Ignition timing

sidecar · Post by **sidecar** » Sat Jan 24, 2015 6:27 pm

Andrewrv8 wrote:I have another dizzy in my garage which I will take a look at, the link suggests running vac-less, particularly if using Eddy 500. Interesting, that could be the answer to the harsh vacuum from carb. The carb does need setting up properly (jets etc) as its still from the box, probably running lean. I will look into MSD for next engine, quite simple to hook up I understand. Damn, I had a lovely lightened flywheel hidden away

What carb do you have?

Andrewrv8 · Post by **Andrewrv8** » Sun Jan 25, 2015 6:58 am

Eddy 500

sidecar · Post by **sidecar** » Sun Jan 25, 2015 9:28 am

Andrewrv8 wrote:Eddy 500

These carbs are hardly ever (possibly never) set right out of the box for a Rover lump. Usually they are way too rich. They are worse on 4,6 then a 3.5. Most 3.5 lumps that Ive worked on needed the cruise leaning off around 8% most 4.6 lumps need the base setting for cruise leaning off between 12-16%. I guess the 4.6 pulls a higher vacuum on cruise compared to a 3.5 so this means that the jets 'see' a bigger depression and end up delievering more fuel, hence the carb needs to be set leaner in order to keep the air fuel ratio right.

This shows up at WOT too, the standard 95 secondaries are OK for a 3.5 but a 4.6 need much smaller secondaries to get the air fuel ratio around 12.5-12.8:1

Andrewrv8 · Post by **Andrewrv8** » Sun Jan 25, 2015 10:22 am

Right ok, not what I expected... downsize to 92 or 89 type thing? Or take it to a dyno and have it set up properly? The garage I'm looking at charge £120 for set up, that would involve setting timing and carb I assume? And a power run

kiwicar · Post by **kiwicar** » Sun Jan 25, 2015 5:58 pm

Hi
I would get a rough set up on the carb before you head for the £120 an hour on the Dyno getting close before you turn up should save time and money, you need the dyno session but do your homework first.
best regards
Mike

sidecar · Post by **sidecar** » Sun Jan 25, 2015 7:30 pm

My experiance of three rollings roads has not been very good, they just thrash the car on the rollers and tell you that everything is OK, they might if you are lucky check the WOT air fuel ratio, whether they would have the jets to change them is another matter!

I think that you are better off buying an air/fuel gauge such as an LC1, then learn how the carb works, after that you are in a position to do the work yourself.

I wrote this ages ago.....

http://how-to-build-a-pilgrim-sumo.wiki ... ing-system

I have changed my mind over a few things but most of it is correct, the main thing that I have changed my mind over this that the settings for a 3.5 are not the same ones required for a 4.6.

Andrewrv8 · Post by **Andrewrv8** » Sun Jan 25, 2015 8:57 pm

Kiwicar and Sidecar, I agree with both of you that I need to learn how to do it myself. This I will do. The link will help as it makes sense and does explain how it works. I've looked at buying an LC1 before and thought it looked complicated but I will invest in one. They are on ebay for £159 - is that about right?

ratwing · Post by **ratwing** » Tue Jan 27, 2015 10:38 am

Andrewrv8 wrote:where is degrees on keyboard?

Hold down the Alt key, type 0176 and you get °

DaveEFI · Post by **DaveEFI** » Tue Jan 27, 2015 12:46 pm

Andrewrv8 wrote:Kiwicar and Sidecar, I agree with both of you that I need to learn how to do it myself. This I will do. The link will help as it makes sense and does explain how it works. I've looked at buying an LC1 before and thought it looked complicated but I will invest in one. They are on ebay for £159 - is that about right?

There are several makers of wideband O2 units. Innovate seem to get a lot of flack for reliability - but that could be just because they are the biggest maker. I believe they have a new model out which may be better.

stevieturbo · Post by **stevieturbo** » Tue Jan 27, 2015 1:29 pm

AEM seems to be very popular, with very few negative reports.

sidecar · Post by **sidecar** » Tue Jan 27, 2015 3:31 pm

I have an LC1, its OK but I must admit I have seen a much better system, it's name escapes me but it is basically the size of a 52mm dial, it stores data such as RPM and vac as well as the AFR, you can then download the data and work out what's going on over a nice cup of tea and a biscuit!

stevieturbo · Post by **stevieturbo** » Tue Jan 27, 2015 3:49 pm

sidecar wrote:I have an LC1, its OK but I must admit I have seen a much better system, it's name escapes me but it is basically the size of a 52mm dial, it stores data such as RPM and vac as well as the AFR, you can then download the data and work out what's going on over a nice cup of tea and a biscuit!

There are a few setups that offer some small logging ability.

Handy for carb cars or where their ecu offers no logging.

sidecar · Post by **sidecar** » Tue Jan 27, 2015 4:49 pm

stevieturbo wrote:
sidecar wrote:I have an LC1, its OK but I must admit I have seen a much better system, it's name escapes me but it is basically the size of a 52mm dial, it stores data such as RPM and vac as well as the AFR, you can then download the data and work out what's going on over a nice cup of tea and a biscuit!
There are a few setups that offer some small logging ability.

Handy for carb cars or where their ecu offers no logging.

You are right, it was an AEM gauge that I was thinking of...

http://aemelectronics.com/files/instruc ... 0Gauge.pdf

They seem to go for around 215 quid, not sure if that includes the actual probe but personally I think it's money well spent and much more cost effective than spending it on a RR session. In my opinion it can take a day or more to get the carb spot on and that's if you have all the jets and rods to hand. A whole day on a RR would cost a hell of a lot and unless the rollers can hold a steady but light load on the engine you can not setup the cruise using rollers anyway.
The calibration kits for these carbs are OK but I have quite often found that the best setup for an engine I've been working on was not even in the kit for the carb anyway! I end up modifying rods sometimes but it is tricky work, I use a rod holder that I made which I spin in my lathe, I then use very find wet and dry to thin the rods down. 1 thou off a rod can make a big difference, my rods are 69 thou on cruise (86 jet) and the car runs just fine at 14.5-15:1 AFR. One thou bigger (70 thou) and I can not even drive the car off my drive as its too lean!

stevieturbo · Post by **stevieturbo** » Tue Jan 27, 2015 4:59 pm

AEM wideband kits are around £150

http://www.ebay.co.uk/itm/New-AEM-Digit ... 46139920be

And yes, they are an excellent tool to have in the car all the time.

the failsafe one that logs might be slightly more expensive.

Daytona sensors make some nice units too, and a good dual sensor/display which also logs. Handy for monitoring each bank, but whether the cost justifies the unit is another matter

http://www.daytona-sensors.com/WEGO4.html

Andrewrv8 · Post by **Andrewrv8** » Tue Jan 27, 2015 8:30 pm

ratwing wrote:
Andrewrv8 wrote:where is degrees on keyboard?
Hold down the Alt key, type 0176 and you get °[/quote

Thanks mate, never would have guessed that!