Running Problem 2.8 Granada - Real Head Scratcher

[NHK244V]

GrannieTwoEight said:

I phoned the carburettor supplier today and he said the symptoms are classic blocked idle jets, I have removed these and cleaned them but he insisted to clean them with air jet and in the hole where they go, as well as strip the jet apart. I can strip it down, take to my local garage and borrow their air hose.

Yes you are right how come it was ok to start with, if it was crap idle from get go then maybe but this problem developed. From what most people have said in the clubs is the 38DGAS will run ok on the two eights without any mods.

Lets see what happens after a proper cleaning. So far thanks for everyone's suggestions.

Andy

It'll run ok but be slightly weak, it really needs larger jets on a smaller engine to be spot on but it will run, i've run unmodded DGSs on pintos and it will run faiyly ok.

[GrannieTwoEight]

Problem is now sorted (touch wood), carb was sent away to supplier for check and they said idle jet was blocked quite significantly, not that I seen anything that looked like a blockage when I removed it. Anyway it now ticks over fine and I am at about 1 and three quarter turns on each idle screw and it will tick over down to quite a low level before stalling.

Now I will try and keep it running every few days and to satisfy myself the problem is not going to rear it's ugly head again. I also might install 5 in line fuel filters just before the carb anyone got spare jubilee clips?

Andrew

[TISPKJ]

Hallelulia !!

[GrannieTwoEight]

Hi

Thought I would reignite this thread as I have begun suffering running problems again with this car.

The long and the short of it is the engine must have an air leak somewhere - the carb set up is exactly as it was when it was running fine before, jets all the same and nothing been changed, and yes carb is clean as a whistle.

Here's what happened, got it MOT'd, everything ok passed the emissions ok, then decided to get it on a rolling road as it seemed sluggish and idle mix screws are out about 6 turns, should be about 1.5 for weber 38dgas.

So I checked up with a few tuners and they said the carb jets I have are fine for the 2.8, they have used the same on other 2.8s with no problems, and wanted to get a consensus on this, 50 idle jets and 135 main jets, even checked with webcon.

I have checked the vacuum from the main front manifold pipe and there doesn't appear to be any major leaks, plus when running the vac needle sits in the correct range specified in the manual.

So why a vac leak? Well despite the readings saying this is apparently an ok range the fact that I have to turn out the idle screws 6 turns to reach an acceptable idle before turning on the fast idle screw 1/2 way to fine get the idle up to 850 or so, and expose the progression holes, and when I put my hand over the carb the revs "smooth out" and increase slightly.

Secondly the rolling road guy said it was very lean over the whole rev range. I am also quite sure it is pinking a bit when mid-acceleration but difficult to hear over the K/N suck of the inlet when I am travelling.

And thirdly I occasionally here a wheezing sound when I turn the engine off - this only happens after extensive long run or when fully warmed through, it appears to come from the N/S lower back section of the engine bay which is strange as there is no vacuum pipes round there, everything is on O/S.

And forth I have double and triple checked everything I can think of in and around the engine bay, testing to as best as I can with the tools I have and have not found anything that would be considered a show stopper, you name it I have either tested it or renewed it.

I realise there is not much that anyone can suggest to check over and above what I have listed so I suppose it is more a rant having had this running problem on and off for the last few years and when I get it fixed it seems to return again.

The initial problem was blocked jets but this is defo not the issue now as these have been fastidiously cleaned out, all filters checked/changed and another once over of timing/plugs/air filter, etc etc.

The strange this is it doesn't seem that far away from running just perfect, it starts fine, ticks over not too bad, drives (but bogs out when initial standing start acceleration) but it is running lean and want to find out exactly why.

[kev b]

Have you tried squirting cab cleaner around the manifold to check for a vacuum leak?

Are you sure the float height is set correctly, if it is too low then weakness will result.

Is there a device like an anti-stall valve fitted? Is it working correctly, can you disable it?

[texaxile]

Complete shot in the dark, and a different engine but with similar problems. Have you checked the Cam chain hasn't slipped a cog, or somehow gone out of sync during the rebuild?. I had issues with a Pinto I had yonks ago, it was mistoothed on the cambelt by one tooth (the dots were one out) and it led to all sorts of problems with idle and starting. Sorry if it's been suggested before.

[dumfriesdave]

Have you tried WD40 all round base of carb and inlet manifold?
If there is an air leak then revs will rise slightly.

Another thought is valve clearances - have they been checked?

[GrannieTwoEight]

kev b said:

Have you tried squirting cab cleaner around the manifold to check for a vacuum leak?

Are you sure the float height is set correctly, if it is too low then weakness will result.

Is there a device like an anti-stall valve fitted? Is it working correctly, can you disable it?

I tried this a while back when I had the gummed up jets and before I changed the inelt manifold gasket = out of desperation!

Float height is as spec

Anti-stall is working correctly, I probably can disable it.

Just as a note the original carb I got I bust the jet thread and had to get a new one. The original one was working fine and was basically new as well with same jets from same supplier as one I have now.

[GrannieTwoEight]

dumfriesdave said:

Have you tried WD40 all round base of carb and inlet manifold?
If there is an air leak then revs will rise slightly.

Another thought is valve clearances - have they been checked?

Checked valve clearances at weekend, they are fine 0.014 inlet 0.016 exhaust. Have not tried wd40 with this new carb or round the manifold since changing the gasket. All new gaskets on carb mounting and tightened squarely with spring washers to take up heat expansion stretch etc.

[GrannieTwoEight]

texaxile said:

Complete shot in the dark, and a different engine but with similar problems. Have you checked the Cam chain hasn't slipped a cog, or somehow gone out of sync during the rebuild?. I had issues with a Pinto I had yonks ago, it was mistoothed on the cambelt by one tooth (the dots were one out) and it led to all sorts of problems with idle and starting. Sorry if it's been suggested before.

No problem always willing to hear suggestions....the V6 has 2 timing gears in mesh and dots were lined up during rebuild. Car was running good initially after rebuild so can discount any mechanical timing issues, first problem was gummed jets, probably due to me leaving it so long and also leaving the air filter off, also set up timing statically and dynamically so should have spotted any problems.

After getting jets cleaned I bust the jet thread some months after as it had been lying a bit so needed cleaned. Replaced carb with new one same spec and had problems similar to before (idle jets 6 turns out just to get tickover, hand over carb straightens out tickover) but everything is clean this time.

[GrannieTwoEight]

Going to try some leak testing. As I said checked with vac gauge but this was pipes off the inlet and onto carb and dizzy area, and to pipework for heating controls. I need to isolate the manifold and check for leaks there although going to be difficult due to valves leaking into cylinder etc.

[GrannieTwoEight]

GrannieTwoEight said:

Going to try some leak testing. As I said checked with vac gauge but this was pipes off the inlet and onto carb and dizzy area, and to pipework for heating controls. I need to isolate the manifold and check for leaks there plus round carb mount, although going to be difficult isolating manifold due to inlet/exhaust valves leaking into cylinder etc.

[final_edition]

As an after-thought, did you re-torque the cyl heads down after initial run after rebuild?

Poss have a crack in cyl head between valves on head face.

[GrannieTwoEight]

final_edition said:

As an after-thought, did you re-torque the cyl heads down after initial run after rebuild?

Poss have a crack in cyl head between valves on head face.

I did torque them down. As par for course I will give it another compression test see what the readings are like, the last time the readings were all fine.

[GrannieTwoEight]

I bought a fog disco machine for £23 and tested the inlet manifold/brake servo to see if there was any leaks. I saw some of the smoke come out of the little spring loaded valve (Looks like some sort of backpressure release valve) on the manifold at the front of the carb - just behind water pipe elbow.

I do remember this valve when rebuilding; thinking back I cannot remember if I disturbed in any way, there is a little brass flat spring that holds down a small bullet type plug into the manifold. When I took it off the spring seems to have been holding up the way and not pressing the little bullet down thus causing a vac leak.

However the even more puzzling thing is that I did not seem to have this running problem immediately after rebuild, and the little spring loaded valve has not been touched since rebuild till now.

So although bending the spring on the valve back to close the plug seems to have improved the running quite a bit I am still not convinced this was causing the problem. I cant think of the life of me why this plug would be set to default open plus there is no reason why it would be forced to shut other than someone pushing down on it.

So much has happened since I rebuilt the engine i.e. swapping carbs, checking everything else and I wonder if the initial tightness of the engine was maybe masking the leak until it bedded in.

I am also thinking that even though I said the initial running seemed fine I did not have the chance to test run the car, only about the road where I live so maybe romancing a bit that it was running perfect!

I also changed over one of the main jets from a 135 to a 142 and this has banished the bogging/stalling from idle to pick up, and the jittering when cruising along at constant speed; I only had one 142 jet in my stock but am thinking of changing the other one over to have a matching pair of 142 main jets.

finally can anyone confirm if my timing should be 6 BTDC ? I read that it should be advanced 3 degrees for unleaded from the normal setting of 9 BTDC.

[sjp63]

advancing 3 deg from 9 would give you 12 not 6 wouldn't it?

[GrannieTwoEight]

sjp63 said:

advancing 3 deg from 9 would give you 12 not 6 wouldn't it?

This is what I am trying to confirm. My understanding of advancing ignition is to take it forward so advancing would bring it forward to 6 btdc.

There is a lot of conflicting info on the net about what advance and retard actually means, does it mean make the spark earlier/later. I did read that unleaded requires an earlier spark so it must mean I have to set at 12 btdc not 6.

Edited by GrannieTwoEight on Wednesday 28th August 21:08

[9xxNick]

Advancing the ignition (which means the same as advancing the spark) means that the spark is timed to fire a larger number of degrees Before Top Dead Centre (BTDC). This means, of course, that it is firing slightly earlier in the four stroke cycle, hence "advance". Retarding is the opposite - the spark fires later.

12 degrees BTDC is more advance than 11 degrees BTDC. TDC refers to the position of the piston in the bore, TDC being the point at which it's at the very top of its stroke.

[TonyRPH]

GrannieTwoEight said:

<snip>
I also changed over one of the main jets from a 135 to a 142 and this has banished the bogging/stalling from idle to pick up, and the jittering when cruising along at constant speed; I only had one 142 jet in my stock but am thinking of changing the other one over to have a matching pair of 142 main jets.<snip>

Here is an exploded view of the 38DGAS.

And here is a tuning guide.

I also found this info in another post here on PH (courtesy of TaimarTurbo).

South African Fords:
XR6/30S/granada 3.0:
45 idles
4.0 Aux venturis
55 accelerator pump jets
142 mains
185 airs

XLE cortina:
45 idles
4.0 Aux venturis
55 accelerator pump jets
145 mains
185 airs


Scimitar (running 3L v6 engine):

SE5 40 DFA-1:
180 mains
60 idles
50 accelerator pump
185 airs correction jet
F2 emulsion tube

• stock dfa uses much bigger mains and idles compared to stock 38 dgas

SE5/5a/SE6/6a 38DGAS 3A:
145 mains
45 idles
60 (OD)/ 70(auto) accelerator pump
185 airs correction jet
F50 emulsion tube

Ford capri 3.0:
Main Venturi 27
Aux. Vent. 4.0
Main Jet 145
Emulsion Tube F50
Air Correc. 185
Idle Jet 45
Pump Jet 70
Pump Bleed 30(1)
Needle Valve 250
Float Level * 40/52.5

For 38 DGAS 6C carb, 3.0 litre European spec Capri OEM jetting was......
27mm choke (main venturi, fixed)
4.0 aux. venturi
142 main jets
185 air correctors
F50 emulsion tubes
45 idle (slow running) jet
55 pump jet (no pump bleed info listed)
2.50 needle valve (gas inlet)

[Incorrigible]

Normally, you would retard the ignition a couple of degrees when running unleaded. I.e. static without vac would be 7 rather than 9 BTDC

Is there a possibility you're running the wrong coil ? I've seen this problem when people have fitted a coil for use in a ballast system in a non ballasted system. The problem being that the coil overheats (but takes time)