Couple questions on 010 350 sbc

So, I've got a 79(i believe) 010 block 350 rebuilt with my pops, who retired from gm in 86, stock cam/crank orielys cam and crank from my old 305. HEI dis. unknown heads(new springs etc), aluminum intake, and a 650 edel. some problems, lifter ticks, and bogs at 1/2 throttle

I'm having problems with initial timing
1. mark on balancer is bouncy and not constant
2. i've tried 6, 4, and now running 0 initial, and i'm not sure what it's running advanced. 4 and 0 make it bog at half throttle, and 6 feels horrible. haven't tried 6+ degrees (will it run?)
I am completely stumped as to why my car is not timing, it's never felt right to me.

Also I cannot figure out why my carb is bogging at half throttle, just before secondaries open (feels like they're struggling to open?)WOT feels great it's a out of the box 650 that WAS running fine. this problem is new, my plans for trouble shoot are seeing if plugs are gapped/clean, and trying to get timing right.

i was wondering if my 305 crank from the original motor is causing any problems/power loss

thanks for any advice, i'm not extremely experience and would like constructive criticism. i am also a broke ass college student with no special tools like vacuum gauge, tach meter, gapper, or any of those VERY convenient tools i should invest in soon  

305 and 350 crank are the same...throw that carb in the garbage and buy you a holley.  



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I tried to run a 305 crank in a 350 but I was told that 305 cranks run a lighter rotating assembly. PITA to balance with 350 internals. But they are the same stroke as a 350. I ended up sticking a 350 crank in the motor.  
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Nobody can fix or diagnose anything without the tools, plain and simple. You could be dealing with a serious failing engine issue such as bad camshaft rather than just an incorrect initial timing setting. What oil do you use?  

Sounds to me like there is a possibly a distributor problem, with the mechanical advance. That can create a bouncy timing mark, as can a lopey-idling cam profile. Check to be sure you can move the distributor rotor freely against the springs, and that it snaps back to the same spot every time. If not, theres your trouble.

The mark on the balancer could also be wrong, balancers go bad and the mark spins a little when they do, messing up your reading. Late timing does crazy stuff to how it runs.

Most V8s I have met prefer at least eight degrees of initial advance. Some end up happiest near twenty.

I have a hundred thousand miles on an Edelbrock carb, they can work great. If a new issue just popped up, take the top off and look for dirt or debris in any of the fuel paths. Careful with the gasket and you may be able to re-use it. This only takes a few minutes.

So where did your HEI come from? How many miles on it? Have you opened it up and had a look at it yet, in search of the trouble?  

darn   i cam back to edit and add some info  and managed to delete it...  

These are the 305/350 crank differences.,. the 2 cranks are NOT the same.
SBC 305 and 350 cranks have the same stroke, same journal size, same casting number but different size counter weights.,. without putting one on a balancing machine it's hard to tell what's what. With the two cranks side by side, you can see the different weight sizes, but when you only have one crank, it's hard to know. 305 cranks are machined on the side of the rear counterbalance, next to #7 and #8 throw and also the face of the front one, next to #1 and #2 throw.
This metal removal compensates for the smaller/lighter 305 pistons.
A ruler laid across the front weights, lays flat on a 305 crank.,. on a 350, it does not.



I would NOT be so hasty and dump that Eddy carb, as was suggested.,. unless you determine that the carb is at fault.
A Holley is no cure all, for every problem.

 
When The Flag Drops,,,



The Bull Chit Stops,,,

P. Engineer.,. Engine Builder

Hi Peter,
 I did the whole 11 yards with this problem
 and that motor is still going 8 years later.

 Value for money Not worth the effort
 Acceleration off the mark..Slight advantage
 Motor will peak earlier with power band by about 400 rpm
 with 290 hp cam...mild 222*....
 
 All the moving parts except the driver were doubley balanced
 My Advice..Stick with the average rules of PRECISE Engineering
 and spend the money....All the best to everybody....    
skyeking

I broke it in with a special oil at this stock car shop. Now I use Castrol GTX sae 30. When I rebuilt the engine I got the hei from my cousin. The relay was burnt out and I replaced that, along with the cap. What do you mean moving it freely against the springs? The balancer is fairly new but it's always possible I'll rule that out though. I will mess with the degrees a little more I am in school and hardly find time to mess with it.

I'm pretty sure my carb problem is the breather, I haven't had a breather on it for a while now. Stupid I know but on a tight budget.  

Kyle-

I asked what kind of oil because ... unfortunately oil manufacturers have changed what goes in the oil in recent years without really changing the label. The oil you've trusted all your life may no longer be good enough, sad to say. Newer rides that have roller cams get by just fine on the stuff, but flat tappet cams no longer can get by on plain oil. I have started using racing oil in mine, so it will live. Some folks use diesel oil but even that is going the same way. What happens when you use today's plain oil now? You might flatten some cam lobes, and thats bad news because metal flakes go all through the engine and that means overhaul. First thing a person notices when this happens is tapping, low power, rough idle. Just FYI.

An HEI has no relay in it- maybe it was the module or coil y'all replaced. Anyway, from what you said its possible that it could be worn out, the distributor itself.

When I talked about the springs and rotor ... what I mean is with the cap off, grab the rotor and turn it. It should turn about an eigth of a turn easily in one direction. You should feel light spring pressure when you rotate it. When you let go of the rotor, the springs underneath it should snap it back to where it was. Otherwise it will screw your timing ALL up. Every time you rev it, the rotor twists against those springs and that advances the timing on the fly while you drive. Its called "centrifugal advance" sometimes. But if that doesn't spring back to the same place every time, you'll never get a steady reading.

The fix is to take out the distributor and disassemble it all the way and clean it. Which sometimes is worth it but if one is very cruddy, its probably got worn bearings and a loose shaft which also screws up the running. Trust me if you have this problem then fix it, you will freak out on how well it runs when fixed.

On an air cleaner- yes you gotta get something on it- you're destroying it without one! But the engine should run the same unless you drive with no hood.

Hope you get time to tinker with it and get back to us. Holler.  

waynep7122:
darn   i cam back to edit and add some info  and managed to delete it...


double darn. It was good too    

The .010 designates 1% more tin by volume.

The good 350 Blocks are .010=1% more tin
and the .020=2% more nickel. My 2 cents....

There are also 350 GM Factory Cranks that are from older engines with a NF on a throw.Look for one of those when your out Crank hunting.I'm talking about GM Factory Cranks!This is not common knowledge. I have never seen it in any writings,UNLESS I missed it. The NF makes for a better gran structure as the crank goes thru it's natural twisting under power loads. You may also find the NF on earlier 307 GM cranks also. These cranks have a 3.25 stroke that were used in later 327 engines.

Just a Little FYI. If you hold the NF Crank by the snout and just (tap the throws with a small brass hammer) you can hear a different sound It's more of a ring. Almost like the forged 350 Factory Cranks. Just wanted to share some information!
Thanks
Bob  

305 and 350 GM Factory Cranks are the same stroke,it takes more weight to balance a 305 Crank with 350 internals. Don't be surprised if the machine shop calls and tells you to find a 350 Crank or the cost to balance the 305 to 350 parts maybe double!  

lets try this again..

if the timing mark is bouncing around...   you might have an ignition problem .. you will probably want to examine the HEI...

start with the coil in the cap..

examine the sides of the central winding for white marks or little dusty circles where high voltage has been leaking..

make sure that there is a solid ground strap that starts under the coil and connects to the center terminal of the 3 wire connector to the base...

that is the spark return path..   without it.. can cause problems..   this is not the black wire from the coil windings. this is the continuation of that circuit.. to make it complete ..  


with the cap and the rotor off.. can you see the tips of the reluctor and the pick up coil???

this is a pick up coil from one version of an HEI...    see the 8 arrow shaped things.. there is a matching device called the reluctor on the distributer shaft..  



i would like you to examine, Without removing the hold down screws... the second layer down on the pick up coil.. its a ceramic magnet. i have found them broken.. this will cause all kind of problems..  as the pick up coil will NOT be creating a nice even sine wave for the module to use to trigger the power transistor to charge and discharge the coil..

i saw above that the rotor does snap back fully and turn freely..


is your vacuum advance hooked up and actually functioning??   does the pick up coil rotate slightly and return when you apply vacuum to the advance canister fitting..  

where is your vacuum advance hooked to..   manifold vacuum.. where there is vacuum at idle.. or  ported vacuum where there is NO vacuum at idle but there is vacuum as the engine speed increases with the throttle opening..

are you setting base timing with the vacuum advance disconnected???

since you have the distributer cap off...  do me a favor..     bring the damper timing marks up to TDC...   does not matter which way the rotor is pointing..  #1 or #6..      rock the crank back to the left about two inches.. then slowly to the right as you watch the tips of the reluctor on the distributer shaft  line up perfectly with the tips of the pick up coil..  when the tips line up perfectly.. that is where the ignition is going to fire at...

once you have done this..    look at the damper..  this will let you know where the base timing is set...

and yes... you can use this to dead stick time the engine..    bring the crank around in normal direction of rotation..  stop without going past where you want the timing on the damper and timing pointer. then turn the housing to align the tips..


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

now with the carb...  an out of the box edelbrock carb is jetted for an average motor .. so big motors are NOT too lean and melt things.. and small motors are not too rich..   there is LOTS of fine tuning...

which # edelbrock...   there is a 30+ page carb turning guide available from the edelbrock web site..

there are all kinds of tuning things for the edelbrock..  

The 305 and 350 cranks aren't the same even though they have the same casting numbers they are definitely different as the balance is different.  



Professional Hi-performance engine builder

Hi Poncho man,
 As you know in this swap procedure the
 main thing is to lighten the 350 piston
 to as close to the weight of a std 305
 and keep the weights identical to 1/4 Gram.
  Double balance the whole damn lot if necessary
 and the harmonic balancer rules go out the window
when you venture into this type of project which
you can in all reality do without.
Experience teaches at a price    
   All the best to the gang...Skyeking in Australia..  
skyeking