5.7GLI slight vibration at idle and knocks 2500-3300 rpm

[TexasCobaltGuy]

Forgot to mention picked up all the parts and the heads from the machine shop.

[Big Block Power]

We used the green roloc for cast iron and yellow fur aluminum. We used scotch bright but you have to be careful as particles can fall in the engine and take out you bearings.

[akorcovelos]

They didn't hot tank the heads before machining them? The coolant passages have an awful lot of scale built up in there.

[TexasCobaltGuy]

Still at it. Starting on the Cleaning of the other side now.

Also verified that the head between the 3 and 5 cylinders isn’t pitted or anything after cleanup.

[TexasCobaltGuy]

Long day today!

Great progress made

[TexasCobaltGuy]

I’m not finding a lot of definitive answers on setting the timing. Anyone have any advice on the degree before DTC I should set the timing?

[Big Block Power]

I'll see if I can find any. Prob around 8btdc akro might remember his. I know you also have to do to put it at base timing. More timing the better. It makrs then faster. You just can't put to much or thing ping and go boom. Hope that helps. Sorry I have to go back to my garage cleaning issue. Bye!

[akorcovelos]

Initial timing is 8* BTDC, all in 32* by 2500 rpm. Don’t advance it beyond 10* BTDC. Advance is handled by the MEFI so just set base at 8* and see how she runs. You can bump it up 1* at a time to see if it runs any better. This all needs to be done with the ECU set in base timing mode which you can do with a paper clip. Pull the paper clip to do your test runs or it won’t advance at all as rpm increases.

[TexasCobaltGuy]

Initial timing is 8* BTDC, all in 32* by 2500 rpm. Don’t advance it beyond 10* BTDC. Advance is handled by the MEFI so just set base at 8* and see how she runs. You can bump it up 1* at a time to see if it runs any better. This all needs to be done with the ECU set in base timing mode which you can do with a paper clip. Pull the paper clip to do your test runs or it won’t advance at all as rpm increases.

I was reading on the engine it does say 8 degrees BTDC (with Shorted Diagnostic leads)

What does that mean. And when you say set the ECU In Base timing mode can you elaborate?

When I set initial timing what should the rpm be? Idle?

[TexasCobaltGuy]

This?

[TexasCobaltGuy]

timing should be at 8° BTDC using the procedure below.1. Connect a 12-volt timing light to number 1 spark plug lead, and use the timing light following the manufacturer’s instructions.NOTE: Be careful not to puncture the wire or boot as this wouldcause a high voltage leak. Make sure that spark plug wires arepushed all the way down into the distributor cap terminals andonto the spark plugs. Nipples must be firmly pushed over theterminals, and boots over the spark plugs. Failure to do so canresult in ignition of fuel vapors in engine compartment or bilge,and may result in fire or explosion.2. Start engine and leave running until thoroughly warmed up.Setting TimingThe timing procedure for Delco DI systems requires shunting(shutting off) the electronic spark advance.1. Start engine and manually set idle speed to 1000 RPM, then doone of the following:At the 10-way DLC (Data Link Connector), starboard frontengine, install a Trouble Code Tool and turn it on - ORIf a Code Tool is not available, use a jumper wire andconnect the white / black wire to the black wire inside theconnector.2. Direct beam of timing light onto timing grid. Loosen distributorclamp, then turn distributor slowly by hand until timing mark is set atthe appropriate timing figure.3. Recheck timing mark; reset if necessary. Tighten clamp bolt.4. Stop engine. Remove jumper lead or Trouble Code Tool.

[TexasCobaltGuy]

Everything is buttoned back up and she started up. Sounds really good. I went thru the timing sequence and best I can tell it is now set 8 degree BTDC.

Won’t be able to take it back out on the lake until next weekend to do a test drive. I’ll keep you posted

[BobRae99]

Excellent. A ton of work for you but a great read for the rest of us while many are sheltering in place at home (like me). Hope the water test goes well. Thanks for sharing.

[akorcovelos]

Did you use a dial back timing light? Good to hear she sounds good, that’s a good sign.

[Big Block Power]

Did you use a dial back timing light? Good to hear she sounds good, that’s a good sign.

That's awesome. Congrats man. Glad we could help you out. Like akro said does your timing light have a degree disk on the back of it. Pictures please. I forget what a timing light looks like. If it Has a dial did you leave the dial at 0 and then set it to 8 on the balancer. Or dial it to 8 and set it to 0 on the balancer.