87 octane bad? and noisy valvetrain?

[romanianfury]

hey guys i have a 94 t/a with about 30k miles on the lt1 motor. i was wondering if it is bad or harmful to the engine to use 87 octane gas? also, i switched from conventional oil to a castrol full synthetic. could this cause my valvetrain to get noisier and about how often should i change the oil with it ( i have heard some say 3k and others 5k-7500miles) i baby this thing by the way and almost never give it more than 50% throttle

[warnerTA]

you never give it more than 50% throttle? why not buy a v6 then? lol....

i would at least run 89... and i change my oil 2500-3k.

[Z28pr0jekt]

These cars are made to run on higher than 87 octane the majority of the time, if not 93 I would at least put in 89/91

Synthetic oil is generally thinner than conventional but if there is excessive noise, the rockers may just need to be adjusted.

I would never go much over 3000 miles on an oil change, I don't care how good the oil is.

[romanianfury]

ok then. thanks guys. so how do i adjust rockers?

[Z28pr0jekt]

http://shbox.com/1/4th_gen_tech2.html#adjust_valves

[romanianfury]

thankyou sir

[StorminMatt]

Compression on an LT1 is 10.4:1 - WAYYY too high for 87 octane.

[hbgben]

Compression on an LT1 is 10.4:1 - WAYYY too high for 87 octane.
That's what i thought. If it doesn't say on the instrument cluster, it should say on the fuel door, premium fuel only.

[popo8]

always the top octane I can find.... (fortunatly the shop has 110 and 112 in stock....)

[TRIPOD]

On synthetic, I'd run it atleast 5k. Just my opinion though.

[undercoverz-28]

always the top octane I can find.... (fortunatly the shop has 110 and 112 in stock....)

i thought too much octaine could be bad too?

[StorminMatt]

i thought too much octaine could be bad too?

Unless we are talking about the detrimental effects of some octane boosting compounds on catalytic converters and oxygen sensors, the only ill effects resulting from the use of high octane fuels is on the wallet.

[Paulster2]

... Synthetic oil is generally thinner than conventional ...

30w is 30w, doesn't matter if it's dino, blend, or full synthetic. Synth is usually considered slicker than dino, but it's not thinner.

[CALL911]

Run whatever the highest premium octane is in your area. For me back home its 93, but where I am currently stationed its only 89 (damn you Oklahoma!). Storminmat is wrong (unless he is talking about race gas octane). LT1's are a high compression engine which requires premium. It will run if you use 87 octane, but it is not going to like it. You may even feel it knock and ping because of it. Seeing as how you can have knock without hearing it, imagine what is going on if you CAN hear it!

As far as the oil goes, honestly as long as it has the proper amount of oil in it, and the appropriate weight, I wouldn't worry too much about running the expensive synthetic vs the regular cheep oil. It really makes little to no difference. I will admit there is some difference from running Wal-Mart brand oil and Royal Purple (enough where you could probably see a difference on the dyno even), but realistically niether one is going to be bad for the engine, and as long as it doesn't get too dirty, and you keep the right amount in it, you'll really be fine either way.

[StorminMatt]

Run whatever the highest premium octane is in your area. For me back home its 93, but where I am currently stationed its only 89 (damn you Oklahoma!). Storminmat is wrong (unless he is talking about race gas octane). LT1's are a high compression engine which requires premium. It will run if you use 87 octane, but it is not going to like it. You may even feel it knock and ping because of it. Seeing as how you can have knock without hearing it, imagine what is going on if you CAN hear it!

As far as the oil goes, honestly as long as it has the proper amount of oil in it, and the appropriate weight, I wouldn't worry too much about running the expensive synthetic vs the regular cheep oil. It really makes little to no difference. I will admit there is some difference from running Wal-Mart brand oil and Royal Purple (enough where you could probably see a difference on the dyno even), but realistically niether one is going to be bad for the engine, and as long as it doesn't get too dirty, and you keep the right amount in it, you'll really be fine either way.

First of all, I never said that it is bad to run premium in an LT1. As I pointed out in an earlier post in this thread, you WANT to run premium in an LT1. 10.4:1 is high compression. So you really don't want to run anything less than premium. In my previous thread, I was merely saying that it is generally OKAY to run higher octane fuel than RECOMMENDED (ie if you wanted to run 100 octane pump gas in an LT1). However, you will not gain anything unless you have done mods to take advantage of it. Also, higher octane gas CAN do damage to emissions hardware if it contains lead (or some other metallic octane boosters).

As for synthetic oil, my experience has shown that it DOES make a difference to use synthetic, at least under certain circumstances. First of all, if you drive hard, it is DEFINITELY better to use synthetic. I tend to be harder on my vehicles than the average person. And before I started using synthetic oil, engines did not last me NEARLY as long as after I started using synthetic. However, if you drive like my mom does, it probably doesn't make a difference. Also, synthetic oil lets you extend the oil change interval somewhat due to the fact that it is more chemically stable AND depends less on additives which degrade over time.

[CALL911]

First of all, I never said that it is bad to run premium in an LT1. As I pointed out in an earlier post in this thread, you WANT to run premium in an LT1. 10.4:1 is high compression. So you really don't want to run anything less than premium. In my previous thread, I was merely saying that it is generally OKAY to run higher octane fuel than RECOMMENDED (ie if you wanted to run 100 octane pump gas in an LT1). However, you will not gain anything unless you have done mods to take advantage of it. Also, higher octane gas CAN do damage to emissions hardware if it contains lead (or some other metallic octane boosters).

As for synthetic oil, my experience has shown that it DOES make a difference to use synthetic, at least under certain circumstances. First of all, if you drive hard, it is DEFINITELY better to use synthetic. I tend to be harder on my vehicles than the average person. And before I started using synthetic oil, engines did not last me NEARLY as long as after I started using synthetic. However, if you drive like my mom does, it probably doesn't make a difference. Also, synthetic oil lets you extend the oil change interval somewhat due to the fact that it is more chemically stable AND depends less on additives which degrade over time.

You seemed vague on your high octane post, thats why I said "unless your talking about race gas".

As for the synthetic oil, I would still say its really debatable how much of a difference it really makes in the end. I would agree to some extent that it does have more benefits, but honestly from talking to many top engine builders including Lingenfelter, I would also say that it does not really benefit nearly as much as people would think. There are many factors that go into engine longevity that do much more than simply running synthetic oil.

[StorminMatt]

As for the synthetic oil, I would still say its really debatable how much of a difference it really makes in the end. I would agree to some extent that it does have more benefits, but honestly from talking to many top engine builders including Lingenfelter, I would also say that it does not really benefit nearly as much as people would think. There are many factors that go into engine longevity that do much more than simply running synthetic oil.

Here's how I see it. Back in the day, I drove a Nissan truck and a Toyota truck for several years. And I used nothing but plain old conventional motor oil. And despite the fact that these both had motors considered 'reliable', I managed to send both to an early grave. Furthermore, I could literally feel both of these motors go to pot over time, as power would decline from one year to the next. Compression numbers also dropped in a similar manner. These motors were in pretty sad shape after, say, 4-5 years. These days, I drive a couple of Honda Civics with B-series motor swaps (the LT1 240SX won't be running for some time). And I use NOTHING but synthetic. Honestly, even though I am older, I can't say that I am really easier on these cars. But they just seem to keep going and going. Apart from chaning oil, timing belts, and replacing the occasional bad wheel bearing or brake pad, I just fill the things with gas. And I REALLY credit the synthetic oil for the difference. After all, engine wear takes place where parts move with respect to one another. And oilis the one thing that comes between them. So the quality of the oil that you use can have a MAJOR impact on the life of an engine, especially if you drive hard.

[CALL911]

As you said, thats how you see it. There are so many factors that go into engine life, it would be hard to say that it was all the oil that made the difference between your trucks who where made by Nissan and Toyota vs your Honda's. I would probably argue that Honda's are built better than Nissans and Toyota's to begin with, but that is just one thing of a multitude of possibilities that make one engine last and one not.

If you believe the oil was what made it last, then use the synthetic oil. I have used it before, and I have used partial synthetic, and I also use regular motor oil. After years of talking with many people who build performance engines for a living, my opinion is just different than yours.

We will have to agree to disagree on this one.

[jaysz2893]

my car has 61 K miles and has seen a lot more than 3000 rpms since i got it. It has had Mobil 1 since its first oil change by the original owner. The synthetic will find any leaks you may have. Typically the timing cover to oil pan seal. You may notice a liitle more valve train noise, but as stated before a rocker adj may help. I do 1 oil change a year since the car barely sees 2000 miles a year. A good quality filter is a goood idea too.

As for Octane, the higher the better especially if modded. My tune calls for atleast 93 (which i can get easlily here in Delaware) I can say for sure that 87 in my HHR has cost me milage over 89. The stupid car is supposed to run on mid grade. I am gonna have it de-tuned for cheap-o gas.. LOL Also, I do run Mobil 1 in it too, i run it in all my cars. I do nitce loger intervals in the HHR and Equinox withthe oil monitoring systems FWIW.

[LOW MILE SS]

Octane rating is one thing but also make sure to buy quality gas. In most cases you get what you pay for. My dad has to buy gas dryer every winter b/c he buys the cheapest possibe stuff. also had a friend who bought from a mom and pop store and ended up w/ a blown motor. Even the local Valero cost a friend a 08 nissan maxima motor. Nissan tested gas valero paid for a new motor. This is my opinion thru experience with my friends,family, and work trucks. I have all my employees purchase gas from the same place b/c of this.