Still Burning Oil? What Type of Oil to Use?

[Webb]

I rebuilt the engine in my TR6 a year ago, and have put like 8000 miles on it since, then, but it's still burning oil. It got several new valves, new valve guides all around, new valve seats, bored .030 over with new pistons and rings, and yet it's still burning a large amount of oil. I've had 10W-30 Castrol non-synthetic in it, but when it burns oil I've been refilling it with Castrol 20W-50 non-synthetic. When I was running straight 20W-50, it burned less oil, but it still burned it. Anyone know the reason for this, or a blend of oil that I could use that might help cut down on consumption?

Thanks.

 

[jsneddon]

Welcome to the forum /ubbthreads/images/graemlins/savewave.gif

Burning or using?

does a blue cloud of smoke follow you around?

How much is the consumption? How many miles to a quart?

What do your spark plugs look like?

 

[Don Elliott]

I rebuilt the engine in my TR3A during my restoration from 1987 to 1990. Right after I was getting 600 miles to a quart of Castrol 10W30. It did this for 45,000 miles so I took out the crankshaft and had it reground for the new rear bearing modification kit. Since then, I have used 20W50 Castrol. With the new seal during the next 44,000 miles, I have had to add a quart every 600 miles. Now go figure.

I just drove to TRA in Ohio and back (2165 miles) with 89,000 miles on the rings etc. and had to add 3.3 quarts. That's 655 miles to the quart of oil. BTW, I got 28 miles per US gallon with overdrive and the power and compression are fine. The oil is not burning and I've tried all the other reasons to prevent leaks.

https://www.britishcarforum.com/ubbthreads/photopost/showphoto.php/photo/1919/ppuser/4127

 

[vettedog72]

Is that amount of oil consumption the norm for a TR3A?

My TR6 did not use much between 3000 mile oil changes (Castrol 20-50w), maybe a half to full qt. I do not run it hard, seldom over 4k RPM.

 

[Geo Hahn]

If it's clouds of blue smoke I would wonder if your rings have seated properly since the rebuild.

If it's just adding oil between changes (like Don) then it may be a mystery you can live with.

I use Castrol 20W50 and add only modest amounts between changes. Fortunately, the price of oil hasn't seemed to increased like gas... Castrol is a buck a quart this week at Checker/Kragen/Schucks.

A question for TR3/4 owners... do you top the oil up to the 'fill' line? I have heard that the reason for the big spread between 'add' & 'full' (about 2 quarts) was because they moved the 'full' mark up at the request of American distributors and that halfway is the better oil level to use for these engines? The explanation sounds like a myth but my TR4 does seem to throw some oil until it gets down to the halfway point.

 

[Bruno_69z28]

My old TR4 motor was the same. It would use oil until it was half way down between the lines (in aprox. 500mi.). As long as I kept it full it would use it. If I left it between the lines, I would only have to add a qt. in 1500 mi.. The motor had the breather pipe. I now have the PCV system on my rebuilt motor. I want to see if it improves the oil consumption.

Bill

 

[ALLAN]

Hi Webb, Like Geo said It sounds like some of your rings havent seated in. Pull your sprark plugs and check them to see which ones have been burning oil. You also need to run a compression check,--- between the spark plugs and any cylinders with a lower compression-that will tell you which ones havent seated in and/or possibly have broken rings or rings not installed the right way or cylinders not bored or honed right and possibly having too much clearence between piston and cylinder.

 

[Webb]

Just so everyone knows, it's been a while since I've posted, but I'm actually not new to the forum. I've been registered for a year or so now, I just kept forgetting my login name because it was something wierd, so I remade my account.

I have noticed that it uses far less oil once I let it run down on the stick some; about halfway as some of the TR4 guys mentioned, but to keep it topped up at the full line requires me to add quite a bit of oil. To give you an idea, I drove to Lynchburg, VA from my house (about 120 miles round trip) and back averaging about 70mph (3500-4000revs the whole way down), and I had to add slightly more than a quart to keep it topped up.

I added a new rubber ring around the dipstick because it was leaking oil, so I'm wondering if that's making it sit up higher, making the full line higher, and consequently fooling me into filling it up to high and then the engine is just burning it off.

I need to let a friend drive my car for a bit so I can actually see what it looks like. I've been told there is a blue cloud when I shift at high revs, but I'm suspecting there is very little coming out under normal driving conditions, as my friend who watched the back of my car didn't comment on any smoke under normal driving conditions.

 

[Alan_Myers]

Hi Webb,

The rings in your rebuilt engine should have seated themselves many, many miles ago. However, I gotta ask, you didn't happen to use synthetic oil in there during the breakin period (first 5000-6000 mi.) did you? That could definitely lead to glazing on the cylinder walls that will keep the rings from ever properly seating.

Frankly I'm not a fan of synthetic oils in these older engines, especially as often as we change oil in our "babies". Even once the engine is broken in, it will tend to sneak past seals and rings a lot easier than mineral based oils will. Many synthetics also have tons of detergents in them (the high or extended mileage oils especially). IMHO that can also cause problems.

Keep us posted what you find.

/ubbthreads/images/graemlins/cheers.gif

 

[Webb]

No, I didn't use synthetic and still don't for the reasons you mentioned. I was quite careful during the break in period to make sure it was done by the book. I don't have a compression tester, and I happen to be broke right now, so it looks like I'll have to wait a bit before I can get a gauge or something to test it with. It runs good and doesn't miss at idle, so I'm assuming it's a healthy engine, but who knows.

It burns the most oil when I get hard on the throttle up past 3500 and especially into 4000 rpms, there's definitly a cloud behind the car that I can even see in the rear view mirror, but if I ease it up to that speed, like on the interstate, it's not noticable, at least not from my vantage point.

 

[ALLAN]

Have you checked each spark plug yet? and also the compression, this could tell you alot

 

[Kurtis]

[ QUOTE ]
It burns the most oil when I get hard on the throttle up past 3500 and especially into 4000 rpms, there's definitly a cloud behind the car that I can even see in the rear view mirror, but if I ease it up to that speed, like on the interstate, it's not noticable, at least not from my vantage point.

[/ QUOTE ]

That sounds like a ring problem to me. You can probably borrow a compression tester from one of the chain parts stores. I know AutoZone has a "lend-a-tool" program. As others have suggested, a compression test is definitely in order at this point.

 

[Geo Hahn]

[ QUOTE ]
Just so everyone knows, it's been a while since I've posted, but I'm actually not new to the forum. I've been registered for a year or so now, I just kept forgetting my login name because it was something wierd, so I remade my account...

[/ QUOTE ]

So then you're really 'Webb Sledge'? Welcome back!

https://www.britishcarforum.com/ubbthread...hat=showmembers

I expect Basil could regain your access to your old identity if you ask him.

 

[MDCanaday]

My input is valve guides, under high vacumn conditions oil goes past the intakes. Knurling the guides can make this a lot better, as can retro fitted seals(easier)Mostly if you dont build-up carbon(on the valves)too much, its just a matter of adding oil...
MD(mad dog)

 

[vettedog72]

To do that much work and get that kind of results is very disappointing. I suggest you determine if the problem is in the head or the block. If you don't know how, there are plenty of people that can guide you through pin pointing the problem. One qt of oil per/tank of gas is pure s… to me; especially since all the work. Find out where the problem is. If it is head related, it can be fixed over a weekend. If it is ring related it would take two weekends. What brand pistons did you install?

 

[Webb]

I'm not sure. The mechanic who was helping me with the rebuilding process ordered them, and I assume they were from Moss or Vicky Brit. That's where 90% of our parts came from.

 

[Webb]

[ QUOTE ]
My input is valve guides, under high vacumn conditions oil goes past the intakes. Knurling the guides can make this a lot better, as can retro fitted seals(easier)Mostly if you dont build-up carbon(on the valves)too much, its just a matter of adding oil...
MD(mad dog)

[/ QUOTE ]

MD, can you tell me a little bit more about what you mean by retrofitting seals and knurling the guides? There's a CarQuest near me that could probably do it for me if I took them the head.

 

[Bruno_69z28]

Webb,
With all the work you’ve done to the motor I doubt knurling the guides will help. You said you replaced the guilds, so they don’t need knurling. Seals help with oil consumption, but even without seals you should not be using this much oil. When you’re on the pedal, you increase crankcase pressure, which forces oil past seals, rings and guides. When the motor is running, remove the oil filler cap as see if there is a vacuum or if there is a lot of pressure escaping. This might be a simple emissions control problem or a major rebuild problem.

Bill

 

[Guest]

Webb, from the description of smoking when you get on the throttle, this sounds a lot like the issue I had with my 54000 mile TR6 engine before it went off to be rebuilt.

In my case it was the valve guides. Are you sure they weren't over-reamed? A compression tester is about $20 from Sears btw. You won't be able to do a leakdown test, but it's a for sure a start.

 

[vettedog72]

Webb:
Retrofit valve seals mean remove and dissemble the head. The area where the valve guide protrudes from the head is machined to allow a piece of round synthetic material to be fitted and retained in the machined area. When the head is reassembled, the valve stem goes through the center of the seal. It reduces the amount of oil that is allowed to slide down (or be sucked down) the valve steam between the guides and eventually into the combustion chamber.

I would not allow a machinist experiment with the head. If you just have to have them get a machinist that has successfully installed valve steam seals in the TR6 head.

Having said all of that, my machinist advised me that he takes about as many retro fitted seals off as he installs (they can come loose, not allow enough oil to get through and other problems). The TR6 is mint to have a bit of oil running down between the guides and valve steams as most all cars of older vintage. The shape of the guide top (the top of the guide as you can see it with the rocker removed) is important when oil consumption is concerned. It may be something to consider.

If you can eliminate the PCV as a problem and you can test the motor to see if the rings are leaking with out super efforts. The general test of the valve guides allowing too much oil to get by is to "back the motor down" to near idle and when you take back off a great cloud will come out of the exhaust. It is not awful if a little puff appears, as that is the nature of the valve/guide setup.