[crhumper]

This question pertains to small block ford engines, specifically a 289. From a number of sources its been recommended to tap the oil galley holes for screw in plugs. Many say to "just run a 1/4'' tap through the hole", but the hole is larger than that required for a 1/4" npt tap. For you guys that have done this yourselves, how do you usually do it?? Thanks

 

[fogged408w]

The oil hole takes a 1/2" press in oil plug, but to tap it for a SCREW in pipe plug you will need a 1/4 18 tapered pipe tap.

http://www.engineersedge.com/tap_drill_chart.htm

 

[crhumper]

Right. I have the correct tap, but the hole is 1/2", while the npt tap requires a 7/16" hole. So you guys are just tapping it anyway?? Thanks

 

[fogged408w]

correct, the tapered 1/4 tap will start loose. If you started with a 7/16 hole and just threaded it as normal then the screw in plug would only scew in a little bit and stick out causing interference with the camshaft retainer plate and/or the timing gear. You want the plug to screw way in so its flush.

If you want, make a practice run on something you can throw away untill your convienced it will work.

http://www.pricemotorsport.com/Oil_Restrictor_Kits/oil_restrictor_kits.html

Part No. OR-01
302-351W Oil Restrictor Kit
(4) 5/16-18 Straight threaded plugs
(1) 7/16-20 Straight threaded plug
(1) 1/2-13 Straight threaded plug
(1) 3/4 Cup plug
(4) 1/4-18 Pipe plugs

******(3) 1/4-18 Pipe plugs (for the front)********


_________________

5 second 1/8 mile



<font size=-1>[ This Message was edited by: fogged408w on 6/27/05 9:36pm ]</font>

 

[beegshot]

Be sure to check the lifter bores on the front when you are through tapping. My 306 had a burr in the lifter bore after the tap ran through. A couple passes with the lifter bore hone cleaned it up nicely.