I am going to tap the 3 holes in the front of my block and put pipe plus in them instead of the normal cheap plugs.

Does anyone know the thread size for the tap?

 

27 TPI, is that what you're looking for the pitch?

 

Actually aren't they classified by like 1/4NPT, 3/8NPT ect.?

That is what I was looking for.

 

That's what ede is telling you. A ¼" pipe tap is actually ¼-27 tapered. The holes for the Welch plugs at the front can be tapped ¼-27, the same as the holes at the rear:

 

Make sure that when you buy the tap, you get the correct size. You are going to want the one that says 1/4 NPT.

 

Thanks alot guys.

Where is a good place to find these taps?

 

I was doing a little searching and 1/4-27 doesn't seem all that easy to find.
I have found 1/4-14 and 1/4-18 but that is about it.
Anyone want to sell/rent me one?

 

Pipe taps are not listed by thread pitch. They're simply listed as 1/4, 3/8, 1/2 NPT. Pipe threads are tapered so a standard thread pitch tap will not work.

Any tool supply place will carry them.

 

Thanks Stephen 87 IROC

I was confused by the 27, I understood pipe threads to be just that 1/4"NPT, 1/2"NPT etc

 

27 threads per inch is for 1/16", and 1/8" NPT, 18 threads per inch is for 1/4", and 3/8" NPT.

Drill tap size for 1/4"-18 NPT is 7/16ths.

 

Menards and True Value Hardware carry them.

 

btw a comon mod once youve installed those oil passage plugs is to drill a .032 -.036 hole in the center of the plug on the pass side of the engines oil passage plug on the front end to spray pressurized oil on the back of the cam/gear/timing chain .
a further mod is to cut a small grouve in the block where the LOWER distributor oil band forms part of the oil passage above the distributor/cam gear contact point to spray oil directly into that area.
and a small grouve in the lower lifter bore surface like this

http://www.compcams.com/catalog/335.html

these three mods tend to supply oil where its needed but the standard system tends to deliver less oil at low rpms, this tends to reduce wear while not effecting the oil pressure noticably (IF THE WORKS DONE CORRECTLY, and YOU ENGINE CLEARANCES were correct to begine with) especially if a high voluum pump and windage screen is used on a baffled 7-8 qt oil pan that you should be useing on a performance engine

 

great tips grumpy!
any chance of doing the first or second steps after the shortblock is assembled?(cam not installed yet)
Eric B

 

if your CAREFULL those steps can be done with the crank assembly in place

 

awesome grumpy!
i think i'll have somebody with steadier hands than mine try it!(if i decide to go there.grease up the drill bit so the metal frags stick right?
E.B.

 

"grease up the drill bit so the metal frags stick right?"

why??
remove the oil passage plug and drill it in a vise,useing a drill press,while protecting the threads with wood in the vise jaws

heres a drill chart, I use a 1/32" bit, as the smallest up to a #65


http://bobmay.astronomy.net/misc/drillchart.htm

on the grouve in the lower distrib band in the block, a few magnets and a triangle jewlers file makes short work of that problem as it only needs to be a few thousands wide and deep

 

gotcha!
looked right past the obvious!

 

Nice tips grumpyvette, I was going to drill the oil gallery plug, but the other tips sound good too.
I don't think I am to concerned about the lifter bore groove as I am running roller lifters.
Do you know of any pics floating around that show the dist. bore mod? Does this mod primarily just spray oil on the dist. gear?

 

"Does this mod primarily just spray oil on the dist. gear?"

it sprays additional oil into the distributor/cam gear contact area

 

NEVER do any kind of grinding or cutting on an engine once it's been final washed and assembly has started!!!

 

IF your against some careful file work with a magnet to catch the
metalic dust, you can easily put the grouve in the lower distributor housings lower band
BTW the picture depicts the grouve SLIGHTLY SMALLER than IDEAL and accomplish almost the same result, the differance is that as you change the ignition timing your also changing the area the grouve sprays as it MOVES as the timing changes (unlike the small grouve in the block)
were not talking about major machine work here, 3 minutes with a jewlers triangle file can easily give you the grouve a few thousands deep and about 3/8" long thats necessary to spray extra oil on the gear contact area, and while its always a better idea to do all machine work then clean the block totally, youll get far more more metalic dust in your engine as the rings and cam lap in, durring a normale engine break in procedure than youll ever get by placing a good magnet (temporarily)next to the area while you file a 3/8" long grouve a few thousands deep. (as almost all dust is instantly trapped on the magnet)(in fact I seriously doubt any can escape the magnetic field)


"Any source for the magnets Grumpy? "

http://www.wondermagnets.com/cgi-bin...catalogno=0001

these are NOT REFRIGERATOR MAGNETS "#0001" can pick up a SBC cylinderhead, and you wont beleive the amount of crud they remove from your oil and prevent from reaching the bearings
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And FWIW, if you're reading this and want to have oil holes in the front lifter gallery plugs, and don't want to tap the holes, and/or don't feel cozy running a tiny drill bit into your engine, you can pull the original cup plugs and install factory pieces that were intended for LT1 engines. Those came from the factory with a 0.030" hole in BOTH front plugs to help oil the timing chain and water pump drive gears. They are pennies each.

You can purchase 1/4-27 (¼" pipe) threaded plugs with the oil holes alread drilled for about four bucks each, GM P/N 361997, so all you have to do is pull the old plugs and thread the gallery holes:

http://www.sdpc2000.com/catalog/1831...h-035-Hole.htm

 

Hey guys I was able to borrow the tap from a co-worker, and it turned out great! You don't even need to drill first. Truly a piece of cake.

Thanks again for all your help and advice.

 

Glad it went well. I apologize for my error in quoting the "¼-27" thread. rgarcia63 gave you the straight scoop on thread pitches for pipe taps.

Are you going with the oiling plugs or just standards?

 

I am just going to drill the two side plugs at .030"

I also made a slight groove in the dist. hole.