Sven, I've got some info to respond, but before I do your question will get better replies and help in the Engine Shop forum so it has been moved there. Back in a bit.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
Sven, Below are a couple of pics from a 1968 Chevrolet Chassis Overhaul Manual that provide ignition timing and distributor advance specifications (outlined in red) that should help answer your questions. If you can provide more details on the year of your 292, we can check further to make sure these remain accurate for your engine.
Last edited by Gdads51; 09/11/20242:05 PM. Reason: replaced pictures with better quality shots
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
Is the engine still in stock form of has it been rebuilt and bored over? If bored over then manuals specs are a starting point, but then it takes diligent testing to get it all right.
22* total advance at 3000 rpm seems pretty low for the 292 even for a heavy truck application which you aren't.
My '64 292 that's punched 0.040 over with HEI and Rochester B is in a C60 and factoring in a loaded truck at 20,000lbs, likes 7* initial timing and slightly weaker mechanical advance springs that bring in timing at 1050 rpm with full advance of 36* around 3400rpm.
On points and without a load, the same engine quite frankly LOVED initial timing at 10* and stock 292 advance springs which followed the factory advance curve.
Is the engine still in stock form of has it been rebuilt and bored over? If bored over then manuals specs are a starting point, but then it takes diligent testing to get it all right.
22* total advance at 3000 rpm seems pretty low for the 292 even for a heavy truck application which you aren't.
My '64 292 that's punched 0.040 over with HEI and Rochester B is in a C60 and factoring in a loaded truck at 20,000lbs, likes 7* initial timing and slightly weaker mechanical advance springs that bring in timing at 1050 rpm with full advance of 36* around 3400rpm with vac advance.
On points and without a load, the same engine quite frankly LOVED initial timing at 10* and stock 292 advance springs which followed the factory advance curve.
Thank you. I will adjust the initial timing and vacuum advance to reach this values and will see how it works
I don´t know something about the history of the engine.... Do you have a picture from your Rochester B vacuum port for me?
Last edited by Sven010; 09/12/20247:01 AM.
1947 Chevrolet 3800 1-ton long bed 292 cui, GM 14 bolt rear-end, 4 x disc brakes In Frankfurt, Germany Pictures in the Forum Gallery
Thank you. I will adjust the initial timing and vacuum advance to reach this values and will see how it works
I don´t know something about the history of the engine.... Do you have a picture from your Rochester B vacuum port for me?
Ill snap a photo for you here in a bit. Some quick reading on your truck via the gallery stated that the truck was restored so I assume that the engine was at least freshened up. Without pulling the head its hard to determine if it was bored over during that or just honed.
Full disclosure, I am still playing with all of this to get my engine dialed in where I want it and the afore stated numbers are where I currently am which is the best I've had it since adding the HEI. I had everything dialed in perfect with the points system but adding the HEI and larger plug gap threw everything to the wind and I've been tinkering ever since.
If in doubt, send a PM to Hotrod Lincoln. He knows his stuff and mentored me to this point that I am at.
I also recommend using timing tape on the balancer IF you get it set perfect to the TDC mark. Dial back timing lights all seemed to read different from one another when used, so I opted for a standard timing light and timing tape. You can make the tape yourself once you measure the diameter on your balancer.
