Club 80-90 Forums

Now I know about engines in general down to pretty fine details having built many over the years.

Admittedly mostly motorbike engines, but also Fords, Rootes Group, Mini's, even a twin cam Lotus motor.

My DG though has me a bit puzzled ( and sad at what it going to cost me and the hassle, but thats another story )

My engine has been fine for the 3 years I have owned the van.
It uses a bit of oil between changes but not alot and never made any oil smoke.

Last week, all of a sudden it lost a bit of power, I was going up a motorway hill at about 70mph ( normally no problem ) there was no miss-firing, (it felt like it was running out of LPG)

I dropped the clutch as soon as I was aware of this and looked behind for smoke !! - there was none.

I stopped right away.

I checked the temp, the oil and re-started it - All seemed OK.

I continued my journey.

Next day it started smoking like mad. It was the rear left cylinder, the rest look ok according to the plugs.

Odd I thought ( along with some "Oh good gracious me, what will I do now's etc )

The funny thing is over the next few days and about 300 miles it is smoking much less !!!

It is still smoking a bit after the over-run ( normally, but not exclusively guides, I know )

I have a theory, but I would like to keep it to myself for the moment and see what the engine experts out there think it might be.

The upshot I know is I need a replacement motor and to that end I am investigating the likelihood of getting a decent used one as the costs and logistics of getting a recon are looking very iffy ( despite the lovely Steve at Gasure being as helpful as he always is )

I dont know this for sure, its only a suggested idea of what might have happened.......... might, possibly, an idea of what....

Piston ring has "picked up" broken and been "eaten"...

im going to second Simon here, almost exactly the same thing happened to me in mid june 2005, stonking up the last long drag before J1 of the M6 (cathorpe interchange) where the M1/M6/A14 meet......... its a long drag, i was in a bit of a hurry trying to make up time lost by flooding on the M6 wales side of brum comeong back from (s)hell island...... anyhow there wernt many numbers left to point at on the speed indecation , and it coughed, dropped power, i dumped the clutch, pulled accross to the grannylane heading for the shoulder, no smoke..... coasted into the slip for the A14 and down to the lights on red...... it stopped........ i started it again, it ran, i limped into the first layby on the A14 switched it off and investigated, oil ok, water ok, not stupidly hot, so put the kettle on, had a brew, rang me brother got him on the way with recovery in mind.....lweft it half an hour, started it, and limped off, smoking like a smokeything, underpowered but not knocking, and moving........ met my brother between kettering and stamford, and he sat with me , i limped all the way home....... dropped the engine out the next day, popped the spare in, it turns out it had spat a ring, eaten it.....

got the assistance of a good mate in nottinghamville to give me a hand to re ring it, and ran it for another 35k miles with an annoying knock( it knocked the little bearing for six too) but it never missed a beat........ its eaten a ring.......i recon

Run it on petrol for a bit and see if that cures it.
Mind you, you can't undo glazed bores....

Yep - you guys are thinking along the same lines as I.

Though I was thinking it "picked up" scored the bores and rings, then bedded itself in somewhat, like fitting new brake pads onto a scored brake disk.

I was wondering if an option was to strip it and re-ring it ( after glaze busting of course ) but I am put off trying it for 2 reasons :-

1 = I wouldn't want to go to all that trouble and expense only to find I had not effected a cure and still needed another motor. ( plus it would make sense to do all 4 whilst I was at it, wouldn't it ? )

2 = I understand that more often than not the studs break and after that I am off the road until I get another motor.

This is not a holiday camper it is a daily driver / works van as well as a holiday camper so I cannot afford to have it off the road for long.

Waiting to hear (re price and availability) from various folks re a good used motor.

Ummmm, decisions, decisions...

Even if it has eaten a ring and everything is a mess in there, you could put a new pot and piston on the engine in short time if the head hasnt been damaged on that side. Thats worst case scenario. You could just go the route of replacing the ring and inspecting the bore. The nice thing about flat 4's is that you only have to remove the head to get an entire piston out cause you can slide off the pot when the head is off, so in my opinion, its not a major job (In comparison to other cars for example).

Yes I had thought of that but was worried by this stud shearing problem.

Anyone care to give an aprox percentage for stud failures ?

Or even = "occasionally" - "50-50" or "most of the time"

Apparrently it only happens when people use water instead of coolant, or poor quality coolant. I suppose if your coolant looks murky and brown, then that may be an issue, but if its clean and as it should be I reckon you'd be alright. I may be wrong there though. Either way to sort the engine out you're going to have to remove it and either remove the head or replace the engine, so youve little to lose really. If the stud breaks, that just narrows down your options.

The funny thing is over the next few days and about 300 miles it is smoking much less !!!

It is still smoking a bit after the over-run ( normally, but not exclusively guides, I know )

quote]
Don't ignore the posibility of gummed rings. More common in the bad old days though. We used to squirt a dose of upper cylinder lubricant (Redex)down the carb with the engine revving.

airhead wrote:Apparrently it only happens when people use water instead of coolant, or poor quality coolant. I suppose if your coolant looks murky and brown, then that may be an issue, but if its clean and as it should be I reckon you'd be alright. I may be wrong there though. Either way to sort the engine out you're going to have to remove it and either remove the head or replace the engine, so youve little to lose really. If the stud breaks, that just narrows down your options.

Aye, understood.

The coolant looked OK when I got the van and I have always kept it in good order with correct amount of antifreeze / corrosion inhibitor ( though I have to admit to not using the VW G12 stuff ) but at over 110,000 miles who knows what went on earlier in it's life !!

Do you have to take the motor out to remove a head / barrel ?

its more the early ones that do the snapped stud thing, later ones do, but not as much as far as ive heard... certainly if it was a early one the risk would be higher..... imo,

and yes you can get a head off without removing the engine, but its far far easier to drop the engine to do it, and quite possibly quicker too.....

just dont count on not breaking any other studs, the zorst ones are prone, as are the waterpipes.....

by all means try the redex thing, but im doubting that will cure it.......

Well strange but true - it seems to have "fixed itself"

I know it ain't right, but at least the smoke has dropped to a barely noticeable level and only can be seen at all after a long over-run and then hitting the gas.

It's not making any funny noises.

I suppose it must have been a "pick up" on the offending cylinder ( noticed when it lost power for a few seconds ) but why it waited a day before starting to smoke is beyond me.

Unless it was coincidence and the lack of power was icing in the LPG vapouriser or summat and the mechanical damage did happen the next day ( though why I can not imagine ).

I have never come across a smoky engine that fixed itself as this has done though !!

Still looking for a DG or DJ etc type motor as I won't be happy trusting this motor for say a trip abroad !!