Engine rebuild brains

[Guest]

Theoretically yes peter.
But also the position of the piston may affect the reading as the crack
may be lower than the pistons position at time of test
Ray

 

[Guest]

You tell me, I haven't a clue any more.
Surely if there was any sort of crack or leak in the head, block or gasket
that vents from a cylinder to the cooling system then that would show up as
a low compression in the affected cylinders?? No? What am I missing here?
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Ray Dadd
Sent: 12 June 2007 14:37
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
So peter it defiantly looking as if it is the head?
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]]
On Behalf Of Peter Browning
Sent: 12 June 2007 15:16
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
According to Haynes (all I have) it should be 171 psi +/- 30 between pots??
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]]
On
Behalf Of Christopher Bell
Sent: 12 June 2007 13:42
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
Pete
I don't have the figures for the petrol engine, but those for the
unturbocharged diesel 12h-t are 400 to 427 psi, and its compression ratio is
18.6 to 1. The compression ratio for the 1FZ-FE (I think that's you) is
supposedly 9.0 to 1, so on a not terribly scientific pro-rata basis you
should be looking for 193 to 207 psi.
The permitted variation between cylinders for the 12h-t is 28 psi, so
again scaling by a factor of 2 suggests 14 psi permitted for you.
On that basis your engine sounds a bit worn, but not unreasonably so, and
the variation between cylinders sounds OK too. I'd say "so far, so good",
since there isn't a cylinder that stands horribly out.
Sorry, not a lot of help. Good luck on the 19th
Christopher Bell
| I've arranged for a mechanical repair assessor to visit the shop with
me to
| watch the stripdown and then compile a report. This will be done 19th
June.
|
| In the meantime I've got them to run a compression test on the cruiser
-
| pots 1 through 4 are 185psi, 5 is 195psi and 6 is 190psi. Does that
give any
| further clues to anyone as to the state of the engine?
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[Guest]

Actually I thought the figures looked good for the a petrol, then again I
was approaching it from an 2F where the CR is 7.8:1 and 165 psi is OK. (Yes
7.8 should run on anything, might be useful if I fit a supercharger!)
Variation also looked OK, only question is why 5 & 6 were higher, perhaps
coolant is getting into 5 & 6 and increasing the compression? Maybe get the
garage to leave 6 at BDC and see if it gets wet?
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Christopher Bell
Sent: 12 June 2007 14:42
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
I don't have the figures for the petrol engine, but those for the
unturbocharged diesel 12h-t are 400 to 427 psi, and its compression
ratio is 18.6 to 1. The compression ratio for the 1FZ-FE (I think
that's you) is supposedly 9.0 to 1, so on a not terribly scientific
pro-rata basis you should be looking for 193 to 207 psi.
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13:39

 

[Guest]

Hi Peter,
Yes, your compression test doesn't indicate this.
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Julian Voelcker
Mobile: 07971 540362
Skype: julianvoelcker
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift

 

[Guest]

Mate it is hard
But you need to think about the movements of the engine
Piston goes up and down so the leak could be behind the piston at the
time of the test. do you understand ?
Valves open and close .so again at the time of the test there could be a
crack in the head above the valve that is closed
Do you see where I am coming from peter? It is not all clear cut
Yours
Ray

 

[Guest]

So if the compression test is not indicating a crack venting to the cooling
system why is the coolant being chucked out?

 

[Guest]

Between 5 and 6 is where the HG originally blew....
Does that indicate something...? Anything..??
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Malcolm Bagley
Sent: 12 June 2007 14:57
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
Actually I thought the figures looked good for the a petrol, then again I
was approaching it from an 2F where the CR is 7.8:1 and 165 psi is OK. (Yes
7.8 should run on anything, might be useful if I fit a supercharger!)
Variation also looked OK, only question is why 5 & 6 were higher, perhaps
coolant is getting into 5 & 6 and increasing the compression? Maybe get the
garage to leave 6 at BDC and see if it gets wet?
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76

 

[Guest]

My thinking was, during the compression test, if some coolant had leaked
into the cylinder would help sealing - ie make it a wet test and the coolant
wouldn't be compressible and so might also increase compression results.
With the engine running the higher internal pressures would force combustion
gas into the water jacket.
If the crack was in the middle or lower part of the cylinder then it might
not show up on a compression check - max pressure during combustion occurs
after TDC. Seems strange for a crack to affect both 5 & 6?
Memories of hoop stress and crack analysis come to mind but I am probably
over-complicating things.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
Surely if there was any sort of crack or leak in the head, block or gasket
that vents from a cylinder to the cooling system then that would show up as
a low compression in the affected cylinders?? No? What am I missing here?
Pete
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13:39

 

[Guest]

But surely a compression test averages all this out? The test is run with
the engine spinning on the starter so it goes through several full
in-squeeze-bang-out sequences so any leak anywhere on the system would show
as an average lower compression?
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Ray Dadd
Sent: 12 June 2007 15:04
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
Mate it is hard
But you need to think about the movements of the engine Piston goes up and
down so the leak could be behind the piston at the time of the test. do you
understand ?
Valves open and close .so again at the time of the test there could be a
crack in the head above the valve that is closed
Do you see where I am coming from peter? It is not all clear cut Yours
Ray

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17:10

 

[Guest]

As I said Pete the test could do with being done at several points as
the crank moves so all the position positions are covered and the all
the valves have been opened .
Also the psi/air that is actually passing thought the crack could be
just a small amount and the accumulation of stokes of the piston which
is creating sufficient volume to create blowing back though the water
system
Just like small breaths blowing up a air bed ?

 

[Guest]

Pete I have the answer
It is 42
This is the answer the everything life the world and the universe
Well I hope that was the number of the hitch hikers guild to they galaxy

 

[Guest]

Your compression test results seem OK, but before you have the head removed, have the garage do a Cylinder Leakage Test, this will give more information than a compression test, it is basically an adaptor in place of the spark plug connected to an air line with a ball valve and gauge, you pressurise the cylinder then close the valve and watch the valve and check for a source of leakage, i.e. gasket, header tank, exhaust, rocker cover cap. They are easy to make or buy or hire but well worth the money as once the head is off you will not be able to diagnose the leak if not obvious. You can even lock the crank in various positions to check the bores in different piston positions.
I am not familiar with your engine but if the head is Ally and block Cast Iron I would suspect the head every time, How did they check the head for cracks? Was it with crack tester paint /fluid? head cold or warm, did they bolt the head down onto a flat plate with a rubber gasket? or was it x rayed? Heads that don't leak when tested cold with paint /fluid cannot be guaranteed when hot or under pressure as in combustion pressure.
Like I say do a cylinder leakage test first I am sure it will show the true cause of you coolant pressurising.
David
Horley Surrey
LJ 70 Colway A/T and brakes work fine now!!

 

[Guest]

Hi David, I suggested the same =96 leakdown test doesn=92t seem a very common
test / tool in the UK, probably in part because of the silly amount they
cost here. I used on a while ago and saw them recently on ebay for around
=A390, then I saw one on ebay in the US for $54, checked postage - $32 so I
have ordered a couple. Two gauge ones are a little different to use, they
have a pressure regulator that you set to say 100 psi, the second gauge
reads the pressure in the cylinder, the difference is a measure of leakage.
One thing about checking at different crank angles is you can only check
points where both valves are closed which is not actually much of a cycle.
Sorry Pete, not likely to turn up before the 19th but if they do I will give
you a shout, as David said easy to make - adapting a compression gauge is
perhaps the easiest way.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of David Charman
Sent: 12 June 2007 22:16
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
Your compression test results seem OK, but before you have the head removed,
have the garage do a Cylinder Leakage Test
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13:39

 

[Guest]

If the coolant is being pressurised when the engine is running surly it's a safe be the will be exhaust gas in the rad, the question is where is the problem head, gasket or less likely block?
Do you have a way of telling before the head is taken off, and what would be your preferred way to examine the head and block.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On Behalf Of [Email address removed]
Sent: 13 June 2007 14:31
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
just do a gas leak test .its a blue die that changes green if theres a
leak of exhaust gases into the water.it just goes on the rad. ask the
snapon man he'l have one for about =EF=BF=BD39.99. ive used these since they
come out ! if it changes colour your heads cracked or the gaskets
leaking,its as simple as that!!
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[Guest]

I was going to ask the same question.
We know there's pressurisation of the coolant and so it must be either head,
block or gasket. I need to know which one it is.
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Malcolm Bagley
Sent: 13 June 2007 13:45
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
If the coolant is being pressurised when the engine is running surly it's a
safe be the will be exhaust gas in the rad, the question is where is the
problem head, gasket or less likely block?
Do you have a way of telling before the head is taken off, and what would be
your preferred way to examine the head and block.
Malcolm Bagley
Stafford UK
FJ45 '75 & FJ45 '76
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of [Email address removed]
Sent: 13 June 2007 14:31
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
just do a gas leak test .its a blue die that changes green if theres a leak
of exhaust gases into the water.it just goes on the rad. ask the snapon man
he'l have one for about 39.99. ive used these since they come out ! if it
changes colour your heads cracked or the gaskets leaking,its as simple as
that!!
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21:42

 

[Guest]

It's good to hear you've had no block problems. Mind you, knowing my luck
I'll be the first.
As to blocked rad, water pump problems, etc I keep coming back to the same
point - I never had a hint of any of these problems before it went in to
have the HG done so why would one of them appear now? Logic tells me it has
to be head, HG or block. But then what do I know?
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of [Email address removed]
Sent: 13 June 2007 19:34
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
ive never had problem with a block,so im 99% sure it wont be that! more
likely the head,either cracked or more likely slightly warped as ive had
that before 0n a 80series! unless of course they didnt use a steel gasket
and/or didnt pull it down right. dont matter what tests you do the only way
to fihd out is to take the head off!!
You say it's pressurising but that does not necessarily mean that it is
getting exhaust gas in, I would still do a gas check, you could have
problems with water pump impellor, blocked rad, stuck thermostat, etc.
as you've already had a gasket fitted - although I'd have thought the garage
would have checked them out first time round and done a gas check.
Chris.

 

[Guest]

Peter
Good luck tomorrow for your engine inspection.
Ray

 

[Guest]

It's today at mid-day for inspection with the engineer.
And thanks.
Pete
-----Original Message-----
From: [Email address removed] [mailto:[Email address removed]] On
Behalf Of Ray Dadd
Sent: 19 June 2007 07:06
To: [Email address removed]
Subject: RE: [ELCO] Engine rebuild brains
Peter
Good luck tomorrow for your engine inspection.
Ray

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