Thread: V8 with Carby-Timing

Holden with the Torana XU1 didn't think so - but anyway this all off topic and not relevant to the question asked by the OP concerning ignition timing.

Originally Posted by 101RRS

Holden with the Torana XU1 didn't think so - but anyway this all off topic and not relevant to the question asked by the OP concerning ignition timing.

The late Harry Firth (Holden Dealer Team) told me at Symmons Plains one day the reason they used the Strombergs on the XU1 was the need for float bowl under carby to reduce/eliminate fuel surge under (racing) cornering and braking.
And fitting Webers was financially out of the question for a Production car.

Also, side float bowls (SU) took up too much space anyway, plus the Strombergs were easy for owners to tune.
I recall seeing a Holden Service Bulletin describing how to set up the linkages and tune the carbs.

By the time the HIF4/6/8 range was becoming available, they (HDT) were developing the next generation Torana with the V8 thus not worth wasting time learning with the SU's.

Apologies to the OP for modifying the thread and slightly off topic, but it was in the interests of 'advising' another easy way to obtain extra hp as from the mods been done to his engine it is obvious he is wanting more!

All good on the Carby choice, Ive rebuilt both my strombergs so will stick with them, bit of an update, the car has been bloody hard to get started and idle, turns out the coil has crapped itself, along with that, the vacuum advance in the dizzy is rooted. Im going to replace both coil and dizzy, can anyone recommend a brand or model dizzy to go for? Currently running a 35DLM8 electronic, cheers for all the advice.

Originally Posted by Summiitt

All good on the Carby choice, Ive rebuilt both my strombergs so will stick with them, bit of an update, the car has been bloody hard to get started and idle, turns out the coil has crapped itself, along with that, the vacuum advance in the dizzy is rooted. Im going to replace both coil and dizzy, can anyone recommend a brand or model dizzy to go for? Currently running a 35DLM8 electronic, cheers for all the advice.

Well there is a vid of someone using a very slightly modded Chev HEI dizzy in a Buick V8 that would work in RRC V8 if you have a search on the web.

Would work underwater with the output of those things.

The electronic ign (inc coil) in my POS replaced the points, condenser and coil in a non-HEI Chev distributor. Was worth the $300 bucks. Can't remember the brand, but was all made in the US.

I'm not sure you have to replace the whole dizzy.......... cap, leads, vac can, sure.

Don't be seduced by fat, bright coloured leads, Bosch induction are great and saved me from repeated backfires and cracked caps.

DL

Originally Posted by 350RRC

Well there is a vid of someone using a very slightly modded Chev HEI dizzy in a Buick V8 that would work in RRC V8 if you have a search on the web.

Would work underwater with the output of those things.

The electronic ign (inc coil) in my POS replaced the points, condenser and coil in a non-HEI Chev distributor. Was worth the $300 bucks. Can't remember the brand, but was all made in the US.

I'm not sure you have to replace the whole dizzy.......... cap, leads, vac can, sure.

Don't be seduced by fat, bright coloured leads, Bosch induction are great and saved me from repeated backfires and cracked caps.

DL

A Buick hei dizzy will drop right in or a V6 with some mods.

In regard to LPG on a 3.9 does anyone know a total timing figure at say 3000rpm including the initial. I have just checked my timing and at 14 degrees, without the vacuum advance connected, it has good bottom end but wont really rev past 3500rpm. Yet with the initial on 4 degrees it will rev to around 5000rpm but loses bottom end. My distributor has around 12 degrees in the vacuum advance and 20 degrees mechanical, so a total of 32 on top of the initial timing setting giving 46 degrees. I thought with LPG the total timing should be closer to 30-32 degrees including the initial 14 degrees I have. I can run it on 20 degrees initial without it pinging but it kills the top end.
I am going to get the distributor remapped but need to know what initial timing to set it at plus the total. Do I just keep increasing the initial timing until it pings and back it off a few degrees and use that figure for initial then get the shop to set the total timing by changing the mechanical advance.

AFAIK you want a lot of advance off idle on lpg. Kinda supported by the figures you've posted.

It helps to have lighter springs on the mech advance in the dist to get early advance for gas. I would think that a shop doing re-curves would have all this stuff down pat..........

go with what they say.

There's a bit of stuff that explains it (including the 14 + 14 + 14 rule and which order to proceed) here:

Timing a 350 on Propane - Alternative Fuels

DL

I spent my 2 hours of exercise today driving the Range Rover up and down a 100km/h section of road, with my mask on. Turns out the best response down low, up to around 2500rpm is with the distributor at 20 degrees but over 2500rpm is not good. To get it to rev out to 4500rpm I needed to set the timing at 8 degrees but at this setting it is very poor up to 2500rpm. All settings done with vacuum advance disconnected.
So it looks like I need to set the initial at 20 degrees and limit the total advance to 28-30 degrees since I previously determined I currently have 20 degrees mechanical advance. Once I can travel I will take the distributor to Performance Ignition and get it remapped.