Cracked my lower intake

[JustA5.0]

This will teach me for wanting to get all the gauges working on the instrument cluster. I replaced the coolant temp sender and torqued it down to the stock 5.0L intake spec, completely oblivous to the fact I have a GT40 lower. Anyways, guess I torqued it down too much as I was doing a coolant flush yesterday and noticed water hissing around the temp sender. Shut the car off and saw the more than a hairline fracture.

This is the first time anything like this has cracked on me, so I'm not sure which direction to take. I am debating whether to get it welded or look for a used lower locally/ebay. I called a few shops yesterday and was told they'd have to look at it before giving me a quote to fix. How much do you think this route would cost (I'll need the hole for that sender re-tapped as well)? I have also read something about getting it drilled and pinned at the same time, but I am unfamiliar with that terminology . Assuming the machine shop does a good job, how much longevity should I expect from this weld? If I can get 5 years+ out of the job it'd be worth it. If it's just gonna crack in a year or two, I'm not sure I should bother.

Now aside from durability, another reason I was thinking about getting a good used lower is my plan (before this incident) was to get the motor rebuilt/freshened up in the spring. I wanted to bore to 306, a nice set of aluminum heads, and cam to match the heads and gt40 intake (I love the tubular look so I'm keeping this). Certainly nothing crazy power wise, but will the increased flow make welding my current lower a poor choice?

Thanks for shedding some light on a crack noobie

 

[86bluecobra]

I would just go get it welded up and drilled and tapped. It will be good as new. I doubt you would ever have to worry bout it again aslong as they do a good weld job.

 

[JustA5.0]

Alright Blue

After doing some more reading, it seems pretty common to have the intake welded and last. Was worried it might be a band-aid temporary solution. Sounds like it should only cost $50 or less for the actual machine work. The place I'm thinking of taking it to does a lot of stock thru to high-end drag motors, so I'm not worried about a poor job, but is there anything else I should specifically ask them to do (other than make it function like new again). And what is pinning? Or is that just another word for tapping?

Also, I remembered now when I unscrewed the old sender it took a lot of force (it squeeked the first few turns), and was either torqued down too tight or had no thread sealant applied. It could quite well have cracked then, and wasn't noticed until the engine temps spread the crack a little more yesterday. The torque spec for a stock lower said 9-17lb-ft for the sender bolt, so I torqued the new one 13lbs. It doesn't seem like a lot to me, but for future refrence how much should it be torqued to on a Cobra/GT40 lower? BTW I could not thread it in very far by hand, before it needed the socket on there.

 

[talladam]

Maybe the threads on the new sensor were f'd up?
My explorer intake had a decent crack in the front left ear. Cost me about 30 bucks to have it fixed. I can't recall what they did besides welding it.

 

[JustA5.0]

If anything I think the old one coming out f'd things up, like it wasn't threaded in properly when originally installed. I did pull the new sender and the threads appear to be undamaged.

Yeah that's a relief it won't cost very much to weld.

 

[tmoss]

use good pipe dope and don't crank down on them for this very reason.

 

[JustA5.0]

Used permatex thread sealant with PTFE, and torqued it down to Ford's spec.

 

[5.0Droptop]

dont tq it.

Tighten it enough to do the job.

If it leaks you can snug it some more.

Otherwise it will possibly crack again.

 

[88stangmangt]

it is a NPT thread so the more you crank on it the more it spreads out what its going into....if it turns out to be more than you want to invest in it i have some explorer intakes for sale.