setting up my "new" 94

[coxfmly]

Hello,
I have just purchased a 94 sub, 4x4, in perfect condition.....subject to the blown motor:(
I was told #4 cylinder has zero compression. No idea why but the motor will be pulled so I will see then....

Once I get the new motor in, I want to install a pyrometer and boost gauge. Where should the temp probe be placed on the down pipe? I noticed an indention about 5" long on the down pipe, clearance or ?. Would it be a good idea to wrap the down pipe in heat wrap?

Would there be a prefered place on the manifold to install the line for the boost gauge?

Thanks...

[Robyn]

Best spot for the Pyro probe is in the crossover pipe, just below the LH manifold connection.

Take a look at things before you pull it apart and pick a spot that will not cause any interference and mark it.

While things are apart, drill the needed hole and install a "weld Bung" (weld it in) in the pipe.

As far as the boost gauge tap, while the engine is apart, drill and tap for a fitting in the air top hat.

I like a spot on the back side of the round tube portion that runs over to the turbo.

1/8" pipe tap is usually a standard.

These things can all be done while the rig is down for the engine swap.

Wrapping the down pipe is not needed.

Now, installing a performance down pipe without the crimps and flat spots is a great idea.

If the rig has a CAT I would seriously thing about replacing it with a flow though unit from "Frozen Boost"

A complete free flowing exhaust will help a bunch to add power and life to your new engine.

The "CAT" plugs up in due time and really causes issues with air flow.

a 3-1/2" system is enough for most applications other than for the HD towing and all out performance hog.

Have fun and keep us posted.

Missy

[6.5 Detroit Diesel]

ditch the cat if you are able to. like robyn said, un needed exhaust restriction. check to make sure you are able to in your area.

the reason for putting the probe in on the crossover pipe is that it is a better idea to get temperature readings before the turbo as opposed to after. call it peace of mind, whatever. but i would rather see the temp before it can hit 1250F pre turbo.

reality is from what I have seen, unloaded driving with a chipped or tuned truck, you will not have to worry about melting down anything, even if you have your foot in it constantly. trouble comes under load when maybe your driving pattern is off a little. that's where that pyro will come into play.

[coxfmly]

Robyn and Detroit Diesel,
Is it best to get the probe as close to the manifold connection on the L/H side or the turbo connection? So I'm going before the turbo, my 6.2 Bank's is after. I will take a look at these areas and let you know if I get lost :)

The previous owner said he had installed a performance exhaust, not sure what type. It looks like a flow master type muffler with a short CAT, might be 3.5" dia.
I will try to get a bit more info on the system and let you know.

Would you recommend a manufacturer of gauges? I have seen sets on line with boost range up to 40 an temp of 2K. Are sets usually in the 3-4 hundred dollar range?

Thanks again for your help, Paul

[Robyn]

Get the probe right up under the outlet of the LH manifold.

This gives the closest reading to the exhaust Ports where all the heat is.

The Cat I refered to by Frozen Boost is a can with a large straight through pipe.

This little jewel satisfies the snoopy peekaboo test at your local Enviro centers.

Causes no restriction but looks way Kewl :rolleyes:

Missy

[handcannon]

Just as an option to the location that MGW described, there is a small flat area cast in as part of the pass side exhaust manifold. This spot is just before the turbo on the side of the manifold facing in towards the motor. You have to drill and tap this spot so it may be as much work to do as removing the crossover and welding the bung on.

I was just able to get my drill in there with the manifold in place, it's close. I started this with a cold motor and drilled in about 3/16ths inch. Then I applied grease to the drill flutes, started the motor and let it idle while I finished drilling through. Between the grease and the manifold being pressurized with exhaust all the metal shavings come out on the drill bit. I then tapped the hole using the same grease and exhaust pressure method. You do have to work quickly to finish the job before the manifold gets too warm to work on. I did let the motor set for a while to cool after drilling and before tapping the hole.

This is not the only way to install the thermocouple, just an optional way, IF you are very CAREFUL.

Don