Kbs

i finally got the engine so it will idle and run! However, with the standard timing, I am getting spark knock on any type of acceleration. I added octane to the fuel but didnt seem to help.
what are the options ? I assume (i no bad idea) its partially related to unleaded fuel but not really sure what to do. Played around with timing, but engine is really sensitive to timing changes. Runs rough with just minor adjustments.. running stock plugs … Any help is appreciated

Olds64

Did you set the timing to the factory spec? If so, you can kick the starter over until #1 is at TDC and compare the mark on your harmonic balancer to the mark on the block. This will verify that the rubber in the harmonic balancer didn't slip and also that the engine didn't skip time on the timing chain.

FWIW, there's no reason your engine should run so lousy on unleaded gas. Especially if you're using Premium gas.

Sugar Bear

What is the engine operating temp when fully warm?
Agree with Olds64 it isn't the unleaded causing the problem; although from a fuel perspective it could be octane related.

Definitely confirm that 0 on the balancer is TDC on the #1 piston.

Good luck!!!

droldsmorland

Lean conditions will cause knock. Verify you have zero vacuum leaks before going any further with adjustments or troubleshooting.
-What are the spark plugs saying?
-What carb and distributor are you running?
-What are you using for tune-up specs?
-Did you set the point gap?
-Verify the distributor vacuum and centrifugal advance settings.

Kbs

Thanks for all the input! I am running a rebuilt std 2 barrel. Distributor is an electronic addition to the std dist. I replaced the plugs . I will do the chk on tdc, hadn’t thought about doing that very good idea. Also running std unleaded will chg to premium another good idea! Will let tou know what i find on tdc.
thanks again !

Charlie Jones

Bingo ! That engine has 9.75 to one compression.
You should be running 91 or better octane fuel.