Tahoe & Suburban The power, space, and brutal towing ability make the Tahoe and its longer sibling, the Suburban, arguably the best full size SUV's on the market today.

2013 Chevrolet Suburban
Platform: GMT 400, 800, 900

Help: Misfire and replacing valves.

Thread Tools
 
Search this Thread
 
Old July 1st, 2013, 9:29 PM
  #1  
CF Beginner
Thread Starter
 
Alwaysdutch's Avatar
 
Join Date: Mar 2013
Posts: 20
Likes: 0
Received 0 Likes on 0 Posts
Default Help: Misfire and replacing valves.

So I started on a valve job on our 350 v8 and noticed that the exhaust valve on the cylinder that caused the misfire had a small opening. I could only see if I hold an LED light on the other side or an air hose. Cylinder 6 had the same issue so I bought two exhaust valves.

Just so you know, I spend $400 on a partial tear down to help speed up the process on figuring out what the possible problem is. There was also a leaking fuel injector on cylinder 8.

Anyhow, I got all the parts and put in the first exhaust valve, but I still see the light between the head and the valve, and feel air when I blow the air hose.

So here is my question:
- Is it normal that there is a possible space (I don't think so)? Can it be the head? Could it be the valves were not the problem, but maybe the leaking fuel injector? (I bought that one as well)

Can it be anything else other than plugs, plug wires, and distributor rotator? I replaced all of that already at first trying to get rid of the CEL.

I could really use some help with this as we are down to one car and I need this one going.

Thanks!!
Old July 1st, 2013, 10:01 PM
  #2  
CF Senior Member
 
Joe In NY's Avatar
 
Join Date: Mar 2013
Posts: 406
Likes: 0
Received 1 Like on 1 Post
Default

You need the seats machined. I would do it for all the valves.
Old July 1st, 2013, 10:11 PM
  #3  
CF Beginner
Thread Starter
 
Alwaysdutch's Avatar
 
Join Date: Mar 2013
Posts: 20
Likes: 0
Received 0 Likes on 0 Posts
Default

I assume that means that the head needs to fixed/shaved/polished to get a perfect round for the valve? (Sorry, I am trying to find the right word)
Old July 1st, 2013, 10:35 PM
  #4  
CF Senior Member
 
Joe In NY's Avatar
 
Join Date: Mar 2013
Posts: 406
Likes: 0
Received 1 Like on 1 Post
Default

Yes. You need the seats in the heads machined, and the valves lapped for a nice perfect fit.
Old July 1st, 2013, 11:23 PM
  #5  
CF Beginner
Thread Starter
 
Alwaysdutch's Avatar
 
Join Date: Mar 2013
Posts: 20
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the info. I did notice that after i cleaned up the area around the valve, the valve seems not to fit all around. I am wondering if the Autozone valves are sufficient. I got the V1807, which are the only ones available in their system. Now it seems that the valve is not a clear fit......
Old July 2nd, 2013, 8:16 AM
  #6  
CF Senior Member
 
Joe In NY's Avatar
 
Join Date: Mar 2013
Posts: 406
Likes: 0
Received 1 Like on 1 Post
Default

If its high mileage, or you have been having issues as to how the motor has been running, I wouldn't expect new valves to fit. If you are working on the heads, do it right. Get all the seats machined. And get all the valves lapped. Over time Valve seats wear out. And they cause low compression and effect how the motor performs. Do this and it will save you from headaches later.
Old July 2nd, 2013, 11:59 AM
  #7  
CF Beginner
Thread Starter
 
Alwaysdutch's Avatar
 
Join Date: Mar 2013
Posts: 20
Likes: 0
Received 0 Likes on 0 Posts
Default

Alright, that is the route I go then....trying to find a reputable machine shop in GA.....

Thanks for the quick turn around in answers !
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
buddyleno
Silverado & Fullsize Pick-ups
4
March 31st, 2017 8:13 AM
novaguy42
Nova & Chevy II
1
October 19th, 2014 11:30 AM
dcoperator
Avalanche
1
April 1st, 2013 8:19 PM
pjb84
Cavalier
4
February 9th, 2011 1:29 PM
Biggumzmcgee
Tahoe & Suburban
2
November 15th, 2009 10:51 AM



Quick Reply: Help: Misfire and replacing valves.



All times are GMT -5. The time now is 10:41 PM.