Bosch 4+ plug MAJOR CARBON BUILDUP??? Hurry!
Thread Starter
Member
Joined: Dec 2001
Posts: 209
Likes: 0
From: Chico, Ca
Car: 88 Formula 350
Engine: 357
Transmission: 700r4 Edge 2900 Stall
Bosch 4+ plug MAJOR CARBON BUILDUP??? Hurry!
I'm in the middle of tightening some exhaust manifold bolts and oil pan bolts...leaks everywhere. Pulled the nightmare plug (passenger side back) and the thing has carbon buildup thick as can be. 1000 miles on the plug see photo.
Diagnosis please..suggestions?
Thanks!!!
Marty
Diagnosis please..suggestions?
Thanks!!!
Marty
Supreme Member
iTrader: (2)
Joined: Jan 2002
Posts: 9,962
Likes: 5
From: Moorestown, NJ
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Dud injector, weak spark to that plug, and blow-by in that cyl. come to mind. Id check to see that that inkector isnt leaking excess fuel.
Senior Member
Joined: Jul 2001
Posts: 649
Likes: 0
From: San Rafael, CA
Car: 1988 Trans Am GTA
Engine: 5.7L TPI (L98)
Transmission: 700RJunk
Aside from the leaks, are you having oil consumption issues or any running issues? It sure looks like a ton of oil is getting in that cylinder, by the rings, down the valve guides, or even a head gasket.
Thread Starter
Member
Joined: Dec 2001
Posts: 209
Likes: 0
From: Chico, Ca
Car: 88 Formula 350
Engine: 357
Transmission: 700r4 Edge 2900 Stall
Just took off the locks on the stage 8 bolts...the bolts were finger tight..hence the exhaust leak. Injectors are new Accel 24lb.
The engine has 1000 miles with new tfs heads and a Felpro head gasket.
I'll ask the mechanic who did the install about the possibility of other loose bolts while I chew his a** about the ones I've already found. I gave him 4 months to install the engine before I started to pressure him. Guess I caused him to rush....
Am I mad........
The engine has 1000 miles with new tfs heads and a Felpro head gasket.
I'll ask the mechanic who did the install about the possibility of other loose bolts while I chew his a** about the ones I've already found. I gave him 4 months to install the engine before I started to pressure him. Guess I caused him to rush....
Am I mad........
Thread Starter
Member
Joined: Dec 2001
Posts: 209
Likes: 0
From: Chico, Ca
Car: 88 Formula 350
Engine: 357
Transmission: 700r4 Edge 2900 Stall
Weak spark could be an issue...I had an MSD plug start to burn on the headers....wrapped some electrical tape around it and called it good!?!?!?!
The plug next to it is fine.....even though I think the BOSCH plugs aren't going to stay in there long.
The plug next to it is fine.....even though I think the BOSCH plugs aren't going to stay in there long.
Supreme Member
Joined: Sep 1999
Posts: 3,197
Likes: 10
From: Manassas VA
Car: 04 GTO
Engine: LS1
Transmission: M12 T56
#8 is the most commonly fouled plug in any SBC. That corner of the engine tens to sit the lowest, thus that hole has the most oil pooled over the valves, thus it tends to get teh worst of valve seal problems, and thus that plug tends to take a beating if you don't do alot of hard running to keep it clean.
Could also be something else, but i didn't see anybody else mention this so i thought i'd throw it out there.
Could also be something else, but i didn't see anybody else mention this so i thought i'd throw it out there.
Supreme Member
Joined: Nov 2001
Posts: 1,526
Likes: 0
From: Cleveland, OH
Car: '87 Camaro LT
Engine: 355 L98
Transmission: T56
is there any fouling on the rest of the plugs, even if it's not as bad as 8? you might need to move up a heat range. whatever you do, get rid of the +4s, they are absolute garbage
Thread
Thread Starter
Forum
Replies
Last Post
89 formula TPI
Tech / General Engine
10
Sep 7, 2015 11:06 AM




