I HATE MY CAMSHAFT!!!

[Kenall]

which of corse is my fault cuz i chose it and installed it...

but it idles like crap compared to the one i took out. i said to myself, what can go wrong with a simple cam change!?!

i upped the duration to 204/214 and have used 1.5 and 1.6 roller rockers but my idle vacum is a shacky 19-20 when it was a SOLID 21-22 before :(

this is the summit 79$ variety for the 1973 small block GM and of corse they have the next size down which I THINK is like the cam i took out, but there are no marks on the cam i took out to tell me what lift, duration, yadda yadda yadda, cept to say that the rebuilding sheet say 'Crane OE'.

i still have the old cam...shood i gamble again and buy a nu 194/204 duration@050 cam or put the old one back in with nu lifters???

[ May 11, 2003, 01:02 PM: Message edited by: Kenall ]

[TexasJ10]

You are scaring me. I planned on putting the Summit 214/224 cam in my 360 and I thought everyone said they were well behaved and idled like stock. I wonder if you have a vacuum leak somewhere else.

[Lindel]

Texas, the sbc and the AMC are two completely different animals. The SUM-K8600 is a good cam for the 360, and as Ken has found out, the sbc (and sbf too) are easy to over cam.

Ken, if the old cam doesn't have much wear, and the cam bearings are still good in the motor, you can reinstall the old cam, but you'll have to buy new lifters again. Are you sure that you don't have a vacuum leak?

[Stuka]

Is that 204/214 at advertised duration or at .050? that can make a huge differance.

Also, (and dont think I am saying you dont know what your doing, just pointing something out) is the cam degreed correctly? If its 1 tooth off it will still run, but will idle terribly. That cam shouldent make the engine lope that much. Even if its the duration at .050, that isnt that much.

EDIT: fixed typo

[ May 11, 2003, 08:22 PM: Message edited by: Stuka ]

[Kenall]

204/214 @050. 272 advertised

no vac leaks, hell, when i disconect a vac line the idle improves!!!

degreed straight up, confirmed that b4.

i shood qualify meself, when i saw it idles like crap i mean COMPARED to how it performed b4 i changed it.

the vac needle slowly pulses now at 19 n 20 compared to a vac needle that dint move AT ALL b4.

[ May 12, 2003, 01:08 AM: Message edited by: Kenall ]

[Midnightwagon]

thats a small cam. i have one a step above it adv @ 282/292 (i think) and it idles great you've definately got something wrong there did you prefill the lifters? some manufactures recommend some dont but i had this one act like a huge cam before i tore it all down again and prefilled the lifters, then it ran great. mine is also the summit special (oh its a summit k-1105) (AAAHHHHHHHH THIS IS MY 666TH POST)

[ May 12, 2003, 03:03 AM: Message edited by: Midnightwagon ]

[Midnightwagon]

BAD JU JU OK NOW I FEEL BETTER ITS MY 667TH

[Stuka]

Kenall: have you tried adjust the mixture of the carb? It will need to be changed with a different cam.

[derf]

If it runs better with a vacuum line removed, I bet you're running way too rich and/or you need to check the timing.

[netbear]

The slight loss of vacuum will happen with the
larger cam timing but I agree with the others,
first I think your carb needs tuning. If that does
not fix it, you need to make sure you don't have one
or more of your rockers too tight. I would back them
off one at a time and try re-adjustment. It could
also be a lifter that's not working correctly.
--
If all of this does not do it, you can put the old
cam back in with new quality lifters. Make sure
you put the break-in goop on the cam to break
in the new lifters if you go this route.

I don't think your new cam is too big for it
to have a smooth idle. Good luck!

[Kenall]

left the rockers in a pale of oil overnight and moved the plungers up n down with an old pushrod before install, (replaced the rods too).

nu 650 carb, compared to the 750 i took off, maybe i shood go back to the bigger carb!

always runs rich, it seems to idle better running rich. when i lean it out so that the disconnected vac line has no effect, it idles even worst. so the best idle, is when it running rich. my edlebrock air/fuel reedout stays at 13:1 during idle.

adjusted rockers while engine running. back nut off till clacking, turn down 1 full turn when it stops.

[netbear]

Hmmm. If your timing is set correctly with the
vacuum line disconnected, and your new carb is
not the problem, and as you've said, the rockers
are all adjusted correctly, then I bet you
have a vacuum leak. I would also try the old carb,
since many times I have seen new carbs that had
problems with idle calibration.

If all else fails, throw the old cam back in
since it seems to have performed well for you.
Summit has a great return policy if the item
you bought is not right.

Recheck your intake to head sealing for vacuum
leaks, recheck the timing and try the old carb.

[miked]

did you degree the cam when you installed it?

<set kenspeak on>
thos in the know say that if not then u will c problms lik this
</>

you can measure the old cam and determine specs, not too hard

edit: re:degreed, nevermind, just read deeper on the 2nd pass thru the post

try spraying carb cleaner around the intake to check for leak?

[ May 12, 2003, 04:04 PM: Message edited by: miked ]

[Wagillac]

I have a crane 272 adv in the 350 that is in my car. It has a little more lope to the idle than stock but will still idle pretty low just fine. It idles fine at 5-600 in drive. I just put a summit K1104 in a 350 for my moms 64 nova. It has a little lope but I like it and havent had any problems with the idle. I realy like a the lope that says its more than just a stock motor with headers and exhaust pipes, sounds nice. I wish I had went bigger in my car.

[Kenall]

dint degree the cam

spraying the intake has no effect

since it picks up a few rpm when i 'create' a vacum leek, i figger i dont have one where the intake and the heads meet.

how about this..since the build sheet for the block reeds 'Crane OE' and i loved how it ran, y dont i go back to a nu 'Crane OE' cam, instead of trying to save a few bucks goin the cheep route, or performance route, what did that get me!?! :(

do yall like the 3 way crank keys?? for a hiway cruiser, do i need to advance the cam?

[Lindel]

I'd install the cam at 0 degrees, or straight up. No timing issues to deal with, and you'll get predictable results.

Check the valve adj one more time. It sounds as if you've adjusted the valve train a little tight.

[Joe J-Truck]

That's not that big of a cam...
Make sure you have the valve lash adjusted properly. You must do this on SBC engines, and having the rocker nuts adjusted correctly is imperative to the performance of engines with adjustable valvetrains. If there is too little or too much preload on the lifters, the valves won't be opening correctly and it will certainly cause the engine to run like crapola.

Here's a link to "running the lash" on a chevy 350:

http://www.chevyhiperformance.com/techarticles/148_0303_valve/

[Quadrawhat?]

do you have your vacuum advanced hooked up to manifold or ported vacuum? It should be ported so no vacuum is applied at idle.

[Goose]

I think I would Go back and readjust those rockers again if youre using 1.5 and 1.6 ratios you have got an intake too tight i bet, The symptoms you are describing on the vacum gauge are indicitave of a burned / open valve. I'd go back in a nd back everything off 1/4 to 1/2 turn. When i adjust S/B chevs i only go about 1/2 turn past clacking

[DieselSJ]

Are you sure about the 204/214 @.050 and 272 advertised? That should be more like a 258/262 advertised. 272 advertised is usually getting into the 220@.050 sized, and those will idle a bit rough.

[Jeep Craze]

I know this has been said a few times before, but if you can unhook your vacuum line(one at a time) and the idle gets better(you are running way to rich). Thats a good way to check ur idle mixture on any carb. If you unhook a manifold vacuum sorce(small line) and your RPMS increase then your running too rich. If you unhook it and your Rpms decrease your running too lean. right at the point where you can unhook it and not notice a huge difference is where you want it. but never do u want it to run better w/ a vacuum sorce unhooked that only indicates that there is too much fuel there)

EDIT: Just read ur post that says it runs better rich. Then u definatelly have a problem either an internal vacuum leak or the cam is just entirelly to big for the motor.But according to summit's guide your shouldn't have trouble w/ ideling until 206 degree of lift@.50 on the intake.

Just my thoughts Craig

[ July 14, 2003, 07:41 PM: Message edited by: Jeep Craze ]

[Stuka]

wow, old post risen from the dead.

JeepCraze: while I partially agree with what you say, a lot of times if you set your mixture with a vacuum guage for the best vacuum, then you will get the "idle goes up a tad with vacuum unplugged" on some engines. Depending on how they are setup.

[Jeep Craze]

All the engines I have ever set up I alsways use the vacuum gauge first then fine tune by pulling a line it works for me so I guess it isn't that far fetched

[Stuka]

Oh I didnt say it wouldent work, just saying it depends on the engine setup. Some setups need to be slightly rich to work right. Was more of just an FYI for some of the others.