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New rebuilt engine-burning oil after 700 miles??
- Thread starter dndkk
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RomanH
Jedi Knight
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Re: New rebuilt engine-burning oil after 700 miles
It seems to me that these engines were designed to consume a bit of oil. That being said, I think you are right that 1/2 liter over 700 miles is somewhat excessive and it should not puff visible smoke on start up.
When the engine was rebuilt do you know if the valve guides were replaced or were they simply knurled to remove the play in the valves?
If the guides were knurled, I would say that that is the cause of the oil consumption.
I recently spoke to an engine rebuilder with over 40 years of experience working on British engines and he informed me that it is not acceptable at any time to knurl the valve guides. Since our engines do not have valve stem seals the valve and guide must fit tight according to the factory specifications. When a guide is knurled it opens the top up like a funnel, which allows more oil to collect at the valve stem and this oil then runs into the combustion chamber and is burned. If you are using an auxiliary upper cylinder oil feed line, remove it. This too leads to more oil usage if the valve guides are suspect.
It seems to me that these engines were designed to consume a bit of oil. That being said, I think you are right that 1/2 liter over 700 miles is somewhat excessive and it should not puff visible smoke on start up.
When the engine was rebuilt do you know if the valve guides were replaced or were they simply knurled to remove the play in the valves?
If the guides were knurled, I would say that that is the cause of the oil consumption.
I recently spoke to an engine rebuilder with over 40 years of experience working on British engines and he informed me that it is not acceptable at any time to knurl the valve guides. Since our engines do not have valve stem seals the valve and guide must fit tight according to the factory specifications. When a guide is knurled it opens the top up like a funnel, which allows more oil to collect at the valve stem and this oil then runs into the combustion chamber and is burned. If you are using an auxiliary upper cylinder oil feed line, remove it. This too leads to more oil usage if the valve guides are suspect.
Bruno_69z28
Senior Member
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1/2 qt. in 700 miles is not bad. Give it some more time for the rings to seat. You could also be burning oil from crankcase preasure in the motor. This could cause oil to be pushed out the rear oil seal and down the valve guides. Check your motors emission systems. Is the smoke blue or black?
Bill
Bill
Re: New rebuilt engine-burning oil after 700 miles
Thanks Folks for your responses... I am feeling a great deal better this morning after reading them..It seemed excessive oil usage to me however perhaps it needs to work it's way in.. (I have a ford with 186k that uses burns no oil at all) As for the heads, they were done but I have no idea if they were knurled but I will endeavor to find out. The smoke was blue however this morning it didn't smoke?? perhaps it was a one hit issue..
Thanks once again for your responses.....................what a great forum..
Thanks Folks for your responses... I am feeling a great deal better this morning after reading them..It seemed excessive oil usage to me however perhaps it needs to work it's way in.. (I have a ford with 186k that uses burns no oil at all) As for the heads, they were done but I have no idea if they were knurled but I will endeavor to find out. The smoke was blue however this morning it didn't smoke?? perhaps it was a one hit issue..
Thanks once again for your responses.....................what a great forum..
Re: New rebuilt engine-burning oil after 700 miles
I just went through a similar occurence last summer and this spring. After having my engine re-built it would smoke on start-up until the engine warmed up, then would go away. Called the machine shop and asked them if they thought the rings hadn't seated yet and they assured me after 1700 miles they had and the cause was more likely due to the PVC valve drawing oil from the valve cover. I should say I have Richard Good's triple carb manifold with the PVC bung behind the second carb. Lately, since the weather has warmed up it hasn't smoked at all. Oil consumption has been negligible- no oil added after 1700 miles, although I did notice after spending this past weekend under the car the front main seal is leaking a little and it's down maybe a 1/4 quart.
** Faulty memory. I just remembered an oil change in November, only about 900 miles ago. My bad.
I just went through a similar occurence last summer and this spring. After having my engine re-built it would smoke on start-up until the engine warmed up, then would go away. Called the machine shop and asked them if they thought the rings hadn't seated yet and they assured me after 1700 miles they had and the cause was more likely due to the PVC valve drawing oil from the valve cover. I should say I have Richard Good's triple carb manifold with the PVC bung behind the second carb. Lately, since the weather has warmed up it hasn't smoked at all. Oil consumption has been negligible- no oil added after 1700 miles, although I did notice after spending this past weekend under the car the front main seal is leaking a little and it's down maybe a 1/4 quart.
** Faulty memory. I just remembered an oil change in November, only about 900 miles ago. My bad.