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The saga continues...........

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Jeepster

Jeepster

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https://www.britishcarforum.com/bcf/showthread.php?97574-Engine-timing-problems

I am still having problems getting the engine running on my BJ8 ( please see post above).


A few few months back I decided to give in and trailered the car to a specialist who took it to a rolling road/tuning specialist. Following this the engine seemed to run better than ever and pulled all through the Rev range (I have had little chance to drive the car since then due to winter and time in the body shop).
The last few days have been sunny so decided to finally get to use the car. I did a few trips of 30 or 50 miles and there was a slight hint that the engine seemed to be getting less responsive.

Things have now started to go back to how things were with the original problems. Poor tickover and the main one being the engine splutters at 3000 revs. It seems to be getting worse with every mile.

Its as if the carbs have slipped out of tune? How can this happen? Or is it something more serious?

ALL ignition replaced. Plugs cleaned. Fuel ok. Compression tested etc etc.

i cant ant easily get it back to the rolling road as its a 6 hour round trip. ( I live in the middle of no where)
 
Since you have done so much, it is hard to add anymore suggestions. But, I'll add my two cents. When you say tickover, (sorry that is not a common term that I hear much) I don't know if you mean it cranks on the starter motor slowly, or that the starter motor is turning it sufficiently but it takes many revolutions before it catches fire and runs.
If you mean that the starter motor is turning it over slowly then I believe after all I have read from your experiences with this car, that the problem is electrical, in-which I mean voltage quality is not good. Either your charging system is not keeping the voltage and battery at a good state or your battery is very poor and not able to be kept at a good state. This would include all the components of the charging system and all the connections such as chassis grounds, etc.
If you mean by the word "tickover" that the starter motor is turning the engine over sufficiently to start but it is taking an inordinate amount of time for the engine to fire, Then I would say it is fuel, or head/intake gasket leak or a massive vacuum leak. One thing I don't believe it is after reading all of your experiences is, I don't believe it is an ignition or timing issue. If the rolling chassis dyno got it running well, then don't touch the ignition or timing, that is probably good and set well enough to not change it and it didn't change itself in such a short period of time.
If it is taking an inordinate amount of time to fire and run while cranking it could be something as simple as the choke not engaging enough at full pull, and the high speed miss could be the choke being stuck partial engaged and the carbs being very rich.
I guess I have to qualify my statement about the ignition. If you have put in an electronic ignition..... then get rid of it. At least for now. When they're not right, you never know what they are doing. Go back to points for now. Also vacuum advance canisters can do weird things. I have had one the put in too much advance at high rpms and caused a miss above 4500 rpms for more than a year before I took it off. so you can take that off and run the distributor without a vacuum advance canister. Be sure to plug the whole over at the intake manifold. If you take it off you may have to adjust idle speed at the carbs because the vacuum canister would have kept the idle up a little. Dave.
 
Did you replace all those ignition parts since it last ran well and the problems started again? If not, check your points gap, if you have points. And have you checked the timing?

I suppose that it could be fuel system related, but I'm fixated on ignition issues today. Like you, I wanted to take the BT7 for a ride today, the first of the season. It had started hard at the end of the season last fall and would not keep running without the choke partially pulled out. Today it would not start at all. I pulled a spark plug. It was dry, so I thought it was not getting fuel. But before messing with the fuel system, I grounded the plug to the block and turned the engine over. There was no spark. A look under the distributor cap revealed that the points were not opening. Either the adjustment screw slipped or the fiber bar that rides on the cam wore. After setting the points and adding a little grease to the cam surface, I rechecked for spark - the engine fired immediately and almost started, even with one plug out. With the plug back in, it ran perfectly on the first drive of the year.
 
I am puzzled why it would go " out of tune" ? If that is the problem?

What at has changed?

And yes, by tickover I mean idle.
 
I assume you have SU's on the car. If so, they do not just go 'out of tune'. The problem is most likely ignition related. What is the condition of your distributor, if the shaft is worn and you are running with points then that can cause a problem both at tick over and at higher revs. Try installing the Powerspark ignition. Its a cheap option and it cured the problem I had at higher revs.
 
I tend to agree with the consensus that this is probably electrical. However, one fuel-related problem you might check is the choke sticking on one of the carbs. When you choke the carbs, the very bottom part (where fuel comes in from the float bowl) moves down to make the mixture richer. Sometimes this doesn't pop back up when you release the choke cable.

This has happened to me on my Sprite, and although the symptoms aren't exactly what you describe, it's worth a check since you been through so many other possibilities.

Keith
 
Hi Jeepster,

Although I tend to agree with those focusing on ignition, I have had similar experiences that seemed to come and go (some for no identified reason). To address one of my few identified causes of a similar problem, does the UK have a change in fuel formulation between summer and winter? Have you a fuel filter installed between the tank and fuel pump? Have you used any fuel stabilizer during winter storage? Have you checked your fuel pump and/or cleaned it recently? Are you using a points or electronic ignition?

Although ignition seems a more likely cause, fuel and its delivery has also caused a similar problem for me in a number of ways.

Just my thoughts,
Ray (64BJ8P1)
 
Thanks for your comments but I think this is more complicated that the usual suspects.

I have tried points x 2, electronic ignition, distributor x 2, coil x 2, plugs leads cap rotor x 2, jets and needles.
Fuel filter fitted before the carb. 2 x fuel pumps and standard fuel with no additives. As I said it's even had a day on a rolling road!
compression test showed all ok but I wonder if it could be something related to the engine? A sticking/leaking valve?

Hope I'm not boring you all with this one as it seems to be going on and on but it is reassuring to have somewhere to clear my head as this is really getting ridiculous.
 
I haven't seen this mentioned. Have you checked the vacuum lines to the brake booster and dizzy advance for leaks?
 
How are the bushings on the throttle shafts ? Have you set the points using a dwell meter ?
 
Managed to locate a rolling road engine tuner within an hours drive so booked the car in for some attention. I am tied up with work next week so has to be the week after that.
I will keep you posted with progress. Fingers crossed.
 
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