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 Posted: May 10, 2021 06:22AM
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CA
Quote:
Originally Posted by vr0000m
Before you go too far, what are the symptoms? Does it lack power? Does it smoke out the exhaust pipe? Is it fouling the spark plugs?
Other symptoms?
Compression tests can be misleading if not done properly!
You say you have a 1275 engine. Is it a high compression engine or a conventional engine? Give us the engine serial number if you aren't sure/don't know. Also pictures of it to verify if it is an A-series or an A+ series engine.

Answer vrOOOm's questions about smoke and power. If the car is new to you you probably won't have a feel for if it is producing the power it is supposed to.
You say it "stinks like blown rings". Where do you smell it? Tail pipe or engine bay? Do you mean it smells like it is burning oil and has blue smoke?

With the engine warmed up and running, remove the oil filler cap and see if there is noticeable air flow out the top. If you put your hand over it, does the pressure build at all? That is the most obvious indication blow-by due to worn/broken rings or valve seals. If it were really bad, you'd likely see various gaskets leaking oil.

Redo the compression test according to the suggestions given.
Use a de-carbon treatment to try and clean up inside the engine.
Drain the tank and put fresh fuel in it. If it IS a high compression engine, it will need high octane fuel.

The car may have been sitting for a long time and may have had oil or some other treatment squirted into the cylinders to prevent rust. If it was oil, it would take a little while to clear out.





.

"Hang on a minute lads....I've got a great idea."

 Posted: May 10, 2021 05:40AM
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Before you go too far, what are the symptoms? Does it lack power? Does it smoke out the exhaust pipe? Is it fouling the spark plugs?
Other symptoms?
Compression tests can be misleading if not done properly!

 Posted: May 9, 2021 07:39AM
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And go get a copy of the factory manual!!!! It will give you step by step instructions on how to remove and tear down the engine/gearbox. It's not necessarily an easy job, but it is pretty straight forward. Just follow the instructions and remember, "Reassembly is the reverse of removal"... mostly.

'72 Morris Mini - 1310cc, K1100 head conversion

 

 

 

 Posted: May 7, 2021 06:36PM
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This is nice feedback.  Thanks.   Let me get some pics of valves and plugs and post them before i pull out the  engine hoist.

----- 
Before you ask, yes I decided to own a 1275 
1980-Something Roofless Mini Shortie in Texas
 Posted: May 7, 2021 03:00PM
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You are in for a HUGE can-o-worms. Hope you like the taste of dirt if you decide to proceed.

93psi is not a bad reading in my book. There are a lot of things that could impact your reading including battery health, starter health, is the dashpot on the carb closed down? Throttle plate? Is your gauge really that accurate to use is as a absolute reading?

I typically only use/trust a compression tester to help me determine if the cylinders are withing 15% or so of one another. If one is low, the absolute FIRST thing I would suspect is a bad valve. A classic mini is not some modern FI car so you're going to be getting lots and LOTS of deposits on your valves. Most heads from the factory are at BEST "flame hardened" seats. But my experience is that the actual valves get pitted.

The min engine is, for all intents and purposes, a utilitarian tractor motor. Cast iron cylinder bores wear oval, and get tapered at an alarming rate. just re-ringing an old motor is not exactly something I would recommend unless you measure the bore and it comes out pretty dang round and cylindrical top to bottom.

A leakdown test or even just shooting compressed air into your plug holes while the cyl is at TDC will tell you where the compression is leaking from: my guess is it's the valves and you'll hear most of the hissing from the exhaust/intake manifolds and not from the dipstick. if you REALLY want to dig into it, pull the head first and do a complete valve job including new guides. If after you do that you don't get the numbers you want, go ahead and tear it all down and have fun beating your head against the internet getting conflicting but well-meaning advice from all of us yahoos. The head work won't be wasted-- just the head gasket will be, and even then if you REALLY wanted to go cheap, some copper spray might allow you to reuse it.

 Posted: May 7, 2021 02:28PM
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US
If you're getting 93psi on a compression test across all cylinders then you problem likely isn't rings. I would think something more like valves or oil not draining back into the crankcase from the head and swamping the valves. What do your spark plugs look like?

Kelley

"If you can afford the car, you can afford the manual..."

 Posted: May 7, 2021 12:51PM
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I just got a 1275 classic.  Love it but after a little bit of diagnosis it appears that the cylinder pressure is 93psi.  Stinks like blown rings.  I know which end of a hammer to hit a nail with but I am no mechanic, if you get the idea.

Am I setting my self up for a nightmare to pull the engine and try and replace the rings?  Is this a nightmare in the making?

Any advice before I get started?

I am nervous as hell about screwing this up and never getting the thing put back together again,

----- 
Before you ask, yes I decided to own a 1275 
1980-Something Roofless Mini Shortie in Texas