74' Corona 18R-c ISSUES - SOLVED!!!!!!!!!!!!!!! for now ...................

[Admiral coFF33]

Hey all

After 3 years my GF's 18R-c Rona RT104 is finally having issues..


i have put in new plugs (weird KGP brand or something as i couldnt find any bosch or NGK)
new leads from bosch coil to dizzy to plugs.
New oil
new fuel filter
owned the carby with some carby cleaner to clean it out
changed water pump to a brand newie (thanks Peewee)
and the timing done (thanks Peewee)

But since this it ran perfecto for around a week , now its REALLY badly idling, when watching the engine in the bay whilst on its shaking like shit like as if its not firing normal causing engine movement.

Also its got a really massif flatspot , when accelerating up to 20kph its fine, then once over it struggles as if you have the handbrake full and your trying to drive....

basically if you stop at traffic lights on a slope of ANY kind, and take off, the car will barely reach 10kph. NO JOKE

Occasionally at the lights the car will also stall. as the idle drops too low.. or as my GF puts it , "it sounds like a few of the pistons dont fine and then the engine shakes hard and it turns off"

Seeing as everything has been replaced. what the fuck can i check for ? the timing cant just go completely out again so quick can it ?

Can i check the carby for a common issue ?
What can i do re: timing or idle without a timing light ?

help me help her , before she kills herself from pulling out in front of a car and her rona not being able to get up to speed ...

[hosking1991]

Sounds like the secondaries are not working(diaphram is shagged) this is pretty common with the 18rc most people replace it with a weber 32/36 with the appropriate adapter plate

also at what rpm does this flatspot occur?

[Admiral coFF33]

unsure as it doesnt have a tacho (auto)



Basically once it hits flatspot 20 - 55 kph ? you can floor it completely , and it will do NOTHING it will put put along at the same rate ... no acceleration

[thomasbl]

When you say "owned carby with some carby cleaner" what exactly did you do?

Check over the changes you have made. ie fuel filter etc and go from there. Secondaries sounds like a logical thing to check. Also check HT lead connections and coil lead connection. Were the plugs pre gapped?

[Admiral coFF33]

Owned with carby cleaner, means i cleaned it nice and well with some carby cleaner (nulon)

can someone explain to me what to look for when you say secondaries ? as im used to EFI engines not carby ...


I look at the carby and see two sides ... one with a butterfly like thing (like the one inside and AFM) and the other is just open with no butterfly thing ....

[MWP]

I look at the carby and see two sides ... one with a butterfly like thing (like the one inside and AFM) and the other is just open with no butterfly thing ....

The butterfly thing you see is the choke, and that is the primary.
The other one is the secondary.
The throttle plates are deeper (look in with a torch).

You should rebuild the carb... it makes a HUGE difference to the way the car drives.
If you not game to do it (its not too difficult), have a good carb shop (not your local mechanic) do it.

If you are game, go buy a carb rebuild kit (for the carb you have), and start stripping it down.

[Admiral coFF33]

is the butterfly thing meant to move ? coz hers appears to be stuck open half way and it never really moves if i pull the throttle cable etc etc ...

[MWP]

Its the choke, it opens as the engine warms up.

Read up:
http://en.wikipedia.org/wiki/Carburetor

[river]

Hi,

The butterfly thing, closest to the top of the carby, when you are looking down is the choke.

When cold it should be closed, and as the engine warms up the auto-choke will open this fully.

Deeper down in the carby is the throttle butterlfy and this moves with the throttle.

I'd hazard a guess that the carby needs a rebuild or something like that. It sounds carby related.

Now, your'e in Perth? If so, there is a mob over there that sell fully reconditioned original carbies. I think you give them your old one, pay some money, and they give you a fully rebuilt factory-spec unit. All you need to do is unbolt the old one and bolt in the new one! I'll see if i can dig up the name for you.

seeyuzz
river

[brett_celicacoupe]

points?????

[roadkill]

Hi,

i'd check to see if there is an inlet manifold leak which can in turn mean it is running lean. Easy way to check is when it is idling cover the air intake slightly with your hand - this will make it run richer to accomdate extra air getting in - if the revs pick up then there is a leak somewhere. If the revs die down then there is probably no leaks. I'd also be looking at compression - pretty easy test to do and recheck your timing. If the dizzy isn't bolted down properly it can easily rotate and make the timing out.

That should be a good few things to check initially.

bEn

[Admiral coFF33]

Hey all thanks for the advice,

i advanced the timing slightly (again) and it has come good when driving, but it has a really really bad miss that happens at random times whilst idleing and happens very badly under load.
This was occuring since the car was purchased, but has gotten worse over the years and now is very obvious

List of things that have been changed again :

Brand new (1 week old now) NGK plugs
Brand new (1 month old now) bosch leads
Brand new (2 months old) fuel filter

What causes such a massive miss when idling ?

Also , she has a BAAAAAAAD problem starting as well ... ESPECIALLY when cold ... engine will just keep on turning over and over but its asif there is either no fuel or no spark ...

but by taking off the airfilter cover and pulling on throttle cable(bar) i can see and smell fuel squirting .. and i pulled all plugs and put them 1mm from head and turned engine to make sure they are sparking ... they are ...

my GF is really sad as she doesnt want to get rid of her brum but i just cant figure out whats keeps going wrong all the time...

Would a new carby fix a shitload of problems as river said ? or getting the carby rebuilt ?

does anyone wanna guesstimate a price for a new carb or a rebuild of it as she really loves her brum and doesnt want the alternative (AE82/AE92)

cheers guys

[Cob604]

hey mate

if i were you id first do a compression test, as i just got mine going & it sounds like it is missing at idle (running on 3 cyls). & id assume it is going to struggle under load.

i rebuilt my 3tc carby my self the rebuild kit cost me $38 from auto one & it took a about 1 hr each night to pull each bit part & then i made a brew of carby cleaner stuff & let each bit soak for the night & followed the rebuild kits instructions & mine turned out fine, no leaks nothing.

but to get it done professionally i got quoted around $150

before you go spending money getting the carby rebuilt, make sure that it is the problem.

& mabye give it a good tune

thx

[Admiral coFF33]

^^ thanks Cob, but how can i "make sure that is the problem" if i have nfi ...

As ive changed all items to do with fuel/spark (apart from diaphram fuel pump) so i guess that means its carby related ?

[jeffro ra28]

As you say slope affects engine running, check float perhaps?