Mercruiser 470 timing - service manual?

[Iroc-Sea]

Hey all,

Removed the distributor on my Mercruiser 470 to replace the side (lifter) compartment gasket. Need to time the engine now.

I believe the timing was revised to 4 BTDC vs 8 as originally specified. I think I have the gist of it but figured it would be worth reading through the procedure first.

Thanks!

 

[nola mike]

Yes, revised timing specs are 4'. Not much to the procedure. Still have points? You'll need to set dwell, timing, idle speed, since they're interrelated...

 

[ROY WILLIAMS]

Hey all,

Removed the distributor on my MerCruiser 470 to replace the side (lifter) compartment gasket. Need to time the engine now.

Wondering if anyone can share the service manual, or the excerpt on timing? I believe the timing was revised to 4 BTDC vs 8 as originally specified. I think I have the gist of it but figured it would be worth reading through the procedure first.

Thanks!

1978 MerCruiser 470. WILLIAMS. 1978-2025!
THE TIMING 8 DEGREES 1990 YEAR. TIMING 1990'S-2025 ENGINE 4 DEGREES. 600RPM ENGINE IDLE. 4 BTDC DEGREES.

ENGINE OIL 30WT. ADDITIVE LIFT 4oz ZINC PLUS.

 

[bigblocksarefun]

 

[nola mike]

There was a TSB that revised the timing to 4'. I don't have it handy ATM.

 

[bigblocksarefun]

There was a TSB that revised the timing to 4'. I don't have it handy ATM.

http://www.mercurypartsonline.net/database/DATA/001/04/1987/EN_17.PDF

 

[ESGWheel]

Removed the distributor .... I think I have the gist of it but figured it would be worth reading through the procedure first.

Just checking to see if your question was answered as it seems you are also asking about the procedure to reinstall the dist. in addition to what the timing should be.

 

[Iroc-Sea]

Thanks all! Really appreciate all of the posts. Thanks for checking in ESGWheel.

I converted the points to electronic ignition a few years back so no dwell to set. I found cylinder 1 TDC on the compression cycle and moved the rotor to the wire 1 position. The engine now runs. It was cranking and binding initially when I reinstalled the distributor.

As far as I understand it, the next step would be to run the engine, point a timing light at the markings on the harmonic balancer and see where the timing is. Then shut the engine, loosen the distributor bolt and rotate, repeating the same process until I find the timing at 4° BTDC.

Does that sound right? Just wondering about RPM. Should setting at idle be sufficient?

Was thinking of buying this to rather than an conventional timing gun to hopefully simplify things:

https://a.co/d/7CrhRf6

 

[ESGWheel]

Nice timing light. I had my kids get me one a couple of years ago, since it was their money, I convinced them the 5568 unit was the way to go. And it does make it easier.

Yes, timing is set at idle. And if the dist is tightened down some but not too tight (so it can still be moved by hand but not by itself) no reason to shut down and move it. Move it while running to get marks lined up, shut down, and fully tighten and re-check.

Please post specifically what ignition set up you have (it’s been converted) as I think for Thunderbolt IV igns you need to ground out a wire to set timing.

 

[Iroc-Sea]

Nice timing light. I had my kids get me one a couple of years ago, since it was their money, I convinced them the 5568 unit was the way to go. And it does make it easier.

Yes, timing is set at idle. And if the dist is tightened down some but not too tight (so it can still be moved by hand but not by itself) no reason to shut down and move it. Move it while running to get marks lined up, shut down, and fully tighten and re-check.

Please post specifically what ignition set up you have (it’s been converted) as I think for Thunderbolt IV igns you need to ground out a wire to set timing.

Awesome, thanks for the tips! I have the Pertronix Ignitor II with the 45111 Flame-Thrower II Ignition Coil. I searched quick, thinking it may be the same as with points but I could be wrong.

 

[nola mike]

Awesome, thanks for the tips! I have the Pertronix Ignitor II with the 45111 Flame-Thrower II Ignition Coil. I searched quick, thinking it may be the same as with points but I could be wrong.

Timing procedure is the same.

 

[ESGWheel]

All good now?

 

[Iroc-Sea]

Yep, thanks gents! Will report back once I get her done.

 

[Iroc-Sea]

Wrapped this up last weekend, thanks again for the help! Worked out well, running smooth. Highly recommend the Innova timing light.