Member Since: 19 Nov 2011
Location: NYC & LA
Posts: 775
Hi guys,
what does suffering from VSR mean on a V8?
is this only on the LPG conversions?
Thanks,
Dave
18th Jun 2015 8:41 pm
Alphamale
Member Since: 28 May 2014
Location: Belfast
Posts: 497
Valve Seat Recession (VSR) occurs to some extent in most engines. It is usually denoted by the need to adjust the valve gaps, but is seldom a problem on modern engines unless they are running on LPG when it is more pronounced.
Because LPG provides no lubrication, in the form of sooting between the valve heads and seats and has no cooling properties (LPG is already a gas when it enters the cylinders whereas petrol is a liquid which, when it enters the cylinder, provides a small cooling effect as it vaporises) the valve and seat abrade each other and small particles of metal ware off. (very simplified explanation) In the end the valve seats receded and the valve stem eventually has no gap with the camshaft (usually the exhaust seats ware the most) so the valve timing is wrong and they open early and close late.
18th Jun 2015 9:39 pm
MrWillfin
Member Since: 04 Mar 2015
Location: Cumbria
Posts: 94
Houston, we have a problem.
I removed the cam bearing caps and maybe due to particulate/contamination in the oil there is serious scoring on the cylinder head side of the journal which is not not normal wear.
Some sort of contaminant got spun through the cam journals. The question is what else, if anything, did it/they score before being trapped in the filter?
I could replace the heads, but Im then very worried about the main and rod bearings as I wouldnt want to rebuild only to find the bottom end is knackered.
Lifting the engine out is not that easy as I cant get the body off in the garage. Maybe with the heads off it would be easier, but then id have to dismantle a new engine to install.
Now seriously thinking about installing the 4.2 supercharged engine instead.....Goodness knows what I've let myself in for...
19th Jun 2015 9:02 am
Alphamale
Member Since: 28 May 2014
Location: Belfast
Posts: 497
Absolutely disastrous, wonder what caused it. With a new head from, say Paddock's, costing £318 inc. it's not cheap. Is it possible for an engineering Co to repair and recut the journals?
19th Jun 2015 10:32 am
MrWillfin
Member Since: 04 Mar 2015
Location: Cumbria
Posts: 94
It certainly is.
Looking at stil getting the heads off and sending up the road to a local reputable engineering company to have a look at. Thing is, teh cam caps, and camshaft bearing points are all roughed up too!
Im more concerned at whether i need to strip the bottom end down, and take a few big end caps off to check they are not screed up aswell.
Hmmmm...Goodness knows what I've let myself in for...
19th Jun 2015 10:34 am
Alphamale
Member Since: 28 May 2014
Location: Belfast
Posts: 497
I'd be inclined to drain the oil and see what debris, if any shows up there. Next I would consider removing the sump to get a look at the crank and see if there is anything obvious. Mind you removing the sump is very involved requiring the front diff and steering gear to be removed, but cheaper than a new engine.
19th Jun 2015 12:52 pm
MrWillfin
Member Since: 04 Mar 2015
Location: Cumbria
Posts: 94
Yeah that's what I'm going to have to do, need to make sure the bottom end isn't screwed before bolting a load of shiny bits of the top half. Shouldn't take too longe really.
I have the LH head off, and the exhaust valves are bent, not a huge amount of VSR to be honest. I was expecting valves tucked into the head. Maybe the issue wasn't VSR after all and just a timing issue.
The block and bores seen fine.
So far, it's a pair of new heads and cams on the shopping list!
RH side off next week.Goodness knows what I've let myself in for...
19th Jun 2015 5:28 pm
Robbie
Member Since: 05 Feb 2006
Location: ¯\_(ツ)_/¯
Posts: 17932
It's not looking good for that engine. Sump-off inspection seems like the next step. Hopefully you have access to a borescope.
Your heart must have sank when you saw the damage. Gutted for you.Land Rover - Turning Drivers into Mechanics Since 1948
Member Since: 02 Jan 2015
Location: pontyclun
Posts: 433
Looks like i have to do this. Got tapping when it cold. Sounds like a valve
19th Jun 2015 6:24 pm
Alphamale
Member Since: 28 May 2014
Location: Belfast
Posts: 497
MrWillfin wrote:
Yeah that's what I'm going to have to do, need to make sure the bottom end isn't screwed before bolting a load of shiny bits of the top half. Shouldn't take too longe really.
I have the LH head off, and the exhaust valves are bent, not a huge amount of VSR to be honest. I was expecting valves tucked into the head. Maybe the issue wasn't VSR after all and just a timing issue.
The block and bores seen fine.
So far, it's a pair of new heads and cams on the shopping list!
RH side off next week.
More like a full head if nothing else is damaged below, new head with cams, valves etc ready to fit £1400 inc. new stripped engine £11,000 +vat and a surcharge of £2500.
You might have guessed the valves would be damaged when you found the cams didn't line up.
Were any of the pistons damaged? Hope you find nothing else wrong, but even if you don't I would be thinking of a full rebuild encase there were any oil ways clogged with just waiting for you to start her up after fixing everything else.
I think if you had to have the engine out, that it can be done without the body off, it's just not as easy and the gearbox etc needs to be dropped first.
Fingers crossed for you.
19th Jun 2015 7:27 pm
MrWillfin
Member Since: 04 Mar 2015
Location: Cumbria
Posts: 94
Well unfortunatley the head issue has beaten me and willjust take up too much of my time to fix.
Now up for sale.Goodness knows what I've let myself in for...
1st Jul 2015 3:24 pm
Disco_Mikey
Member Since: 29 May 2007
Location: Dundee, Scotland
Posts: 20789
Member Since: 04 Mar 2015
Location: Cumbria
Posts: 94
Anyone doing a v8 strip down, I also bought a full Genuine LR Head gasket set, head bolts, and full timing chain incl tensioners etc which cost a small fortune which are no longer needed!Goodness knows what I've let myself in for...
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just waiting for you to start her up after fixing everything else.
