blew second plug same hole
Thread Starter
|
Freshman User
Joined: Feb 2009
Posts: 31
Likes: 0
From: ohio
blew second plug same hole
I recently replaced my beloved 91 f 350. She had 350,000 on her 5.8l and was still going strong. Body and ele. system was getting tired. Replaced her with 2000 Ex. 6.8l. Though I got a good deal 4500. out the door with 121012 on the clock. All was well til tuneup time. After tuneup started blowing plugs. Never heard of that happening. Started doing my homework and found this to be a common problem. Seems like an easy fix though, tap the hole and use a save-a- tread insert. I have done this to 2 holes 15 min. job. Blew plug num. 3 now comes the bad news. Previous owner must have this happen as well and tried to repair using wrong size insert. The treads in the plug hole are all bugged up and the right insert goes round and round. Since the temp here hasn't been above 30 since Dec. I used j.b. weld as tread locker and 2 weeks latter, so far so good. My question is does anyone know if you can go double oversize on the insert. Also if I have to replace the head can you use the 3v head on a 2v block as I've heard the 3v heads are almost garrentied not to blow plugs.
Posting Guru
Joined: Jul 2006
Posts: 1,720
Likes: 1
Ok you have a problem. I have seen (don't know if this is possible on yours) a pipe nipple cut to fit and taper threaded into a cylinder head. Then the pipe internals were cut to fit the spark plug. Short of something drastic like this I think a machine shop is your only choice or replacement head. Best of luck on this very difficult problem
Hotshot
Joined: Feb 2003
Posts: 11,537
Likes: 27
From: Long Beach, Ms.
Posting Guru
Joined: Jul 2006
Posts: 1,720
Likes: 1
Stop and contact Blownoutsparkplug.com
This is interesting. It is very similar to the taper pipe nipple end that I have seen used on a previous engine. The taper has better gripping force than the straight thread replacement. When I covered the pipe nipple this was to form the taper thread section. Then it would have to be internally threaded to match the plug. What was on the site was almost identical to the pipe nipple repair however more professionally done as we didn't have all the machine tools.
Posting Guru
Joined: Apr 2004
Posts: 1,342
Likes: 0
From: Georgia
I recently replaced my beloved 91 f 350. She had 350,000 on her 5.8l and was still going strong. Body and ele. system was getting tired. Replaced her with 2000 Ex. 6.8l. Though I got a good deal 4500. out the door with 121012 on the clock. All was well til tuneup time. After tuneup started blowing plugs. Never heard of that happening. Started doing my homework and found this to be a common problem. Seems like an easy fix though, tap the hole and use a save-a- tread insert. I have done this to 2 holes 15 min. job. Blew plug num. 3 now comes the bad news. Previous owner must have this happen as well and tried to repair using wrong size insert. The treads in the plug hole are all bugged up and the right insert goes round and round. Since the temp here hasn't been above 30 since Dec. I used j.b. weld as tread locker and 2 weeks latter, so far so good. My question is does anyone know if you can go double oversize on the insert. Also if I have to replace the head can you use the 3v head on a 2v block as I've heard the 3v heads are almost garrentied not to blow plugs.
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
Fleet Mechanic
Joined: Aug 2005
Posts: 1,339
Likes: 5
From: NJ
Trending Topics
Postmaster
Joined: Jan 2005
Posts: 4,424
Likes: 12
From: BC Canada
The 3v head wont be an easy bolt on. What I think you want is the later 2v head with the increased thread for the plug. There was an update on the later models, pre 2005 when the 3v came in. Or you could replace the whole engine and tranny with a 3v and torqueshift :-)
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread
Thread Starter
Forum
Replies
Last Post
coloradoclimber
Modular V10 (6.8l)
6
Jan 13, 2014 07:35 AM
videopro192
1968-Present E-Series Van/Cutaway/Chassis
15
Feb 1, 2010 03:02 PM