I have an '87-and-later style (one-piece rear main, center-bolt valve covers) TBI 350 in a mid-80s El Camino. It has a Crane 2032 roller camshaft, nothing radical. I did the conversion from carburetor to TBI myself on the 305 it replaced, using GM Camaro/Firebird components. The engine now has about 50K miles. I typically drive the vehicle once a week, even in winter, and I take care not to short-trip it - I don't drive it if it's not going to stay at operating temperature for at least 10-15 minutes.
It never freezes here, and once a year I take it on a long road trip (about 900 miles) in the middle of August, when it's typically 105 F in the middle of the day. I've been changing the oil and filter approximately once a year. I'm on pace to put 4000-5000 miles on it this year.
My only concern is that after swapping the old worn-out 305 for the 350, a mistake was made - one of the new, larger injectors ended up crooked in the injector pod, and the resulting gasoline leak put a lot of fuel into the crankcase. We recognized the problem (hard to miss - the engine didn't run well) and didn't drive it until that problem was fixed, and immediately changed the oil and filter, because I know gasoline cuts oil. What I've always wondered, though, is how much (if any) damage that event caused.
At 50K miles on the engine, it uses a quart in 1500-2000 miles. Early in the engine's life I used Pennzoil 5W-30, and then I switched to Mobil 1 to try to extend the intervals because I was driving a long way for work every day. Now I typically drive it about 30 miles to work and back one day a week, and on weekends, so it gets 50-100 miles on it a week.
I've been doing oil changes yearly since retiring it to "pleasure" status, and if I remember right, what's in it now is a mix of what I had left of Mobil 1 10W-30, and SuperTech conventional 10W-30. I'm still using my stock of ACDelco PF35 filters, and I change the filter once a year with the oil.
The engine doesn't leak or smoke, and the oil stays clean-looking. It has about 3100 miles on the oil since I changed it last January, it's medium-brown, and I have to turn the dipstick and squint to see where the lighter-colored oil at the top is on the stick (IOW, it's not much darker than fresh out of the bottle). Valve guides tend to be a factor on Chevy small-blocks, but I don't see the puff of blue smoke at start-up that I saw with the worn-out 305, so they may be OK for a while.
My feeling is that with this low mileage, and considering I warm it up to operating temperature every time I drive it, I can probably never benefit from synthetic. I'm hesitant to extend the OCI out more than a year, simply because I'm a little nervous about not being able to get the filter off after a long time! My feeling is to just keep going with either SuperTech or Pennzoil conventional and not worry about it.
This engine has very strong oil pressure, never shows lower than 30 at idle, and about 45-50 at cruise. I see very slightly lower pressure with 5W-30 than 10W-30, and with 5W- the pressure comes down a little quicker as the engine warms up, but someone who is not familiar with the car wouldn't notice it. I don't see any difference in consumption between the two grades.
Is there any compelling reason to use synthetic oil in this application? My inclination is to keep going with whatever recognized brand of conventional oil is on sale, combined with an ACDelco or Fram filter, and keep changing it once a year like I"ve been doing.
It never freezes here, and once a year I take it on a long road trip (about 900 miles) in the middle of August, when it's typically 105 F in the middle of the day. I've been changing the oil and filter approximately once a year. I'm on pace to put 4000-5000 miles on it this year.
My only concern is that after swapping the old worn-out 305 for the 350, a mistake was made - one of the new, larger injectors ended up crooked in the injector pod, and the resulting gasoline leak put a lot of fuel into the crankcase. We recognized the problem (hard to miss - the engine didn't run well) and didn't drive it until that problem was fixed, and immediately changed the oil and filter, because I know gasoline cuts oil. What I've always wondered, though, is how much (if any) damage that event caused.
At 50K miles on the engine, it uses a quart in 1500-2000 miles. Early in the engine's life I used Pennzoil 5W-30, and then I switched to Mobil 1 to try to extend the intervals because I was driving a long way for work every day. Now I typically drive it about 30 miles to work and back one day a week, and on weekends, so it gets 50-100 miles on it a week.
I've been doing oil changes yearly since retiring it to "pleasure" status, and if I remember right, what's in it now is a mix of what I had left of Mobil 1 10W-30, and SuperTech conventional 10W-30. I'm still using my stock of ACDelco PF35 filters, and I change the filter once a year with the oil.
The engine doesn't leak or smoke, and the oil stays clean-looking. It has about 3100 miles on the oil since I changed it last January, it's medium-brown, and I have to turn the dipstick and squint to see where the lighter-colored oil at the top is on the stick (IOW, it's not much darker than fresh out of the bottle). Valve guides tend to be a factor on Chevy small-blocks, but I don't see the puff of blue smoke at start-up that I saw with the worn-out 305, so they may be OK for a while.
My feeling is that with this low mileage, and considering I warm it up to operating temperature every time I drive it, I can probably never benefit from synthetic. I'm hesitant to extend the OCI out more than a year, simply because I'm a little nervous about not being able to get the filter off after a long time! My feeling is to just keep going with either SuperTech or Pennzoil conventional and not worry about it.
This engine has very strong oil pressure, never shows lower than 30 at idle, and about 45-50 at cruise. I see very slightly lower pressure with 5W-30 than 10W-30, and with 5W- the pressure comes down a little quicker as the engine warms up, but someone who is not familiar with the car wouldn't notice it. I don't see any difference in consumption between the two grades.
Is there any compelling reason to use synthetic oil in this application? My inclination is to keep going with whatever recognized brand of conventional oil is on sale, combined with an ACDelco or Fram filter, and keep changing it once a year like I"ve been doing.
