Thread: New motor woes...kinda

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Ok I have my 496 running and i think i went a little over board for a street toy. So, I have never had a motor with this kind of power. It is 10.5 compression, 284 590 lift, 320 Pro Topline heads, Demon 850, with a muncie 21, and 3.73's

Now question one - This motor shakes an assload at idle, but then again the cam lobes a lot, sounds like a pro streeter. Its doesnt seem un-natural that it shakes the car as much as it does, but do you guys have some wild motors that shake the hell out of your car? And about 2,000 on the tach my shifter shakes like a paint mixer at wal mart.....but the stock 454 made it do that as well....and plus listen to the 55 in Two Lane Blacktop...that muncie is making the shifter sing, so i think everything is ok there.

Now question 2 - Total noob question here, but i was trying to hit the motor with a timing light, but i have never had a balancer with numbers all the way around....just been around the stock balancers that have a notch in them.....so can anyone give me some advice about a balancer with degrees that go all the way to 60.....my light at idle, without the advance being plugged in is at 25-28...I didnt think a motor would run like that. I tried to retard it and she didnt like that much. I went back to 25-28 and she runs like a raped ape, no popping or pinging. I know i am a moron with this balancer though, but i have to learn some how.

Thanks guys....sorry this was so long.

The number of degrees on the balancer doesn't make any difference.

At what RPM does your engine idle? Maybe you're getting some mechanical advance in at idle.

Put a timing light on the motor and run it up to about 3500 RPM (or to where the advance stops moving) and see what your total advance is. There should be about 20 degrees in the distributor. If you see 45-48 degrees, then you have a true 25-28 initial. If you see less than that, then your distributor is advancing some at idle.

Have you checked true TDC with a piston stop to see if your balancer is accurate? You can pick one up from Summit for less than $10.00, and they should be in every hot-rodders' tool box.

the timing tab is not used but O on it tdc is best done when you put the engine to gether but if this was not done it can be a pain in the back .for setting timing if you have a msd i run one blue and a lite sliver spring your timing will start fast and will be all in before 2500. use the red or sliver bushing .i run this at the crank 10 to12 and run it up to 2700 and check it it should be all in from the tab at 2700 it should be 36 this is mark on damper your engine is jump all over ??? it may need some timing and carb work i run a285 at .050 and is 748. lift roller and dose not jump like yours but it dose shake the cement. isyour lifter set rigth ??you would be surprised many people get this wrong and spark plug gap if it msd i run .035 .check 7and 5 if they are mix it will shake but it will run flat

Did you happen to put solid/POLY motor mounts in when you installed the engine. If you did your transmitting /most all the engine vibration directly to the car. A cure is to go back to heavy duty rubber mounts. Make sure you have a rubber mounter tranny mount if your running rubber engine mounts or you'll break the tranny case.

Ok i will check the timing with the advance plugged in and around 3500. The shake is just new to me because i have never had a motor like this before, so i am not worried about that anymore....and i used poly motor mounts/trans mount.

The balancer at TDC is dead on 0 and the rotor is aimed right at #1. So we shall see what the total timing looks like at 3500.

Thanks guys
Ill keep you posted.

do not ckeck with vacum advances run the timing up to where it stops and lock it down at 35 to38 timing .when this is done check vacum pull it could be as much as 47to50 on pull .i do not use vacum advances for a engine like yours and bigger .i lock it and put more on crank and go with the lite springs if you use the vacum pull check to see if it s ported vacum or not you will need ported this will not pull at idle

Ok so i ran the motor up to 3500 and hit it with the light.....and it topped out at 52 on the balancer.....so that isnt right.

So i tried to retard the timing and the motor did not like that at all.

So i re-TDC'ed the motor and everything lines up just fine.

So i have the carb on the "out of the box" settings....i never dialed it in with a vaccum gauge, because i never liked the timing, that and the motor would only idle at 1000. When i dropped the idle down it would stumble and sputter.

So should i set the initial to 10-12?
And maybe dial in the carb the right way and hope it cleans up?

But the last time i tried this the motor shook very violently, and it was obvious something wasnt right.

So i am lost now. HELP!!!!!

how do you know were top dead center is ? this is very hard to check when it s together i think you have something not rigth .start with one thing at a time is the fireing order rigth ? check it. is the lifters set rigth check them . do you have a intake leak? all of this or one thing can give you .what you have who put the engine to gether ? is the cam in it rigth ? what is the duration@ 0.50 what cam you have? did you try any thing that i reply to you on? i have many built many big blocks with 275 to280 duration @ 0.50 and run them on the street with out to many problems here is somethings to think about you said it will not idle below 1000 check you many not be on your idle circuit you may have to crack the rear barrels so you can set idle mix s

A 284 degree cam shouldn't be any big deal in a 496. I've had cams that big in a 350 and just had a nice choppy idle. Of course, it all depends on the lobe displacement angle ground into the cam as to how it will idle. I'd be lookin' for a vacuum leak.

i do not think you ran a 280 roller cam in a small block ?? on the street?? i am talking at 0.50 dura not adv dura .this is one big cam you can run somthing this big in a big block but you shure in the hell know it in there 280 at 0.50 and the lobe sep do not help that much when the cam is that big i know i had them at 112 110 108 and they all were choppy

Originally posted by pat mccarthy
i do not think you ran a 280 roller cam in a small block ?? on the street?? i am talking at 0.50 dura not adv dura .this is one big cam you can run somthing this big in a big block but you shure in the hell know it in there 280 at 0.50 and the lobe sep do not help that much when the cam is that big i know i had them at 112 110 108 and they all were choppy

Go back and look at 4-speeds first post and look at the lift. That lift is for 284 advertised, not 284 @0.050" lift.
284 @ 0.050" lift would have a lift in excess of 0.700".

ok so it not big at all and i do not take this as a very big cam i did not look at the lift at this thing is not that ratty i thought it was in the mid 600 lift and i look at cams at 0.50 sorry

Way small cam for a 496, or even for that c/r.....or is it just me?? What chamber size are those heads, and what pistons are you using?