Author Topic: Too much blowby (Read 5007 times)

TPW · « **on:** February 26, 2008, 06:34:57 pm »

I just got done rebuilding my 5 cylinder turbodiesel again, and it's still using too much oil. When I first drove it, I got over 500 miles to a quart, and it started going down from there. After 3000 miles it was getting less than 100 miles to a quart. Some was leaking out of bad seals, but most of it was blowby that I caught in a catch can. I thought it could have a cracked ring or two, but after pulling the head and taking out the pistons, none were cracked. The only bad thing I found were two rings lined up on number 4 piston. The head was rebuilt at a rebuilder that understood these diesel engines, so unless the valve stem seals and valve guides were shot, it shouldn't be the cause of the oil consumption. Any ideas? I already have 3rd oversize rings and pistons, I couldn't find a total seal in third oversize.

jackbombay · « **Reply #1 on:** February 26, 2008, 06:58:33 pm »

100 miles to a quart :shock: Little to none on the ground when parked overnight? If all that was getting burned I'd think the exhaust would be rather blue, is it?

TPW · « **Reply #2 on:** February 26, 2008, 07:17:11 pm »

No, exhaust looked OK, but lots of oil filling the catch can. Before this rebuild, when it did have a cracked ring and it was getting 50 miles to a quart, I didn't see any blue exhaust.

burn_your_money · « **Reply #3 on:** February 26, 2008, 07:53:49 pm »

How's the turbo?

TPW · « **Reply #4 on:** February 26, 2008, 08:15:17 pm »

Turbo city rebuilt it for me 3000 miles ago. If the turbo was leaking oil out the seals, I don't think it would be coming out the top of the valve cover.

TPW · « **Reply #5 on:** February 28, 2008, 05:31:30 am »

What sort of problems would I have with cast rings if I'm only running 10 psi of boost?

jimfoo · « **Reply #6 on:** February 28, 2008, 06:31:14 am »

Quote from: "TPW"

I just got done rebuilding my 5 cylinder turbodiesel again, and it's still using too much oil. When I first drove it, I got over 500 miles to a quart, and it started going down from there. After 3000 miles it was getting less than 100 miles to a quart. Some was leaking out of bad seals, but most of it was blowby that I caught in a catch can. I thought it could have a cracked ring or two, but after pulling the head and taking out the pistons, none were cracked. The only bad thing I found were two rings lined up on number 4 piston. The head was rebuilt at a rebuilder that understood these diesel engines, so unless the valve stem seals and valve guides were shot, it shouldn't be the cause of the oil consumption. Any ideas? I already have 3rd oversize rings and pistons, I couldn't find a total seal in third oversize.

Did you just look on their site or did you call them about rings? I called them and got 3rd oversize for my 1.9. I just had to give them a few dimensions. They can also modify rings you send them.

TPW · « **Reply #7 on:** February 28, 2008, 03:35:44 pm »

I do see that they have 3rd oversize for a 1.6, which is the same piston size. I keep thinking that most of the problems I have is because the chrome rings wont seat good, and I'm not able to bore the cylinders out anymore. That's why I ask about cast rings like Deves. Do they hold up well as long as I don't increase the boost to over 10 psi? Or how easily do the Total Seals seat?

jtanguay · « **Reply #8 on:** February 28, 2008, 04:41:42 pm »

Quote from: "TPW"

I do see that they have 3rd oversize for a 1.6, which is the same piston size. I keep thinking that most of the problems I have is because the chrome rings wont seat good, and I'm not able to bore the cylinders out anymore. That's why I ask about cast rings like Deves. Do they hold up well as long as I don't increase the boost to over 10 psi? Or how easily do the Total Seals seat?

not sure how well they seat, but the total seals will get rid of blowby from the ring end gap... buy some of their quickseat dry lube... supposedly that stuff works great at seating the rings

TPW · « **Reply #9 on:** February 28, 2008, 06:02:17 pm »

I just got back from the shop, and I think I see what the problem is. When I installed the new rings (from Top Line) there was only about .10 mm end gap. Now there is over 1.0 mm. I can't feel a new ridge on the cylinder wall (I reamed the old one off), so I have to assume the rings wore down in less than 3000 miles. I'll try to talk to someone at total seal tomorrow.

jtanguay · « **Reply #10 on:** February 28, 2008, 11:28:28 pm »

Quote from: "TPW"

I just got back from the shop, and I think I see what the problem is. When I installed the new rings (from Top Line) there was only about .10 mm end gap. Now there is over 1.0 mm. I can't feel a new ridge on the cylinder wall (I reamed the old one off), so I have to assume the rings wore down in less than 3000 miles. I'll try to talk to someone at total seal tomorrow.

did you measure the cylinder bore's? maybe they're too wide... that will give you a nice big ring end gap right off the bat... thats where total seals would help a little bit.

TPW · « **Reply #11 on:** February 29, 2008, 05:04:05 am »

I did have the machinist measure the bores 3000 miles ago, then they were the right size, an were out out of round yet. If I can get the total seals, I'm sure they'll help. In the tech portion of their website it mentions that with standard rings the blowby will start at 7%, but with a little wear it goes to 20%.