Hopefully everyone had a safe and happy new year! I was able to further investigate my problem. First of all, it had another severe episode and this time while trying to clear itself the SES light came on. I do not have a scanner but I went to Autozone and the code description was "multiple mis-fires" I pulled the coils and checked them hot and they all tested ok. Changed my oil and piddled around until it was cold and checked them again. No real change. Everything within the normal ranges and pretty consistent coil to coil. This morning after sitting all night I pulled off the FPR vacuum line again and do smell a hint of fuel in it. I also noticed that my coolant was down about 2 -3 inches from the last oil chance (3K miles) and there is a lot of oily muck laying in the valley between the UIM and the heads. Looks like she may have the startings of the dreaded UIM failure. I have a Dorman replacement that I got new off ebay about a year ago. I figured I'd need it sooner or later. It does not have the replacement stovepipe in it though like the new ones. Could someone make a drawing of the replacement unit? I have a machine shop and could make one. I could possibly make some for others as well???!!!

Bob...you are on the right trail. I'm off to post the link for Bob D and Bill Buttermore as they are the stovepipe experts. I know Buttermore posted the specs plenty of times, I can't quite locate them though.

See PM, Bob.

And I think Archon got the right link with this

http://www.bonnevilleclub.com/forum/...769&highlight=

Here are some reduced diameter stovepipe specs. All in inches.

Overall length............................................ .................................................. ........................1.42
Base (shoulder) diameter for 95-98 stovepipe bore in lower intake manifold......0.750
Base (shoulder) diameter for 99-up stovepipe bore in lower intake manifold......0.625
Shoulder height (to be flush with lower intake manifold deck)...(approx)................0.275
Minimum recommended pipe O.D. above shoulder.......................................... .........0.500
Minimum wall thickness (stainless steel)............................................ .........................0.035
Minimum wall thickness (aluminum)........................................ ......................................0.060
Maximum bore size based on above (aluminum)........................................ ................0.380

That'* for basic pipes. If you can obtain corrosion resistant aluminum alloy, that would be preferred for improved cooling from contact with LIM bore. Commercial pipes (APN, Ken-Co), are turned from mild steel. Chamfer 60* bottom of shoulder to help start into bore when installing. Radius profile at top of pipe to minimize possiblility of whistle.

That takes care of the stovepipe. But for the best protection for your new UIM, you need to shield the hot pipe so most of the heat from the pipe will be reflected rather than absorbed into the plastic. This can be done by sleeving the UIM, or by shielding the pipe with thin-wall stainless. Here are two options:

1. Enlarge UIM bore and JB weld in .875 x .805 x .820 length sleeve. With a .500 pipe, the insulating gap produced is 0.152.

2. Increase height of RD pipe shoulder by .150 and turn this top shoulder to .710. This will allow a thin wall (.750 x .710 x 1.05 length) shield to be press fitted over the top shoulder to create a shield around the pipe. This protects the UIM bore without altering it at the expense of a smaller insulating gap between the pipe and heat shield. Gap produced with a .500 OD pipe = 0.105.

I have the .875 x .805 in 304 stainless and the .750 x .710 in 321 stainless and will sell you a piece of either for $5 including postage. I also sell 304 stainless stovepipes for 95-98 models for $10. These comprise a .625 OD pipe with a .750 OD ring pressed on one end. They work well but will not conduct heat as well as aluminum. I purchase all my tube stock from McMaster Carr in Chicago. PM me if interested.

Below I have included a drawing of a reduced diameter pipe the same diameter as the pipe supplied with new Dorman UIM kits, that is, .510". The base or shoulder of this pipe would be turned to .750 to fit the LIM bore of 95-98 L36 engines, and would be turned to ..625 to fit the LIM bore of 99 and newer L36 engines.

Actually, that link is for altering a Dorman pipe for the 95-98 models. And Bob said he did not have the Dorman pipe with his kit.

That darn Archon....geez....that guy! lol