Moss Motors, Ltd

I think it is made of bakelite. JB Weld will work to repair it, it is an epoxy adhesive and will hold up to high temperatures.

 Dave

OK, got everything back together runs slightly better than it did before.  However, it is backfiring, though not as much as before, and now after a backfire at shutdown, it is very difficult to start and will not idle.  Also, sometimes it just slowly drops RPMs and stalls.  Anyone have any thoughts?  I found where my mystery small metal cylinder went, it is the spacer for the thottle cam.

I have to admit, I was very worried about completing this.  It seemed for a while the fates were against me (couldN'T find a manifold, not enough gaskets, breaking the induction heater).  I'm actually shocked that it runs.  I'm still not sure if I have all the vacuum lines in the right place.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

Everyone's gone kind of quiet... chirp... chirp... chirp...

Played around with vacuum hoses for a little and I'm still confused but I may have them right.  Gulp valve and vacuum advance share a "T" joint and connect to the manifold via the anti runon adaptor (or should that be the signal pipe adaptor?).  The E.G.R. valve connects to the manifold via the signal pipe adaptor (or should that be the anti runon adaptor?).  Any way, I still have too many things that need vacuum and not enough adaptors to put them into.  My SU has NO VACUUM PORTS.  However, for all my play musical vacuum hoses, it still runs like s**t, so I think that I must not mended the induction heater well enough.  I just got an insulator plate for TR3 on the advice of the Moss Tech guys, and I will replace the induction heater with these and hope that makes a difference.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

DK,

The TR insulating block sounds like a good idea. I would eliminate the EGR valve for "test purposes only" right now. This is easily done by creating a solid gasket for it. It may be causing a problem. EGR vacuum actuating hoses were tapped in separately, not into any Tee. Just make sure all vacuum leaks are plugged for now, and mess with the timing. If you still can't get it to run reasonably, you may have some other, unrelated problem. Repost once again and we'll git 'er done.

---

Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Final got a break to get under the hood of my car.  I have eliminated the EGR as described and am still having the same problem.  I re-timed it as described in the manual (it was very retarded!).  When I reconnected the vacuum advance as directed by the manual, it advanced ALOT.  So I adjusted the timing to compensate.  Why would it jump so drastically?  If I had a vacuum leak, would it advance like that?

Took it for a spin and it seemed fine.  However, after 10 minutes or so, it would not idle for more than 10 seconds.  It will drive but not idle.  When I let off the clutch to go from a stop, it is very sluggish (almost to the point of stalling), I have to really rev it up move. 

Any thoughts?

Some things crossed my mind:

Vacuum leak?  Was I supposed to use some sort of lub or sealant on my gaskets?

Heat.  My heat shield is all but gone (well, it is gone).  Is there too much hot air in the carb?

Carb is bad?

Thanks in advance for any help/advice.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

Re the timing, there is a static and a dynamic setting for the engine. The dynamic timing is RPM and vacuum dependent, so you might expect some shift when the connection to the carbs is made. Usually it is specified at some particular RPM, probably all in the manual.  Do you have a timing light?

From what you say, it seems OK until warmed up - which could well indicate that the heat shield is not doing it's job. Perhaps it's worth sorting this if just to elliminate it.

Hope you can get to the bottom of this.

Cheers,

Ed

---

I want my MGB

Hope this doesn't post twice - first attempt seemed to get lost.

I'd expect the timing to change when the vac line is connected. Do you have the spec. for dynamic timing, and a timing light to check it?

The problems you have when the car is warm do hint at an ineffective heat shield. Might be worth replacing this just to eliminate it. I note you are in Utah... it must be hot under the bonnet before you start the car

Good luck chasing this one down,

Cheers,

Ed

---

I want my MGB

I am using a timing light although it is creatively wired.  I use the lead for induction heater to power it.  I have heard some folks say that you can advance your timing until the pings/pinks then back it off slightly.  What is does a ping/pink sound like exactly, because my little car aready makes a lot strange noises, I don't know if needs any more.  I'll look into a new heat shield.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

Pinging/pinking - a little hard to describe. It can sound a bit like a diesel motor, an added harshnes to the normal sound of the cylinders firing. The test to set the timing is usually to advance timing until it pings under load e.g. full throttle acceleration in 3rd or 4th gear, then back off in small increments untill pinging is just avoided. This will be somewhat dependent on fuel grade, with lower octane petrol more susceptible to this pre-ignition behaviour.

This brings me on to another point - fuels - which are not the same formulation as those available when the car was built. This means that the timing settings in manuals & reference publications are not 100% optimum today. They are a good starting point pun intended... but a little deviation may offer better running in practice - hence the popularity of the "adjust to avoid pinging" method.

It goes with without saying that the rest of the ignition (points, rotor, leads, condenser) and fuel system should be in good nick before one attempts fine tuning.

Cheers,

Ed

 

P.S. Sorry for the double posting earlier, I had some odd browser behaviour at the time...

---

I want my MGB

OK, I'm going to try a third time to get a reply to post...

Pinging or pinking (take your pick...) is a sudden harshness in the engine note, usually under hard acceleration. It can sound a bit like the car has suddenly become a diesel, but will stop if you let up on the accelerator.

Your total ignition advance should be expected to change when you reconnect the vacuum line. It's quite unlikely that this is causing problems in itself, unless you have the wrong distributor fitted.

The timing sspecs most of us see are based on running and tuning the cars with the fuels available at the time. Fuel has changed, so whilst the timing figures are a reasonable starting point, one can often get better running with careful tuning. This is where the experimental timing method comes in useful. By advancing the ignition setting gradually to find when pinking occurs, and backing off to just prevent it, it is possible to get a near optimum setup. This will of course depend somewhat on the fuel grade you use.

There's a pretty good description of the technique here:http://mgaguru.com/mgtech/ignition/ig116.htm

Ed

---

I want my MGB

Any recommendations on the heat shield?  The original seemed to just crumble away, what about the stuff you wrap around the exhaust manifold?

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

Hmm, a new shield isabout $85 according to the present catalogue - This is the ZS carburettor setup isn't it?

If you don't want to fork out for a new one, it might be possible to pop-rivet some insulation material onto the side that faces the exhaust - assuming the old sheet metal is sufficiently intact. Looking at the Kragen website - you might consider some of the heat shield materials here http://www.partsamerica.com/ProductList.aspx?categorycode=3638E

Cheers,

Ed

---

I want my MGB

I looked at that but wondered how to apply it.  I have the ZS setup but with an HIF conversion and no CC.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com

Oh yes, I remember now - you're using a single HIF.

To fix the shielding material, you could try pop rivets, with suitably sized washers to spread the clampping force - a rivet on it's own is likely just to pull through the material.

Just a thought.

Ed

---

I want my MGB

More info:  I haven't worked out the heatshield yet.  I did notice that it happened when the cooling fans kicked in, the RPMs would drop to the point that it couldn't maintain an idle.  I have the fans relayed off one of the brown wires leading from the fuse, I think it goes to the ignition relay but don't quote me on that, because I kept burn out my thermostat switch.

---

Dave Kiernan

www.airforce.com
www.dosomethingamazing.com