304 Timing Querie.

[Nut Kracker]

Hi all.
Sorry if this is a bit long winded, but the more information I give you, the more I hope to get back.

What I am wondering is. How much (if any) is the engine timing effected by how much the engine has been modified?

As some of you may be aware my engine (VT 304ci) has been modified.
Modifications are......
MAF less tune.
Custom high rise intake manifold & OTR.
Twin 63mm T/B.
Heads ported & polished.
Roller rockers.
Double valve springs.
Extractors 2 1/2 cat back.
Crane 888241 Hydraulic Roller Cam.
Specifications......
Series and grind number. Components.......HR-226/345-2S-10
Deg. @ .050” Cam Lift Int./Exh....226/230
Deg. Adv. Dur. Int. Exh..............288/292
Deg. Lobe Separation.................110
Open/Close @ .050” Cam Lift Int./Exh........8 38 50 0
Lash Hot Int./Exh............. .000 .000
Gross Lift Int. Exh.............. .552 .563

What I'm trying to say is.
With my engine, would the factory timing (12 Degrees BTDC) be suitable.

I had the timing re set a little while ago @ factory 12 BTDC, as the dizzy became loose and it was popping and farting all over
the place.
I don't know what it was set at, at the time of the modifications and I can't get in touch with the engine builder to ask him.

It just seems to me, that up to around 60Kph and just going through the gears normally, it seems to be ever so slightly hesitating
and there is the occasional little "pop" out the exhaust, if there is not enough accelerator given, when changing up through 2nd to 3rd.
But drop it back a cog or two, give it a little bit and it pushes you back in the seat.
I realise the cam kicks in at around 2800 (and boy, does it ever), but it's just the lower end of the revs I am wondering about.
There wasn't any hesitation before the timing went south on me.

It does have a fairly lumpy idle and the base idle sits at around 950 to 1000 rpm.


Everything else checks out.
No DTC's set.
Ignition parts, IE. dizzy, coil, module etc. all check out ok.
Leads, spark plugs, replaced 6 months ago.
No vacuum leaks.
Injectors all good. As is fuel pressure.
All the 3 letter sensors and the O2's replaced 6 months ago.
Battery, alternator etc. all good.

Any opinions greatly appreciated.
NK.

 

[Darren_L]

it all depends on what your tuner has done (I assuming and hoping you've had it tuned!)
Most tuners will retain the 12deg base timing and adjust the ignition advance throughout the maps from that base.
In which case you should keep the 12 deg base timing.

 

[Nut Kracker]

Thanks for that Darren.
I'll just keep plugging away at it.
It's not that bad really and I suppose maybe, I'm just a bit picky.

It has been tuned.
I asked the builder a fair while ago and he seems to think it's a Kalmaker W72 mafless.
But trying to confirm this has been futile, as I can't get in contact with him
and Kalmaker wont reply to my emails.

 

[delcowizzid]

should be set at 10 degrees in diagnostic mode ie jumper in pins 5 and 6 of the aldl plug.weather your tuner even checked it before tuning is anyones guess but its the first thing i confirm before even starting a tune or fitting a tune.to rich will pop out the exhaust too lean pop out the intake spark miss will pop out the rear too if the exhaust loads up with unburnt fuel and air.if its tripping the knock sensors from to much timing or too lean they will pop and fart sometimes and seem like a miss

 

[Nut Kracker]

should be set at 10 degrees in diagnostic mode ie jumper in pins 5 and 6 of the aldl plug.weather your tuner even checked it before tuning is anyones guess but its the first thing i confirm before even starting a tune or fitting a tune.to rich will pop out the exhaust too lean pop out the intake spark miss will pop out the rear too if the exhaust loads up with unburnt fuel and air.if its tripping the knock sensors from to much timing or too lean they will pop and fart sometimes and seem like a miss

Thanks del.
Are you sure 10 Deg BTDC would be ok?

I took it to a mechanic here that has a very good reputation and told him to jump pins 5 and 6,
and also told him to set it at 12 degrees.
As far as i know he did jump the pins because the jumper I made up is missing.
I assume he forgot to give it back to me.

The only reason I didn't do it myself was, that it would cost me more to buy a light and crows foot
spanners, than to pay $40 for the labour.
I might just bight the bullet and go and buy them.

In the picture below, I know where TDC is , but could you or anyone show me where the 10 deg BTDC would be??

 

[Darren_L]

each graduation is 2 deg
the long mark between the 'A' & 'R' is TDC or zero deg

so 10 deg advanced is the long mark on the left side of the 'A'

 

[someguy360]

Even a 355 etc will still be set to 10 degrees base timing, the rest is adjusted in the tune.

Set it to 10 degrees (you can bump it up to 11-12 if you run if you only run it on 98, I wouldn't recommend it on 91), I would say if you are having issues then you need to take it to your tuner and get the tune touched up.

As soon as you start modifying the engine like that, if the tune isn't 100% right you are going to have driveability/performance issues, take it back to whoever tuned it when the work was done and get them to look over it.

 

[Nut Kracker]

each graduation is 2 deg
the long mark between the 'A' & 'R' is TDC or zero deg

so 10 deg advanced is the long mark on the left side of the 'A'

Cheers.....Appreciate that.

Even a 355 etc will still be set to 10 degrees base timing, the rest is adjusted in the tune.

Set it to 10 degrees (you can bump it up to 11-12 if you run if you only run it on 98, I wouldn't recommend it on 91), I would say if you are having issues then you need to take it to your tuner and get the tune touched up.

As soon as you start modifying the engine like that, if the tune isn't 100% right you are going to have driveability/performance issues, take it back to whoever tuned it when the work was done and get them to look over it.

Thanks mate.
I don't think it is tune related, but just something mechanical that's ever-so-slightly amiss.
And as you said, if somethings not 100% on an engine like this, it'll be noticeable.
I do, on rare occasions run 98. But due to the financial situation at the moment, I've been running on 91 or 95.

As I mentioned before, I can't get in touch with the tuner.
As far as I know, he's working on the oil rigs of the WA coast and has closed his business (Chip Control in Sunbury Vic).
He doesn't answer his emails either.

I'm in Echuca Vic. and as far as I know, no-one around this area can access the Kalmaker tune.
If anyone does know anyone, give me a shout.
There is a place in Epping (Melbourne), but getting there and money is a problem at the moment.

Thanks everyone for your input........

 

[Immortality]

Yep, take it back to 10° BTDC base timing and see what happens.

What fuel was the engine tuned with?

 

[someguy360]

I might just bight the bullet and go and buy them.

This is what I use, it will become your best friend (304 uses the 9/16)

Offset Distributor Clamp Wrench 2 Piece SET 1 2'' AND 9 16'' | eBay