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WBXOily
Posted: 25 Nov 2017, 11:15
by itchyfeet
This is What2do's engine that was leaking oil from the spark plug hole, we checked compression and they were all low, not quite lower than VW min spec but that's not saying much, min is 8 bar If I remember ( my DG is 12-13 bar)
Figures were
No1 10 bar ( leaking oil out of plug hole)
No2 8,75 bar
No3 9 bar ( broken rings)
No4 11 bar
So it got removed and another engine fitted and now I'm going to take a look at what's wrong.
P1040855 by
Paul_Barr, on Flickr
P1040856 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 25 Nov 2017, 11:23
by itchyfeet
We pulled the heads off at his house and the first came with barrels, and two of the rings were broken on one piston, the other side came of OK.
20171118_143039 by
Paul_Barr, on Flickr
So I took it home to play with and sneaked another of his old engines in while he wasn't looking
20171118_151853 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 25 Nov 2017, 11:29
by itchyfeet
on the bench today for a closer look
P1080712 by
Paul_Barr, on Flickr
and it's clear the rings didn't just break as the barrels came off because the barrel is scored.
P1080717 by
Paul_Barr, on Flickr
what's a bit strange to me is how clean the top of the pistons ( except broken ring piston) and heads are and yet what's all the crud in the spark plug?
I'd expect an oil burner to be black inside?
This is an LPG engine, plugs were changed 1 year ago.
P1080718 by
Paul_Barr, on Flickr
P1080719 by
Paul_Barr, on Flickr
P1080721 by
Paul_Barr, on Flickr
P1080722 by
Paul_Barr, on Flickr
P1080723 by
Paul_Barr, on Flickr
looks like some oil was leaking from a pushrod so not all being burnt
P1080724 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 25 Nov 2017, 19:18
by itchyfeet
I want to take valves out to see if valve guides are worn.
Barrels need to come off head first , I use a floorboard lifter, it works for me to separate barrels, one side will move first then back and forth with chisel one side hammer the other until it comes off.
P1080725 by
Paul_Barr, on Flickr
P1080726 by
Paul_Barr, on Flickr
P1080730 by
Paul_Barr, on Flickr
the other barrel really needs a vice this was stuck on really well, needed to beat it with a lump hammer, studs stop it falling on floor when it finally moves.
P1080737 by
Paul_Barr, on Flickr
P1080738 by
Paul_Barr, on Flickr
I
Re: WBXOily
Posted: 25 Nov 2017, 21:09
by itchyfeet
Easiest to give the springs a thump with a socket to loosen cotters
this is 1&2 side
P1080777 by
Paul_Barr, on Flickr
pretty oily on back of valves
P1080779 by
Paul_Barr, on Flickr
some bits of metal I made to help make the measurement
P1080780 by
Paul_Barr, on Flickr
worn but well in spec and less than other engines I have tested that don't burn oil.
P1080781 by
Paul_Barr, on Flickr
3&4 side is just the same
P1080783 by
Paul_Barr, on Flickr
P1080784 by
Paul_Barr, on Flickr
P1080795 by
Paul_Barr, on Flickr
usual cracks between valves on three of four cylinders this is the worst so these heads can go back after a clean and valve grind
Re: WBXOily
Posted: 26 Nov 2017, 11:07
by itchyfeet
Next to remove pistons
all this has to come off, need to remove pulley to get old water pump bolts out, another reason not to store engines the pulley and flywheel rust
P1080740 by
Paul_Barr, on Flickr
an allen key just won't do it , they were stuck in well.
P1080741 by
Paul_Barr, on Flickr
rag around piston so you can't loose clip in sump ( I'm not rebuilding the bottom end oil pressure is good)
P1080745 by
Paul_Barr, on Flickr
as barrels are off the piston needs supporting, some bits of wood work
Pulled the pin with my home made M8 rawlbolt puller
P1080747 by
Paul_Barr, on Flickr
No 3 has a very bad burr on the circlip groove, this apparently happens from the pin bashing it, never coming out with that so out with the reamer
P1080754 by
Paul_Barr, on Flickr
P1080756 by
Paul_Barr, on Flickr
studs are A1
P1080764 by
Paul_Barr, on Flickr
other side out too
P1080768 by
Paul_Barr, on Flickr
again studs A1
P1080769 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 26 Nov 2017, 17:17
by itchyfeet
pulled the tappets one side to check cam and while it's worn its OK and not too bad
P1080771 by
Paul_Barr, on Flickr
hello cheap oil filter alert
P1080773 by
Paul_Barr, on Flickr
broken bolt, what20do can drill that out
P1080774 by
Paul_Barr, on Flickr
mmm end float desperately needs setting, should be 0.07-0.13 this is 0.27
P1080775 by
Paul_Barr, on Flickr
rags in holes and back in the store until I have parts
P1080776 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 26 Nov 2017, 18:42
by what2do
A1 studs - that's because I look after them, meticulously...
Re: WBXOily
Posted: 26 Nov 2017, 19:15
by itchyfeet
what2do wrote:A1 studs - that's because I look after them, meticulously...
yeh but you didn't know they were good before, you could have been meticulously looking after rusty old studs like these
P1080183 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 26 Nov 2017, 21:42
by itchyfeet
piston and barrel check next
P1080785 by
Paul_Barr, on Flickr
P1080788 by
Paul_Barr, on Flickr
bore gauge isn't very accurate but it's better than nothing and accurate enough bearing in mind the difference between piston and barrel can be up to 0.2mm
P1080790 by
Paul_Barr, on Flickr
P1080791 by
Paul_Barr, on Flickr
No1 93.95/94.06 =0.11
No2 93.93/94.05 = 0.12
No3 93.88/94.07 = 0.19 ( broken ring)
No4 93.97/94.06 = 0.09
this is a bit worrying but it sealed before
P1080792 by
Paul_Barr, on Flickr
I think this could be the cause of low compression, this is way over the limit at 1.7mm at the top and ( where it actually runs) and 1.4mm at the bottom where you are supposed to measure ( who knows why because it never runs there)
I only checked No1 so far
P1080794 by
Paul_Barr, on Flickr
Re: WBXOily
Posted: 26 Nov 2017, 23:53
by 937carrera
You clearly know what you are doing, but don't forget, pistons are shaped along the height, and not generally round, neither are used bores, so you need to be sure that you are measuring in the right places and identifying whether it is the pistons, bores or both that are worn.
Re: WBXOily
Posted: 27 Nov 2017, 07:50
by itchyfeet
937carrera wrote:You clearly know what you are doing, but don't forget, pistons are shaped along the height, and not generally round, neither are used bores, so you need to be sure that you are measuring in the right places and identifying whether it is the pistons, bores or both that are worn.
interesting comment
VW manual state to measure in certain places which don't alwys make sense to me.
piston at skirt in vertical plane -seems logical its where wear is highest.
barrel is shown at top -logical because rings are there and wear is highest but not where piston skirt is and the spec of 0.2mm max is the difference
Also barrel measurement shown on horizontal axis - not logical to me ( I measure vertically because its worse)
Rings at base of barrel where they never run -not logical to me ( I measure at top also where its worse)
can you shed any light on this?
Re: WBXOily
Posted: 27 Nov 2017, 18:02
by 937carrera
I'm getting to the limits of my understanding here, I'm not an engine builder, but have built a few and had a few race engines built for me, I even had to custom design some pistons when an engineering shop planed a block when I had told them not to.
I believe that pistons are not round when cold because you want them to be round when running and up to temperature and the material is not evenly distributed, largely because of the gudgeon pin. So they are cast / forged allowing for the differential expansion. Similarly the top of a piston is hotter that the lower area so the dimension above the first ring tends to be smaller - to a greater extent on turbocharged engines.
Bores are round when new, but, perhaps to a greater extent in boxer engines, they tend to wear oval.
I think it's best to simply measure where the manufacturer advises. They know where the measurements are being taken and what the wear limits when comparing those measuring points. If you are taking measurements at different points, the basis for the clearance calculation has changed so is the resulting answer of value ? It' a bit like measuring in inches or cm. Both function well as measures of distance, but you need to know which one to use at any point in time, (otherwise your Mars lander crashes)
Re: WBXOily
Posted: 27 Nov 2017, 18:55
by itchyfeet
Yes that's pretty much what I'm doing measuring where the VW manual tells me to.
I'm not building a race engine so as long as it looks Ok and within spec it goes back.
Re: WBXOily
Posted: 27 Nov 2017, 19:18
by 937carrera
OK, with the concerns you expressed about compression I thought you were looking to replace pistons or barrels and the measurements were going to help you decide how far to go. I didn't want you to junk perfectly functional components.
Have you decided where the oil was coming from yet ?