Cylinder Bores Damaged, Advice on Proceeding??

[321Away]

Have a customers car in with head failure, 2.5TD, exhaust valves on 2,3,and 4 show signs of water ingress, not a real problem, normally replace head etc, HOWEVER, cylinder 4 shows signs of 'pitting' around the rim, similar to a high perfomance turbo charged petrol car thats been running lean and pinking, the damage has deformed the top edges of the bore and it no longer has sharp defined 90 degree edges, question is, has anyone seen anything like this before and the customer is asking for advice, should he proceed with just a head/gasket replacement or engine/block swap out? if required will upload pics of the bore.

Julian

[Titan1995]

That is is tough one....If my own I would chance a head. However, this is a customer's vehicle.
Best be cautious then eh.

[321Away]

thats pretty much what i said to the customer!! basically he's after advice on how to proceed, whether to chance a head or go for an engine swap out, looking at some of the companies on fleabay, again i know its been mentioned before, but 1 wonders how these companies claim to refurbish an engine, supply and fit for under £1k and make a profit! have seen horror stories of these types of companies supplying rubbish, basically steam cleaned and painted units!

so what the customer (Mick) is after advice as to how to proceed! an independent show of virtual hands as it were!

Julian

[francophile1947]

I've never seen anything like that, but wouldn't the pitted edge prevent the head gasket getting a good seal? If so, just replacing the head would probably only be a temporary cure.
Like you Julian, I can't see how anybody can recondition an engine, and fit it, for such low prices, unless they've got a source of cheap Chinese pattern parts.
Simon Jones posted this link for £1250 http://www.ebay.co.uk/itm/Mazda-Bongo-9 ... 1594wt_922

[peterrc]

Hi Julian, if the piston ring is below the pitting at TDC I would go with a head change unless the pitting reduces the compustion chamber volume significantly.
What do you think has caused the pitting?

[321Away]

The used part of the bore is below ther pitted area, its the dmage to the deck thats the concern as technically the bore is no longer round, the sealing ring on the gasket is a feww mm wide and technically would seal, but my concern is that if bongo's manage to leak with a full 4mm seal, how long would it last when it only has 2mm for 40% of its circunference?

Mick was in earlier and after a long discussion, i think the idea is to replace the engine with a nearly new unit that is in the garage that came in an import? i'll post pics of the bore when i bring in my slr and can take a decent pic.

Julian

[Allans]

Julian, I've had one in where the head had partially 'melted' between the valves, due to overheating. (There may be a photo of it on my website.)
It had pitted and the piston wouldn't operate fully.
The customer wanted a budget repair and was prepared to take the risk.
I glaze busted the cylinders, cleaned the tops, thoroughly, carefully.
I fitted a new head to this.
It bled fine.
It's been running for 2 years, no problems.
Lucky.

You mentioned the cheap 'fully conditioned' blocks/engines.
Some of these replacement units will be fine.
But I have a customer who had one of these fitted elsewhere. It had no compression, wouldn't run.
She had it replaced FOC under warranty.
The replacement vibrates at 2500 rev.
She came to me for advice after this happened.

So If I was going to supply and fit a reconditioned block, I'd prefer to get it reconditioned myself, by engineers I knew. (As you know, (some members may not) when you supply and fit, you're responsible for both the part and the workmanship, so the risk is all yours.)

Julian, under your circumstances, '2mm for 40% of its circumference' I'd prefer to fit a decent replacement block and head, or complete engine.

[David Edwards]

I thought my repair was a straight forward job, "just dropped a valve" I was told, well I bought a new head had block skimmed, new timing belt and all bits, new pistons and rings, new bloody injectors, the list goes on, bloody engine still knackered so I now have to source an engine, what a bloody nightmare, so if you know of a couple of decent engines, you lot being "in the trade" lol, give me a shout please...I would say get another engine and avoid all the bloody problems I have.

[Northern Bongolow]

any idea of the cause julian. has it been running normal fuel, or bio, or veg. or may it be the delivery of the fuel, maybe pump or injector dribbling in fuel??.

[rita]

any idea of the cause julian. has it been running normal fuel, or bio, or veg. or may it be the delivery of the fuel, maybe pump or injector dribbling in fuel??.

I would think that it is more likely water (antifreeze + excessive heat) that has caused this type of fault.

[Velocette]

Just a thought, could the mating surface be reclaimed by metal spraying?

[mikexgough]

personally.... I would go Allan's route to see if it can be saved.... if not then "new" bottom end..... Customer go ahead and cash willing of course.... Have you any local engine shop(s) who may (customer willing) be able to sort the bores/pistons for you... Just another option...
I use these guys....not cheap but one of the best

[321Away]

As far as i know the vehicle has only been run on standard diesel.

The valves on 2,3and 4 and pitted, getting worse in that order, its the cylinder of number 4 thats badly damaged.

After talking to the customer on sat, it looks like its going to be a rebuild on an engine and then drop it in, i will get round to posting pics! keep forgeting camera and digital cant focus close enough to show details!

As rita says, i was thinking, cold water hitting hot metal? or as ady says poor injection,but after bit of research (google) it would seem that diesels should run lean anyway and that (obviously) detonating is normal for them, so not sure how or why! so looks like a full rebuild and engine swap out.

Julian

[Northern Bongolow]

julian, i was thinking along the lines of faulty injectors maybe. if they are firing jets of fuel rather than a mist of fuel.
look forward to the pics.

[321Away]

you can see some of the damage and it contiunes around most of the bore.

Julian