Subject: Second opinion
From: Andy Luckman
Date: 31/07/03 12:26 GMT Daylight Time
Message-id:


I have had a Rialto come in for some attention. I'm pretty happy about my
diagnosis, but would appreciate a second opinion.

Customer reports water loss and hot running. A quick check showed a small
wet patch on the ground below the radiator overflow, suggesting it is being
blown out.

Found the closed circuit breather system had split hoses and repaired them.
Replaced radiator cap.
Checked timing OK.
Slow running seemed smooth enough, suggesting mixture OK.

Customer had it back and reported better temperature stability but still a
small coolant loss after 100 miles round trip.

I have taken the plugs out to find them looking like there has been a major
snowfall in the compression chamber on 1,3 and 4. Number 2 looks normal.
The plugs are not any that I have heard of before so can't check they are
correct. The only details on them is R6 Beru Ultra 306. This engine would
normally be happy on NGK BP5/6 ES.

Compression test shows (1) 140 (2) 160 (3) 160 (4) 180) all dry.

No obvious water egress routes anywhere, the hoses are all in good condition.

My feeling is that there is a slight warp in the head due to hot running,
leading to a head gasket leak into the cooling system. One long shot is
that the plugs are completely wrong and it is only they that have
overheated. I really don't want to lift this head, but I reckon it is a
good bet that I will have to. What do you all think?

The chances of a head gasket leak into 3 out of four cylinders and the engine
still be running ok and giving good cranking pressures seems rather low. In any
event a badly warped head is extremely unlikely to be ok on a centre pot having
failed on both outside ones. They warp would be greatest in the centre. I
conclude that your diagnosis is not correct in so far as you believe it to
indicate water leakage into all 3 cylinders.

Not sure what "major snowfall" indicates with respect to the plugs. Do you mean
they are just white or they are a normal brown but with white deposits of some
sort on them? If water is getting into the cylinders then maybe it's getting in
via another route than the head gasket i.e. inlet manifold but if so I fail to
see why it isn't getting into number 2.

The obvious thing to do would be to check further for leaks in the radiator or
hoses, either visually or better still with a pressure test. Change the plugs
for known correct ones and check the fuel mixture on a CO meter, as well as the
basics like valve clearances and cam timing. A "sniffer test" into the
expansion bottle would tell if combustion gasesd were getting into the cooling
system. Taking the head off at this stage seems premature.


Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
"How's life Norm?"
"Not for the squeamish, Coach" (Cheers, 1982)

In article , Dave Baker
URL:mailto
The chances of a head gasket leak into 3 out of four cylinders and the
engine still be running ok and giving good cranking pressures seems rather
low. In any event a badly warped head is extremely unlikely to be ok on a
centre pot having failed on both outside ones. They warp would be greatest
in the centre. I conclude that your diagnosis is not correct in so far as
you believe it to indicate water leakage into all 3 cylinders.

I felt that it was compression leakage from No.1 if anything, pressurising
the cooling system.

Not sure what "major snowfall" indicates with respect to the plugs.
Do you mean they are just white or they are a normal brown but with
white deposits of some sort on them? If water is getting into the
cylinders then maybe it's getting in via another route than the head
gasket i.e. inlet manifold but if so I fail to see why it isn't getting
into number 2.

An effect I have never seen before. The plugs are fouled with a brilliant
white deposit, with No.2 being the only exception. I have seen overheated
plugs, but these are different. If I get chance, I might upload a pic for
your interest.

The obvious thing to do would be to check further for leaks in the
radiator or hoses, either visually or better still with a pressure test.

Visual check seems fine. I have no pressure tester here.

Change the plugs for known correct ones and check the fuel mixture on a
CO meter, as well as the basics like valve clearances and cam timing.

This is a sensible next step of course.

A "sniffer test" into the expansion bottle would tell if combustion
gasesd were getting into the cooling system.

Don't have a tester. :-(

Taking the head off at this stage seems premature.

I was hoping you would say that. Lifting the head is a bitch of a job
because the head invariably is corroded around the studs!


--
AJL Electronics (G6FGO) : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

"Andy Luckman" wrote in message
...
In article , Dave Baker
URL:mailto
The chances of a head gasket leak into 3 out of four cylinders and the
engine still be running ok and giving good cranking pressures seems
rather
low. In any event a badly warped head is extremely unlikely to be ok on a
centre pot having failed on both outside ones. They warp would be
greatest
in the centre. I conclude that your diagnosis is not correct in so far as
you believe it to indicate water leakage into all 3 cylinders.

I felt that it was compression leakage from No.1 if anything, pressurising
the cooling system.

Not sure what "major snowfall" indicates with respect to the plugs.
Do you mean they are just white or they are a normal brown but with
white deposits of some sort on them? If water is getting into the
cylinders then maybe it's getting in via another route than the head
gasket i.e. inlet manifold but if so I fail to see why it isn't getting
into number 2.

An effect I have never seen before. The plugs are fouled with a brilliant
white deposit, with No.2 being the only exception. I have seen overheated
plugs, but these are different. If I get chance, I might upload a pic for
your interest.

The obvious thing to do would be to check further for leaks in the
radiator or hoses, either visually or better still with a pressure test.

Visual check seems fine. I have no pressure tester here.

Change the plugs for known correct ones and check the fuel mixture on a
CO meter, as well as the basics like valve clearances and cam timing.

This is a sensible next step of course.

A "sniffer test" into the expansion bottle would tell if combustion
gasesd were getting into the cooling system.

Don't have a tester. :-(

Taking the head off at this stage seems premature.

I was hoping you would say that. Lifting the head is a bitch of a job
because the head invariably is corroded around the studs!


--
AJL Electronics (G6FGO) : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

Andy,

If you want another engine (complete and can be seen running) I have one.

Roger
N. London.

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