Carbon Buildup in Exhaust Port

Shane4188 · Post by **Shane4188** » Sat Jun 04, 2005 12:06 am

Has anyone else ever had a problem with carbon buildup in the exhaust port that slows the spree down over a period of time. I have been using the right oil for the job, Lucas injector oil. I have not under any circumstances used marine oil. The oil is not the prime suspect for the carbon buildup in the first place. I have friend who drives the crap out of his spree. Periodically I find my self scraping the exhaust port. Last time I did this i took the head and jug off. I was wondering if you think I could just simply remove the exhaust, move the piston down and scrape the port clean where carbon walls have built up. Does anyone else ever have any problems with this slowing down over time? I have another friend who seems to think that drilling out the exhaust port will help. I simply believe that this is stupid and that it will destroy the backpressure needed by this engine. Please give me any ideas that you think are legitimate, or words of advice. I know that I will have to replace all gaskets ect. if i pull the jug, i would rather not do this. If anyone has any experience in this area please let me know. Thanks!

vette76 · Post by **vette76** » Sat Jun 04, 2005 11:34 am

well, im not sure. BUT DEFINATELY DONT DRILL OUT THE PORT!

mikehailwood · Post by **mikehailwood** » Sat Jun 04, 2005 12:35 pm

I have successfully cleaned the exhaust port as you propose. With the exhuast pipe removed and the piston in the down position I scraped carbon deposits loose as best I could. Then I removed the spark plug and blasted about 45 lbs. of air into the spark plug hole to expell any carbon which might have made it's way into the cylinder. We have not experienced any problems after having done this.

vette76 · Post by **vette76** » Sat Jun 04, 2005 2:23 pm

right. even if u missed any it would have been blown out the exhaust anyway.

Shane4188 · Post by **Shane4188** » Sun Jun 05, 2005 12:41 am

well, i just looked at your forum and have done just what you proposed. I took a mirror and turned it toward the exhaust port, then i took the piston to it's lowest position and began scraping out some of the carbon from the side of the exhaust port wall. after i did that for about 10 minutes i preceded to put some carb and choke cleaner into the exhaust port to hopefully gather up some of the carbon dust and it stated that it eats up some of the carbon deposits. I am sure it did not eat up much, but i thought it would be worth a shot. Then i put it all back together and gained about 3 mph out of cleaning it out. It was only running about 27mph, not it runs around 30. This is what seems to be standard maintenance about every 500 miles or so. I am glad i did this, next time i will be sure to use my air compressor and blast the carbon out, that is a good idea, thanks for the replies guys!

PS. I knew that drilling out the exhaust port was a bad idea, it would defeat the backpressure that the engine needs. My friend is just a numbskull sometimes. Thanks guys!

Shane4188 · Post by **Shane4188** » Mon Jun 06, 2005 2:54 pm

I did this procedure to my spree, not my friend's this time. Scraping some carbon out of the exhaust port gained me an additional 3 mph in comarison to what i was going. It runs great for now. I guess this is standard procdure about every 1,000 miles. It helps to not use premium gas. Premium seems to have more buildup than other types. In this case, Shell V-Power does not "clean my engine as I drive". Shell has good gas, but that v-power stuff is overrated and Bull****.

Tippmann98 · Post by **Tippmann98** » Thu Jun 09, 2005 11:46 pm

numbskull??? its called expermentation.... say that now when im passing you pullin a sonic jay... lmao

Shane4188 · Post by **Shane4188** » Fri Jun 10, 2005 12:10 pm

I would hypothesize that the experiment would fail. If you drilled into the actual block than the piston would catch the new hole and probably rip the rings.