Originally Posted by ksmdigital
I'm in the middle of installing my new UIM with a new EGR tube on the lower intake manifold.
The old EGR tube had come out by it'* self and I don't want this to happen with the new EGR tube.
The directions said to tap the tube in place with a socket, but I still think that I can pull the tube out by hand.
Would some RTV help to keep the tube inplace or should I try to tap the tube in harder?
The highest temperature RTV I know of is Ultra copper rated at 700F. I think the exhaust gas temperatures will exceed that. [EDIT: But the hi-temp RTV may work OK anyway because you are on the cool side of the pipe against the aluminum of the LIM which is cooled by circulating coolant to 200F. As long as your engine cooling system is properly bled of air, the RTV should never see 700F even though the inside of the pipe may greatly exceed that. In addition, the metal at the base or shoulder of the reduced diameter pipe is very thick, so a significant tremperature gradient might be expected between the gas and the RTV. Still, there is no reason to take a chance on RTV - you can just use the dimpling method described below.] BTW, to make sure you don't introduce air bubbles into your engine consider this fill method: http://www.bonnevilleclub.com/forum/...=article&k=100
Whose upper are you using? If it is an APN, the new stovepipe should drive into your lower intake manifold bore OK, assuming you have a stock manifold with a 3/4" bore. If the pipe is just a little loose, you could dimple the side of the base in a few places with a center punch to tighten the fit in the bore. Don't strike it so hard that you distort it out of round or it may not go in at all. Like willwren said, if there are any gaps, they will quickly fill in with carbon from the exhaust gas.
If you are using a Dorman, and it only came with one stovepipe, it is sized for the 5/8" bore in 99-'03 lower intake manifolds. It will not fit your manifold without an adapter ring. You can cut a .250" ring from a piece of 3/4" tubing with a .065" wall thickness and press this onto the shoulder of the Dorman pipe. This will allow you to use the 5/8" shoulder pipe in your LIM. If you can afford to wait, I can send you one of these adapter rings. The method of pressing on the ring is shown here: http://www.bonnevilleclub.com/forum/...ic.php?t=54769
An even better fix if you are using a Dorman upper in a 95-98 is to install a shielded pipe. This begins with the adapted pipe described above, but the ring is cut very short to allow a thin-wall metal shield to be driven on top of the ring around the pipe. This provides a heat shield to protect the plastic EGR bore in the new upper, and when used with the .510" OD Dorman pipe, provides an air gap between the pipe and the shield of .100". PM me if you have the Dorman and are interested in this option.
Here is a 5/8" pipe with a short adapter ring for a 3/4" bore, and a short, thin-wall shield driven on top of the ring. The little shield is intended to protect the plastic UIM gasket frame. The Dorman pipe is much smaller at .510" and would provide a much larger gap than what is shown here. Imagine that shield extending up to the top of the plastic of your UIM but shorter than the top of the stovepipe.
This is the sort of thing you would like to achieve. A metal sleeve to protect the plastic UIM, and a reduced diameter stovepipe to provide an insulating gap between the hot pipe and the sleeve. The modification shown below is a 5/8" pipe with a thin-wall (.805" ID) sleeve set in place with copper RTV. The gap is .090". The APN kit will give you a sleeved upper and a gap of .125". If you want this ultimate protection with a Dorman, you have to sleeve the upper or shield the pipe.
Dorman is supposed to be providing both 3/4" and 5/8" pipes in the newest kits. I don't know if these have yet hit the market. If so, make sure you are using the right pipe. If it is the right size but just doesn't fit tightly, try the dimpling method.