mac85

I don't want to be radical..But I would like a nice "gated" idle. The best sounding idle I remember was a 69-Z28 with a 302 I think.. Ideals?

Number 1 cylinder cam lobe has worn down to the point the engine was backfiring into the intake.. Just recently rebuild engine ..Cam tolerances was fine then. Re-did heads and replaced lifters, and etc.. But now I will need a new cam and lifters again.. Improper break-in? Harder lifters? Not lubed properly? Just not sure...


What is your recommendations for a new cam..???

I also have the 3.07 rear end, so my road rpm's is approx. 1800..

Master__Shake_

This cam is nice if you want a stock-style duration with slightly higher lift.

If you want a rougher idle, this cam would be more fun while still retaining its "in the powerband" range of the TPI intake, as well as lift that stock heads can handle.

Both cams should run very strong with the stock ECU and come with lifters in the kit.

mac85

I'm also reading about converting to hydraulic lifters.. Is this something I should consider???

mac85

Thanks Master__Shake,
I'm really lost when it comes to undersatndling all I should about this stuff, but I'm learning..I hate the car is broke, but it's really been "continuing education" at it's best. The more I read, the more I understand how little I understand.. I've always heard "there's a thousand ways to skin a cat". I think there more ways to cam a L98, 350!!

corvette_bob

Sorry to hear of your misfortune. When you swap the cam, remember to clean out your oil pan and pick-up. you don't want any of that old lobe causing further damage.

The reason for the loss of a lobe after the engine rebuild MIGHT
have something to do with the oil that's widely available. From what I've been reading lately, most of the new cars being built have roller cams in them. The oil companies aren't putting in the proper oil components for break-in of flat-tappet cams because it's not needed as much. It's not effecting the engines w/ alot of miles as their cams/lifters are already broke in. When you go to buy your next cam, ask about "redline" oil. I hear they are addressing the issue with the proper additives. Also, it's possible that when you reuse an OEM cam, It is NOT unheard of to have problems breaking in new lifters to a used shaft.

Of the two cams suggested by Master_Shake_, I'd go with the CompCams grind and their lifters. I've been suckered into Crane's stuff twice. I should have made better choices.

Master__Shake_

I assume you mean roller lifters? Converting to roller is a pain because you have to buy the lifters, which are usually $250-350 for a good set, along with the cost of a retro roller cam itself which is another $250-300.

For the small amount of power "under the curve" they give, I'd say rollers aren't worth the extra money invested unless you plan on putting a lot of miles on it. I'm not knocking roller cams by any means, as they're hard to beat on the street, but the money spent isn't always worth the outcome in all applications.

mac85

Master__Shake, you are correct.. that should have been rollers..

Corvette Bob may be on to something.. I did a 45 min. warm up, changed the oil, then started diriving..changed at 1500, after that it was 3000 and then had the problem.. I will not do that again!!!

Looking at the specs:

I see LSA on the original cam at 114.5, with a Duration of 202/207 and Lift of 0.413/0.428.

The Crane at at LSA 114 with a Duration of 210/216 and Lift of 0.440/0.454

The Comp Cam at LSA 112 with a Duration of 206/212 and Lift of 0.434/0.444.

In terms of lope, does a lower LSA have a greater lope, or is it tied more to duration...

The other factor I forgot to ask about is what to expect in terms of fuel useage..How much difference will it make, not take it really matters, I would like to know what to expect...

rodj

Flat tappet cams like yours require NOT letting the new engine idle
(> 1500 rpm ) for at least 20 min to maintain enough oil splash on cam lobes so as to break lifter / lobe in.
Roller cams require no such break in period

cv67

Lunati #60101 256 Voodoo is a great cam for the TPI
213/219@.050
256/262 adv duration
112 lobe sep.

Will make good torque, pass smog and smooth idle.
Other choices listed above are good also.

Put this one in a 86 Iroc 350 with cheapo performer heads touched up, ported tpi, accel runners and shortys on an $850 messican rebuild shorty 10-1 cast pistons TJ Wong tune - it was funny how strong the car pulls for what little it has in it. 2nd gear pulls like it has a stroker in it. Doesnt make sense but it worked.

mac85

I spoke to Summit and they indicated I needed a "computer controlled" cam and I would not be able to acheive any real idle lope.. The cam they recommended is a CCA-12-256-4..It has a Duration of 206/212, Lift of 0.425/0.440 and a lobe separation of 112.. What do you think?


http://store.summitracing.com/partde...0&autoview=sku

Note: That should have been 12-388-4, NOT12-256-4..

cv67

Thats practically a stock cam, not worth it imo

mac85

[QUOTE=cuisinartvette;1567926041]Lunati #60101 256 Voodoo is a great cam for the TPI
213/219@.050
256/262 adv duration
112 lobe sep.

Do you think the Lunati would have any issues on a stock setup..i.e. Computer Controlled /Iron Heads/ Standard Rockers, springs..? The CAT is removed with flowmasters, but thats about it..

cv67

Spring upgrade, rest should be good to go.

Master__Shake_

That's basically the first cam I suggested, with a slight less lift on the intake side. Any cam with an LSA above 111 is a "computer friendly" cam, 114 being optimal.

That being said, I believe you or the people at summit have numbers mixed up. CCA-12-256-4 has .449/.456 lift, 212/218 dur @ 112LSA. It is a very nice cam, and should be very streetable. Personally, I don't always trust the "Operating RPM range" specs because that set of duration would be more inclined to feed a 1500-5500 cam, and anything over 5k is really a waste for stock TPI.

It basically comes down to this: Do you want more low-end or more rev? CCA-12-256-4 will rev more, but CCA-CL12-249-4 will have more low-end grunt. It's your call. Either way, find a kit with lifters so you aren't mix-matching.

mac85

Qoute from Master__Shake..
"It basically comes down to this: Do you want more low-end or more rev? CCA-12-256-4 will rev more, but CCA-CL12-249-4 will have more low-end grunt. It's your call. Either way, find a kit with lifters so you aren't mix-matching."

Very good wrap-up of a subject thats been beat to death several times..I now understand MUCH more than I did this time yesterday..

SO... I decide that for my purposes, ( having the 3.07 rear-end ratio and wanting some more rev's and a hint of "lope" ) that the Comp Cams CCA 12-256-4 will fit the bill..BUT when I go to Summit (and other sites also) it says.. 1987 and up..Plus it doesn't come packaged as a kit with lifters.

I call Comp Cams back (very helpful company) and they assure me it will work fine with in the 85.. BUT the springs may be "tight" which must connect to what Cuisinartvette about needing to replace springs if you use the Lunati.

BTW the Lunati has practically identical specs. to the Comp Cam.

Lunati #60101 256 Voodoo 213/219@.050, 256/262 adv duration
112 lobe sep.

Comp Cam CCA-12-256-4 212/218@.050, 256/262 adv duration, .449/.456
112 lope sep.

The 87 has Alum. Heads and rollers doesn't it?

So is this direction O.K. or I am missing something..I'm not feeling warm and fuzzy..How do I make sure I get the correct Lifters and Springs for the 85 Iron-Heads. I seem to be getting conflicting information from the different parts houses..

Thanks in advance, as I think we're close to finishing this one out..

cumbercr

I have an 85 L98 with a Competition Cam 12-402-4. 212.0/218.0 duration, .444/.444 lift and 114 lobe centerline. Competition Cam describes it as a slight mild to choppy idle. It feels like stock to me. Anything with less punch would be a waste of time and money.

If you are sticking with the original hydraulic flat tappet, I like the 12-364-4. 216/223, .499/.493 and 113 lobe centerline. Its also designed for a 350 TPI. It works fine with a stock converter. You may need to upgrade the chip and exhaust to reap full benefits, but there should be a significant increase in Hp and torque. They recommend 1.6 roller rockers.

powerpigz-51

I have the Summit G5000 TPI cam Specs 112 sep intake .420@204 exhaust .442@214 They claim 40 HP in a 305....I highly doubt it but I do not have the chip. It is a slightly higher than stock and it is at a good price for a whole kit. Honestly, I wish I would have gone hotter, but I have a few mods and higher compression than stock, so it might be perfect for your engine.

mac85

I thiink I'm in the ball park of where I need to be..I like the Comp Cam CCA-12-256-4 at212/218@.050, 256/262 adv duration, .449/.456 and 112 lope sep. I've just got to make sure about the head and spring issue..

If I can't resolve the head and spring issues the Lunati #60101 or the Crane could still work..I'm just a bit concerned about the Crane from the comments that Corvette Bob made about he Crane.

Thanks for all the input, it really has helped greatly..Any additional insight would always be welcome..

cv67

Both the Comp and Lunati would run about the same, just personal preference.

mac85

Cuisinartvette,

Do you have any ideal what the Comp guy meant by "the spring would be tight, but O.K." I've heard good things about the Lunati, I think it can be bought with lifters and (and maybe the right springs?) as a kit..

I'll probably make a decision tomorrow about which one....