Read this article for setting lash.....it's interesting, http://repairs.willcoxcorvette.com/c...ve-adjustment/

 

That's the method I use. The authors are John Hinckley and Duke Williams - from National Corvette Restoration Society web page.

I had the damper redone by: https://www.damperdoctor.com/

 

Hi Jebby,

we used new gaskets! The rear bowl has a level window, the front just the screw. We set float height dry initially, and then used the driblle method for fine tuning.
The float valves we used used came with the recon kit and aren't exactly the same as those originally fitted - might this be the problem?

Cheers

Es

 

IIRC there were two different dampers for different years because the timing tab location changed. An inch or so off could mean you have the wrong year damper or the the wrong year timing cover/tab. Is that possible knowing the cars history? How original is it?
Something else to investigate.
But sounds like you are on the right track now with a couple small issues.

<edit>
Found something on what I remembered about the tabs. TDC moved about one inch between 69 &70.1. The pre-1969 damper has the TDC line on the outer ring at the 2:30 o’clock position- or 2º before the keyway centerline- i.e. the line is to the LEFT of the keyway, looking at the front of the damper or engine. The keyway is seen in the ID of the damper nose. Includes a majority of the 2.30" small journal main engines and the 1967-69 2.45" large journal engines.

2. The damper used from 1969 to about 1995 has the TDC line at the 2 o’clock position- or 10º before the keyway. You'll find that aftermarket dampers are the 10º type, as are the bolt-on tabs sold by the aftermarket, unless they're adjustable


Also found a way to check if your damper has slipped.

Checking the outer damper ring for movement

Draw a sharpie line as shown in the image below. When the timing light is pointed at the TDC line, the sharpie line will also be seen. By revving the engine and running it at different speeds, if the outer ring is loose, the line on the outer ring will be seen to move independently of the line on the inner hub. Over time the line may be seen to have separated as the outer ring has moved independently of the inner hub

 

Came across this on Amazon and ordered a set. If you do not have a dial back timing light or want to double check it, here is a neat tool. Plus easier than trying to mark your damper.

 

If it is not Holley spec components then yes....it could be an issue......also, I know you guys are paying attention but there are three common metering block gaskets and make sure you have the right one and that the bowl is snug. When you have it apart again, inspect the back side of the metering block gasket (the side that goes from block to main body) for witness marks of fuel crossing into the channels for the boosters.....

Jebby

 

I keep these on the wall and if your car leaves my house it will have one on it........I have two timing lights, a straight up strobe and a Innovate Dial Back Digi.....the Digi is great but if you have a MSD or Mallory box, it can confuse a dial back light and delay it a degree or tow......which doesn't sound like a lot, but on a 500 horse engine can mean 20-40 horsepower......
I verified this to be true on the dyno years ago........and if you look, the Pro's have a Snap On strobe only mounted to their Dyno........the point is that if you have a MSD box and stock balancer, then you get the above timing tape on your engine.
I wish MSD just made them in a strip of all the same ones.....all I ever use is 6", 6.75", 7" and 8".

Jebby

 

Doesn't the MSD reduce to 1 spark above 3K? Just curious....how does it affect timing.

 

It actually doesn't.....but when you dial in a delay on your light, by the time it makes it through the module it can be a degree of on your light.....the actual timing is what it is.....this is why a strobe is preferred here....
you may never notice with a street engine......it is just one of those "good practice" things I picked up when I did this for a living.

Jebby

 

Thanks!

 

A big thanks to Lars, Jebbysan and others! I was able to follow all the instructions and the '73 is running really good/has more peppiness/quicker response for sure. I think the distributor was sitting in the right spot or pretty close before I tore into it. I made a line on the distributor and intake manifold with a sharpie just in case this got outta hand and I needed to put it back where it was. When it was all said and done, that line still pretty close to where it was, so my main issue was the spring tension. I took one spring off, moved the distributor til I was "all in" by about 3k rpm. Then I took off other spring, put one silver+one black spring from the Mr Gasket kit in there/fired it back up and had to move dist almost back to where it was for the 36 degrees at 3k rpm.


The vacuum issue was a little trickier than I thought because I was really expecting good vacuum out of the sorta long pipe on right side of the carb that was capped off. Wrong, nothing there, so I found good vacuum at the right front top of carburetor.




The vac line going to the right (fwd) comes around and hits a T underneath the gizmo attached to AIR pump. From the T one goes to the AIR device, the other goes into the TCS solenoid. The other vac line (at right front of carb) makes a quick 180 and goes into choke on carb (I think that's what that is). All I did was add another T by the AIR device and then capped off the TCS valve where vacuum advance from distributor used to go.




The only other thing I'm not sure of is what model vacuum canister do I have on the distributor? At idle IIRC the advance was up to 18 with vac plugged in (12 without). The only markings I could see was a "B1" on the flat piece coming off the vac canister in bottom of distributor, underneath the part that spins. I'm not gonna lose too much sleep over it right now cause it runs good, didn't hear anything funny, and water temp oil pressure looked normal.

 

Ok after spending all morning dredging the interwebs I've figured out that the "B1" on the vac advance can means it is a VC24A. Do any of you know what the specs are for that can? Further dredging of the internet turned up nothing. BTW, I'm getting about 14" of vacuum measured by the mityvac. I know there is something about a 2" rule in the papers, but I'm not totally clear about that. Any help would be appreciated, thx in advance.

 

From some of Lars's detailed information:

P/N ID# Application Starts @ “Hg Max Adv (Distr. Degrees @ “Hg.)

VC680 B1 1959 – 63 All Chevrolet 8-11 8 @ 16-18

1964 Corvette exc. FI

1964 Impala, Chevy II

1965 396 High Perf.

1965-67 283, 409

1966-68 327 exc. Powerglide

1967-68 All 396

1969 Corvette 427 High Perf.

1969 396 Exc. High Perf.

1969 Corvette 350 TI

1969-70 302 Camaro

1970 400 4-bbl

1970 396 High Perf.

1970 Corvette 350 High Perf.

1973-74 454 Exc. HEI

Comments: This part is still available through NAPA stores. BW part number V280.