Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Idling puzzle

MOR404, if I read you correctly your car is running fine, though a good condition and properly tuned standard engine should run smoothly at circa 750rpm, though an engine that has been tuned may not run smoothly at low revs. A change of camshaft can alter where the maximum power is generated in the rev range.. If a higher performance cam has been fitted then perhaps higher compression pistons too also the distributor advance curve may also have been adjusted to suit, though if any or all of that has been done I might expect the carb would have been changed for one with a larger throat(s) and jets, though if it had been tuned to that degree I would expect it would be wearing a pair of sidedraught Webers.

Trying to determine which cam might be fitted to an engine may not be too easy to determine exactly.. Fitting a degree disc to the crankshaft and measuring the amount of lift and duration of one of the inlet valves and likewise for one of the exhaust valves, can be then compared to a chart of various camshaft types that one might expect to find in a Kent engine from the cam grinders of the time, such as Piper etc.

When you say the timing marks are off.... you are using a strobe, but first to be sure one would ideally confirm the static and pulley marks do indeed determine Top Dead Centre TDC... But we are getting into things you are unlikely to be involved in..?

I am guessing your mechanic swung the dizzy to get maximum revs while idling then perhaps backed it of just a tad to get the engine running as it does at present, though did you check the mechanical operation of the bobweights in the dizzy and of course the vacuum operation too...I take it that you also lubricated the dizzy centre spindle ...? Have you carried out a compression test, to compare the cylinders against each other for balance.(similar readings).?

Mr Button, I have no idea if all the V8`s Morgan received were from the Land/Range Rover production line or if some were picked up from the Rover SD1 production line which may have a different cam and carb set up from the mud plugger, more so if any came from a Vitesse SD1 I suspect a check of the engine numbers may give a clue as to the state of tune, including compression ratios...?

"Mr Button, I have no idea if all the V8`s Morgan received were from the Land/Range Rover production line or if some were picked up from the Rover SD1 production line which may have a different cam and carb set up from the mud plugger, more so if any came from a Vitesse SD1 I suspect a check of the engine numbers may give a clue as to the state of tune, including compression ratios...?"

Now that is a thought. I will attempt to explore this this Winter. I do know that all Rover V8's do not perform the same. Some are very good and some are rather poor. I do know the 3.9 I have now. Came from a Morgan. Is much better than the 3.5 I had a Machinist build for Me using Buick 215 Specs. It had a Rover/Morgan block and Buick 215 heads. Actually this 3.9 engine Is about all I can handle in My +8 Bitsa. I am happy with it.

Glad that you finally seemed to have got it sorted. As I said previously the timing is never as it should be on these engines and the marks are normally way off that is why it is good to establish TDC and set your timing from there. In my case it was a good 10 degrees out and now I have the TDC marked with white paint and the correct timing set from that point.

Thank you all

I was still not happy with how the car is working so yesterday I decided to take off the carb again and inspect myself alone in my workshop. Also I wanted to read the exact model markings on the side of the base. I left all the settings as they were and upon moving the throttle linkages I noticed there are times when the throttle stop screw does not touch the lever. At this time the opening of the butterfly on the primary throttle shaft is open the thickness of a folded paper and also at this point the choke is closed. Is this normal. When I turn the linkage again it touches the stop screw. is there something wrong there which is causing the problem on idling. I tried to follow my Morgan workshop manual but have not managed to identify what could be wrong. My carb is a Weber 32 DGAV. I left the auto choke pipe connection with the three screws on the car.

I had an issue with the idling on mine - would run perfectly, then would die at every junction and roundabout. Sometimes I could get it to 'not stall' with a little bit of choke. Always easy to start straight away.

Turns out it was the idle jet (the one facing the bonnet) that was continually clogging. Mine had sat for ages before I bought it and can only assume there was some flash rust in the tank than was being dislodged - small enough to get through the standard mahle filters but big enough to clog the idle.

I fitted a new 'cleanable' glass fuel filter, and carry a can of carb cleaner and a spare idle jet (in case I drop it when cleaning).. Quick roadside remove of jet from carb and out of the holder, good squirt of cleaner and back to normal.

The new filter seriously reduced the number of blockages (I was getting one every time I filled the tank) and with extended use I now appear to have flushed the bulk of the crud out of the tank. I've only had the problem occur once in the last 6 months or so. Easy fixed at roadside.

Thought you might find this article useful?

https://www.racetep.com/weberadj.html

Thank you Britmog. I just printed a copy to take to my garage. I now think that the car is running as it should, but with those instructions I can do the tuning myself.