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TR4/4A Oil in Cyl # 1

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spbvmb

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I have a TR4 with 2000 miles on professional rebuild. The engine suddenly started to burn oil with pretty good exhaust cloud. Checked compression which is right where it always is at 175 and matches other cylinders. Plug from #1 is very oily and spinning engine without plug blows oily smoke out plug hole. One would expect the usual valve guide, ring, cracked head, loose wrist pin, etc would compromise the compression. Stuck ring would be best guess. Awaiting suggestions.

Thanks, Phil Brooks
 
Valve guide problems usually don't cause low compression readings. I'd be checking if perhaps your rebuilder used intake guide seals (not original) and one has come loose. Also lose the external rocker feed, if one has been fitted (which would be why the seals were needed).

Everything else I can think of (including a stuck ring) would cause low compression, unless perhaps there was just enough oil in the cylinder to match the (unoiled I assume) results from the other cylinders. Pressurizing the cylinder with air (eg a leakdown test) might tell you more.
 
TR3 Driver. Thanks for your suggestions. The part of the puzzle for me is that this engine has never burned any oil nor any smoke from exhaust. Then from one minute to the next poof, out comes the smoke. Wouldn't a valve guide were slowly. There is plenty of oil on top of head.

Phil
 
It is very easy to overlap the expander on the 3 piece oil rings. The symptoms are as you describe; oil in one (or more) cylinders, little or no effect on compression, smoke from that cylinder. Don't ask how I know.
Tom
 
spbvmb said:
TR3 Driver. Thanks for your suggestions. The part of the puzzle for me is that this engine has never burned any oil nor any smoke from exhaust. Then from one minute to the next poof, out comes the smoke. Wouldn't a valve guide were slowly. There is plenty of oil on top of head.
Click to expand...
Sure, which is why I was suggesting a seal that became dislodged. That can happen from one stroke to the next. BTDT
 
+1 on what Tom said on the oil control ring. One of our club members experienced the same issue.
 
TR4nut said:
+1 on what Tom said on the oil control ring. One of our club members experienced the same issue.
Click to expand...
But did it suddenly start burning oil 2000 miles later? Seems like an incorrectly assembled oil ring would cause problems immediately, rather than after some 50 hours of operation.
 
Actually yes it did - not sure why but perhaps the spring shifted after some use.
 
Is your engine equipped with a PCV valve? If so, you might have a bad diaphragm that's allowing excessive oil into the intake causing what you describe. Check the easy/cheap things first...hope that's it.
Rut
 
TR3driver said:
Valve guide problems usually don't cause low compression readings. I'd be checking if perhaps your rebuilder used intake guide seals (not original) and one has come loose. Also lose the external rocker feed, if one has been fitted (which would be why the seals were needed)
Click to expand...

Can you explain more about why the ERF should be removed?
 
TR3driver said:
Interesting, thanks!
Click to expand...

OK guys I found the problem. My "oil" was a mixture of fuel and antifreeze. Blown head gasket shorted out the plug and made an oily like mixture. No indication of coolant in oil but will change anyway. I learned a lot from all your suggestions.

Thanks for your help,

Phil
 
Phil,
Happy to hear you found a relatively simple issue...much better than the alternatives!
Rut
 
DornTRoriginal said:
Can you explain more about why the ERF should be removed?
Click to expand...
IMO it puts way too much oil on top of the cylinder head. The rocker assembly is not designed for full oil pressure (and doesn't need it under normal conditions). Might not hurt on a fresh motor, but with a bit of wear it will put more oil past the intake stems, and rob oil from the rod & main bearings (that do need it).

Those Standard-Triumph engineers didn't design that clever oil metering mechanism just because they were bored!
 
Rut said:
Phil,
Happy to hear you found a relatively simple issue...much better than the alternatives!
Rut
Click to expand...

Good news as long as you find and fix whatever caused the head gasket failure. Tom
 
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