327 Break in prep (timing)

[ddversatile]

Hey guys I have a question on the initial timing i should run on my fresh rebuild 327 needing a cam break in. I seen FSJunkie's post about the proper initial timing for a 327 being 8* BTDC but i think i saw in my Service Manual it being 5*

From what I've read too retarded timing will cause overheating and too advanced will ping/detonate. Should I set my timing for 8* and rely on the ported vacuum to do the rest I've read some people manually advancing it and later setting up the vacuum but I don't know if I am confidant doing that and want your guy's input.

I have just got my carb working right now and was looking to break it in this week. Gonna be 5* C outside but will have water/snow ready if she gets hot.

Also made a oil pump primer out of an old dizzy

I also set the idle on the 2300 Holley to the factory benchmark (2,1/2 turns out) and i think it will be fine because at 2000-2500 a guy wont be using the idle circuit right? Will be able to fine tune it once the break in is over though.

[bufurd]

5* or 8* firing it up won't really matter, the most important thing in the position you're in is that the engine fires up quickly to not wipe the lube off the new cam before it's running to lube itself properly. Also are you using a zinc additive or a break in oil or better yet Diesel engine oil to protect the cam and lifters. Regular (modern) motor oil will likely take out a flat tappet cam and lifters over time. Good luck, nice engine.

[ddversatile]

5* or 8* firing it up won't really matter, the most important thing in the position you're in is that the engine fires up quickly to not wipe the lube off the new cam before it's running to lube itself properly. Also are you using a zinc additive or a break in oil or better yet Diesel engine oil to protect the cam and lifters. Regular (modern) motor oil will likely take out a flat tappet cam and lifters over time. Good luck, nice engine.

Thanks, and I am using Amsoil High Zinc straight 30 break in oil for the 20 minute break in, then changing again with the same oil for 500 miles then switching onto Amsoil ZROD 10W-30

[Crankyolman]

...or better yet Diesel engine oil to protect the cam and lifters. Regular (modern) motor oil will likely take out a flat tappet cam and lifters over time. Good luck, nice engine.

Modern diesel engine oils have been quietly cutting back on the amount of Zinc and Phosphorus for several years now so using diesel oil is quickly becoming as much of a problem as other modern oils. The better option nowadays is an oil specially formulated for vintage cars.

[bufurd]

You are correct about taking some of the zinc out of Diesel engine oil, it still has a lot more than modern gas engine oil.. The new specialty oils available now to address this problem only proves there was a problem on old flat tappet engines using modern gas engine oil. Either is good.

[SC/397]

I set the timing by pulling all of the spark plugs out and setting it with just running it with the starter. At least you know where it is when you start it. Once it is fired up check the timing and make sure that it advances while it is running.

[Ristow]

I also set the idle on the 2300 Holley to the factory benchmark (2,1/2 turns out) and i think it will be fine because at 2000-2500 a guy wont be using the idle circuit right? Will be able to fine tune it once the break in is over though.

rpm has nothing to do with what circuit is in play in the carburetor. throttle position does. you will be on the idle circuit free revving at 2500 rpm.


set the timing mark at about the 10 degree mark on number 1. then set the distributor so the points just crack open. you can watch/listen for the spark. with electronic you set it so the reluctor is just about to line up with the coil pickup.



then you are not rolling the motor over at starter speeds looking for correct ignition timing.

[ddversatile]

Thanks Ristow!

[FSJunkie]

Well I don't remember what I said back then, but it was probably close to ten years ago and my attitude since may have changed with experience. I run both of my 327's at 5* BTDC at 500 RPM with the vacuum line removed. That was the specification for both the low compression and the high compression 327's, however low compression engines specified 8* if high octane fuel was being used.

Do this rather than guess around on setting the timing the first time:

1. Remove the passenger's side valve cover.
2. Rotate the engine while watching the rocker arms for cylinder No. 6. Watch for the exhaust valve to open, then close, and for the intake valve to just start opening. That is TDC overlap for that cylinder, which means it's companion cylinder (No. 1) is on TDC compression stroke.
3. Rotate the engine to whatever timing mark you want.
4. Install the distributor with the rotor tip pointing toward whichever cap tower you want cylinder No. 1 to be.
5. Rotate the distributor body clockwise until the points just barely crack open. Use a test light across the points if you have to. Make sure the rotor is pointing at the proper cap tower for cylinder No. 1.
6. Lock the distributor down.
7. Congratulations, you have just static timed your engine within a degree or two of accuracy. No guesswork on startup, no backfiring 180* out.

Plain old cheap 10w-30 plus a bottle of Lucas TB Zinc Plus is what all of my engines were born with. After that it's Rotella T4 10w-30, which has more than enough ZDDP to make me comfortable. My oil clearances are proper so I run 10w-30.

[ddversatile]

Thanks everybody, with your advice it fired first crank. Didnt even get hot, maintained consistent oil pressure throughout the 20 minute break in (started 55 but dropped to 40 with heat synch and held 40 the rest of the time)

[bufurd]

Awesome, good to here, I hope you're relatively young cause you're never gonna wear it out. That's a great engine.

[rang-a-stang]

Wooo Hooo! Video?