Carbon on intake valves - ZR-1 Net Registry Forums

Torchred96 · 11-12-2011

As you probably know, I have been doing the injectors and secondary throttle blades mod and a few other things while i'm in there.....I was looking into the intake ports on the heads to make sure I didn't drop anything into them, I noticed a pretty good amount of carbon on the valves..

Of course, I am tempted to do something about it, but what can I do? Is there any known solvent for carbon buildup? Hate to ignore it. Recall I have a bunch of miles 133k. The engine doesn't smoke...(oh and it doesn't like alcohol or drugs either).

thanks

1990 415 · 11-12-2011

Drive it like it was meant to be driven and blow the carbon off the valves.

Torchred96 · 11-12-2011

I'll certainly do that, but will it actually blow the carbon off? or is that a myth?

batchman · 11-12-2011

I think the old saying really applies to carbon in the combustion chamber, which was common on lazily run carb'ed cars. For today's EFI intake tracts you should look into Seafoam or similar. Haven't tried the likes of that in the ZR-1 yet though...

Best,
- Jeff

1990 415 · 11-13-2011

Quote:

Originally Posted by Torchred96

I'll certainly do that, but will it actually blow the carbon off? or is that a myth?

It is no myth. LT5s need to see 7000 rpm on a regular basis.

Ccmano · 11-13-2011

If you drive with the secondaries turned off (at the valet switch) regularly, this is what happens. Even Haibeck recommends you leave the switch on for full power at all times. That way you'll get into your secondaries from time to time and help keep them clean. In extreme cases a carbon accumulation like this it causes hard starting, rough idle, knocking and dieseling because the carbon absorbs the fuel. I've seen cars (not ZR-1's) that literally would not start because of this.

As for cleaning there's Seafoam,Techron and BG44K. These can either be put into the fuel or introduced directly to the intake. We used to do this on Benz's that had this issue with Techron. It's tricky, I don't recommend it unless you know what your doing. You run the risk of hydostatic lock if you use too much too quickly. There are systems on the market that allow shops to do this eliminating the risk. Many shops offer this service now.

Your best bet is to run a few tank fulls with high concentration Seafoam, Techron or BG44K (read the directions) and do a bunch of high rpm runs occasionally. I like the BG44K the best.

H

Torchred96 · 11-13-2011

Ccmano and Jeff, I read a little about the bg44k and seafoam b4 I posted but I was looking for personal recommendations for the Z and what some of our experts thought and so thank you for your thoughts.

I'm gonna try one of the products and see how it works out. I don't experience any of these symptoms (" hard starting, rough idle, knocking and dieseling") but just looking at those valves doesn't make me warm and fuzzy.

Thanks again to all who replied.

tomtom72 · 11-15-2011

Okay, I'll fess up! After my recent bout with spark knock I was fairly panicked and bummed out. The cause turned out to be loose spark plugs.

But. In an effort to chase down the reason for the knock I ran down all the various codes that could have been logged in by the ECM. No, I had no DTC's even in history. Sooo, I bought about six cans of seafoam. I added one can to a tank full six times, but skipping one tank each time. Okay not exactly a whole 18 gallons but you get the idea. Okay, so I find the loose plugs and after I fix that ( jez I can be so dumb sometimes ) I noticed the motor sounds different. It seems to be breathing easier? Or smoother? I don't know it may be my wishful thinking? It just seems like she's her old self again, and nothing broke from using the seafoam.

I had an issue with dumping it in the brake booster hose that's why I did the six tank fulls. Go to their web site and read up on all the instructions and think about which cylinders the booster hose is near. That was my sticking point on not doing it that way. How do the front cylinders get an even dose???? Gas tank takes longer for sure, but everybody gets a little bit!

Tom

FU · 11-15-2011

Quote:

Originally Posted by tomtom72

but everybody gets a little bit!

Tom

We are still talking about the LT5 here ?

scottfab · 11-15-2011

Quote:

Originally Posted by 1990 415

Drive it like it was meant to be driven and blow the carbon off the valves.

nuff said.

11-12-2011	#1
Torchred96 Join Date: Jul 2011 Location: Homestead, Fl Posts: 248	Carbon on intake valves As you probably know, I have been doing the injectors and secondary throttle blades mod and a few other things while i'm in there.....I was looking into the intake ports on the heads to make sure I didn't drop anything into them, I noticed a pretty good amount of carbon on the valves.. Of course, I am tempted to do something about it, but what can I do? Is there any known solvent for carbon buildup? Hate to ignore it. Recall I have a bunch of miles 133k. The engine doesn't smoke...(oh and it doesn't like alcohol or drugs either). thanks __________________ Sam 1991 ZR-1 :salute: Last edited by Torchred96; 11-12-2011 at 12:42 AM.

11-12-2011	#2
1990 415 Join Date: Feb 2009 Location: Canada Posts: 309	Re: Carbon on intake valves Drive it like it was meant to be driven and blow the carbon off the valves.

11-12-2011	#3
Torchred96 Join Date: Jul 2011 Location: Homestead, Fl Posts: 248	Re: Carbon on intake valves I'll certainly do that, but will it actually blow the carbon off? or is that a myth? __________________ Sam 1991 ZR-1 :salute:

11-12-2011	#4
batchman Join Date: Jun 2009 Location: I live at Devens, one run at a time Posts: 455	Re: Carbon on intake valves I think the old saying really applies to carbon in the combustion chamber, which was common on lazily run carb'ed cars. For today's EFI intake tracts you should look into Seafoam or similar. Haven't tried the likes of that in the ZR-1 yet though... Best, - Jeff __________________ [I]91 ZR-1 #1840, autocrossing in SCCA BSP. FIC S/S's DRM chip/Watson/Borla/lid/LW batt&headlights, springs, shocks, pads & lines, quick rack & Turn One, camber brace, 32/22mm sways, A/C halfway deleted 17x11 & 12 CCW's, 315 & 335 Hoosier A6s [/I]

11-13-2011	#6
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Carbon on intake valves If you drive with the secondaries turned off (at the valet switch) regularly, this is what happens. Even Haibeck recommends you leave the switch on for full power at all times. That way you'll get into your secondaries from time to time and help keep them clean. In extreme cases a carbon accumulation like this it causes hard starting, rough idle, knocking and dieseling because the carbon absorbs the fuel. I've seen cars (not ZR-1's) that literally would not start because of this. As for cleaning there's Seafoam,Techron and BG44K. These can either be put into the fuel or introduced directly to the intake. We used to do this on Benz's that had this issue with Techron. It's tricky, I don't recommend it unless you know what your doing. You run the risk of hydostatic lock if you use too much too quickly. There are systems on the market that allow shops to do this eliminating the risk. Many shops offer this service now. Your best bet is to run a few tank fulls with high concentration Seafoam, Techron or BG44K (read the directions) and do a bunch of high rpm runs occasionally. I like the BG44K the best. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold. Last edited by Ccmano; 11-13-2011 at 11:54 AM.

11-13-2011	#7
Torchred96 Join Date: Jul 2011 Location: Homestead, Fl Posts: 248	Re: Carbon on intake valves Ccmano and Jeff, I read a little about the bg44k and seafoam b4 I posted but I was looking for personal recommendations for the Z and what some of our experts thought and so thank you for your thoughts. I'm gonna try one of the products and see how it works out. I don't experience any of these symptoms (" hard starting, rough idle, knocking and dieseling") but just looking at those valves doesn't make me warm and fuzzy. Thanks again to all who replied. __________________ Sam 1991 ZR-1 :salute:

11-15-2011	#8
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Carbon on intake valves Okay, I'll fess up! After my recent bout with spark knock I was fairly panicked and bummed out. The cause turned out to be loose spark plugs. But. In an effort to chase down the reason for the knock I ran down all the various codes that could have been logged in by the ECM. No, I had no DTC's even in history. Sooo, I bought about six cans of seafoam. I added one can to a tank full six times, but skipping one tank each time. Okay not exactly a whole 18 gallons but you get the idea. Okay, so I find the loose plugs and after I fix that ( jez I can be so dumb sometimes ) I noticed the motor sounds different. It seems to be breathing easier? Or smoother? I don't know it may be my wishful thinking? It just seems like she's her old self again, and nothing broke from using the seafoam. I had an issue with dumping it in the brake booster hose that's why I did the six tank fulls. Go to their web site and read up on all the instructions and think about which cylinders the booster hose is near. That was my sticking point on not doing it that way. How do the front cylinders get an even dose???? Gas tank takes longer for sure, but everybody gets a little bit! Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member