1971viking

I have a new timing chain cover and was wondering if using a 1/4 x 20 tap to thread it was correct?

MDchanic

I don't have any of those screws in front of me, but I halfway think they're 5/16x18.

At the risk of sounding obvious, look at the screws, and tap out the holes to whatever size the screws are.

- Eric

Oldsmaniac

I never installed a new one and thought they would be already threaded?? I dont think they are as large as 5/16 or even 1/4. As Eric said compare an old bolt and tap accordingly if necessary.

Octania

a) which holes?

b) the smaller ones are 1/4-20, but

c) those screws I believe make their own threads as they are inserted- notice the trilobular design, which also acts as a self locking feature. To tap the hole would defeat that feature.

MDchanic

I'd tap 'em anyway - it's just the way I am.

- Eric

1971viking

The two holes near the bottom. Thescrews in the old timing cover were 1/4-20.

So don't tap it? I thought this would be better and stronger than letting the self tapping screw do the work.

Looks like this.

Oldsmaniac

I would tap it first, why put metal shavings inside the engine even though thats what the factory did?

1971viking

The timing cover is off the motor so no shavings.

I read on this forum that you don't have to remove the entire oil pan to put the timing cover off/on. They say just losen the front bolts. This would be great since the oil pan gasket is only 1 month old (composite rubber cork). Hate to take the entire pan off and start over but if that is the correct way to do it then I guess I will. Nothing like doing everything twice.

ah64pilot

What did you use to seal that oil pan gasket with? I did the same thing when I first put my motor together, I forgot to install the oil slinger and had to pop the front cover off after the pan was already sealed.

I used aviation form a gasket that doesn't ever get hard so I was able to do it quite easily, but I did have to loosen more than just the front bolts on the pan. I believe I had to do over half the bolts to get the pan off enough to put the timing cover on. In the end, it only leaked a minimal amount at the front seal...but then again, I used aviation form a gasket that doesn't harden. If you used anything else it may leak on you.

IMO, if the motor is out...doing it right will save you headache later.

1971viking

I used RTV Blue and a fel-pro compsite gasket. I think I will start over and pull the entire pan since the motor is already out.

ah64pilot

Can I make a suggestion?

When you go back together with it, use a new composite gasket and coat it with Fel-Pro Aviation Form a gasket on both sides. On the end seals use Ultra Copper under and on top of the rubber seals. Then torque the pan down as usual.

The aviation form a gasket will look like wet oil when it's all "dry"...but it never really hardens and I guarantee you will not have a pan leak on the side rails. The reason for the Ultra Copper is because it stays pliable and never get's "hard". If you notice a drop from the front or back seal, you can spray it with Brakleen and "push" more Ultra Copper into the leak area and it will seal it up. At least, this has always been my experience.

I also use Ultra Copper on the intake manifold ends (no rubber seal) and around water jackets. It's good high temp stuff

1971viking

OK

Timing cover tapped. Pan off, old timing cover off. Need to prep for new gaskets.

Fel-Pro Aviation Form for the pan gasket and ultra copper for the rubber ends. On the way.

How about the water pump. Spray copper gasket on the paper gasket or something else?

TripDeuces

Couldn't you also weld 1/4x20 nuts to the back of the timing cover and not worry about shavings, stripped holes, etc?

11971four4two

What I have seen done is install threaded rod so it is flush with inside of the timing cover and weld it. Now you have a stud (or studs) for alignment of the water pump. Use a nut and washer , being careful not to over tighten and strip the 1/4-20 threads , to hold the pump in place while the other fasteners are started.

Octania

I think unless you have an engineering degree or two and lots of money on hand for R&D, you will be hard pressed to devise a better solution to fastening the water pump in place than the factory used.

Unless your factory parts are no longer serviceable... then, sure, work your best voodoo on what you got.

http://www2.dupont.com/Plastics/en_U...ign/DCI283.pdf

http://www.fastenal.com/web/products...l.ex?sku=32586
Trilobe, or Thread Rolling, screws have a blunt tapered point that requires a pre-drilled or punched hole; eliminates chips and permits replacement with standard screw.
http://www.americanfastener.com/fast...eadrolling.asp
http://www.taptite.net/taptite/duotaptite.asp
TAPTITEŽ screws were the leap forward in high production assembly using threaded fasteners. DUO-TAPTITEŽ screws represent the refinement of the TRILOBULAR™ principle for specific demanding applications.
DUO-TAPTITEŽ screws have generous lobulation at the screw point for easy entry and optimum thread forming action plus reduced lobulation in the screw body holding area. A stabilizing threaded dog point insures ready, aligned entry, with easy pick-up requiring minimal starting end load.
DUO-TAPTITEŽ screws & bolts are available in inch and metric sizes, with head style to suit.
ADVANTAGES
•High vibrational resistance
•Good axial alignment
•Low end load
•High strip-to-drive ratio
•High prevailing torque
•Good torque tension relationship
Better starting stability - Axial Alignment
Less cocking at start of driving operation ... the self-aligning characteristic of DUO-TAPTITEŽ screws reduces operator fatigue; eliminates interruptions in production; adds speed to every fastening operation. Suitable for automated and robotic assembly.