Nalanthi
New member
- Joined
- Jul 10, 2013
- Messages
- 36
- Reaction score
- 0
- Points
- 0
- Vehicle Year
- 1990
- Vehicle
- Ford
- Engine Size
- 4.0 OHV
So much as I hate to start a thread... I figure that it's time to reach out to the community to help me scrape the bottom of the barrel.
The backstory: Successful 2.9 to 4.0 swap happened about a month ago and ran just fine until an underlying issue with the HG/heads garaged me until I could assess the situation. Machine shop took forever (friend of a friend), but came back to me with one supposedly cracked head and the other with supposed valve problems (not sure I believe that second one). Not wanting to take any risks, I located a pair of heads verified 12k miles and tested fine - $50 a pop. Dude had them and never used them - obviously wanted them gone.
The heads arrived and were simply immaculate... no carbon anywhere and the valves were still for the most part shiny. I proceeded to rebuild the 4.0, new gaskets, head bolts, etc. all torqued to spec as outlined in the Chilton manual.
I fired 'er up - no smoke and no pressure in the coolant. I glove tested it JUST to be safe and everything seems to check out ok, but... For some reason it's dogging badly - almost feels like I'm behind the wheel of the 2.9 all over again.
What I know:
Not really sure if this is compression-related, as the block/rings/pistons were fine post-teardown and nothing leaks. I had to bastardize the vacuum system after a cluster I forgot fell across the exhaust manifold and fried off, but believe all major components necessary for a non-dogging engine are hooked up - a4ld, throttle body, etc. #3 is potentially suspect, as yanking fire doesn't affect idle. Fire and fuel verified in cylinder... so this probably isn't looking too good for me.
...hoping to high hell I don't have to yank a head (again) - not that it's a difficult job. The 4.0 is easy to work on.
The backstory: Successful 2.9 to 4.0 swap happened about a month ago and ran just fine until an underlying issue with the HG/heads garaged me until I could assess the situation. Machine shop took forever (friend of a friend), but came back to me with one supposedly cracked head and the other with supposed valve problems (not sure I believe that second one). Not wanting to take any risks, I located a pair of heads verified 12k miles and tested fine - $50 a pop. Dude had them and never used them - obviously wanted them gone.
The heads arrived and were simply immaculate... no carbon anywhere and the valves were still for the most part shiny. I proceeded to rebuild the 4.0, new gaskets, head bolts, etc. all torqued to spec as outlined in the Chilton manual.
I fired 'er up - no smoke and no pressure in the coolant. I glove tested it JUST to be safe and everything seems to check out ok, but... For some reason it's dogging badly - almost feels like I'm behind the wheel of the 2.9 all over again.
What I know:
Not really sure if this is compression-related, as the block/rings/pistons were fine post-teardown and nothing leaks. I had to bastardize the vacuum system after a cluster I forgot fell across the exhaust manifold and fried off, but believe all major components necessary for a non-dogging engine are hooked up - a4ld, throttle body, etc. #3 is potentially suspect, as yanking fire doesn't affect idle. Fire and fuel verified in cylinder... so this probably isn't looking too good for me.
...hoping to high hell I don't have to yank a head (again) - not that it's a difficult job. The 4.0 is easy to work on.
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