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ted gaulke
Unregistered guest
Posted From: 213.122.149.201
| | Posted on Friday, 09 April, 2004 - 08:07: |    |
with reference to David Gore's posting of the 14th of march,i find that from studying the pictures that the spirit engine looks to have had regular oil changes and the shadow engine has not. did the spirit engine fail due to improper adjustment of the hyd.pump or case hardening failure on the camshaft(obvious wear on cam pump lobe)whereas the shadow engine is not showing the same type of wear,some pitting on the lobe but the cam itself is very black with contamination.is this the dreaded black death that is talked about since the early eighties? |
Robert Chapman
Prolific User
Username: shadow
Post Number: 45
Registered: 5-2003
| | Posted on Saturday, 10 April, 2004 - 23:49: | |
Ted,
I think I can answer your question because as you know they were my pictures.
The pictures of the Spirit engine do indeed show that the owner had kept the car well serviced with regular oil and filter changes.
The failure was caused by an incomplete chill hardening process.
Because these rubbing components experience such high surface contact loads it is important that the surface finish and hardness be correct as they rely heavily on boundary lubrication.
The pictures of the Shadow camshaft are from the car we converted to a GMC engine. The owner Dr Les Mighalls has previously mentioned on this forum that he had spent 70,000 AUD servicing this car with a recognised facility, I leave it up to you to judge whether he received value for money.
I will ask David to post the other pictures of the dismantled engine, after it finely gave up with a broken piston. The piston skirt was broken by a distorted liner; the liner had been crushed out of shape .006 (oval) by corrosion build up that subsequently cracked the block.
The contamination is evident throughout the engine as will be seen in the pictures.
The plebeian slang “black death” used by some in the UK is a generalisation for contamination(sludge,gum,varnish,residues etc) that can be caused by several problems, most obviously and commonly recognised is the lack of regular and frequent oil and filter changes, but also by poor quality oil with low levels of detergent, dispersant and oxidation additives, incorrect regulation of the cooling system, excessive blow-by allowing the by products of combustion (carbon, acid and moisture) into the oil overloading it to a point were the particles can no longer be suspended and are not removed by colloidal function, and inadequate crankcase ventilation.
This type of contamination in my experience is unusual in local engines, being more regularly associated with engines brought in from the UK and Europe.
This problem has been around for many years, I believe one of the first to recognise it was the GPO in the engines of their fleet of small red delivery vans.
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David Gore
Moderator
Username: david_gore
Post Number: 236
Registered: 4-2003
| | Posted on Sunday, 11 April, 2004 - 05:52: | |
Robert, will do when you can get the pictures to me as these will be of great interest to everyone.
Your comments on oil breakdown are very pertinent given the current practice of recommending extended oil change intervals - I have always believed varnish/sludge accumulation was best prevented by using quality oils and frequent changes especially for cars used in stop/start city driving; 10,000Km is the longest I would want to go for city cars and 20,000Km for long-distance country cars. |
Pat Lockyer.
Unregistered guest
Posted From: 81.131.42.92
| | Posted on Sunday, 09 May, 2004 - 07:56: | |
David any sign of pictures yet or are they still being developed or whatever.
This is a very important issue that needs to be aired for all true enthusiasts of the mark.
I sense alot of folks probs are connected with this issue and at great expense |
David Gore
Moderator
Username: david_gore
Post Number: 246
Registered: 4-2003
| | Posted on Sunday, 09 May, 2004 - 10:51: | |
Pat,
I have received the photos from Robert but I have been preoccupied with a series of personal problems that have taken all my time and I have not had internet access from my computer to upload the images after I scan them - I hope to be able to do this later today or this evening.
PS the photos are awesome and really show what can happen - thanks to Robert for sharing this with us. |
David Gore
Moderator
Username: david_gore
Post Number: 252
Registered: 4-2003
| | Posted on Monday, 10 May, 2004 - 03:22: | |
At last I am able to post Robert Chapman's photos of the Shadow II engine - hope you find the ability of this forum to display pictures such as these interesting and informative.
1. Shows broken piston on major thrust side. Crack starts from oil holes and works downwards following the pin boss web on the inside of piston.
2. Shows cylinder bore still with cross hatch hone marks visible. These marks should have been long gone on an engine of this mileage. Brown marks/stains half way down are caused by blow-by. The piston rings on this engine have never bedded in.
3. Shows total loss of oil control. Oil control ring is completely stuck in groove.
4. Show cylinder block with total contamination of the camshaft valley.
5. Shows oil wash around outside of crown. This is evidence of oil being pumped upwards into the combustion chambers by worn rings in worn ring grooves. The carbon in the centre of the bowl shows that oil has also been coming downwards.
6. Shows inlet valve with heavy carbon build up, caused by oil coming down the guide.
7. Shows large carbon particles caught in oil pick up filter.
8. Shows contamination of heads.
9. Shows contamination of inside of crankcase.
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