Blown out core plug next to starter motor.

[Jimbo]

Evening every one,
Coming home from a leasurly drive to Redditch and back I noticed white smoke at the rear of the car and a the temp gauge increasing.
Pulled over sharpish to find I've lost all the coolant and the core plug closest to the starter motor has popped out.
I've actually found the core plug.
My question is why would this happen and what damage may have been caused?
Obviously a compression check would be in order incase of a blown gasket.
There's no mayonnaise in the oil and it's clean ( I only changed it 2 days ago)
And the drive seemed ok right up till I parked it up at the side of the road.
I do hope this isn't too serious.
:-(

 

[Jimbo]

Anyone have any advice how to fit a new core plug? I've looked in the Haynes manual but it doesn't mention them?

 

[jonbills]

Put a little rtv on it and tap it in with the biggest socket that fits.

 

[Peter Bartlett]

What is rtv?as I have a leaker as well unfortunately under the carbs so its a case of everything off and new gaskets.

 

[Jimbo]

Rtv is a water proof sealant, thanks jonbills I will give that a go.
Just need to get some plugs now

 

[Rob Gaskin]

Not done this but I thought core plugs were 'domed' and when inserted were tapped with a hammer on the dome to spread them. Or is that my 'hammer' engineering coming out?

 

[Jimbo]

Yeah you are right regarding a certain type of core plug but there's 2 main types.
One style like you say is convex so when hit with a hammer they spread creating a seal but is only applicable if the hole they go into has a shoulder
The other type is an interference fit so when driven in makes the seal which are used in holes with no shoulder which appear to have been used in my block.
At least that's the sum total of what I know about core plugs

 

[Jimbo]

Just did s compression test and my lowest reading was 10 3/4 bar and highest was 11 bar does that sound about right?
Started the car up and it fired up ok
Hopefully once I've banged a new core plug in if it holds water it should be good to go.

 

[Rob Gaskin]

Just did s compression test and my lowest reading was 10 3/4 bar and highest was 11 bar does that sound about right?

I think that's low tbh.

 

[Jimbo]

what should it be rob?
annoyingly i did the compression test when i first had the car and i didnt write the results down but i think it was around 11 or 12 bar but i really cant remember.
only other info i could find was this forum that said it should be around 150psi (10 bar) dry and 165psi wet (11 bar) but no idea if that would be correct?
http://www.atlanticz.ca/forums/index.php?topic=2697.0

 

[Rob Gaskin]

I tested my standard car recently and they were all around 12 and very consistent.

My old trackday car was 200psi which works out about 14.5 bar.

 

[Jimbo]

ah gotcha will have to have a closer look.
i might try taking the carbs off so it can breathe properly and see what result i get.
i only recently had a go at adjusting the valve gap in the rocker box so i might just whip it off and double check i havent overtightened them leaving the gap a bit small.

 

[Jimbo]

also meant to say i did the test with a cold engine because untill i fix the missing core plug i cant reun it up to temp.
could that be another reason for lower pressures?

 

[MaximG]

In your original description you described clouds of white smoke. Would this not be an indication of a blown head guasket between a cylinder and a waterway?

 

[jonbills]

I think a blown head gasket is unlikely to blow your core plug out - the rad cap only holds 10psi or something. Unless you've got other symptoms I think I'd just say it's one of those things.
My engine has about 175psi. As long as the cylinders are all about the same, I wouldn't worry about it too much.

 

[Jimbo]

In your original description you described clouds of white smoke. Would this not be an indication of a blown head guasket between a cylinder and a waterway?

yeah i would have thought so too looking back but it was comming out of the wheel arches and all of the back end.
i had a rover head gasket fail and had plooms of smoke coming distinctly from the tail pipe and would do it all the time even when idling.
the datsun didnt give off smoke for long andonce i stopped i could actually see droplets of blue antifreeze all over the rear of the car and mostly up the drivers side arch just behind the drivers door going back so i dont think it was actually burning it just dumping hot antifreeze everywhere.

i suppose the only way to tell is to get the new core plug in and fill her back up and see if she smokes unless i can get the system pressure tested after the new core plugs in.
i agree with jonbills as the last thing excess pressure is really going to blow is a core plug.
all the rubber pipes or a gasket or the radiator cap i would expect to go first or show signs.
this just failed all of a sudden and dumped all the water very quickly and would expect it to be pretty hot coming straight out of the block all over the starter moter/gearbox and under the car hence a lot of white smoke.

oh well i do hope it is a simple fix.
worst comes to the worst how hard is it to change a head gasket?
im ok with most mechanical things but the timing chain looks a bit daunting in the haynes manual.

thanks for all the input though guys its much appreciated

 

[Rob Gaskin]

worst comes to the worst how hard is it to change a head gasket?
im ok with most mechanical things but the timing chain looks a bit daunting in the haynes manual.

As with a lot of things it's worse reading about it and especially doing it for the first time.

These engines are quite simple in relation to their power.

The most important thing is to not to let the chain tensioner 'pop out'.

 

[Jimbo]

thanks guys,
hopefully it wont come to that.
i was really hoping after all the work shes had over winter i would just enjoy driving her this year.
will keep you posted how i get on.

regards

james

 

[Jimbo]

heres a pic i finally got off my phone of the offending plug and in the background you can just make out where it came from

 

[jonbills]

Looks a bit rusty. Fingers crossed that's why it fell out.