No compression #1

DAS · Nov 4, 2014

I recently discovered this forum and I could have saved a lot of time through the years with what I have found available here. I always seem to go a "bridge to far" so I will lay out what I have and what I plan for next.
1948 8n smokes a bit and misses and is low on power. I'ts been that way for a while but I use it a few hours a year and have gotten by. Good spark. Compression on #1 is 0. Tablespoon full of oil into cylinder. Still 0 compression. Mini-cam through plug hole shows piston top okay.
This is where the leap starts. Ask old hokie if sleeve kit I purchased years ago for a 9n will work on a 8. Order parts before I know if the sleeves are steel or cast...........STOP!
Cylinder #2 60lbs.
Instead I plan to remove manifold and check on valve movement even if I don't know what to look for. Any redirection for a missed step will be greatly appreciated

souNdguy · Nov 4, 2014

no way i'd order parts before knowing what liners it has. hek. someone may have knocked liners out and be running merc os pistons bare.

as for removing manifold. um.. ok. I think I'd opt for removing a valve cover. while not common, it's also not RARE for a valve to stick open...

that's my advice. IMHO.. it's the fastest / cheapest / least invasive route, and the least likely to run into problems ( like breaking a stud off etc... )

DAS · Nov 4, 2014

[See what I meant about a leap. I was removing the manifold to get at the valve cover side plate. It still looks like I may need to. Am I wrong?

mhb@ufe · Nov 4, 2014

(quoted from post at 15:48:35 11/04/14) [See what I meant about a leap. I was removing the manifold to get at the valve cover side plate. It still looks like I may need to. Am I wrong?

There is no need to remove the manifold but removing the carb is helpful.

Mark

souNdguy · Nov 4, 2014

you can remove the valve covers with the carb and manifold in place. tight fit.. but doable, unless you are 8' tall and your hands are the size of dinner plates.

Graham of New Zealand · Nov 4, 2014

Check the simple cheap things first. Could be simply
no tappet clearance holding a valve open. Might be
burnt out valve

Dell (WA) · Nov 4, 2014

DAS.........FYI, the "spec's" of the N-Engine is 90psi (min). A NEW rebuild N-Engine will test out at about 125psi. Generally, stuck valve will cause a "whoosh" in either intake or exhaust depending on cause.

As fer oiling fer compression test, recommend you use ATF 'stedda engine oil. ATF is HIGH detergent and will "un-stick" stuck rings and valves.

Me? I'd do several days of AFT treatment before I turned a wench. Just 1-oz of ATF down each sparkie hole every day. I have a "squirt'em" oil can that I use 'cuz the spout reaches under the gastank. .......squirty Dell

dakota dave · Nov 4, 2014

Check for a stuck valve. You can take the valve side covers off
without removing anything else. I did a coworkers 9 n last year
no compression on a cylinder. Valve was stuck. Sprayed it
down with deep creep and lightly taped the valve stem with a
brass punch and light hammer. Turned it over several times
spraying deep creep on all the valve stems. Put the plate back
on and ran it for an hour. It's been working great for a year
now. If it won't free up your only out a little time you can still
take it apart. It common for a valve to get gummed up and
stick on an engine that sits a lot.

DAS · Nov 4, 2014

This is why I appreciate the help and information. I really would not have had time to do much until spring. Now this is something I can try now. It fits in better with more of the symptoms I see but really couldn't explain.(I was so looking forward to an in-frame OH) The oil thing was something I learned from my dad to seal around the piston to see if it affected compression. He was born in the 19th century. Now a question about the ATF. Do you soak it and add more or add and run it every day.
MY plan now is to go with the ATF and monitor changes in compression. I'll keep you informed how it works.
Thanks again

Dell (WA) · Nov 5, 2014

DAS........generally, the ATF will drain down the cylinder walls into the engine oil. Remember yer only puttin' about 4-oz of ATF into 6-qts of 30wt engine oil.

Remember, when taking compression readings ittza 5-rummpa thing. At least 5 strokes of the piston, which is 10-strokes of the crankshaft. Gotta have BOTH valves CLOSED to measure compression. ........Dell, bored outta my gourd with election coverage

No compression #1

DAS

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souNdguy

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DAS

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mhb@ufe

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souNdguy

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Graham of New Zealand

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Dell (WA)

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dakota dave

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DAS

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Dell (WA)

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