More V8 Issues

[Aragorn]

I'm trying to get the disco moved down to blackpool, so i tried to do some bits and bobs to it today to get it ready. Thinking all i'd have to do was retime the motor with the vac advance disconnected, and check the diff oil levels, i set to it.

Got it nicely set to 7deg BTDC, and popped the vacuum advance on. No change, still showing 7deg BTDC. I got angry for a few minutes thinking i'd fitted another duff dizzy, Took the cap off and ensured the vac mechanism was moving as it should be when i sucked on it and it was.

So i start it back up, pull the vac line off the carb and sucked on it hard, the revs climbed a few hundered RPM, stopped sucking and it dropped back down, so from that i suspect that the dizzy is just fine.

Question is why the vac line isnt pulling any vacuum? i got a "long pokey thing" and jabbed it into the hole on the carb just incase it was somehow blocked inside, but that didnt seem to make any difference. Am i right in thinking with the vac advance fitted it should be advancing at idle?

Its also used a little coolant every time i've taken it out over the last few months. Last time i run it i thaught it hadnt used any, but today i've noticed something. Before i started the motor, the level was about 1cm below the "MAX" tag, when i'd looked after driving it last time, it was above it. Sure enough, this time after having run it for 10mins or so while messsing with the timing, it was back up above the max line by a cm or two. From that we could surmise that its losing water thru the overflow pipe, but that leads to the question as to why the level is going UP in the first place?

If the headgasket was blown, the level would surely go down?

[Hybrid_From_Hell]

Rev the engine and see if it advances and drives properly

Or add a tube and suck to see if dizzy moves

Basically at tick over there will be no advance

Coolant, could be air working out of the system, so don't panic yet, do some miles and

see if the levels move significantly, some headers will refuse to run at the "Max Line"

spitting out some water, and then settle down to a happy level, no, I have no idea

why "BL" may have something to do with this, like "Lucas" and "Broken" and "Sh**e appearing

so often in the same paragraphs

Nige

[Aragorn]

I revved it up to 1500ish while watching and it advances round beyond "BEFORE" on the pulley. Its basically set as it was before, and i found that it went ok, but it was perhaps a little flat. Problem is ive no idea what to expect from this engine in a 2 ton disco. Full throttle doesnt really provide much "go" compared with say 60% throttle, and giving it full bore doesnt really do much in the way of accellerate, it just slowly builds speed. Perhaps i'm just expecting too much from it, but i'm sure my mates TDi 90 has more guts than this does.

I think i'll get an AA membership sorted out, cross fingers and toes and set off for blackpool I'll need a fuel tanker in tow too no doubt!

I'd like to get some megasquirt on there and see if i can make it run nicely, but having just moved money is rather tight just now, so atm if i can get it moved to blackpool then i can work on it as and when i have time, while hopefully actually getting some use from it.

[Aragorn]

Or add a tube and suck to see if dizzy moves

Nige

I did that, with the cap off, sucking shows the little arm moving inside the dizzy, and with the engine running, sucking makes the revs climb, which i presume means the dizzy is advancing correctly!

[Hybrid_From_Hell]

OK

Last thought - different V8 dizzys have differening setting for timings, check the model of yours against

what it should be 7 BTDC may be wrong for it, as with all thing BL they make life hard for owners

Nige

[SteveRK]

If the vacuum tube is fitted on the air cleaner side of the carb' then don't expect to see any vacuum on idle.

[Aragorn]

The rocker cover label says (iirc) 6-8dec btdc, so i went for 7, its probably fair to say even those timings will be rather conservative

The vac tube appears to be on the manifold side of the carb, hence i expected some vac at idle, clearly theres just not enough to pull the dizzys advance in.

[paintman]

Markings for TDC etc are 'thereabouts'at best. Set by finding a nice piece of quiet road, get up to 30 in 4th then floor throttle. If no rattly pinking advance dizzy & try again until it does. Then turn back until it JUST pinks.

According to spec my RRC should be set at TDC+/- 1 deg. According to the marks its actually running about 8deg BTDC.

[Quagmire]

My 3.5 was set to 8 deg i think, and runs well at that position. At this setting you would get pinking under load if you were too heavy footed and running on unleaded.

However, running on LPG most of the time that didnt matter and when on petrol you could just "drive around" the pinking if you know what i mean.

Megajolt ran the car for the first time tonight though, after i bodged some leads together! yay! Roll on payday and proper fastlane leads

[Hybrid_From_Hell]

Forget whats on the rocker cover

The build of the engine dictates the Dizzy fitted, so in effect

the dizzy is matched to the engine, change the dizzy for a different type

or number and you then need to check and use the timing for the engine

that dizzy came out of, there are some dizzys that run tickover at ATDC !

Don't assume that the engine timing you engine says you need is what you

have set if the dizzy is from a different number - you can find all the

timings for the V8s I have them somewhere but goggle will prob be quicker

Nige

[Aragorn]

Hmm, i see what you mean now, it will depend on the mechanical advance provided by the bob weights in the new dizzy. I've no clue what that dizzy came off though, and i dont really fancy pulling it apart to check :/

I'll see if i can read the numbers on the side of the dizzy casing, you think that will allow me to identify the bob weights?

[Aragorn]

ETC6951 is all i can make out looking at it.

The "35DLM8 lucas part number is obscured when its fitted, so i cant see any additional letters or numbers round that area.

Does that help at all?

[Quagmire]

This might help- follow the links for an online Lucas dizzy profile calculator.

Check this out

[Aragorn]

Thanks, as i feared though, it only gives the maps based on the full lucas part number.

I'm now back in blackpool, so i cant get anything else off the dizzy than the ETC6951 number, and that its a 35DLM8.

I would think that all ETC6951's would be the same lucas part? if so, does anyone have one they could look at and give me the Full lucas number off?

Cheers.

[Aragorn]

more oddly, i pulled the old dizzy out to see what its code was....

its an etc6976, however the lucas number is 35dlm8-42652A, which is not on that list linked to above at all...

[steve_d]

If you go onto Rimmers web site and look for distributor you will find a dozen or more 35DLM8 variants for different engine sizes, manual, auto and compressions.

They will each have different mechanical timing and possibly different vacuum timing as well so it is important to fit the right one.

Both the ones you mentioned are listed.

Steve

[Aragorn]

TBH i'm not going to change the dizzy, i'd just like to get this one timed up as close to "correct" as i can.

If i can manage to get the truck down here without it blowing up, i eventually want to have a go fitting megasquirt to it, and obviously that will render the dizzy redundant anyway.

I think, seen as this is a dizzy from a 3.5 EFI range rover, if i find the static timing for one of those, that will give me the correct advance setting for this dizzy?

I think i'll dig out my Autodata CD's and see what they say.

[FridgeFreezer]

Pushing the accelerator more will probably just result in burning more fuel rather than taking off like a rocket. If it runs smoothly and sounds happy then unless something else is giving you cause for alarm (eg smoke / terrible mpg / overheating etc) I'd say you're probably as close as you can be with this clockwork gubbins

[Bull Bar Cowboy]

I think, seen as this is a dizzy from a 3.5 EFI range rover, if i find the static timing for one of those, that will give me the correct advance setting for this dizzy?

I think i'll dig out my Autodata CD's and see what they say.

The correct timing (and the required timing curve) is not related to the dizzy (the engine determines the requirement and the dizzy is the mechanism that supplies it).............. it is a function of the how the engine is setup (cam timing, CR, Combustion chamber shape, & breathing). As the cam / breathing is different for a carbed V* as opposed to an EFI then the dizzy will be set up incorrectly (in the perfect world) , however, it can be made to work. The end result will be that the curve of the EFI dizzy may be a little aggresive, but it will probably be OK. I would be inclined to set the timing at 6BTDC @ idle (about 750 rpm).

The vaccum advance curve (i.e. the diaphram unit)may also be different ........ take the vaccumm advance unit off the old dizzy and fit it to the current dizzy.

[Aragorn]

Thanks for the tips.

Vac advance unit on the old dizzy is burst, so swapping that over is a no-go.

I didnt hear any pinky type noises, but its not a noise i'm accustomed to hearing anyway, and as the engine is new to me its hard to tell exactly what is "normal"

I think its current setting is about as good as i'm going to get it.

I've had a look thru autodata and found this:

For a 1989 EFI Range Rover (ie the motor the dizzy came from), it says static timing is 3 deg ATDC for 95 ron fuel, then it says the distributor advance (without vacuum or static timing) is as follows:

3-8deg at 1200rpm

18-22deg at 2200rpm

22-28deg at 3200rpm

If we compare this to the Disco 3.5 Carb listing we get the following:

Static timing = 6 +/- 1deg at 750rpm

Advance (again without vacuum or static)

0-3deg at 1000rpm

13-21deg at 2400rpm

22-28deg at 3600rpm

So it would seem that the advance curve on the EFI dizzy is a little more aggressive although levels off at the same place, but because the EFI motor had less static advance (-3) the overall advance is lower when compared with the carb engine which was running 6+28.

I'm going to plot the three curves in excel see what i come up with, will post them in a minute...

[Aragorn]

The three curves:

[Bull Bar Cowboy]

The design for the RV8 is 28 degrees max mechanical advance……… (yes you can have more (up to about 34 degrees), but this was the safe limit for petrol that may be sh!t in some parts of the world).

If you want to be sure of the static timing then look at the bob weight cam for the old dizzy and make a note of the number stamped on it………..

28 - (Number x 2) = static timing.

Like I said above, the EFI dizzy will probably work fine but the curve will be more aggressive ……….. but the vaccum units may be very different (also they may not be).

[Aragorn]

Well thats not what the autodata numbers say?

It suggests that both the disco and range rover dizzys add 28deg mechanical advance (meaning they both have the same 14deg advance cam), but the rangey runs 3ATDC static and the disco runs 6deg BTDC static?

As the graph suggests, that means the rangey runs with a TOTAL of 25deg max advance, and the disco is more like 34deg total advance?