Plugging air pimp holes in heads?

[MrKwik]

I have a set of heads that I need to cap the holes at the back of the motor where the air pump tubes bolt up and also need threaded inserts to mount the accessories on the front of the engine. I have heard poeple talk about putting a short bolt or broken off spark plug in there before. Now I dont plan to put a spark plug in there but I tested it to see if it fit so that I could find an appropriate size bolt but the plug is too small and I cant seem to figure out what size bolt it takes. I also tried a helicoil for the size of the accessory bolt on the front of the head but it fit too loose. Is this some oddball thread or does anybody know exactly what size it is? I would use the threaded inserts that ford sells but they are $15.50 each! I can think of alot better things to spend $60 on. Does anybody else sell the inserts or are there other options?

 

[ROBSLXTASY]

yea

How about a 7/16's inch bolt??Worked for me..

 

[cmb91LX]

I have used 7/16 bolts in the past as well

 

[drillgod2000]

i just made my own cover plates and used the stock bolt to hold them on.

 

[bobcatv8]

Air pimp???
Purchase only 2 of the proper inserts from Ford for the front holes. Then plug the back holes with bolts or whatever. There isn't any good substitute for the OEM inserts to shrink down the thermactor holes to the proper 7/16 size that I know of.

 

[89MustangGX]

I believe the bolt size is 5/8" IIRC -- and you will probably need to cut down the bolts. The threads are probably full of carbon, which will make threading them difficult. Clean them up good and go at it!

 

[dcarlson]

i just made my own cover plates and used the stock bolt to hold them on.

This is the easiest way to go. As was said, the stock holes will be caked with carbon and a real pain to thread in, unless the heads are new.

 

[5spd GT]

. If you are going to delete the smog pump then you will need a threaded insert known as a thermactor plug. They screw into the back and front of your heads. Put silicone on the threads to prevent any exhaust leak when installing them. The thermactor plugs you will use for the front (same as back) will go to make the head holes smaller so the accessories can bolt up like your power steering stud and one of your bigger alternator bolts that go through you alternator bracket. The back thermactor plugs you will use just block off and delete the smog equipment’s previous hookups. You can get them at a Ford Dealership - part # F4ZZ-6E086-A or you can buy some from Summitracing - part # TFS-51400265 and they run anywhere from $3 to $12 dollars from what I have seen. Summit has them cheaper.

Good Luck

 

[cheddarbacon]

gasket silicon

I have found that filling the hole with gasket silicon wont leak and stays hard and cool no matter how hot the motor gets.