Engine got hydro locked diagnosis/fix

[scoobydo123]

Been very unlucky with this but maybe there is some hope.

Due to a faulty injector oring on a side feed injector during diagnosis of a issue cylinder 1 got hydrolocked;-(
Engine started to misbehave during idle and came to a slow stop. Thought it may have been an injector plug so reseated them all and it done it again. Went over it all again and this time when I went to crank the engine I heard the starter clonk, this is when I realised what was going on.

Took plugs out and had compression and got petrol coming out of cylinder 1 :-( Have since done a compression test and here are my cold figures those in brackets are after adding 15ml of oil.

1. 140 (215)
2. 180 (250
3. 170 (230)
4. 180 (240)

Previous engine hot figures around 6 months ago

1. 182
2. 178
3. 183
4. 190

Head needs to come off for decoke as the car had light load knock caused by carbon deposits confirmed with borescope. This was caused by many years of poor running not attended to by previous owners. The ignition timing was extremely retarded as was cam timing due to headskim beyond service limits.

Before taking the head off do you guys think it is worth running the car again to see if the compression recovers after cylinder 1 events or waste of time? At minimum do you think it would be a good idea before taking head off to do a leakdown test to try and establish what is up with number 1?

Not looking for perfection anymore but getting the best of what I have got. Prior to number 1 issue the plan was decoke to get knock under control so head off and not a full refresh as it is on a tight budget.

Engine is Nissan ka24de

Any thoughts guidance very much appreciated as lost a bit of interest with it now need motivation ;-)

[Boosted LS1]

I'd run it if it were mine assuming you've sorted the issues. It may turn out fine, if not then proceed with your plans. Good luck. Change the oil, it may be full of petrol.

[stevieturbo]

just run it

[scoobydo123]

Boosted LS1 said:

I'd run it if it were mine assuming you've sorted the issues. It may turn out fine, if not then proceed with your plans. Good luck. Change the oil, it may be full of petrol.

Thanks a lot yes will change oil. Here are pics of the top of piston 4 which looks like burnt toast.

Now can see why it was knocking.

Here is an explore around cylinder 1 and cylinder 4. You can see the pintle cap in 1 that holds the oring in place. Have recovered that using the camera down the spark plug hole and grease on a straw.

https://drive.google.com/file/d/1YkPq994Y3u01PlApl...

https://drive.google.com/file/d/1DBgx9AXhe0v1jaVih...

So annoying as I was more than happy to pull the head to get rid of the carbon build up which ultimately needs doing. Here is a recording of the knock sensor under very light load. As soon as you hit cruise speed and anything more than the lightest of touches on the peddle results in ping. On the below link if you skip to around 1min 18 seconds you can hear what I have been trying to fix. Even if I retard timing by 8 degree still get ping. Can assume that it is due to the carbon igniting the mixture when it starts glowing.



https://drive.google.com/file/d/1zumbvgFPXdVVpQh3L...

[scoobydo123]

Here is cylinder 3 think the cleaned area may be from the top end clean substance I put in half a tank ago before knew how bad it was in there



And cylinder 1

Edited by scoobydo123 on Tuesday 16th May 18:09

Edited by scoobydo123 on Tuesday 16th May 19:38

[scoobydo123]

stevieturbo said:

just run it

Hi Stevieturbo thanks for commenting. Have updated the post with the reason for why I was investigating the running issues in respect to knock/pre ignition. I was resigned.to the fact that a decoke was required. Maybe if lucky then all the years it has been running pinging away atthe lightest of loads that the HG was already on downward trend and that was my mechanical fuse. If it has bent the conrod as not run it like it then damage is isolated to tha tone component rather than scoring of the bore.

[stevieturbo]

Are you now saying the head gasket is gone ??

Was it just idling when you think it locked up ? Or being used hard ? If idling....I really doubt anything has bent unless the rods are made of cheese

[HustleRussell]

If you want to know if the rod is bent before you take the head off you can put a DTI down the spark plug holes can't you?

[scoobydo123]

stevieturbo said:

Are you now saying the head gasket is gone ??

Was it just idling when you think it locked up ? Or being used hard ? If idling....I really doubt anything has bent unless the rods are made of cheese

The car was at idle. What happened was a pintle cap decided to partway with the injector. Likely cause was after changing the factory in tank pump I clamped the return from the fpr and new pump provided more pressure than what the pintle cap would take and on these injectors the pintle cap "holds" the injlector seal in place. Headgasket was fine as far beforehand as far as I know but maybe due to the knock that the engine has been subjected to for so long maybe was not far from expiry date.

The pintle cap has been recovered from the top of the piston and is no longer complete it has a split in it but also around a 4mm piece missing from the edge of it.

Thanks

Edited by scoobydo123 on Thursday 18th May 18:25

[scoobydo123]

HustleRussell said:

If you want to know if the rod is bent before you take the head off you can put a DTI down the spark plug holes can't you?

100 PC the head needs to come off as the engine needs a decoke. I have a dti gauge. So guess the procedure is measure total lift of cylinder 1 and compare to cylinder 2 and major difference means bent rod. My dti only supports a 10mm throw and would find it tricky to move between cylinders for the accuracy required.

[richhead]

scoobydo123 said:

100 PC the head needs to come off as the engine needs a decoke. I have a dti gauge. So guess the procedure is measure total lift of cylinder 1 and compare to cylinder 2 and major difference means bent rod. My dti only supports a 10mm throw and would find it tricky to move between cylinders for the accuracy required.

measure from the top of the block to the same point on the piston, and repeat, this should be easy to repeat bore to bore, tbh a bent rod is usually obviouse to the eye once the head is off, im assuming its an old petrol if your looking at a head off decoke, if so, its unlikely fuel was the cause of a bent rod, maybe coolant could be, but also unlikely, rods dont bend easy, most engines would just burn all but a massive amount, top fuel dragsters do occasionly hydro a cylinder, but they are running litres of fuel per second per cylinder. and within seconds have destroyed the sparkplugs and basicly rely on detination to run.

[scoobydo123]

It was deffo hydrolock from fuel as an injector oring dislodged on a side feed injector so the bore filled with fuel. It is 1997 vintage. At sometime in its history it had a headgasket done this retarded the timing to the point that ign timing was retarded as the dizzy runs from the back of the exhaust cam on an eccentric slot. Even at maximum adjustment it was only running 7 degree base timing. There was evidence of over fuelling as the cat was also empty. If you look above there are some video links to show the carbon build up and also am audio file of pinging that I can reduce if I run extremely retarded but obviously performance is major down and it still pings a bit. Not actually understanding your instructions for checking conrod with head off I assume. Thanks

Edited by scoobydo123 on Friday 19th May 06:39

[scoobydo123]

Got the head off. Fluid was leaking fairly quickly from each combustion chamber when the cam was removed and valves sitting on the seats.reground the valves and now after 4 hours only lose a very small amount from the inlet valves where as before they would be empty in 20mins or so. Have some strange lines on cylinder one and obvious blow by as per the attached. Also bores are glazed.

Edited by scoobydo123 on Friday 2nd June 06:46

[Chris32345]

If it was leaking enough fuel to lock the cylinder I'm surprised it isn't totally ducked

[scoobydo123]

Seems like I may have got lucky. I reground all valves. Removed carbon build up and sharp edges on combustion chamber and cleaned top of pistons. Have partially re-assembled and run a cold compression test and now have 180psi on cylinder one so got my missing 40psi back. Will be checking the fuel rail and injectors off the car to make sure no more pintle caps wanting to part company.

https://drive.google.com/file/d/1Mpzhhz5yo0fPEF2qX...