Initial timing Delco EST

[padn]

I bought a Barr Marine delivered GM 3.0 longblock. When setting the initial timing the Barr marine engine manual describes 8 ?BTDC at idle with timing shunt engaged - reading the Mercruiser Service manual, it describes 1 ?BTDC - using the same timing method.

For your information the engine can hardly idle if timing is set according to Mercruiser specs. but runs fine using Barr specs. Using Barr specs seems like the right choise.

I am wondering whether two versions of the same engine (different placement of the timing mark at the harmonic balancer) is delivered from GM - does anybody know ?

Br.

Peer

 

[JustJason]

Re: Initial timing Delco EST

What there is, is many different types of ignition systems. Points, EST etc... they all time a little differently. Do you know what you have or an ignition system or can you post a pic of your distributor?

 

[fat fanny]

Re: Initial timing Delco EST

If it is EST the 1 degree is correct but you will need a inductive timing light to check the advance to make sure it's correct but Jason will know more following that but keep in mind to jump out the shift interpretor and distributor wires when performing this procedure at the correct times.

 

[Bt Doctur]

Re: Initial timing Delco EST

http://www.boatfix.com/merc/Bullet/98/98_14.pdf
Service bulletin ,timing the 3.0

 

[padn]

Re: Initial timing Delco EST

Hi
We are talking about a DELCO EST distributor on a GM 3.0 Longblock 2008 delivered by Barr Marine - remaining configuration is Mercruiser 140 1979.
As far as I can see the block and distributor is identical to a 2009 Mercruiser 3.0 - and thats why I am wondering why Mercury describes initial timing 1?BTDC and Barr describes 8?BTDC - thats quite a difference.


Peer

 

[JustJason]

Re: Initial timing Delco EST

Okay...

If you got a long block than it did not come with an ignition system. If swapped over the ORIGINAL ignition system from the 1979 block then you have a points ignition, and not EST.

Your best off now posting a pic of what you have.

 

[padn]

Re: Initial timing Delco EST

Hi JustJason - the longblock came with Delco EST ignition system - see attached picture - so the original coil and distributor has not been reused.

Peer

 

[padn]

Re: Initial timing Delco EST

This is current configuration (see attachment):

Peer

 

[JustJason]

Re: Initial timing Delco EST

Unfortunately those pics don't help. We need close up pics of the distributor housing and wiring.

I'm kind of surprised the long block came with an ignition system... maybe that's a Denmark think. Doesn't happen here.

If it really is EST then you can follow BT Docturs link to time it.

 

[padn]

Re: Initial timing Delco EST

Hi - I think I have found the reason for the difference - My Barr Engine manual describes timing 8?BTDC at 850 rpm with timing shunt engaged - Mercruiser initial timing is as far as I can read in the Mercruiser Service Manual 1?BTDC at 500 rpm (it only describes "IDLE") - with timing shunt. This gives a module advance at 10?. Looking at the timing curves in the Mercruiser Service Manual it describes total advance 16? BTDC at 850 rpm - subtracting 10? module advance equals initial timing 6? at 850rpm - which is comparable with the Barr Manual 8?BTDC (and within +/- 2? tolerance).

Am I totally wrong here ?

Thanks for your inputs.
Peer