Exhaust manifold hole

Airtractr

Registered User
I asked about this a few posts ago and got a lot of good response but I have encountered an unforseen problem. I have a 94 pass side manifold I have used and it has a fine thread hole in the aft portion that looks to be a place where the O2 sens would thread in. I had down tubes made without cats and had the O2 sens bung placed on the pass side down tube as per original. I now need to plug this hole in the manifold and was told it was 18mm x 1.5. I ordered a plug from summit and a bold from fastenal. I just got the bolt and it is nowhere near the correct size. Anyone encountered this? I'm now concerned the plug I ordered is wrong too. I'll try to get some calipers on it and measure it shortly.
 
AHH! THANK YOU! yes, I just put the calipers on the hole and it is approx.
(.801) as measured by my digital calipers. The 18-1.5 plug will plug the O2 sens holes sure enough but now that I know what this was for obvoiusly that is not what I need. I seem to have packed away my auto math handbook, anyone remember how to convert a decimal to millimeters? Or just know the thread for plugging the egr hole?
 
There is a plug available from Ford, an older application on some vehicles that didn't have EGR. The Ford plug is E8TZ 9G458 A, about $24 wholesale price. It's M22 x 1.5, so you may have trouble finding something generic to fit there.


cheers
Ed N.
 
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