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Post by valhalla on May 18, 2018 23:38:24 GMT 1
I haven't got any nice pictures yet of the latest project (for a good reason), but she presents herself quite well if you don't look too hard!
Mrs. Valhalla decided that one V70 was not enough, and I was likely to be getting bored on my sabatical (I'm not.....) so she prompted me to go and have a "look" at a Spare or Repair local car that has just conked-out 10days ago after running fine for 21years with its first owner. The car in question is a Volvo V70 Phase 1 (P80 platform) with the VAG 2.5 diesel turbo 5cyl unit under the bonnet. Volvo called this engine its D5252T unit (Diesel 5cyl 2.5litre 2valve/cyl). As memory serves me correctly, this unit was used by VAG in a few of its 1990's products, the LT was one, and Audi used it in its high-end applications. It used to have a mixed reaction; one one hand it was smooth and powerful and a good advanced design, on the other hand it has some foibles with that advanced design.....
I looked at the car. I have never only just "looked" at a car, so I bought said car.
Said car is in metallic green, one-owner, 171,000miles, and was a non-runner. I could see that the pump belt was all there, but there was something a bit strange around a new'ish tensioner. I didn't want to turn the engine over, as I suspected that the stoppage 8days previous might have been valvetrain related (the D5252T has this reputation), but I was happy that the engine was fairly well serviced at a regular interval, and the main cambelt at the other end of the engine was clean and dry, if slightly more "used" looking than the pump belt.
The car towed home really nicely on the A-frame, so I was happy that the main running gear was also in good order, and the old girl looked really quite smart in the sunshine. Some minor issues, as you would expect for 21years, including a slightly pushed-back bonnet by a couple of mm, some stone chips on the bonnet, etc. etc. MoT was due until August this year, so a bit of "ticket" if I could fix the engine quickly.
My hunch was correct. I eventually got around to taking the camcover and all the belt covers off today, and number-one suspect was revealed;
Having been reminded of why this engine series has a bit of a "reputation", I went through as much stripping-down of the head as I could today. The cambearings are line-bored directly into the head, and the tappet housings are machined directly as well, so the whole head is considered an "assembly" for when it goes wrong. Not wanting to leave any stone unturned, I looked for the reason behind the failure, and I eventually found it smack on the end of the crank; the crank pulley bolt was loose! More exactly, the pulley bolt had allowed the crank timing pulley and the TV damper unit as an assembly to freewheel around the end of the crank nose, as there are no keyways anywhere on the this engine at-all. So the mating face on the sintered TV damper unit to the crank has scuffed away, which is a common problem on this sort of design if it ever loosens. There should be a key on the sintered crank timing gear - mine is sheared
Moving back up to the top of the engine, I looked more closely at the tappets, and although they indicate major issues from their "stuck down" attitude on some cylinders, what I believe may have happened is that they have taken the brunt of the impact between valves and pistons. So the worse ones have mushroomed, then stuck down, whilst a couple have just collapsed on the hydraulic valving without sticking in the tappet guide housing/cyl head;
So I'm stripping the head further over the weekend, just to see how bad the valves are likely to be, and to see if I can unjam the stuck tappets. If anyone knows of a good D5252T head, I might just have a candidate.....but I'm not giving-up on this car. It might be old, but it's interesting. OK, an interesting "economic write-off", but I'm no believer in giving-up!!!
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remmington
Apprentice
Owns Spark Eroder
Posts: 4,966
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Post by remmington on May 19, 2018 6:53:26 GMT 1
It is possible to fit the pump belt tensioner the wrong way round on these.
This engine was fitted to the Audi 100 and LT vans as you said.
We used to maintain loads of Audi 100 taxis with this engine fitted longtitudinal (spelling?) not transverse as in your Volvo.
I have never had the head off any of these engines even after star ship mileages (500.000 plus miles).
But I have done loads of these which have chucked the pump belt off for no reason at all.
Normally Phase 1 V70 estate cars suffer fuse box water ingress which wrecks the loom and the whole key reader system. I had a Silver W-reg one. This is what happened to mine. It was a manual 2.4 five cylinder petrol - and truthfully it would return 45mpg on the run. Mine had the full thermal incident - wiring fire near OS front - it went for scrap after this.
I like a seven seat estate car. Shame they have stopped making them. Not keen on people carrier type vehicles - I just don't like the look of them.
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Post by studabear on May 19, 2018 18:40:04 GMT 1
I had a look at this post early this morning but never clicked on the pics. That camshaft is a bit broken lol.
I'm sure you will soon have this sorted, certainly interesting to follow.
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Post by studabear on May 19, 2018 18:43:01 GMT 1
163034748834 item number on eBay for a complete head.
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Post by valhalla on May 19, 2018 23:49:46 GMT 1
163034748834 item number on eBay for a complete head. Thanks Stu - I have already been watching that one, as I will explain;
The damage to the end of the crank is a bit more severe than I thought, but not irretrievably....... 
I have missed the "elephant in the room" in my post above..... The crank timing gear should be keyed on this engine!! In my case, it has sheared from being impacted by the valvetrain and pumping torques, due to the crank pulley bolt being left loose by some previous miscreant in the trade. I have been able to clear the remains of the key (normally part of the sintered gear) from the crank, but I'm going to have to work fast tomorrow to establish how butchered the crankcase components are. Two out of 5 injectors are out at the present time, and I hope to get the other three out tomorrow afternoon, then look into the bores with the camera. All being well, I'll then clean the crank end-face with a whetstone and guide (old crank timing gear will be a good guide) to provide a driving/thrust face for the TV damper, which itself is bolted to the timing gear to drive it around without itself using the key that is part of the molded component. This is essential to provide all the driving torques in the correct path through the crank and gear - without this, the engine is a total write-off IMHO.
All being well, the cylinder head can be removed and replaced with a good 2ndhand unit & Elring gasket/cyl head bolt kit, then new TV damper, new crank timing gear, and a new set of timing belts/pulleys/bolts can be ordered and fitted.
More photos to follow!
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Post by valhalla on May 19, 2018 23:56:04 GMT 1
It is possible to fit the pump belt tensioner the wrong way round on these. This engine was fitted to the Audi 100 and LT vans as you said. We used to maintain loads of Audi 100 taxis with this engine fitted longtitudinal (spelling?) not transverse as in your Volvo. I have never had the head off any of these engines even after star ship mileages (500.000 plus miles). But I have done loads of these which have chucked the pump belt off for no reason at all.Normally Phase 1 V70 estate cars suffer fuse box water ingress which wrecks the loom and the whole key reader system. I had a Silver W-reg one. This is what happened to mine. It was a manual 2.4 five cylinder petrol - and truthfully it would return 45mpg on the run. Mine had the full thermal incident - wiring fire near OS front - it went for scrap after this. I like a seven seat estate car. Shame they have stopped making them. Not keen on people carrier type vehicles - I just don't like the look of them. I think I might have the answer to that. It's very common for the Bosch pumps of this vintage (with the MSA controllers) to have a lot of end-float on each pumping operation, ie. the pump gear can thrust forwards by a couple of mm each time the pump elements work. Some pumps were worse than others, mine on this V70 D5252T is middle-of-the road for 170k miles, about 1.5mm. So it is important to check the pump wear each time the pump belt is changed. Caught in time, the problem can be alleviated with an overhaul.
Good to know that you have seen inter-stellar mileages on these engines - I was beginning to doubt myself!!!  |
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Post by Noberator on May 20, 2018 15:16:59 GMT 1
It is possible to fit the pump belt tensioner the wrong way round on these. This engine was fitted to the Audi 100 and LT vans as you said. We used to maintain loads of Audi 100 taxis with this engine fitted longtitudinal (spelling?) not transverse as in your Volvo. I have never had the head off any of these engines even after star ship mileages (500.000 plus miles). But I have done loads of these which have chucked the pump belt off for no reason at all.Normally Phase 1 V70 estate cars suffer fuse box water ingress which wrecks the loom and the whole key reader system. I had a Silver W-reg one. This is what happened to mine. It was a manual 2.4 five cylinder petrol - and truthfully it would return 45mpg on the run. Mine had the full thermal incident - wiring fire near OS front - it went for scrap after this. I like a seven seat estate car. Shame they have stopped making them. Not keen on people carrier type vehicles - I just don't like the look of them. I think I might have the answer to that. It's very common for the Bosch pumps of this vintage (with the MSA controllers) to have a lot of end-float on each pumping operation, ie. the pump gear can thrust forwards by a couple of mm each time the pump elements work. Some pumps were worse than others, mine on this V70 D5252T is middle-of-the road for 170k miles, about 1.5mm. So it is important to check the pump wear each time the pump belt is changed. Caught in time, the problem can be alleviated with an overhaul. Good to know that you have seen inter-stellar mileages on these engines - I was beginning to doubt myself!!! These V70 diesel engines are interference aren't they. |
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Post by valhalla on May 20, 2018 22:57:26 GMT 1
Oh yes, these engines are very interference......
I have loads to update on the work today, but the board isn't uploading files properly, so I'll wait until it's fixed. Otherwise it's full-steam-ahead on the car at the moment. |
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Post by Joepublic on May 20, 2018 23:01:13 GMT 1
Has there ever been a non interference OHC diesel? To get the CR the pistons have to get close to the valves?
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Post by valhalla on May 20, 2018 23:10:27 GMT 1
Has there ever been a non interference OHC diesel? To get the CR the pistons have to get close to the valves? More or less spot-on. Fortunately for me in this case, as I was going to post before the board decided to play-up on the uploaded attachment/s, the D5252T has vertical valve stems, so contact is a clean and square strike on indented pockets cast into the piston crowns. So, as far as I can tell on this one, no long-lasting damage. |
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Post by rhyds on May 20, 2018 23:29:10 GMT 1
I remember someone on here describing a Mitsubishi diesel where the pistons would hit the valves but that a rocker arm would take the brunt of the impact and the engine could be saved?
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Post by valhalla on May 21, 2018 23:02:39 GMT 1
That might have been the case here - the hydraulic tappets have taken the brunt of the impact before the camshaft snapped into several pieces - but because of the mushrooming of the tappet units into the cylinder head tappet-bores, the likelihood of getting away with it fully in this particular case is very slim indeed. The tappet housing is part of the cylinder head in this D5252T unit, so the whole lot is machined as one.
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Post by valhalla on May 21, 2018 23:05:44 GMT 1
This is what I was going to post yesterday;
I've had a fairly good go at confirming that the bottom-end is OK for a new cylinder head assembly. The other 3 injectors came out pretty easily (all five have never been disturbed, so seats are A1 as well as the injector washers) and I was able to get the borescope down into the block on all five cylinders to confirm that everything is likely to be OK. There's no inclination on the valves, so the heads have kissed the piston crowns on the cast recesses exactly square, hence no obvious damage there. I then moved down to the crankshaft nose to confirm that everything on that end of the block was recoverable. That meant taking stock of the crank end thrust face, which was in a bad way; Attachment Deletedand then very carefully whetstoning the thrust face of the crank until it was just cleaned-up; Attachment Deletedafter which I decided that it was all fine to go ahead with the cylinder head purchase. Which is just as well, as I had already pressed the "BUY IT NOW" in the early hours of this morning..... |
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Post by valhalla on May 21, 2018 23:15:57 GMT 1
I have moved on a bit from this status last night, which was with the inlet manifold out of the way, and a few of the exhaust manifold bits on the way;
The D5252T in this application is an absolute peach to work-on; loads of access, good-quality fixings, etc. etc. so this is all a very nice holiday from the usual rubbish I get through the doors these days!
The importance of the TV damper thrust-face to the end-face of the crankshaft cannot be overstated, as the full valvetrain loads have to be passed through this joint. If the keyway of the timing gear comes into play, as it did a couple of weeks ago, then it's GAME OVER. The key is only there to initially time the cambelt and gears, it isn't used to drive the system at all. Because the gear was so bad, I bought a new one last night, along with a new crank timing gear, new cambelt set (with water pump, as that will have been stressed when the engine locked), new genuine Elring head gasket and bolt set, all to go with the secondhand head assembly when it arrives. The TV damper could not have been salvaged, as the recession of the metal was too great to give the correct distances for the timing-gear clearance to the oil pump housing;
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Post by valhalla on May 23, 2018 0:11:00 GMT 1
I didn't get much done on the Volvo today; had to work the shop in the morning, then straight to the MoT station to get a Pass on the 110 Hard-Top (more-or-less sold to a local couple). Then back home to address a minor point on the MoT (just for peace of mind before the sale goes through) which I had caused myself by gilding-the-lily last week on the track-rod balljoints gaiters (I managed to split the N/S gaiter doing the O/S a few days ago - doh!!)
Then my favourite Passat turns-up whilst I'm having a cup of tea - brakes gone again...... That's a tale in itself for another thread.....
So the Volvo got pushed out onto the front compound tonight, almost there with the head though.... Just need to get the fuel lines released from around the head, then the securing bolts can be released. I'll have to see if there's some time tomorrow to actually lift the head and get some photos of the pistons.
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