I usually get smoke at start up and at times i also get it at idle. (smoke is blueish white)

Is there any particular way of determining whether i have bad valve seals or if the problem is my piston rings without taking anything apart?

The engine was rebuilt back in november with forged internals, so im leaning towards valve seals but im not just smoking at start up, also at idle.

 

Not really any way to tell without ripping into it. Valve seals can be done with the heads still on the car - you just need to use some method of keeping the valves from falling into the head when you remove the retainers - some use air compressor with an adapter that screws into the spark plug hole, others use a piece of small rope, and feed it into the spark plug hole filling the chamber with rope so that the valve cannot fall (just make sure the end is tied off somehwere).

 

If you have excessive ring blowby, you'll get alot of smoke out of the valve cover - take the oil fill or PCV valve out and see if there's alot of smoke there (like a smoke stack alot of smoke) - that's usually blowby on the rings. I suppose a compression check will alo tell you ring condition.

 

I do have a slight blowby but nothing major, i can see a bit of smoke come out when i unplug the oil cap but its not a lot.

thats a sign of bad rings right? hope not since these rings are only a few months old

 

I'd put my money on bad valve guides. I had that problem with two different sets of heads. Theoretically you shouldn't see much smoke at a cold idle. As the engine warms the bronze valve guides, being a metal, will expand. If they are excessively worn oil will seep down into the combustion chamber and burn.

The "smoke" you see coming from your oil plug should just be crankcase vapor. That's what the breather tube or filter is for.

 

Yeah the smoke only happens after the car is warmed up enough, and at start up.

I have two breathers on the right and 1 pcv valve on the left, really hoping youre right and its just vapor. I had a guy look at it and he said it was blowby from the rings, and that the smoke was the rings also. But then i had another guy look at it and he said it was the seals, so yeah...dont know what to believe.

 

A lot of guys use the plain "0" ring seals instead of the superior "umbrella"
seals. The o rings seals tend to let a older motor "puff" at idle.

 

If the car has a lotta miles I'd do valve seals for peace of mind if anything. If you have shop air and a spring compressor tool they can be done in an afternoon. If your pressed for time you can even do them a few at a time if the rocker cover gasket is reusable.

 

My car has about 2500 miles, I heard I can get some thin valve seals, and some copper seals. Which seals would last me longer?

 

i guess im now confused on what yall are discussing. we might be on different pages

to me it sounds like your BRONZE VALVE GUIDES are shot. the way I understand it is that they are pressed into the cylinder head. and i had multiple sources tell me that it was easier to replace the cylinder heads, which i did, than the valve guides

you've sparked my interest. could someone give some clearification. thanks.

 

My bad I meant bronze not copper lol. But which are the best quality seals? I'm trying to figure out why mine are shot after just getting my engine together back in November

 

Double check your intake bolts- I had an oil consumption issue, and it turned out to be that my 'new and improved' intake bolts lost torque to not even finger tight.

Discovered it AFTER I pulled the engine and replaced all the guide seals. I cropdusted especially on decel- small furry animals and children passed out or ran in fear of their lives, but idle wasn't near as bad as you are describing.

 

Hmm I'll check the bolts, come to think of it my header bolts came loose about 2 weeks ago due to all the vibrations from my engine. I wouldn't doubt it if the intake bolts are loose

 

When you put your engine back together what heads did you use. Are they used, approximately how many miles on them?

 

Vortec heads, they were machined and I bought Everything new for them. I remember new lifters kicked my *** price wise.

I'm not sure how many miles were on the heads originally

 

Not that it was surely the main cause of my oil issue, but my machine shop used cheap a$$ 50 cent guide seals when they machined and assembled my heads. About 1/2 of them were chewed up. I had all new hardware as well. It won't hurt any to change them out- I used the Felpro Blue viton seals.

I think a lot of times some of us get so wrapped up in heads, valves, studs, etc, that we forget about the guide seals being worth the time and money as well. I'll admit I never gave them a thought when I bought the parts for my heads.

 

Valve guides are the bronze sleeves that the valve slides up and down in. All the symptoms you've described makes me think they are worn. I've been told it's a common occurrence with sbc heads. And I've had the same problem. In my case I replaced the cylinder heads because as I said before they are pressed in. I doubt the machine shop replaced them when they redecked the heads for you, but I wouldn't know.

There's no reason to think it's the rings, seeing as you just replaced them, unless you reused the pistons or didnt have the cylinders bored or at least rehoned.

 

The block was machined and bored 0.30, I agree with hawk i was so wraped up in the build that I didn't pay attention to the seals. When I replace them I should go with felpro then? I want something that will last me, I heard mr gasket supposedly had durable seals

 

stock seals are junk...ive seen em go bad after a few thousand miles,but its hit or miss i got lucky and my stock engine with 140k miles is just now developing the slight smoking at startups when cold...it not a terrible issue but its like anything else IMO .. take it to a shop (or if youre equipped) have them replaced a small issue will always eventually lead to a larger issue

 

i like to know too

 

You could also get a leak down tester, it's screws into your cylinder and you pressurize it when that piston is at tdc. Then you look at the leakage rate. That would tell you if your rings or valves had gone. I picked one up at harbor freight for 60 bones.

 

its not a totally definitive test , but it will give you a good bit more info
have a friend follow you in his car ,someplace safe , to test drive your car like a long stretch of back rural road,, put the car in gear and run it up during hard acceleration at full throttle to lets say 5000rpm, then suddenly let the throttle snap closed and let engine compression slow the car, heavier smoke during hard acceleration when cylinder pressures high and intake vacuum is low generally indicates worn rings or piston damage, heavier smoke during deceleration as you let the engine drag the cars speed down, when the cylinder pressures low and intake plenum vacuum is high generally indicates bad valve seals or worn valve guides, be aware that a leaking intake gasket can suck oil into the ports from the lifter gallery also. obviously a LEAK DOWN test in conjunction gives you a better picture as to the cause of the oils source


http://forum.grumpysperformance.com/...e+seals#p15765

http://forum.grumpysperformance.com/...+guides#p24722

http://forum.grumpysperformance.com/...=leak+down#p49

http://forum.grumpysperformance.com/...p=17973#p17973

 

how the hell do you do valve seals without removing the heads?

 

Well...

First, you have to keep the valves closed. Usually, this is done by taking a compression tester hose, screwing it into the spark plug hole and applying air pressure (make sure you take the schrader valve out of the hose first) You'll have to remove the rocker arms because the motor will turn to BDC when you put the pressure in the cylinder. But you gotta do that for the next step anyway.

Next, you use an over head valve spring puller (screw or lever type) and remove the spring.

Then replace the valve stem seal and reverse the steps. Repeat for all the cylinders.

This does work and it should help, at least for a while. The underlying problem (as others have pointed out) is the worn valve stem/guides allowing the oil to pass in the first place. The reason the factory used "crappy old o-rings" is because when the clearance is right you don't need much of a seal at all. The fancy umbrella and spring assisted seals are only needed when there is too much clearance.

 

I used some nylon rope and fed it through the spark plug hole. That with an overhead valve compressor and life was good.

 

ohhh man I misread and thought it said valve SEAT not SEAL LOL