Big oil leak
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jehagadone
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- Joined: Wed Aug 17, 2022 12:54 pm
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Big oil leak
Started my 52 Ariel four today, last ran in 1962.
Engine completely disassembled and reassembled in 2024.
There is a big oil leak, oil dripping off cylinders, mostly left rear cylinder but other places too, lots of oil.
Checking with trouble light it looks like oil is coming out between cylinders and head where head gasket is.
Please tell me what happened.
thanks, Jerry
Engine completely disassembled and reassembled in 2024.
There is a big oil leak, oil dripping off cylinders, mostly left rear cylinder but other places too, lots of oil.
Checking with trouble light it looks like oil is coming out between cylinders and head where head gasket is.
Please tell me what happened.
thanks, Jerry
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will_curry
- Holder of a Golden Anorak

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Re: Big oil leak
I wonder how flat the top of the cylinder block is. You got quite forceful freeing off those seized pistons.
The rocker box drains down onto the cam followers and cam through the head gaskets and there can
be quite a lot of oil especially if a morgo pump has been fitted. Is there any sign of the cylinders blowing?
The rocker box drains down onto the cam followers and cam through the head gaskets and there can
be quite a lot of oil especially if a morgo pump has been fitted. Is there any sign of the cylinders blowing?
- simon.holyfield
- Holder of a Platinum Anorak

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Re: Big oil leak
Check your rocker oil lines too - I went down a bit of a rabbit hole with a top end oil leak and eventually found two things - one, that the feed into the front of the rocker box needs a copper sealing washer (it cooks fibre washers) and two, that I had a very poor joint on one of the unions.
So bad that there was oil all over the steering damper!
So bad that there was oil all over the steering damper!
cheers
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
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jehagadone
- Posts: 42
- Joined: Wed Aug 17, 2022 12:54 pm
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Re: Big oil leak
That is fantastic memory.I wonder how flat the top of the cylinder block is. You got quite forceful freeing off those seized pistons.
The pistons were moderatley stuck, not to bad, came out easy with the fixture I made.
I check head and cylinder both were flat.
Using original two piston pump.The rocker box drains down onto the cam followers and cam through the head gaskets and there can
be quite a lot of oil especially if a morgo pump has been fitted.
Head gaskets are ok, checked nuts, all were tight.Is there any sign of the cylinders blowing?
To much oil even if gasket failed.
Head oil line fitting is dry.Check your rocker oil lines too - I went down a bit of a rabbit hole with a top end oil leak and eventually found two things - one, that the feed into the front of the rocker box needs a copper sealing washer (it cooks fibre washers) and two, that I had a very poor joint on one of the unions.
This is a Jed Clampet leak, Jed move away from here, movie stars, swimming pools (american comedy)
Thanks for the replies, I appreciate the help.
I've seen a lot of strange things in this life.

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will_curry
- Holder of a Golden Anorak

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Re: Big oil leak
That is some oil leak - impressed.
For what it's worth Jed and family made it to the UK. One of my fellow instructors was nicknamed Jed.
He was tall, came from wildest Bedfordshire but didn't have the money.
One problem I had with my Mk1 was that the studs on the cylinder head fouled the 3rd fin on the cylinder
before the head had settled as too much had been machined off the cylinder over the years. The nuts
seemed tight and they were but they weren't pulling the head down properly.
For what it's worth Jed and family made it to the UK. One of my fellow instructors was nicknamed Jed.
He was tall, came from wildest Bedfordshire but didn't have the money.
One problem I had with my Mk1 was that the studs on the cylinder head fouled the 3rd fin on the cylinder
before the head had settled as too much had been machined off the cylinder over the years. The nuts
seemed tight and they were but they weren't pulling the head down properly.
- simon.holyfield
- Holder of a Platinum Anorak

- Posts: 5162
- Joined: Mon Oct 17, 2011 11:16 pm
- Location: Norfolk
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Re: Big oil leak
Does the compression measure up ok?
cheers
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
- Bob.Murphy
- Holder of a Golden Anorak

- Posts: 1211
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Re: Big oil leak
Check the oil pressure gauge in the tank - is the oil union leaking ??
Bob.
Bob.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH
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jehagadone
- Posts: 42
- Joined: Wed Aug 17, 2022 12:54 pm
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Re: Big oil leak
Very rare name in usa, never met any Jed.For what it's worth Jed and family made it to the UK. One of my fellow instructors was nicknamed Jed.
He was tall, came from wildest Bedfordshire but didn't have the money.
All cylinders 90 psiDoes the compression measure up ok?
Oil gauge was reading 10 psi, have not verified gauge is accurate.Check the oil pressure gauge in the tank - is the oil union leaking ??
External oil line and fittings on head are dry.
- simon.holyfield
- Holder of a Platinum Anorak

- Posts: 5162
- Joined: Mon Oct 17, 2011 11:16 pm
- Location: Norfolk
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Re: Big oil leak
That 10 psi is with the engine hot? Cold? Idling?
My MK1 runs 70 psi on cold idle, about 25 when hot. If you're seeing 10, thats suspicious to me.
My MK1 runs 70 psi on cold idle, about 25 when hot. If you're seeing 10, thats suspicious to me.
cheers
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
Simes
Machine Registrar (registrar@arielownersmcc.com)
'51 Square Four,
'58 Huntmaster,
'42 W/NG,
'30 Model A
https://ariel-square-four.blogspot.com
Re: Big oil leak
I think this is going to be technical - moved!
SG
SG
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