Manifold Installation

Charles Reese

Charles Reese

Well-known member
Waiting on Santa so got to thinkin ….. any tips on installing the exhaust/intake manifolds… order of tightening nuts (i.e. nut #2-3, then 1-4; or does it really matter), how tight, tighten to block before tightening intake to exhaust manifold bolts etc., etc. ??

This will be done with garage temp in the 50s so have concerns about metal expansion once engine is started (i.e. breaking ‘ears’ of the manifolds).
 
35 ft lbs torque only to block. manifold shrinks and expands greatly with temp swings and must be allowed to move underneath the nuts/studs. Else it will crack or distort
 
Just finished this job. Ordered exhaust manifold from Bratton's (page 60, part # 13690). Very fine quality casting.
Instructions call for torquing to 45 pounds, a little at a time spacing the pressure among all four nuts. I tightened 2,3,1,4.
You will need to retorque to 45 pounds after you have started engine and when everything is hot. Maybe several times.
You will also have to check (with a straight edge) that intake and exhaust manifolds are perfectly level. If not then they will need to be "decked". Also check the fit of the glands. Manifolds must mate to the block without gasket in place. If not glands will need to be ground down.
Good luck,
Smurph
 
Work from inside nuts OUT!!! Tighten exahut only and finger tighten intake. Torque to 30#, run...tighten intake tight. torque exhaust to 35, heat, torque to 40#. Drive car........ Check torque up to #45 re tighten intake. Check fit with feeler gauge. Use copper gaskets only and take your time.
 
Be sure to have the exhaust and intake manifolds surfaced prior to installation. They must be mated together when surfaced. Any machine shop can do the job. This step will insure an even mating of the manifolds to the block which provides for a good seal. You do not want any leaks.
 
msmaron said:
Charles remember that when you have it planned to the manifold it will only mate with that one.
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that's why i really dont want to break 'em ... been chasing insidious fuel leak and water seeping at head/block ... took manifolds off to touch up paint ... couldn't locate my notes with installation tips (order, torque, etc) so posted ... thanks for helpful responses :o
 
Good chance you will crack the manifold if you tighten it to 45#. Watch the gasket and when it starts to compress you have it tight enough . Do a search .Lots of posts on this subject.
 
I agree and only tighten to what feels comfortable. I don't use a torque wrench, but at a national meet about 8 years ago I saw a guy break his manifold before 35 pounds was reached.
 
use a 3/8th hand ratchet, socket, extension and common sense....
then more common sense after a couple of hot and cold cycles
 
Purdy Swoft said:
The main problem with over tightening is warping the exhaust manifold.
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Mitch//pa said:
use a 3/8th hand ratchet, socket, extension and common sense....
then more common sense after a couple of hot and cold cycles
Click to expand...

I was told early on to ignore the torque ratings for the manifold and the oil pan. 10 years so far so good.

This is not to say many have used a torque wrench with success on these items.
 
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