The Stovebolt Site Forums The Shop Area Engine Shop Installing Exhaust/Intake Manifolds

Am in the process of installing exhaust/intake manifolds on a 3100 216 engine. Is there a certain sequence to tighten the bolts and what is the recommended torque setting? Any particular do's or don'ts?

5ptstar,

First, lay the mating surface of the manifold assembly on a flat surface. If it lays flat on the surface (no significant "air gaps"), you have a high probability for a good seal.

If it has gaps, you could try two sets of gaskets, or take the assembly to a machine shop to have the assembled mating surface planed ($50 job, probably).

Here are torque specs for later 235/261 engines - they should be OK for the older 216/235 engines.

Maybe someone has a link to the specs for a 216, or they can post a link to a Motor's Auto Repair Manual torque-specs page?

I tighten from inside bolts outwards - by feel (no torque wrench). If I could get a torque wrench in there, I would use 30 ft-lbs as max for all bolts and tighten in this sequence: 1/3 max spec (10), then again at 2/3 max spec (20), then finally at full/max spec (30).

Please do not ask me how you torque the intake manifold to a different setting from the exhaust manifold. I look forward to reading how others do that.

One don't is to not fully tighten the bolts that hold the two manifolds together until after they are mounted to the engine. They need to be able to "float" a little in order for the intake manifold to properly seat on the alignment rings.
Mike

5ptstar,

Are your manifolds now apart or bolted together?

Manifolds are now apart

Ditto on Tims tightening sequence. I put mine on tonite and tightened the ends first and the manifold Assy did not sit flat on the head, there was a gap on the lower edges. I loosened and did it Tims way and it sit perfectly flat now.
On the torque specs , the shop manual has the exact opposit range
Center clamp bolts 15-20 ft lbs
End clamp bolts 25-30 ft lbs .
I say tighten until tight, you results may vary.

Thanks, everyone. I have days-off coming up and plan to install the manifolds then.