295 smoking

[bowtieracin]

I'm working on a 92 marathon with a 295 that I just bought. It's smokes pretty good I put new valve seals in it that helps some but it still seems to smoke pretty bad all the time. It has a 175 lb compression both holes. From looking at the studs when I adjusted the Rockers the valves don't seem to be wore bad at all any ideas suggestions? Thanks

[newtjl]

How bad were the valve seals? It will smoke for a while if it filled the muffkin up with oil but will eventually burn off. Id be surprised if the rings are worn out with that kind of compression. Another possibility, however remote, is that it has too much oil in it. Is it lifted or stock? Lifted will throw your oil level off. 1.5 quarts is the correct amount. I recently replaced the valve seals on one and it still puffed a little smoke for the first 18 holes as it burned out of the muffler. The valve seals were shot, teflon completely worn out of them. I see the owner occasionally and he said its doing fine now.

[bowtieracin]

Thanks for your reply!! The seals were worn some yes.thats what I thought about the rings and that much compression I haven’t seen much better. It’s not lifted the oil was right on. I thought about burning out the muffler.

[nickdalzell1]

How fast is it going? We got a smoker in and it had one broke connecting rod as well (was putt putt putting on one cylinder) and the guy said he had it going 28 MPH. The governor spring was run all the way in as well meaning he went way too fast and ate the rings and one rod. It was also lifted and he had a tachometer installed. He stated it 'started cutting out at 4500-5000 RPM.' Yeah. I don't doubt it. Poor little Robin engine :(

[bowtieracin]

Its running good

[jclark138]

Hey- glad to hear it!

[CP241]

You can still have great compression and smoke like a train.

The different rings have different functions. The thin little rings are oil control rings. If they are seized in the landing from lack of oil changes, overheating, etc. They cant do their job. They're small, thin, and damage easily.

The middle ring is the scraper ring. It is beveled and its job is to scrape the oil down off the sides if the cylinder walls when the piston travels down. This ring does some for compression, but that's not its main purpose. If this ring is damaged, it leaves extra oil on the cylinder walls and can cause smoke without affecting compression. The top ring with the chrome outside does most of the compression work. The chrome outer surface helps it hold up against the heat better, and helps it glide more easily over the cylinder walls. This ring has everything to do with compression, and nothing to do with oil control and smoking.

To further add to that, when oil is burned, excessive carbon deposits are left behind on the top of the piston, inside the head, exhaust valve, and exhaust port. This extra carbon takes up space, which will also raise compression just due to sheer physical space for combustion being smaller.

It's not uncommon at all to have perfect compression and the motor still run like a dream, but smoke like a train. It doesnt mean theres not something wrong. Just means the compression rings are not damaged badly.