SBC Experts, help with timing marks

OK, I am admittedly a Ford guy but have a Chevy questions. I have recently had a timing issue with two small block Chevy's. Both of these are 383 strokers that use an 8" damper from a 400. Both of these have the timing pointer on the drivers side of the motor like most 350's I have ever seen. To get either of these motors to run decent I have to time them about 30 degress or more BTDC using the timing cover mounted marks and the 400 balancer.
Obviously neither of these motors is really running 30+ degrees of initial advance, so I have to believe that the 400 balancers are designed for a different location of the timing indicator on the motor. Can anyone confirm this for sure and possibly tell me how many degrees difference there are between the different ones?
Ideally I would use a dead stop and find TDC and remark the balancer or the indicator but unfortunately the one that is currently available to me has the motor in such a position that you ca barely get spark plugs in and out, much less try and thread in a stop or a dial indicator.
Any chevy guru's know the skinny?

 

Thanks, as mentioned I do understand how to use a stop, I just can't get the one I have that fits the Vortec heads in between the frame rail and the spark plug hole

 

Some chevys have the timing tab more to the center of the timing chain cover. You actually have to look with the timing light straight down behind the water pump. I am not sure what years and cid had which. We just had a small block come in with the same problem and we found out the advance plate in the distributor was actually hanging up. I picked up a bushing kit for it and it fixed the problem. My initial timing wasnt as high as yours though.

 

First thing I checked was the Dist. A small MSD in one car and and HEI in the other - I even tried a 2nd HEI that I know was running good in another SBC to be sure. Pretty sure it has to do with the timing marks.

 

In addition to the top-tab versions, 7 and 8 inch balancers use different part numbers for the add-on tab. But that's a lot of variation, 30 degrees.

Having owned a couple stock balancer 400s and 383s that slipped. I gotta ask. Did those engines reuse stock GM 400 balancers?

good luck

 

No, both have new SFI Approved aftermarket dampers. The difference seems to be about 15 degrees (Trying for initial of 15 degrees, but reads 30 to run right)

 

Another method to check is the 'zero cross over'. If you're not familiar with this it is an easy methid to check TDC; pull plugs, rotate eng with socket & on #1 cyl when exhaust is closing as intake opens there is a point when both valves are open the same amount - this is called zero cross-over and that'l be TDC.
All 400's i am aware of have the timing tab down low.

 

FWIW it's real easy to bend a 7 inch tab to clear an 8, then you're hosed. Apparently to the tune of 15 degrees.

 

You probably did, but I'm wondering if you pulled and plugged the vacuum advance line when you set initial timing?

 

yes

 

You might want to go to www.professionalproducts.com there is some real good info on Chevy balancers since smallblocks used 3 different pointer locations the website will tell you the correct GM part number for the pointer to fit your application.

 

Always check #1 TDC before you bolt the heads on. Old balancers slip, you may have mismatched parts...
You don't even have to time by #1 if you know where TDC is on any piston.

 

He is correct....a harmonic balancer is a hub with a rubber sleeve around it and a hub pressed over that....during racing and reving....they can slip.
Since you can't get a stop into the #1 hole....go down to your local speed shop.....get 2 timing tapes to put on your balancer, they're cheap.
Next, get a spark plug, bust out the middle, tap it out and install a hardened bolt. Take all your remaining plugs out....you should be able to turn the engine over by hand. Put your stop in to the plug hole, making sure you have a big radius ground on that hardened bolt so you won't gouge the piston. Put on your timing tape.....or you can use a degree wheel. Turn the engine over by hand slowly till it stops....don't force it any further, record that #, then turn it the other way, do the same thing. Between these #'s is TDC. Make a mark on your balancer, and put a good timing tape on with 0 lined up on true TDC that you just found.......wipe the balancer down good with alchol and spray some clearcoat on it to protect your tape.......now you can time to your hearts content!

 

small chevys had three different damper pulley that had the timing marks at different positions from the keyway. the late dampers 84 and up timing mark was 30 degrees right from keyway early was right above at 2 degrees and mid was 10or15 somewhere like that cant remember . make sure your timing tab matches your damper!

 

this post made me ask this...when the cam timing dots are lined up on the[sbc]cam&crank gears is this tdc#1or if iremember rite it istdc for #6?

 

Ditto for SB Ford. When the timing gear marks are aligned, #1 TDC firing.

 

timing marks together is #6 but timing marks up #1 and no 400 that i know of had the tab behind the waterpump

 

Rodding Roundtable is having a discussion on this and there's quite a bit of info about mis-matched balancers.

http://www.roddingroundtable.com/forums/viewtopic.php?t=9971

 

I didn't read all the responses so this may have been covered but if you can get to any cylinder to get TDC just mark the balancer at TDC for that cylinder and check the timing with your light hooked to that cylinder.

 

And if you do find that your balancer has "slipped", don't just make a new timing mark. The balancer for the 400 isn't just a harmonic balancer, but is part of the dynamic balancing of the reciprocating assembly as well. If it slipped, you need a new balancer.

 

Here is a neat idea for a way to find tdc. This was actually brought up in a tech week before. Find the biggest tie wrap you can and put the big end in the spark plug hole and use that for your stop. Works pretty well and wont damage any parts

 

Exactly - this has a split duration cam, so that won't work, it also isn't really all that accurate, only within a few degrees

That link is for Audio and computer cables ??

same issue on all 8 cylinders. Mid engine with the frame very close to the spark plugs

As mentioned above, NEW dampers on both motors, and two different brands - same issue

Problem with the Vortec heads is the spark plug angle is very flat and I tried the longest bolt I could slip between the frame and the plug hole and the piston didn't touch it.

I will check that out.

This was a brand new crate motor and I used the damper they recommended. The other one was a custom built up motor. Both have the same problem and it has to be that the motor was supplied with a typical 350 style timing tag and the 400 damper is different.

 

Yea, I guess we'll have to make one!OOOOOOOKKKKKKK, lets get that plug out of #1 agian, get a piece of rod, a piece that will just go thru the center of the plug, bend it into a gentle curve, pull that bolt out of the plug shell, drill a hole thru the side of said plug, (with the plug outta the head), tap that hole we just drilled out for a setscrew, try 1/4 or 5/16 NF threads, if you got a tap and die set. Now, put the curved rod so that it hits the top of piston and then tighten the setscrew. Now, find TDC.....

Now, if all else fails.....just pull the timing cover off.....

 

When I was dirt tracking, I would zero in the degree wheel with a stop before installing the heads. We then drilled a 1/4 hole in the timimg tab, next we turned the crank to where 38 degrees was on the degree wheel and drilled a hole though the timing tab hole just deep enough to hold a drop of yellow paint, we did the same for 36 degrees and white paint. though we had locked advance this system could be adapted to your initial advance needs. Hook up a timing light, start he motor and turn the distributor untill the mark you want can be scene in the timing tab hole, lock down the distributor and recheck.

 

Why would you use 400 externally balanced crank dampeners on internally balanced small block engines?

 

Hmmm!
What say ye Hotroddon?

 

Cause his engine is a 383. Most of them are externally balanced.

 

Hey.....I bet next time this fella installs a engine.......he'll have the TDC issue taken care of before its hooked to a cherry picker! Ha!
I imagine it would be a pain doin' this in a bodied chassis............

 

I thought a 383 was a 400 block with a 350 crank...No?

 

Only problem with chevy's, with the smallblocks, like the bb's, they had such a long history, with so many diff. configurations, it isn't hard to get stuff that will throw you off......hey.....thats what roddin' is about. but ya gotta be careful though.....with balancers......you could mess up a engine fast if the balancing ain't right......just like what Pasadena brought up....