O sh*t mayonaise

[Crelesy]

I allready told you guys that i rivived an Ventoux 839 engine from a 20years stand still. It fired right up after cleaning out the tank en cleaning the carburator. It ran crappy but it was alive.
In the days after I checked the valve clearances and after a big elektrical shock from the distributor I bought those new to. (Lines ,divider ,capacitor , points and in the end the ignition coil as well). After changing all that it ran way better.
But it would only run good above 1000rpm. Everything less gave a backfire now and then and lower than 800rpm the backfiring makes it stop running.

I noticed a lot of water drops splatering out of the exhaust and out of the vent hose from the head to the carburator. So I lifted the valve head...
This is after way less than a hour running stationairy and ocasionaly revving it a bit. Fiddling whit caburator settings and dizzi timinglight.
I 'm wondering if it's only the head gasket or worse.
I have a complete gasket set allready but i need it running 29 oktober. And have little time. I have to take out the motor to change the complete piston bush gaskets because I lack a car lift. So I hope these are okay.

I fear for the worst but I lack the experience to back it up. ( First Ventoux engine I touched) so thoughts are apriciated!

O and later on i pulled the sparkplugs to check if they were wet. The were dry but one crush ring on cilinder 2 sparkplug was not crushed. Turns out there is a bad tread in there. So the head needs some love and care. I can check the valve seats then allso. And maybe this could produce a stutter or backfire in my opinion as well.

 

[angel]

I would drive the car for a lengthy distance so that oil gets up to operating temperature and most of the condensation in the engine evaporates before suspecting a head gasket failure. How is the oil in the sump?

 

[Crelesy]

Yea I normally would. But I can not drive it now. No plates , no insurance. Still on french plates.

The water drops comming from te vent litteraly taste like coolant glycol or something. So I think that's enough to tell it's leaking somewhere

 

[harbourseal]

Hi Ive, I think that you are looking at a full Head gasket change. And some work on the head. It can be done in some hours.
If you outsource the work on the head itself it might take 3 days. Depending on how busy the machineshop is.
But then you still don’t know what is happening in the cast iron block.

 

[malcolm]

If you run the engine for a few minutes then drain a little oil and the oil looks like mayonnaise then you have a problem. If the oil looks like normal oil then you likely don't have a problem. There doesn't seem like a lot of water in there.

It isn't surprising for an engine that has been sitting for a number of years to suck in a little water from the environment. It will go away in time if the engine is OK.

 

[Crelesy]

Okay. Lets just hope for the best, and start with only the head then. First i wil check if i have 4 bolts with big enough a washer to hold the cillinderbushes in place. Don't want to accidentaly ruin de cillinder gaskets down in the casing.
Just hoping the sparkplugs thread is fixable. I don't want an helicoil fix. Its always a pain when i encounter one on the job. So I ain't putting one in my own stuff.

I intent to check the valves and seats as well. The valve clearances were to wide. So I guess there wil be a lot of gunk there to. (With normale wear they would be to narrow if i'm not mistaken)

Now to find a time machine en get on with it!

 

[edwin]

Re the plug thread. I had the same problem in the 60's on my first car, a Fiat 500 Giardinier ( should have kept it !) and a mechanic said get a Helicoil, a kind of thread within a thread which i screwed on the plug, and then screwed the lot into the engine, and it worked for over 60,000 miles and was still going strong when I sold the car. I even think I changed the plugs, and the helical stayed in the engine, and did not come out again.

 

[edwin]

Yes Helicoil are on the internet.

 

[angel]

A thread insert, like helicoil, in an aluminium component is stronger than tapping directly in the metal.

 

[Crelesy]

Finally it's running great!

I took off the head and checked the seats and valves. They were all leaking when i filled the ports with petrol and cillinder 4 was corroded badly. I think it had an open valve for some time and condensate corroded in the head . It's hard to get on picture but i tried. So i scraped all the softspots in the aluminium out and smoothend the sharp edges out. (Maybe the sharp edges will glow and start firing the engine)
Cleaned and polisched all the valves and seats manually.
For now it's good enough. I'll try to find a new head later on maybe. But first i will run it as it is. No point in finding a head if and when the virus strikes i'll be rebuilding the complete engine with cam and everything.
So still in doubt of fixing the backfires and hesitations i put on the cleaned head again.

It started good. Ran it for 5 min on 1000 rpm and it ran better then before but stil inpossible to drive it or drop rpm to 700ish. But than a big BANG and off was the engine with a lot of smoke!
Petrol everywhere. Carb was flooding like a fountain! So I pulled the carburator and looked inside.
It never flooded before so why now. Took 15mins to find out.

Normally floaters drop down on there own weight
I think E10 isn't good for plastic either. The float had gained some size on the float axle. So I reworked it a bit and all was good.
So again ran the engine for 20 mins now. Still crappy. Shut it off and went to bed. Did some pillow reading and translated some french topics about this kind of problems.
I silently cried a bit when i found out it was a simpele fix.
Cillinder 1 and 4 both are at top at the same time. So when i checked timing it seemed okay. Never thought about firing order. It was all wrong in the beginnig. When i bought it I took pictures of the distributor lines. It did make sense the way the were. When i changed plug 1 and 4 the world opend! I slamed my forehead and did a little dance at the same time. It ran at 600 rpm stationairy and i could drive it up my steep driveway (I live down a dyke) never killing the engine!
Did some tweaking on the mixture and set the timing back a little, back to spec. No more backfiring and stuff. After an hour fiddling allso no more mayonaise.
So me happy and me feeling a fool for not reading the fucking manual! Just thinking it was right when i bought it. Stupid!

But still happy after all.

 

[Crelesy]

O and I allmost forgot.. bought a m14x1.25 machinetap. And gently turned it in the sparkplug hole. The other way down from inside the chamber.
Spec says 27newton (don't know lbs) for tightening the sparkplug. So I did and didn't strip out the tread. I guess Lucky me that the tread was'nt stripped out all the way down. Only bent in for the first 4 or 5mm. All is good now.