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Hydraulic, fair idle. Needs headers, gearing and stall converter. Good street/strip cam.
Advertised Duration (Int/Exh): 300/300 Duration @ .050 (Int/Exh): 246/246 Gross Valve Lift (Int/Exh): .515/.515 LSA/ICL: 108/104 Valve Lash (Int/Exh): Hyd/Hyd RPM Range: 2500-6500 I copied the above from the Lunati website, is this the camshaft you've got? If your engine was going into a 4-speed Vega to fry the little tires off I could see you having some fun, but a Chevelle with stock gearing and factory converter won't be a joy to drive. The factory torque converter probably offers a lot of drag on the engine in gear at 1100 rpm - and probably stalls somewhere from 1300 - 1500 on a stock engine. Your 3000 RPM converter will definitely help matters. You've got a mild bracket race camshaft with a tight converter and tall gears - in a car that's no lightweight. You'll be rolling at 25 mph in 1st gear just to get the engine working on the cam. This is why Lunati mentions the loose converter and gearing changes to work with it. If it were me, I would go with a lot milder camshaft instead of changing all the other stuff. With some changes and some advice from other folk on the forum that may have been in your shoes you may be able to make it more driveable. |
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Cam
Yes, that is they cam Thats In my motor. I know a milder cam would work better, but I'm working with the stuff i already have In my garage. I got the motor on a trade replacing a tranny in a guy's blazer for him. He never paid me so here we r.
Its in a 82' cutlass supreme. I already have a Dacco Pro-competition 33-3500 stall converter, and an Eaton Posi w/ 411 ring gear. I know these will help the low end a LOOOOOTTTT, but I have a newborn and work 10-12 hrs a day in a factory, so It'll be a little bit till i can get it all changed out. I'm just tryin to figure out if that will change the idle in gear?? Right now it goes from 1100 rpm in park down to about 550rpm in gear, and that cam don't like 550. Is there anything i can do to get the RMP's up enough to make it a little more drivable temporarily??? |
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headers
oh.... I forgot, It does have headman shorty headers on it. Also I really don't wanna hange the cam cuz I got $800 put back so far towards a set of AFR heads 65cc chamber, 195cc runner, that will put me around 11:1 CR. With those heads, pistons, that cam, and that CR.... It should down right scream, Im hoping to achieve 500HP+ with that set up. or atleast close to it.
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I can't think of anything that will help your idle vacuum / quality other than running as much initial advance as you can work with and playing with the vacuum advance can on your HEI to maintain vacuum advance when you're in gear.
I assume you have manifold vacuum to the distributor advance can. There's two problems I can see biting you here, when you put it in gear the low manifold vacuum will drop even lower, possibly below the rating of the power valve in that 600 dbl pmpr, causing a rich condition and it won't idle well. The second problem that could occur is when you drop it in gear the manifold vacuum drops to a point below where the distributor advance can pulls in, so you lose additional advance that keeps it idling smoothly. In neutral it may be humming along OK, but put it in gear and all of a sudden it's lost a bunch of timing and running rich - ugh. You mentioned something about a power valve change so perhaps this isn't an issue. |
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vacuum
yea, I have the dizzy canister hooked to the vac port on the front of the carb base plate. and the modulator valve to the other. How much vac. does the modulater valve pull??? I know that on the TH400 there is a kit that allows you to remove the modulator valve, but i think you gotta have a full muaual valve body... right?? I dont care to shift it myself If I could save a litte vacuum. LOL
Yes I've got a brand new holley coming same as the one i have now but they are putting the right stuff in it to match my motor. They were already supposed to have it done but didn't do it, but i can't complain, atleast thier willing to work with me and are givin me a brand new one. I can get it to idle at 800 in gear, but then its at 1600 in park....... |
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Between the cam and the single plane intake, you've shot yourself in the foot using a stock converter. I doubt if you're makin' enough torque to stall it to 1200. The looser converter will make a world of difference. I can understand using the cam if you had it on hand and money was tight, but why did you order a converter with a stall that high? Wouldn't a 2500 have worked better with that cam? I may have been doin' it all wrong, but I try to match the converter stall to the low limit on the operating range of the cam.
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I know it is hard to find the time, but I would just change out the cam and forget hotrodding a few years. Get that kid a little older first.
A 355 with 76cc heads, -5cc pistons, and 0.040" thick felpro head gasket makes around 9.65:1 cr. With a 3.08 gear, stock converter, and 9.65:1 cr, I would install a cam with 214 degrees on the intake and 214 on the exhaust and with 114 LSA. This cam should idle low enough for the stock converter and have a late enough intake closing point to work with that compression ratio, old iron heads, and pump gas. Summit has cam and lifter kits for 90.00 that would be around the size that I mentioned above. I would also recommend that you use ZDDP additive during cam break-in and at each oil change. cost another 10.00 at each oil change for the ZDDP but worth it when running a flat tappet cam with todays relatively abrasive oils. |
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That cam needs a lot lot lot of timing at idle to idle properly.
The short method is to simply lock out the mechanical advance and reset the timing at 36° BTDC at idle. You can find 36° on the balancer by wrapping an length of masking tape around the balancer. mark where the two ends of tape meet. Remove the tape and lay it out flat say on a counter top. measure the length of your two marks you make on the tape while it weas on the balancer. 1/10th of that length is 36°. Mark the tape at 1/10th the length of the circumference and reinstall the tape around the balancer referencing the circumfrence marks at TDC. Mark off the 36° point on the balancer using the 1/10th length you made on the tape. Now you can set the timing at 36deg BTDC. Once you have done this readjust the carb idle mix screws. It will never idle right with the stock stall converter. With you young family you'd be much better off with a mild hyd cam and stock converter and gears as all you'll achieve is burning a lot of gas for nothing. Summit #K1102 is just right for your situation. A lot lot easier to change the cam and lifters than change the gears and converter. http://store.summitracing.com/partde...2&autoview=sku |
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You got the right idea but I think that summit cam is too small to run 9.7:1 cr on pump gas. A good cam for a 3.08 gear and stock converter but not enough to handle the 9.7:1 cr. It will detonate. So 214 with a wide 114 lsa will make it idle smooth at low rpms and close the intake valve late to bleed off cylinder pressure.
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Cam
OK guys, I appreciate the suggs. , However did you read my last post??? I don't really get why everyone makes it seem like a major job to change the converter and gears.
I am putting the Stall in this weekend, Its less than a day's work. I can drop the tranny, pull the stock T/C out and stick the new one that I ALREADY have In, and lift it back up in there in under 6hrs without ever taking it out from under the car. It wouldn't even take that long if i had a lift, but i'll be working on my back so it'll take a little longer. No big deal..... I just need to know if this will help my idle or not?? I'm not trying to be combative or rude or anything, and for those of you that are supportive, I'm sorry you gotta hear this. It just gets extremely frustrating when I ask for assistance with an issue and people start telling me to change my set-up. I have plans for this set up, and if it doesn't work out like i plan then I'll hafta learn from that and incorporate that knowledge into my next build. I see this happen on here all the time. A guy asks for help with one thing and all of a sudden a bunch of people start critiqing his stuff to thier own personal preferences. Then the person says well I think I'm just gonna stick with what i got, for what ever reason of his own be it financial, future plans or just preference, and some guys still try and push the issue. Then If they don't do it your way you won't help them with thier origonal problem. Its kinda childish. Thats why we are individuals, we are all different and all have different Ideas and aspirations. It's not my place to tell you how to build your motor unless you ask me to. I'll tell you what may be more benificial, and if you don't like my idea, thats fine no big deal. Its yours not mine, but I'll still try and help you to the best of my ability to solve your problem cuz thats what i want other to do for me. And for whoever said that i hould hang up hotrodding for a few years, It ain't gonna happen. I LOVE this hobby, and as long as i can physically turn a wrench I'll never quit. As soon a my son learns to walk He'll out there right beside me, Infact, He's 4 months old and I already have a car for him. Its an 82' mustang and I'll never get rid of it. I plan on it being a project for me and him to do together. I simply don't wanna change the cam, cuz I'll just hafta change it back in the near future. The heads, stall and gears are going in. The stall is this weekend, And it will be sometime this winter for the heads and rear-end. The only thing I don't have yet Is the heads, But like i said I already got $800 put back towards them. I'm not gonna just sell the posi, ring and pinion, and stall just to buy another cam?? no. Things I don't mind doing is changing the intake, carb, ignition system, timing, ect. How much vacuum could I gain If I went back to a performer RPM?? I have 3 of them in the garage. I mean there's gotta be a way to make this thing Idle In gear better. I know I'm not the only one in the world using a cam this size. If you have any suggestions that don't involve selling all the stuff i have and changing my whole set-up, or quitting hotrodding. I'd be more than happy to hear them. Thanks Danny |
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EatonDE; I have an idea for you that might work. How about an idle boost solenoid that would trigger from shift linkage when put into Drive? Those carb mounted solenoids were used on Rochester carbs alot in the 70's and I believe into the 80's as well, and were tripped with engagement of a/c clutch, so as to compensate for compressor load. Basically you could do a "perfeshunal rube goldberg setup" with a limit switch tied into shift linkage somewhere, feeding + power to a custom mounted (adjustable) idle boost solenoid. And by doing it this way it would only engage the solenoid with ignition on and trans.linkage in Drive, although you could add another limit switch to be activated in Reverse, or feed from b/u lite switch. Whadd'ya think?... -Jim
Last edited by j.d.brown.042964; 10-06-2008 at 10:41 PM. Reason: spelling |
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Timing
FBIRD,
So let me make sure i understand you right First I wrap the tape around the balancer marking both ends, then find 1/10th of that and mark it on the tape. Put the tape back on the balancer lining up the 2 circumphrence marks that i made on the tape with the TDC slit that in machined into the balancer. Then with a timing light i can line up the mark I made on the tape that is 1/10th of the circ. with the 0 degree mark on my timing tab scale that will put me at 36 degrees. Unless I'm misunderstanding you, Isn't that a little much for the base or do you mean 36 total?? I'm not questioning you, just trying to make sure i understand. This should be mechanical only with the vacuum unhooked and the hose plugged right??? |
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idle selonoid
Jim,
That sounds like a good idea, but where would I get these solenoids from. I have seen them on Q-jet carbs before, but is this something i could buy?? How would I mount the limit switches, down on the tranny linkage or on the column?? Do these even work on holley carbs??Just for curiousity sake, How do the other guys do it?? Like i said walla go, Im sure I'm not the only one runnin a cam thins big. Infact I know a lot of guys on here are runnin bigger ones. Will it not be enough loosness when i put the Stall in this weekend?? I've never ran anything bigger than a comp 280 magnum, so I'm still learning. I will get this lined ouot one way or another. Thanks for the good positive feedback and ideas Jim, keep em coming. |
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stall converter
Techinspector,
I didn't build this motor, I got it from a buddy that owed me some money for fixing his blazer. But anyway, I got the stall this big for 2 reasons, 1 cuz the guy i got the motor from told me that he was running a B&M 2500 and it wasn't enough and could definitely use more. 2 I got this Dacco brand new for $85. Thats why I'm gonna use a 33-3500 stall. |
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