[Healeys] Four cylinder woes, part two!

Bob Haskell rchaskell at earthlink.net
Thu Mar 12 17:41:41 MDT 2020


Steve,

When you have the lifters out, have a look at the cam lobes.

Low compress test means low combustion pressure which means high stress 
on the crankshaft?  I don't know; just asking if someone does.

Shipwright's disease is just around the corner. :)

Cheers,

Bob Haskell
Austin Healey 3000 BN7/BT7 registrar

On 3/12/20 7:29 PM, Steven Kingsbury via Healeys wrote:
> Latest update, took the head to a friend's machine shop and took the 
> valves out. All the intake vales had build up of soft carbon, a sign of 
> burning oil I was told and I'm going to have to also pull the pistons to 
> redo the rings. Fun, but I'm here, so why not? I'm also going to get new 
> valve guides pressed in and replace the ones in the head as the valves 
> seem to rock a bit going up and down. The head though is not warped and 
> is straight, but I will get it checked out for cracks and resurface the 
> head to make it super smooth.
>     I'm also going to drop the pan, and push the pistons out of the 
> block and replace the rings. And yes, I will plastiguage the crank to 
> make sure it's in good shape and install new rod bearings when in there.
>     I am also going to remove the tappet cover and take a good, hard, 
> close up look at all the lifters to make sure that's not a problem. 
> Right now, in for a penny, in for a pound. Sterling that is.
>     Basically, I'm making sure everything is correct this time and then 
> I will have no one but me to blame if it doesn't work. But all in all, 
> it seems pretty simple. So stay tuned for further updates as they happen.
>     Thanks for all the input, suggestions and guesses. This is actually 
> quite the fun project.
> Steven Kingsbury
> 
> On March 12, 2020 at 12:38 PM, John Harper <ah100register at gmail.com> wrote:
> 
>> Hank
>>
>> The fact that number 2 exhaust valve is not the same colour as the 
>> others might be a clue. Maybe it is not closing fully? It would be 
>> worth checking for a stuck valve guide, broken spring or just lost  
>> clearance. A partially seized rocker is possible but not likely. This 
>> may not be the problem but it would not take much effort to pull the 
>> valve out and check for any burning on the working face.
>>
>> Best regards
>>
>> On Thu, 12 Mar 2020 at 18:18, <gradea1 at charter.net 
>> <mailto:gradea1 at charter.net>> wrote:
>>
>>     Hi Steven-good to hear from you!
>>
>>     That's a nice test, but I would magnaflux the head for cracks
>>     between 2-3 and have it shaved flat..could be a head gasket leak
>>     due to warped head...especially if valves and rings checked good.
>>
>>     Also, I don't recommend  NGK plugs- use Champion N-5...maybe cause
>>     of carbon on valves. Unless cam is flat, valve spring broken or
>>     tappet rods bent/broken, problem is in head-block fit.
>>
>>     Regards, Hank Leach
>>
>>
>>     -----------------------------------------
>>
>>     From: "Steven Kingsbury via Healeys" __
>>     To: healeys at autox.teamnet <mailto:healeys at autox.teamnet>
>>     Cc:
>>     Sent: Thursday March 12 2020 9:40:25AM
>>     Subject: [Healeys] Four cylinder woes, part two!
>>
>>     Okay, here's the latest! I finally got to pull my head If you
>>     remember, I had 155 lbs of pressure in cylinders 1, 3, and 4 and
>>     only 25 lbs in cylinder number two. So with the head off, I was
>>     prepared to find a problem with I flipped it over to expose the
>>     valves, no such luck. Other than number two exhaust valve being a
>>     bit black, no cracks, nothing stuck and it looked fine. So then I
>>     went to look into the cylinders themselves, walls smooth, flat
>>     high compression pistons smooth, number three a bit rough on the
>>     top, but other than that and good.
>>        So then I went back to the head, put the spark plugs back in
>>     and filled the combustion chambers with paint thinner to see where
>>     it would leak out. Filled each chamber evenly and waited. Twelve
>>     hours later, and other than evaporation, no leaks! All chambers
>>     still even in their fluid retention.
>>        So then I rotated the crank to get all the pistons to an almost
>>     even position and put paint thinner in the cylinders at the same
>>     depth. No quick leak, not one cylinder faster than the others and
>>     all the fluid finally drained out smoothly and evenly in each
>>     cylinder.
>>        I'm a bit stumped. My next step is taking the head to a guy in
>>     town, an old machinist who builds his own engines and runs his car
>>     at Bonneville in the 300 mph range. He knows what he's doing and
>>     I'm sure he will give me some sage advice and help. Also as a side
>>     note, I went over the head with a magnifying glass and can see now
>>     cracks, but that doesn't mean they are not there I know. I was
>>     just thinking with a 100 pound plus difference, something would be
>>     obvious.
>>        I am also going to be taking off the tappet cover on the side,
>>     inspect all the lifters and see what I can find there. Like I
>>     said, I'm a bit perplexed, but I'm not done. I will find something
>>     wrong! Here are some photos for you, maybe you can see something I
>>     can't.
>>
>>     IMG_20200311_143602.jpg
>>     Here's the head, upside down and you can see the exhaust valve on
>>     number two is blacker than the others, but no cracks, chips, or
>>     visible damage.
>>     IMG_20200311_172123.jpg
>>     And here's the fluid I placed in the combustion chambers. It
>>     didn't drain out and just sat there.
>>     __
>>
>>
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>>
>> -- 
>> Best wishes
>>
>> John Harper
>>
>> AHC UK 100 Register Secretary
> 
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