[Mytmouse]

Took my 67 SS Chevelle out of storage this weekend and did a tune up before putting it on the road. I have to admit it has been a long time since we (my brother-inlaw and I ) did a tune-up like this (points, plugs, condenser, rotor etc.) so we may be a littl out of practice (bought this car only about 8 months ago) Every thing was going fine until we went to set the timing according to the 67 Chevrolet Assembly manual. The manual said set the timing at 4 degrees BTDC. Looking at the marks on the timing plate it looks like this A !!!!!!! 0 !!!!!!!! B. To get it to idle with the Vacuum advance disconnected and plugged, I had to set the timing at the first mark too the left of 0 which no matter how you look at it is not 4 degrees. Is it possible that the timing chain is worn so much (matching numbers motor) that the timing marks are off. It was set right on 0 when we started but it seemed to run a little better the more we moved the mark to the left of 0 but we didn't want to move it to far because it seemed we were going in the wrong direction

Also since I got the car the engine has had a little knocking noise when the car is at idle .....about 800 RPM but when I raise the idle to about 1200 it goes away. I don't think it is a rod knock as it appears to be doing it sometimes and not others and goes away at increased idle speed . Could this be something related to the timing like ping or chain slap, etc.

Any ideas???


[This message has been edited by Mytmouse (edited 04-26-99).]

 

[COPO]

I'd have to say that each line ! is 2 degrees. I would set it between 12-14 degrees B. If you ping when at 14 degrees then bring the timing down to 12.

On the noise, I'd change the oil/filter, set the solid lifters if you have solids and dump a can of GM EOS in your oil. See if the noise gets quieter. It may be that the upper block is getting more oil as the rpm increases which stops the noise.

Maybe someone else can elaborate.

Mark

[This message has been edited by COPO (edited 04-28-99).]

 

[Fred Aldrich]

COPO's right on re: markings.
Correct Dist PN is 1111170 for '67 396/350
Mechanical advance curve is:
0 deg @ 900 rmp
8.5 deg @ 1250 rpm
17 deg @ 2000 rpm
32 deg @ 5000rpm

Chev recommends that timing should be set to 4 deg btdc (that's two marks toward B)

If you have high octaine fuel or lowered compression ratio, car should take 38 deg total advance. I would set timing at 6 deg btdc with this distributor. Idle quality with vac advance disconnected is not important since reconnecting it will change the timing at idle.
If you're still running original 10.25/1 compression ratio, then you'll have to retard the timing until detonation goes away. Otherwise, your engine will be junk in no time at all.

------------------
Fred Aldrich
Web Site: www.GeoCities.com/~69_chevelle




[This message has been edited by Fred Aldrich (edited 04-28-99).]

 

[Mytmouse]

Thanks COPO and Fred.

I dug a little further in the assembly manual (don't know why I couldn't find it when I was doin the timing on Saturday....maybe all the grey matter in my head is migrating outside.)and confirmed what both of you guys have told me about the timing. Right now I am sitting on 0 or maybe one mark to the left of 0 and it is hard to start. I will move it to or three marks to the left ( this is the direction it starts to smooth out anyway) and see what happens. I only run Sunocco Ultra 94 fuel and believe the engine to be original inside so, if that means 10:25/1 pistons, then that is probably what is in there. I think the car sat for many years before being "restored" in about 1996) but has been run pretty consistently for the last 3 or 4 years.

Fred,
Do you suspect the knocking noise to be poor detonation? Because the timing right now, and when we started the tune up, was already 4 degrees retarded minimum. Experienced this noise last year when I bought the car and that this noise will go away when I advance the timing??? That is my hope and will try when I get it back from the muffler shop (custom exhaust and headers time) later this week

COPO,

Oil and filter was changed right before I stored it (about 3 weeks before) in November. At that point I put quart of Risolene in it because I had a sticky lifter problem and that seemed to go away within a week. The car has hydraulic lifters (no solids) and the noise does not appear to be in the lifter area although chasing engine noises I know can be frustratng at times. I keep thinking it is related to the timing and hope by advancing it this will make it go a way. The noise sounds alot like the knocking sound a motor makes when you shut it off and it wants to keep running because of pre-ignition.

Thanks again for the suggestions. Your help is greatly appreciated by this "old" rookie



[This message has been edited by Mytmouse (edited 04-27-99).]

 

[chev64]

Mytmouse, Has your engine been restored? If not you may have carbon build-up inside and it needs to be cleaned out with a combustion chamber cleaner, GM makes a good one.

 

[Fred Aldrich]

Detonation sounds a little like popcorn poping. Crackling (pre-ignition) noise made by an engine "running on" with the ignition off is is very similar.

------------------
Fred Aldrich
Web Site: www.GeoCities.com/~69_chevelle

 

[Mytmouse]

Chev64,
Can't say for sure whether engine has been rebuilt but I suspect not. All I know is that it is the original engine.Combustion chamber cleaner, is this a fuel additive???? Is there a name or do I just go to Dealer parts department and ask for pint/quart of combustion chamber cleaner???

Thanks

 

[COPO]

I'll say that the problem will go away when the engine is timed correctly. By the sound your describing it sure sounds like too much retard in the timing, it's getting chocked up and coughing.

Mark

 

[73Malibu]

I would certianly check for timing chain slack. You can put a stethascope on the timing cover while it is running to check for the noise. The 32 year old chain must be stretched out. I will also agree about the carbon build up. The cleaner would be called carbon remover or top engine cleaner. Good luck

Frank