89 Chevy 454 smokes on startup and under load - The 1947 - Present Chevrolet & GMC Truck Message Board Network

wyattglock · 07-16-2010, 10:41 PM

I have an 89 Chevy R3500 1 ton dually that I just bought last Saturday. It has been eventful, new fuel pump on the first day. New plug wires, cap, and rotor on first day. Second day, custom tow bumper made after rear brake line blew out, pics later.
My question is, there is a pretty good light blue cloud at startup and under acceleration. I know this is oil being burned off, but what type of valve stem seals do these engines have? I have replaced all the vacuum lines and put in new plugs. I have also installed a second set of plug wires since the first set was crap. The A.I.R. system was disconnected when I bought it, so I am not sure about EGR function. The timing is good, it is right at 4 degrees BTDC with the ECM unplugged. It runs up to 13 degrees BTDC after plugging in and restarting the truck. I am pretty sure the truck sat for several years, the mouse nest covering the intake and the fact that I bought this truck in Central MI and it has very little rust are pretty good clues to that.
Thanks in advance for the help.

wyattglock · 09-07-2010, 07:01 PM

I have started the project of changing the valve stem oil seals. The biggest problem I am having is the number 1 cylinder is not holding pressure now that I changed the intake valve stem seal. With my luck it is a piece of carbon under the valve. Initially it held 90psi with no problem, so I changed the intake seal. Then when I went to change the exhaust side, it dropped off to 20psi and won't build from there. I have already decided that if I have to pull the heads, the stock ones are not going back on. If I have to go to the trouble of pulling one, it will get an upgrade!

**PRattenbury** · 09-07-2010, 07:45 PM

Quote:

Originally Posted by wyattglock

I have started the project of changing the valve stem oil seals. The biggest problem I am having is the number 1 cylinder is not holding pressure now that I changed the intake valve stem seal. With my luck it is a piece of carbon under the valve. Initially it held 90psi with no problem, so I changed the intake seal. Then when I went to change the exhaust side, it dropped off to 20psi and won't build from there. I have already decided that if I have to pull the heads, the stock ones are not going back on. If I have to go to the trouble of pulling one, it will get an upgrade!

Yeah, sounds like maybe a bad valve. Sorry bout that.

wyattglock · 09-08-2010, 12:02 AM

Thanks, I was kind of wondering if the valve was bad. I am going to try again tomorrow and see if I didn't overtighten the intake valve causing it to stick open. Hopefully that is what it is, but I am not holding my breath. I'll post a pic of the seal that I pulled off the number 1 intake valve tomorrow when I get home from work, it is no wonder why it smokes on startup so bad.

wyattglock · 09-08-2010, 02:50 PM

Yep, that is what I was hoping for. I proved that I can overtighten stuff and still think of the worst case scenario! I loosened the intake rocker arm and removed the exhaust rocker, then hooked up the air to it and voila! It built up pressure like it is supposed to. Amazing what happens when you don't give the air a path to leak out of the cylinder on! Should be done with all the seals in a little while. I will post pics of the seals that I took off when I am done.

07-16-2010, 10:41 PM	#1
wyattglock Registered User Join Date: Jul 2010 Location: Lafayette, IN Posts: 621	89 Chevy 454 smokes on startup and under load I have an 89 Chevy R3500 1 ton dually that I just bought last Saturday. It has been eventful, new fuel pump on the first day. New plug wires, cap, and rotor on first day. Second day, custom tow bumper made after rear brake line blew out, pics later. My question is, there is a pretty good light blue cloud at startup and under acceleration. I know this is oil being burned off, but what type of valve stem seals do these engines have? I have replaced all the vacuum lines and put in new plugs. I have also installed a second set of plug wires since the first set was crap. The A.I.R. system was disconnected when I bought it, so I am not sure about EGR function. The timing is good, it is right at 4 degrees BTDC with the ECM unplugged. It runs up to 13 degrees BTDC after plugging in and restarting the truck. I am pretty sure the truck sat for several years, the mouse nest covering the intake and the fact that I bought this truck in Central MI and it has very little rust are pretty good clues to that. Thanks in advance for the help.

09-07-2010, 07:01 PM	#2
wyattglock Registered User Join Date: Jul 2010 Location: Lafayette, IN Posts: 621	Re: 89 Chevy 454 smokes on startup and under load I have started the project of changing the valve stem oil seals. The biggest problem I am having is the number 1 cylinder is not holding pressure now that I changed the intake valve stem seal. With my luck it is a piece of carbon under the valve. Initially it held 90psi with no problem, so I changed the intake seal. Then when I went to change the exhaust side, it dropped off to 20psi and won't build from there. I have already decided that if I have to pull the heads, the stock ones are not going back on. If I have to go to the trouble of pulling one, it will get an upgrade!

09-08-2010, 12:02 AM	#4
wyattglock Registered User Join Date: Jul 2010 Location: Lafayette, IN Posts: 621	Re: 89 Chevy 454 smokes on startup and under load Thanks, I was kind of wondering if the valve was bad. I am going to try again tomorrow and see if I didn't overtighten the intake valve causing it to stick open. Hopefully that is what it is, but I am not holding my breath. I'll post a pic of the seal that I pulled off the number 1 intake valve tomorrow when I get home from work, it is no wonder why it smokes on startup so bad.

09-08-2010, 02:50 PM	#5
wyattglock Registered User Join Date: Jul 2010 Location: Lafayette, IN Posts: 621	Re: 89 Chevy 454 smokes on startup and under load Yep, that is what I was hoping for. I proved that I can overtighten stuff and still think of the worst case scenario! I loosened the intake rocker arm and removed the exhaust rocker, then hooked up the air to it and voila! It built up pressure like it is supposed to. Amazing what happens when you don't give the air a path to leak out of the cylinder on! Should be done with all the seals in a little while. I will post pics of the seals that I took off when I am done.



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