Wrecked

I'm gonna be swapping out my intake and exhaust manifolds in a week or so. My question is, is a torque wrench required to get a leak proof seal at the motor? If so, what brand/model would anyone recomend? Something pretty accurate but not too hard on the wallet.

5-90

Yes, you will need one to get even torquing on the gasket.

Any decent-quality 3/8" drive will do - just don't be afraid to spend a little money on it (I'd say $30-60 or so. Don't get stupid.) The "click type" will be preferred for when you're working on the lower rear manifold screws.

Helpful tips for the job:
1) Retain the little bowl-shaped washers. They're there for a reason (I could go into the engineering behind the decision, if you like.)

2) Replace the screws outright. 3/8"-16x1-1/4". I prefer to use bronze screws (prevents seizing, and they hold up better,) but carbon steel screws may be used. If you use carbon steel, use SAE Grade 5 and not RPT NOT SAE Grade 8! These screws are in a position where they will incrementally lose strength over time (due to heat-cycling,) and SAE8 will be more sensitive to the process than SAE5. Experimentation and extrapolation show that, after about fifty heat cycles, the SAE5 screws will have more strength remaining than the SAE8 will! (I also use bronze because copper-based alloys respond to heat cycling in the opposite manner to iron alloys - bronze screws will get incrementally stronger. If you have the option, get "half hard" silicon bronze or half hard aluminum bronze.)

3) A light coat of RTV copper on both sides of the manifold gasket won't go amiss - an even coating that is just enough to say it's there. As the screws loosen over time (they will,) this will help keep your manifold gasket from burning through.

4) Recheck torque on the manifold screws annually. I usually find a couple of them have loosened slightly - particularly the lower rear.

5) Studs - both extreme ends and the top centre hole. You can cut new studs out fo 3/8"-16 brass threaded rod without any trouble. Retain in the head with LocTite #242. Use the nuts and washers. (As you wrestle with the manifold, you will rapidly find that they are there for a reason!)

6) May as well replace the collector nuts (bottom of the exhaust manifold) with brass as well - they should be threaded 3/8"-16. In fact, most of my exhaust hardware (at the engine or undercar) is brass or bronze - and for good reasons!

Wrecked

5-90

Thanks for all the tips. Would these bolts be like what you are talking about? http://www.fastenal.com/web/products...u=75021&ucst=t

5-90

Yah - but get Si-bronze or Al-bronze, they're stronger than brass. They're what I tend to use.

I plan to experiment with using "true" Belleville spring washers as well to replace the OEM dished washers - I expect those to work better, I just need to sort out how many to use and in what arrangement.