[Kaylah]

I'm not having a good day lately, both of my "projects" are getting a little to bittchy lately. But I want to ask about my Chevy Firebird.

This car is not your "warm weather" vehicle. I have a few add-ons that I haven't added yet because I had to move. But I have a question about this burning oil phenomenon.

As you know its a 305 4bbl, but it seems to blow smoke more in the hot months than in the winter. I have no performance problems whatsover, which is good. But sometimes I'm at a stoplight and I can smell the oil burning. This drives me nuts! Here the car runs fast and quiet, but it stinks like an old 307!

My first inclination is valve guide seals, and I'm hoping its not rings. But if my rings were going, what other kinds of symptoms might I experience besides the obvious blue smoke. If this thing needs rings, its going to get its butt replaced with some kind of high compression 327 or 350, and to hell with all of this smogmalia!

Oh yes, and how difficult will it be to replace valve guide seals?

Thanks guys...K

[gt2betubbed]

I don't know how difficult it is to replace the guides, and if it did need them, I would take the heads to a machine shop and them gone over all the way. Have you done a leak down test with some oil? I think that's the way to see if it's the rings or not.

[Kaylah]

How did we do that leakdown test again? Maybe I'll give it a try.

[troy-curt]

Valve guide seals are easy to replace. pull one and you will see what kind of shape they are in. If they are hard,broken,shrunken,or missing, then replace them. Originals are o rings, replace them with umbrella seals. HTH

Good Luck
Troy

[gt2betubbed]

Hey Troy, the most I've ever done to a set of heads was pull the valves and springs out. Do the guides just "pull out" like you said?

I think a leak down test is when you fill the cylinder with air and then do it again with some oil in the cylinder. If the oil made a good difference (better seal), then your rings are bad.

[troy-curt]

Nothing has been said about replacing valve guides, just the seals.

Valve guides have to be pressed out and in. usually done by a machine shop, with heads off and disassembled.

You will find the leak down test procedure in the knowledge base.

Troy

[87442lover]

The obvious question. Did you up the grade of the oil any? In the summer on a older 305 you'll need to run 10w-40 at least and possibly 20w-50.

Stupid question, but serious problem that everyone always overlooks. My olds 307 loved to burn(more like EAT) any oil 10-30 or below. It did okay on 10-40, but liked it's 20-50 after 150,000 miles.

In fact I'm supprised no one here has suggested it yet before talking about replacing valve guides or seals, come on now.

[Kaylah]

Well I'm due for a change in about 800 miles...I'll give the 20W50 a try. Funny thing about those SBC's, even though the 305 far outperforms that dawg of a 307, some little traits still hang on...like blue smoke.

[troy-curt]

Originally posted by 87442lover
The obvious question. Did you up the grade of the oil any? In the summer on a older 305 you'll need to run 10w-40 at least and possibly 20w-50.

Stupid question, but serious problem that everyone always overlooks. My olds 307 loved to burn(more like EAT) any oil 10-30 or below. It did okay on 10-40, but liked it's 20-50 after 150,000 miles.

In fact I'm surprised no one here has suggested it yet before talking about replacing valve guides or seals, come on now.

Come on now?

When your engine reaches its operating temperature, all the above oils are the same viscosity. Come on now. lol

Troy.

[87442lover]

Originally posted by troy-curt
Come on now?

When your engine reaches its operating temperature, all the above oils are the same viscosity. Come on now. lol

Troy.

FILL IT WITH GEAR OIL! The 83-88 montes with 305's only put out 180HP / 225lbs.
The olds 307 HO of '85 was 180HP / 235LBS. and the '87 HO was 170HP / 255lbs. in stock form. Plus you ever see a stock monte beat a stock 442? I dont think so.

Plus if you think all oils are the same, then fill your engine with 5W-20 and tell me how it runs

EDIT: JESUS! 87 montes came with 320/320 duration! How the hell could it idle?!?! chebby!

[troy-curt]

87442lover,

I have no idea what your talking about. Hp and lbs????
On this thread we are discussing Blue smoke. A heavy oil will not fix a mechanical problem.

You need to read up on what the weights of oil mean, and what they are used for.

The difference in the weight of oil is measured when it is cold.

[87442lover]

Originally posted by troy-curt
87442lover,

I have no idea what your talking about. Hp and lbs????
On this thread we are discussing Blue smoke. A heavy oil will not fix a mechanical problem.

You need to read up on what the weights of oil mean, and what they are used for.

The difference in the weight of oil is measured when it is cold.

Horse powerr and Foot pounds of torque. and your telling ME I need to read up
it was too another reply not yours. I know the oils have different weights. NOW a lesson for YOU. The higher the weight, the more lubrication, thicker it is, and ability to stay in place at operating temp. Viscosity.

The W signifies that it will flow "like" a thinner oil at colder temps.

so 20W-50 will flow like a straight 20 weight oil at cold temps, BUT offer the same protection as a 50 weight oil. Get it?

That is why in older engines you have bigger gaps between the surfaces of the moving parts (valves-to-guides, rings-to-cyl. wall, etc.) and a heavier/thicker oil is required
to fill these gaps to help stop blow-by in older engines(the thin layer of smoke coming out the tail pipe). All oils DO NOT have the same protection at high temps. 5W-20 has very BAD lubrication qualities at high temps and is very thin for modern day cars.
10W-30 has moderate qualities and is used for engines at about 25,000 miles to 100,000, or 120,000 miles. 10"W"-30 also has good cold temp qualities.
10W-40 has excellent high temp qualities but can cause pre-mature wear in newer cars because it can NOT lubricate smaller spaces very well like 20, or 30 oil.
20W-50 Flows like a 20 weight oil in cold temps, but is used for worn out engines that have alot of wear on them and it offers a high viscosity protection at operating temp. Usually around 150,000 miles to 200,000 miles or so.

Now don't get pissed, I had to take a ****ing class in this BS at my previous job, so I know VERY well what qualities oil does and does not have!

Ed

EDIT: Simply put, 10W-40, (10 weight at COLD temps.) (40 weight at hot temps.) Also if your not happy yet, look at gear oil (75W-85) isnt it thicker? Or no smoke (something like 150 weight), they thick'n it up to fill the gaps, get it?

[troy-curt]

hummmmmmm,been a macanick for 50 years i didn`t know all that there.

[Kaylah]

OOOPS... Didn't mean to dog your olds 307.

I was referring to that DAWG of a Chevy 307 that came out after they did away with the 283 and before they came out with the 305. That was BLUE smoke city!

[BstMech]

The 'W' stands for 'winter and multi viscosity oils have polymers added that expand enabling the higher viscosity rating at operating temps.

Does this make me an 'oil nerd'?