OIl for LT1 ?

Messages
238
Location
Girard, Ill
Just purchased a 72 vette equiped with a LT1 engine. Vette has 85,000 miles on it using dino oil. Can I safely switch to Syn or should I stay with dino? Any other suggestions would be appreciated! Thanks!
 

Al

Messages
19,152
Location
Elizabethtown, Pa
Well-I think you need to be careful here. Early 70's seals could possibly leak with PAO/Esters. I probably would not risk it and would opt for The GTX or one of the other well regarded dino oils like Motorcraft, Chevron, Pennzoil, or Schaeffer's. On the other hand leaking rear main seals was a fact of life for chevy engines [Big Grin]
 
Messages
2,556
Location
Columbus Ohio
I have no experience with the LT-1, but I have had a few LM-1 engines, and have experienced no ill effects from switching to a synthetic. You may want to consider an auto-rx treatment first (seal conditioning), or even a neutra purge (IIRC, bob did a test which showed that neutra causes seals to swell slightly). You may even want to use a HM oil that uses esters, to swell the seals slightly.
 
Messages
5,358
Location
Gone
yankees1, Normally, I encourage people to try out synthetics, even on higher mileage autos, but given the vintage of your Vette I would approach with caution. My concern is your seals. What you could do, if your car is not a "leaker" or a "burner," is run a test interval on synthetic--I wouldn't go anything less than a 10W30--and see what happens. I don't think you will "hurt" anything...you might just end up draining it quicker than the cost of the synthetic justified if you don't like the results...but if it does work, you're set I think your best course is to watch this thread for a while and hopefully our "seal experts" will clarify whether seal material in '72 was such that you could have a problem with synthetics. Then you could make a solidly informed decision. [ August 14, 2003, 06:50 PM: Message edited by: pscholte ]
 
Messages
1,203
Location
Oregon
quote:
Originally posted by yankees1: Just purchased a 72 vette equiped with a LT1 engine. Vette has 85,000 miles on it using dino oil. Can I safely switch to Syn or should I stay with dino? Any other suggestions would be appreciated! Thanks!
I have a 1970 LT 1 crate motor in a 68 Z 28. and have 2 more LT 1s in the garage. I would just use a dino oil in it. If the seals are old some stythetics might leak more. As you might know these motors have forged pistons in them. So keep the revs down when the motor is cold. For many years I used a 20w 50 in mine. Alot of people ran straight 30wt in these back in the 70s. Anymore I use a 15w 40 diesel motor oil (Delo 400) in it. I don't know how rich yours runs but these motors do get some fuel in the oil. So change the oil every 1500 - 2000 miles or once a year what ever comes 1st.
 
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