Drill and Tap Intake Manifold

[bknbronco]

Anybody drill and tap there intake manifold for a extra temp sending unit?

I would rather not use a aftermarket intake and id rather not use a water neck with the port.

 

[DirtDonk]

Subscribing. Have only done it to a thick section of an EFI intake near a runner for the IAT sensor.
Very easy to go too far with a pipe tap, which is why I mentioned it in your other thread. So go easy on that part after the hole is drilled.

Interested to hear what others have done.

Paul

 

[Broncobowsher]

A lot of people just use a Tee fitting. Both sensors in one hole or one in with the heater hose. That's how ford did it, the nipple for the heater also held the ECT for the computer.

I don't see why you couldn't drill and tap. The hardest part would be finding the right spot. You need a place that doesn't interfere with anything. Is lined up with the water passage. Is flat enough that you will be drilling and tapping squarely into material. And the wall thickness is enough to support the threaded hole.

 

[Skytrooper15]

I talked to the guy that did my engine work at a machine shop and he said to do a proper job on cast iron to tap a new hole he heats the intake up to 600 degrees and then drills and taps a hole usually in a thick spot on the intake.I go along with most members that said to use a tee fitting or either let a machine shop do the job.

 

[Steve83]

Temperature doesn't work with a T - there has to be flow past each one. Pressure works with a T, but not temp; and Ford never put 2 temp sensors on a T.

Why do you need 2? When I needed another temperature switch for my (temporary) e-fan, I soldered another bung into the copper heater nipple I had soldered together a few years before (when they weren't available new):


(phone app link)

 

[pcf_mark]

I needed two - one for EFI sensor and another for the stock gauge. I drilled and tapped the intake at the rear where the crossover for the head is located. Learned two things - it is very thin and cracked. Then I learned it was 20-30 degrees cooler because the water had not circulated through the head yet. Then I switched to thermostat housing that had a drilled and tapped fitting right out of the box! Now my EFI is in the manifold, stock gauge is in the t-stat housing and heater hose is in the other hole at the front. Advance Auto $15.

I was tempted to splice it in the heater hose too but it looked like one more chance to leak with the extra hose clamps.

 

[bknbronco]

pcf_mark.....did it crack when you tapped it or not until you installed the sending unit and tightened it? I cracked a intake manifold once by over tightening a sending unit and had to weld it up. Mind you that was a stock hole not one i added.

Aa "T" fitting seems like the worst route to take as well as the ugliest and most inaccurate......not a option for me. Someone mentioned needing a flat spot to drill and tap. I got skill son.....i have drill and tapped many things that were round including my steering box valve housing. Another guy mentions needing to heat the manifold to 600 degrees? WHAT??? were not welding it. I tapped my steering box and never heated it. Never heard that in my life.....should i be peening it as i tap it too?

The thermostate housing seems the easyest way for sure. BUt Ill keep looking for ideas where to drill and tap the intake.

 

[Steve83]

The t-stat housing doesn't have continuous flow - that's why Ford usually puts the sensor on the heater core loop outlet.

 

[migs]

I put the sniper's water temp sending unit on the manifold in place of the unit for the factory temp gauge. And just to keep the factory gauge functioning as a redundant backup, I drilled and tapped the thermostat housing for the original sending unit... real easy job with the pre-cast hole and chamfer already there.
It's running a 195 thermostat and the temp readings between the two don't seem to vary much.
I hardly look at the stock gauges anymore... with the sniper's handheld unit mounted on the dash I have just about every gauge readout I need on display.

 

[bknbronco]

The t-stat housing doesn't have continuous flow - that's why Ford usually puts the sensor on the heater core loop outlet.

Which makes no sense because my heater does not flow until i open the valve.

 

[bknbronco]

I put the sniper's water temp sending unit on the manifold in place of the unit for the factory temp gauge. And just to keep the factory gauge functioning as a redundant backup, I drilled and tapped the thermostat housing for the original sending unit... real easy job with the pre-cast hole and chamfer already there.
It's running a 195 thermostat and the temp readings between the two don't seem to vary much.
I hardly look at the stock gauges anymore... with the sniper's handheld unit mounted on the dash I have just about every gauge readout I need on display.

I dont plan on mounting the sniper control unit, ill get it running and throw it in the glove box. Is the stock guage accurate below operating temp or just once the t-stat opens? Ill be ordering the neck with the port for sure just in case i decide pulling the intake is more work than its worth. That water neck port looks nice and clean. Thanks for the pics. Are you using the sniper Hyperspark distributer?

 

[tirewater]

Which makes no sense because my heater does not flow until i open the valve.

The temperature difference is probably pretty minimal regardless of heater valve position. The later CA emissions Broncos have two temperature controlled port vacuum valves (EGR & Vacuum advance) on the elbow.

 

[bknbronco]

The temperature difference is probably pretty minimal regardless of heater valve position. The later CA emissions Broncos have two temperature controlled port vacuum valves (EGR & Vacuum advance) on the elbow.

really? so why do we have radiators in our trucks? why do we have tiny power steering coolers? the radiator in a heater box is pretty big and my heator fan is huge. Sure it works fine but i dont see that location being a good choice. Water neck would be cleaner.

 

[tirewater]

I dont plan on mounting the sniper control unit, ill get it running and throw it in the glove box. Is the stock guage accurate below operating temp or just once the t-stat opens? Ill be ordering the neck with the port for sure just in case i decide pulling the intake is more work than its worth. That water neck port looks nice and clean. Thanks for the pics. Are you using the sniper Hyperspark distributer?

If you put a sensor in the thermostat housing, the reading won't be very accurate until after the thermostat opens. My second gauge would sit at ~90-110 degrees until the thermostat opened, then it would shoot to ~190.

I wouldn't use the thermostat housing for FI as it could affect cold drivability.

 

[bknbronco]

If you put a sensor in the thermostat housing, the reading won't be very accurate until after the thermostat opens. My second gauge would sit at ~90-110 degrees until the thermostat opened, then it would shoot to ~190.

I wouldn't use the thermostat housing for FI as it could affect cold drivability.

no ill put the FI sensor in the intake stock location. Just would like my guage to be accurate. Thanks for the real world testing and feedback. I think the water neck and heator hose will be the same outcome. Tapping the intake would be the best and hardest choice.

 

[tirewater]

Yeah, it would be best to put the FI sensor in the stock location and relocate the temperature gauge.

Here's a picture of a heater outlet elbow (ford ranger) with a temperature sensor bung on it. Even with the heater valve closed, that elbow is going to be pretty hot from heat transfer from the manifold as well as any turbulent flow. That said, even if it was 10 degrees off, I wouldn't use it for a gauge. (I'd have to do some testing first).

no ill put the FI sensor in the intake stock location. Just would like my guage to be accurate. Thanks for the real world testing and feedback. I think the water neck and heator hose will be the same outcome. Tapping the intake would be the best and hardest choice.

 

[Broncobowsher]

Even with the heater flow turned off there is enough turbulent flow and heat conduction that it is a good reading. Done it before, everything is good. There is more error in the senders that that tiny location change. You could also argue that the stock temp sensor isn't valid because it is only getting water temp off the driver's side head and the passenger side head mixes in after the sender.

I saw the OP was Minnesota so I didn't suggest this, but it works fine in AZ. Tap the heater water off the back of the intake and use the 2 port up front for the gauge and computer. The downfall of this is the water isn't as hot as it hasn't traveled through the heads yet. But you don't need that much heat in AZ typically.

 

[pcf_mark]

I cracked my intake when tapping it with the pipe tape.

I have the same "slow" warm up on the factory gauge using the t-stat housing but one the t-stat opens it ready as accurate and me EFI gauge.

 

[Skytrooper15]

pcf_mark.....did it crack when you tapped it or not until you installed the sending unit and tightened it? I cracked a intake manifold once by over tightening a sending unit and had to weld it up. Mind you that was a stock hole not one i added.

Aa "T" fitting seems like the worst route to take as well as the ugliest and most inaccurate......not a option for me. Someone mentioned needing a flat spot to drill and tap. I got skill son.....i have drill and tapped many things that were round including my steering box valve housing. Another guy mentions needing to heat the manifold to 600 degrees? WHAT??? were not welding it. I tapped my steering box and never heated it. Never heard that in my life.....should i be peening it as i tap it too?

The thermostate housing seems the easyest way for sure. BUt Ill keep looking for ideas where to drill and tap the intake.

I am telling you how a professional machine shop does his tapping on cast iron not how some shade tree mechanic welds cast iron.By the way cast is very brittle and I wouldn't attempt to tap an intake manifold.

 

[bknbronco]

I cracked my intake when tapping it with the pipe tape.

I have the same "slow" warm up on the factory gauge using the t-stat housing but one the t-stat opens it ready as accurate and me EFI gauge.

Ya thats what i was afraid of.....the pipe thread tap wants to expand the hole as it cuts and the result is cracking. Same result if you over tighten a sending unit. And if you tap it on a radius the hole will push up instead of out and will crack that much easyer. Maybe heating the metal combats this but i dont think 600 degrees would do much.