennis

[billyrb]

Sure, shoot it my way. Once I reset timing / dizzy / cam, I hope it runs well. If not, I'll be yanking it out. Heck, I may just put in a new one first to remove all doubt. Then, I'll sell the existing cam on Ebay or something to recoup some of my costs. My gut feeling is that it was installed wrong, and that I am off on the dizzy. Let me know what the part #'s are. Thanks.

[billyrb]

Narrowing down the problems still......I think my intake is slightly off.....the heads were surfaced, but not by much. But, the intake wasn't. That ain't good. Also, the heat shield was removed from the intake (by me, to clear the oil-bypass mod), which also isn't good.....ahhh, the ball of twine begins to unravel....

[Al Johnson]

Sounds like you're on the right track for the oil problem. The pan should be on the intake, or it will burn oil.

As far as the cam, I'm running a K8600, same specs as yours. Installed 2° advanced for better bottom end. It has gobs of torque, right off idle up to around 4500. Still pulling, but starting to slack off. So I think something else is wrong in your setup, other than cam choice. If there's a chance it was installed retarded, that could explain the high RPM bias. Ignition also, as previously mentioned. You're on the right trail, it's just going to involve some nasty work to fix, if you have to redo the cam installation.

Good luck!
Al

[bigun]

did you degree the cam or just put it in

[Hammer]

Sounds like the cam is retarded too far. Plus the oiling issue. The simple test for the oiling is to pull your fill tube cap and watch it at idle. And triple check your PCV valve to make sure that is working. I haven't ran with either the valley pan or the small pan on the intake in years, and only get a little oil blowing up the fill tube at higher rpms.
I like the numbers on the cam, but I would run it either 2° or 4° advanced to get the great bottom end it can give you. I usually recommend the plain old Edelbrock performer cam. But these other cams offer a little bit more, which works especially well with the 401's. Or maybe slightly advanced in a 360.

[Marvin Gates]

Just one thing to remember "ENGLE" not Ingle! Engle has been around since the 50's and have been a winner for years, the younger people don't know about them cause they don't advertise. Their quality is known by old drag racers. They used to do all the cam work for Don Prudome when he started out in the 50's (and was never beaten in top fuel) at Lions Drag strip. HMMMMM I guess I'm old. I have talked to Chris about his cam and have seen it in action at Gorman 2002. Most of the off the shelf cams are designed off of the chevy platform so if you want the real deal, go for something that is designed for the motor that you are using! Just my humble opinion. smile.gif

[billyrb]

Good points, gentlemen! I am going to dig up my old machine-shop receipt for the short-block. See if it mentions cam install. The shop installed it for me, so I am unsure if it was retarded, straight up, or advanced.

As for ignition, I have a DUI HEI setup, but I may also be one tooth off.

Sheesh. I hate always working on my motor.

[jaber]

Well, on the bright side, you are giving this first timer alot of notes for my first rebuild. THANKS.

[billyrb]

Jaber, I am FULL of notes for a rebuild! One main thing to look for, that most people don't know about, is the timing chain gear. Just out from the center, there will be a hole drilled on each side of the gear (front & back). On most, this hole doesn't connect from one side to the other. If not, you have to drill it out. That hole is to allow oil to pass through. If it isn't drilled all the way, you can chew up your distributor gear / cam gear, etc. I had a post on it a while back. Here is the link for it:Timing Gear Modification Required (http://www.ifsja.org/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=2&t=009595)

[Michael]

Originally posted by Lindel:
Ryan, I'm not knocking the Ingle cam at all, Ingle has a very good reputation, and the price isn't at all out of line.

Take a look at the Summit SUM-K8600 model, and compare the numbers. My only complaint with it (and not the cam's fault at all), is that you need to install it "straight up". In other words, don't advance the cam during the install, you'll lose a little torque off the bottom that way. I haven't tried retarding the cam, but I know for a fact that installing the cam in the stock configuration will give you a definite "seat of the pant's" boost, off idle.

The price of the cam is less than $100, including the lifters, and a roller timing set (the old "while you're in the area" syndrome) is only about $45. (This is also a Summit part)I agree with Lindel. The cam you metioned is the sum-8601. PAW sells the same cam under there name. From Super stock industries or whatever their name is. It is the same cam I run on mine and I love it. Lots of low end torque and top end is even better. As far as the idle and vaccum. It does have a rough idle and my vaccum is low due to the high duration and overlap on the valves. I would go with the 8600 for sure.

[billyrb]

Wow, I have gotten tons of info from ya'll. I took it, researched it all, and was still wondering if my cam was working properly / if I over-cammed it. So, I talked to one of the most knowledgeable AMC Engine Builders & Racers in the nation (he was the guy that, during my first rebuild, caught the timing-gear oil passage that wasn't drilled all the way through). I gave him the specs on the engine, and instantly he said that with my compression (roughly 8.5:1) that cam is WAYYYYYY too big. He described how he thought that cam would run, and it is almost exactly what I am experiencing.

After talking for about an hour and change, I am going to eventually swap to the Crane Cams H-260-2 (same one 88GW recommended). I am also going to change a few other things, but more on that later. After the holidays, I may pay that guy to do the work for me, just so I can watch a master at work.

Thanks for all your help!

[GaWag]

Well Ryan if you do go for another cam I am running the comp cams rv cam. I do not know the spec. It is in the book tho. You know my rig and it runs and idles smooth. Even with my 35's and 3.31's I get a little jump off the line. Can't wait to regear.

Steve

[badaboom]

billyrb,

I ditto the engle cam, angle. I have utilized there cams in the past and have been very happy.

I am currently running the competition cam 268H
in my J-10 AMC 360 and have been happy with it also.1500 -5500 rpm range

Duration:advertised @.050 valve lift 1.6 Rocker
IN EX IN EX IN EX
268 268 218 218 .456 .456
lob separation angle 110 degrees.

Good luck on you exploratory surgery.

[ChuckWag]

Ryan:

This may sound like blasphemy, but why not consider putting in a stock cam?? Everybody in our group who has put in the DUI and other fancy stuff did so (I think) with the stock cam, and they're all running fine. Look at Tweety-bud: fat cam = PITA with timing, tuning, etc, etc.

RedWag is straight up, only mod is the headers. And it'll pull the chrome off a trailer hitch!

I'm considering pulling the fat cam and pistons outa the 350 in Tweety-Bud if I can';t get her smoothed out...this is a Jeep...not a racecar.

.02 from a simpleton grease-monkey...hee-hee

CR