Distributor Advance Test for 85 V8 County

[Carslil Jim]

Hi,

M LR aways starts in a flash with full choke and soon you can drop it back to a smooth low idle.

But the LR looses power as soon as it is under load, to the point that on a steepish local hill, I rapidly go down thru the gears and finally the engine sputters. As soon as I depress the clutch, the engine returns to a smooth idle and I can crawl away in first gear, but still with little or no acceleration. She just does not respond to the accelerator.

M LR aways starts in a flash with full choke and soon you can drop it back to a smooth low idle. I checked the plugs on one side and they are all correctly set at 29/1000 inch, so I am assuming the other side is OK too.

On a downhill run it will gather speed, and on the flat it will gather speed very slowly.

I suspected fuel, but I seem to have quite reasonable flow at the carbs.

Now I suspect my distributor advance is not operating.

What test can I do, and how do I fix the problem?

[Blknight.aus]

the test is just to hook up a timing light and watch the timing mark move as you rev the engine with the vacuum advance disconnected and blocked off.

if the timing mark moves in a sane and logical manner with varying engine revs then the mechanical advance is ok.

Connect a small tube to the vac advance on the dizzy and suck on the other end you should be able to make the timing jump all over the place by sucking and gently blowing on the tube. IF that doesnt work then the vac advance has problems.

IF thats all good hook the vac advance up as per normal and rev the engine again. If the timing moves erattically now OR as it does with just the mechanical advance then your vac line or supply is leaking/questionable and needs replacing.

if all of that is good go buy a can of areostart and start spraying around all the inlet manifold joints and vac lines (dont forget the brake booster) if the engine revs change from a steady idle within a couple of seconds of you spraying a line/joint then you have a manifold leak.

HOWEVER..

If you have the V8 with the twin cd175's fitted its more likely that you have ruptured the rubber diaphragm on one or both carbies or dropped the throttle linkage from the left to right carby. To check this remove the intake horns from the carbies with the engine running and give it a rev, if you dont see the air/fuel piston lift up out of the way of the butterfly then that carby is sus.

Best of luck.

[Carslil Jim]

Blknight,
I am humbled. Thanks a million. I will test and report.

Jim

[Carslil Jim]

Hi,
I switch between thinking the lack of power is fuel or advance. I have now pulled the carbs apart and checked the fuel lines are clear, and installed a new filter. No dirt in the carbs and the diaphrams looked good.

The fuel pump is pushing up fuel, but not in large quantaties or at high pressure, so that might be the problem. On a hill the LR starts off OK (not dazzling), but soon runs out of puff and actually sounds like it has lost all fuel or spark. I am thinking it is running out of fuel.

I did check the vacuum advance by sucking on a tube and that increased the idle revs quite a bit, so the timing may be way off, but at least I know the vacuum advance works.

But I decided I should check the distributor (as per yr note) so I went looking for the timing marks on the bottom pulley. I can't see any marks or a pointer they would line up with. With the 3.5 V8 is there any other timing mark options? (the book says bottom pulley)

[Freestyler]

If it starts off OK and then die's it sound more like a fuel issue. Electrical one tend to be intermitant or fail straight away under load. I assume it still has the Facet fuel pump? They have a mesh filter in side of them. You may also have a blockage in a pipe which could be the rubber in the hose starting to fail or just a build up of crap. Try taking off the fuel cap, disconnect the suction line and blow some air down it with a compressor. Also do the same the other end, disconnect the hose off the carbies. The diaphrams can look ok but have a pin hole in them. The best way to check them is with the engine running undo the 2 black caps on top of the carbies ( where there should be some oil). and with them just sitting there open the throttle. They both sould come up the same amount at the same time. The timing marks are on the bottom pulley on my county and the marker directly under the water pump. It is a little hard to get the right angle with a timing light to check it.
Tim

[Carslil Jim]

Freestyler,
Many thanks for the info. Yes, I do have Facet pumps. One is not used and I want to switch the two around, because I think No 1 is not delivering the goods but I dont know if the positive lead just pulls out of the pump, or if it is hard wired in there and I need to disconnect further up the wiring harness.

If anyone knows the answer please let me into the secret. (there is a pic of the pumps with another post from me on this subject).

[Freestyler]

The wire doesn't pull out of the pump itself but should have a joiner about 8 inches from the pump.
Tim

[Carslil Jim]

After lots of thinking and testing I decided the spark and timing was alright, so lack of petrol was the problem. I replaced the Facet pump with a new one and now and at last (...this saga has gone on for months while I fixed other problems) the LR is driveable.

Thank you to everyone who contributed with advice and ideas. I owe you all a beer!

Regards

Jim