MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Moisture in distributer cap

I'm getting the occasional poor starting due to moisture build-up in the cap. I have a 123 dizzy with a Bosch cap. This fits very well and it's been suggested to me that the condensation build up is due in part to the fact that the cap fits so snugly. It was suggested by this guy that I drill a few small holes in the base of the cap to allow the condensation to evaporate.
Is this a good thing to do or is there a better sollution?
Many thanks in advance

Gary
Gary & Gaps

Yes Garry, the cheaper fake Bosch has the holes already built in. And I never had any condensation anymore. From a damp Amsterdam

Flip
Flip Brühl 948 frog 59

WD 40...couple spay shots

Prop
Prop

Yes Prop, the WD40 is good for getting rid of it but I'd prefer not to have to take the cap off each time.
Gary & Gaps

Some distributer caps that have been exposed to glycol are porous and will absorb anti freeze. Although they appear to be dry they will collect moisture on the inside.Cars that will not start early in the morning most times will after the cars becomes warmed from sunshine and the moisture dries up.
darnoc31

Many thanks for your replies.
I'm aware of how the moisture gets there, what I need to know is if drilling small holes around the base of the cap (as Flip says is built in on the Bosch copy)is a good thing or if there is a better method?
Gary & Gaps

I know this sounds off the wall, but how about silica gel?

Get a very small bag of it, and place it in the dis' somewhere it won't catch on anything. I've never tried this, as I have never had the need, but it could work for the small amount of moisture that's likely present. And you will only need it in the cooler weather I would think.

Better than drilling holes in the Dis'.

Or, how about a thermal insulation on the outside of the Dis' cap?

You do this on air extract from bathrooms to stop condensation on the inside of the hose. You wrap insulation around the hose and it solves the problem.

Why are some cars plagued by this problem and not others I wonder?
Lawrence Slater

Gary,
sorry I don't know about drilling holes as a cure, I do wonder how brittle these caps might be and if drilling might put in an unseen hair crack that might cause intermitent problems

I've had my 1-2-3 fitted 2 years now so next year I'll change my rotor and cap

I've never had moisture problems, my car is always outside as I don't have a garage

might seem daft but - do you always park your car in the same position either outside or perhaps in a garage with a window or a garage with carpeting or matting on the floor

I'm thinking of the car/dissy cap being in a position to pick up moisture somehow by where it's parked in relation to what could induce moisture - which could have many variables to get moisture someimes and not others, even things like when and where the sun shines on it or localised or whole areas of damp in a garage
Nigel At

Sorry gary,

I didnt initially grasph the question....how to keep the moisture out???

I like lawerances idea .... Anti mositure baggie.

Im not sure how i like the idea of drilled holes with the midget, as this cars are always leaking one fluid or another, and picking up only god knows what off the road surface

But my toyota 22re has holes in the dissy which now im guessing is for the reason your posting.

Btw ... Is your car a daily driver???, if not, maybe just leave the cap off each tim you park it for more then 3 days at a time, I find i like to give my car a fast look over before i take it out ...oil level, coolant, brake fluid.. basic electrics, tire pressure, ect ect.
So it wouldnt take but a second to install it

Prop
Prop

Hi lawrence,

I thought about a small silica gel bag but I worried that it might interfere with the rotary arm. Perhaps the insulation is a good idea.

Nigel,

The car is parked in exactly the same place in my very small garage (a bit damp when it rains, I must admit) the only way that I can change the position is to reverse in to the garage as I currently park the car nose in first.

For the reasons which you give, I really don't want to drill the cap.
I may design a dizzy cap cozy.


Many thanks for all of your replies.
Gary & Gaps

Gary,
yes you could try reversing in then

and/or removing unnecessary stuff from the garage that holds moisture (like mats and carpets)

and/or provide the garage with ventilation (that keeps the rain out)

for standard dissy caps you can get a (rubber) cover for the dissy cap but I remeber being told many years ago that they (could?) make things worse

I can't ever remember having damp inside the dissy, my cars have normally been outside where they get a lot wet and damp but also a lot of ventilation

Carcoons are framed now so perhaps that might be an answer for inside your damp garge

for a non-daily car, when I rented a concreate garage from a neighbour that was still damp inside despite installing 20 square inch (effective area) permantly open covered vent I used the old style inflate only Carcoon, it was very good, not that I'd recommend it but you could even put the car in wet and it would dry out
Nigel At

Gary,

I have not suffered this on midgets (famous last words), but really bad on old Hillmans why ?

If the garage is damp, try laying polythene sheet/tarp on the floor (i.e dpm)+ odd ply on top if necessary and see if that helps as mosture could be drawn up by a warm engine etc.

The early mini's etc did hace a 'platic mack' moulded to go over the dissy and lead entries.

R.
richard boobier

Nigel sometimes I think the only unnecessary thing in Gary's garage is some old motor car, no I mean enough bits to make another "some old motor car". He has more hard tops than soft Mick...

Gary, wotcher mate, I would think the moisture is only atmospheric as you think

I used to (I had form in this game remember) wipe out any moisture I found, quite common on Metros I recall and when dry spray WD40 inside. The WD40 would always find more dampness when sprayed. Instead of a misted spray try to flood the inside of the cap with it then after shaking it out mop it bone dry. "It ain't a five minute job if you do it properly guvner".

When you have a dry inner surface to the cap, just before replacing the cap on the dizzy, seal the edge it sits on with Vaseline (Lois might save you a trip to Lloyds for this, I have a small tin in my toolbox because of this problem) the Vaseline should help keep out atmospheric moisture if you make a decent job of it.

Silica gel sounds good but I don't think it can be guaranteed not to interfere with the 'everyday life of a Sprint Competitor' inside a restricted space.


To be honest, reversing in and having the dizzy closer to the outside air movement could make a huge difference

It isn't easy to see but Gary really doesn't have much manouevering room at his garage, specially if some clown encroaches his parking area in a Midget


Bill 1

Hahaha...Now i feel much better about the size of my shop....its a warehouse in comparison, 10' X 20'

Prop
Prop

That looks suspiciously like the sort of garage where I keep my car Gary. ie. council lock up. Ours are in really good condition and I've never suffered any damp in the dissy. The Mini thing with the plastic cover was to stop the ingress of water from the road rather than atmospheric damp and I remember before a proprietry one was made available, using a household glove with the finger ends cut off to make a water resistant barrier around the dissy. May be worth trying though. Bill's sugestion of WD40 seems about the best to me though it is a bit of a PITA doing it every time.

Bernie.
b higginson

I think Bill's saying do it once and seal with Vasoline - course you've got to find the cause to prevent having to do it again

I'm sure my neighbour said not to use WD40 on the inside of the cap as it insulates but I'll take Bill's word for it as he's experienced

I see what you mean about the garage, at least it's not concrete, could you perhaps get one or two 9"x6" air bricks in the back wall if there are no air bricks already
Nigel At

The WD40 method is the one which I've been using but it's a pain, especially if I'm wearing my Saturday night fever white suite (or going out wearing anything smarter than dirty jeans or an overall) athough there is always a box of latex gloves in the car to keep my hands clean.

I will try the WD40 then Dry then vaseline seal method, however since my garage has good airflow, the moisture forming on the inside of the dizzy may (as Bill once told me) be caused by condensation forming on the dizzy drive shaft due to differences between external and internal tempuratures rather than moisture ingress.

I'll let you know how I get on.
Gary & Gaps

That should be Saturday night fever white suit!
Gary & Gaps

I read it as suit anyway, hence my poor spelling

unless you need to move your hardtop collection you could try that just reversing in, perhaps the other way round might give more ventilation and/or less damp

perhaps Prop could come up with fixed drain and vent tubes on your dissy cap, both would need one way valves of course or perhaps an outer covering of rhino rubber, leave it with Prop

. . . and a moisture gauge for inside of dissy cap

. . . and a second for ambient moisture

yeah, leave it Prop he’ll sort it
Nigel At

Not sure what Bill was refering to Gary but condensation occurs when warm moist air contacts a cooler surface and drops its moisture content. This is because warm air can hold more water than cold so it is easy physics.

However what is occuring in your dissy?

Somehow warm moist air is entering your dissy and is then condensing on the cooler cap. The only place I think that this moist air is coming from must be the engine.

The products of combustion contain large amounts of moisture and result in "mayo2 inside the rocker. This is due to these products passing the piston rings and finding their way into the rocker box where they meet a cooler surface and the water drops out of suspension.

Based on that is that happening somehow to your dissy? Is it possible that engine breathing is somehow finding its way into the dissy cap? Not sure how that could occur but I would want to try a different distributor for a week or so to see if the problem persists?
Bob Turbo Midget England

I'm not sure that was entirely what we were saying Gary, but...

The method I describe should be able to keep the inside of the cap at a fairly "same" humidity at most times.

Bill 1

Latex? Vaseline? ambient moisture? Cap Cozies? polythene sheeting?
Who would ever have thought car maintenance could ever be so kinky
Will we be seeing you in your disco gear tomorrow at the Ace Gary?
Matt1275Bucks

Could be......
Gary & Gaps

Matt

photos

we need...
Bill 1

This thread was discussed between 08/10/2011 and 10/10/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.