Idle spark 355 424 ?

[Jaso74]

Hi All .

Just having a slight crank issue with new engine and old direct drive starter on 355 .
Not sure if it is just the sound of the starter trying to deal with the higher CR or if there is a little too much cranking ignition spark advance or a combo of both .

Anyway was going to try backing off cranking spark advance a smidge and see what it does. Using $11p and looking in TP5 maps for spark , it appears I may have to just remove some from the 400 rpm cell in the "20-100 KPA main spark advance map vs rpm" ? Is that the right way to go about it ?

Thanks for any ideas or help .

[vlad01]

Pretty sure no advance is available during cranking, only once the engine is above a certain rpm (ie. running), will the ignition go into bypass mode and allow the ECU to control advance. It's always locked at 10 deg while cranking which is the ignition module's responsibility, ECU has no say in this stage.

I'd say it's your starter most likely, those Bosch units are terrible and always have been (trauma from my VW days ) . My brother's one was crap for years and finally died (side of the road of course) and he got a cheap 150 buck reduction gear one, and it's never been so good! Better than factory and starts easy as now.

Anyway, just check your base timing while cranking in case the dizzy is off. Should be that 10 deg BTDC.

[Jaso74]

Thanks Vlad .
Yeah timing has been base set at 10 deg and mark on balancer checked too.
I figured it was starter mostly but thought I'd ask .
Thanks .

[immortality]

Check all your battery, starter and earth connections on the block, battery and chassis and starter motor.

It could be a tired starter motor.

You could also try a different starter motor relay. The starter solenoid needs a good power supply for it to work properly, the starter solenoid can draw a decent amount of power. There is also a fusible link somewhere IIRC, that might be damaged.

Vlad is correct, when cranking you only get the timing advance the dizzy is set too.

[Jaso74]

immortality - Yeah honestly I'm pretty sure the starter has done a lot of work if it fits in with the rest of the running gear .
Earth wise good , starter relay good , have constant cranking when needed etc it just struggles when hot mostly like a polling starter motor does or same as when timing too far advanced . I'm more than happy to change out the starter motor to a high torque/reduction starter motor , just need to know which one to get . I've heard several stories of getting the wrong one or doesn't fit correct for various reasons which sounds crappy as . The more I look the more I see conflicting info that really makes me less confident in getting the correct one !
Anyway I will journey on and with any luck get the right one to suit the VR 304 .

[immortality]

Could also try some heat shielding around the starter.

Some heat sleeving around the starter cables couldn't hurt either, heat really increases resistance in electrical components and pushed up current draw.

[Jaso74]

Yeah fair point. Might have a look for some wrap and see what I can find.

[vlad01]

If you do replace the starter with a modern type, permanent magnet compact design with gear reduction. They don't suffer from heat anywhere as much as the Bosch design, in fact it will be irrelevant. The newer designs are much more efficient and negate the "flat battery effect" the older Bosch style ones have.

On ebay, they are about 100 bucks, but they looks like the Bosch ones, so not sure if they have planetary reduction gears or not, or just a mere copy of the Bosch direct drive old design. I think my brother's one was a Jaylec brand and looked a little different to the ones on ebay.

[vlad01]

Yep, it was the jaylec one.

All silver and shorter motor with longer housing for the reduction gears. Not that cheap on this ebay listing though.

Makes sense though, get what you pay for.

https://www.ebay.com.au/itm/17378047745 ... R5S2wuPAYw

[immortality]

You really are hanging a lot of crap on the Bosch starter motor when you consider it's probably the original that was fitted sometime in the mid 90's.

Interestingly, The Holden motors never had major starting issues like you see on some US models.

My old VH 308 had some starting issues but then we added a starter motor relay with some decent size wiring and problem solved but in the end the brushes were worn out and that's just what happens with old stuff.