Date: Fri, 5 May 2017 12:32:50 -0400
Reply-To: David Bohannan <fjazzbass@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Bohannan <fjazzbass@GMAIL.COM>
Subject: Re: 2.1 wbx Compression Test
In-Reply-To: <CAB2RwfjZfFUd-GumVamKg2YjeT+6KLz9Fe3+pWTK_Uqi_v_S6A@mail.gmail.com>
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I failed to mention removing the rocker arms... this gave me a pretty good picture of what I had going on... I agree that leakdown would be a good idea- I pretty much knew it was time...
Dave
> On May 5, 2017, at 12:10 PM, Neil N <musomuso@GMAIL.COM> wrote:
>
> Thanks Dennis.
>
> The Gowesty vacuum type throttle switch was disconnected because the
> wires were slightly in the way of the AFM-filter housing. In
> hindsight, a hasty thing to do. The ignition coil lead was
> disconnected from coil, throttle body valve held open during test.
>
> It's occurred to me that the lifters may be at play here. The engine
> sat for some time unused. I ran it before the compression test, heard
> zero lifter noise so I assumed the lifters were fully pumped up. If I
> recall, it took several cycles of the starter motor to bring each
> cylinder up to its' maximum pressure.
>
> Looking at my notes, when purchased, this is what the mechanics test
> showed for engine compression:
>
> 130 120
> 140 140
>
> I had wondered about doing a leak down test. An air compressor
> purchase may be in my future!
>
> Neil.
>
>> On 5/5/17, Dennis Haynes <d23haynes57@hotmail.com> wrote:
>> A compression test is not complete without also doing a leak down test.
>> Also, when doing a compression test you want to disable the fuel pump and
>> ignition coil or at least center the center coil wire to ground. Throttle
>> should be held open. What did you expect to accomplish by disconnecting the
>> throttle switch?
>>
>> As an extension of a leak down test when you get a cylinder with a low
>> reading you can bypass the gauge set and put full available air pressure in
>> the cylinder. Be sure the crankshaft is secured for this. For the ultimate
>> extension of this test you can remove the rocker arms so you can test the
>> piston-rings at both the top and bottom of the cylinder. During these tests
>> remove the pressure cap and have the coolant topped off all the way to the
>> brim. Major internal leaks will quickly be obvious with the coolant pushing
>> up or bubbling. Very small leaks or leaks that open under heat or pressure
>> may still hide.
>>
>> I discovered this anomaly on Fun Bus around 200K. I have also seen it on
>> other engines. Since Fun Bus does not have any coolant issues and the leak
>> down test is good I am still driving it and it is now over 313K
>>
>> Dennis
>>
>>
> --
> Neil n
>
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>
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>
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>
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