Ron - I admittedly not not consider a recent overhaul in my response, but -
just a "hot tanking" will not remove the carbon from the intake manifold (
it MIGHT from the heads, since there is usually less build-up). If someone
does not "chop" it out of the intake manifold with a chisel, screwdriver
or whatever - it will remain. Which reminds me of another thing to watch
for during overhaul - sometimes (almost always has been my experience), hot
tanking the cylinder heads will not remove the crud built up in the
"unused" oil passage to the rocker arm shafts (BIG BLOCK ONLY), and if the
heads are re-installed on the opposite bank that they came from - guess
what? NO oil to the rocker arm shafts. Always run something through these
holes BEFORE you send them to the machine shop. I always remove the oil
galley and freeze plugs from the block before I send it also - that way it
gets cleaned, much better than it does if they are removed AFTER the
cleaning process, which most of the time IS when they get removed. The
small block engines don't have the rocker oiling problem because of a
different system of oil feed - the big blocks feed both banks from the same
cam bearing, and the small blocks do not. If I think of any more of the
ways I've been screwed up during relatively simple steps of engine
building, I'll pass them along. DaveG.
----------
> From: Ron Waters <Ronbo97@xxxxxxxx>
> To: L-FORWARDLOOK@xxxxxxxxxxxxx
> Subject: Re: [FWDLK] Exhaust Manifold Heat Riser
> Date: Sunday, November 08, 1998 6:06 PM
>
> Dave (and others) -
>
> Thanks for your responses. I think it would be worthwhile to
post them to
> the group, since a lot of people may have the same question. I've
included
> Dave's response below. BTW, I wouldn't bet the rent that the exhaust
> manifold is clogged with carbon. I had the engine rebuilt 8000 miles
ago.
> Also had hardened valve seats installed. I paid an extra $125 for this
> service. Very worthwhile.
>
> Ron
>
> ----------
> > From: David Grove Grove Automotive <groveautomotive@xxxxxx>
> > To: ronbo97@xxxxxxxx
> > Subject: Re: [FWDLK] Exhaust Manifold Heat Riser
> > Date: Sunday, November 08, 1998 3:15 PM
> >
> > Ron - in your case, your mechanic is right - you might notice some
> > driveability problems in cold weather with the heat riser open - but I
> > doubt it. On cars built in the mid 70's up until fuel injection it's a
> > different story. They hesitate, backfire, stall, etc, due to the
leaner
> > mixtures calibrated into the carburetor, where heat is needed to
vaporize
> > the fuel. I would not hesitate to say that undoubtedly the passages in
> > your intake manifold that allow the exhaust heat to travel from one
bank
> to
> > the other are plugged up solid with carbon anyway! Unless you have a
big
> > block engine - I would almost guarantee it. Therefore - you must keep
> the
> > valve in the open position (all the way), or you may end up with some
> > burned valves on the right bank. While it is true that your fuel
milage
> > would be better with a "hot" intake - I don't think the driveability
will
> > suffer, the only thing you might notice is improper choke operation (if
> you
> > have a "divorced" choke - I can't remember), it may take a long time
for
> > the choke to open all the way. DaveG.
> >
> > ----------
> > > From: Ron Waters <Ronbo97@xxxxxxxx>
> > > To: L-FORWARDLOOK@xxxxxxxxxxxxx
> > > Subject: [FWDLK] Exhaust Manifold Heat Riser
> > > Date: Sunday, November 08, 1998 5:06 PM
> > >
> > > There is a manifold heat riser on the right exhaust manifold of my 58
> > > Plymouth. Like most of these things, mine is frozen up. A mechanic
I
> > > spoke to told me that they're not really necessary unless you plan to
> > drive
> > > your car in icy cold weather. Since I only drive the Plymouth on
warm
> > > days, is this a good solution ? What I actually did was open it up
2/3
> > of
> > > the way, so a little heat will go up while most will go out the
> tailpipe.
> > > Any thoughts on this ?
> > >
> > > Ron
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