[NoVa-Corvairs] Noob May Need a Good Used Head
FrankDuVal
corvairduval at cox.net
Sun Mar 5 23:35:15 EST 2017
Yes, that piece of shroud (driver's side front, where heater hose
adapter fits) is trapped by the exhaust manifold.
After looking at Clark's catalog and the Junkyard primer, I am confused
as to what a 3880708 head might be, as the two do not agree.
But, Vernon's pictures in his two emails leads me to believe 3880708 is
an open chamber 110 HP head, used on all A.I.R. engines, typically
called smog heads. His is a 1966 110 HP AIR head, where yours should be
a 1969 110 HP AIR head, same thing.
You probably have matching heads. Sounds like time to send your heads to
the ranch like Vernon did. Sad that we have to replace seats, but going
with all new deep seats is the current best way to keep your car on the
road without worrying about dropped valve seats.
Frank
On 3/5/2017 6:37 PM, Dan Weiss via Novacc-list wrote:
> Passenger head ID number ends in 0708 and checks with the numbers Bob
> provided.
>
> Driver's head ID remains elusive. Not on front vertical edge.
> Removed heater shroud and on the bottom horizontal edge. Tried to
> remove the housing for the left heater hose but looks like it is part
> of the tranny housing.
>
> So either I won't know the bad head's ID number until it comes off, or
> if it is supposed to be hidden in the back under the heater shroud (as
> one person suggested to me), then it may not be the correct head.
>
> Dan
> On Mar 4, 2017 11:20 AM, Dan Weiss via Novacc-list
> <novacc-list at corvair.org> wrote:
>
> Bob,
>
> Had to drive it with the knock about two miles when it happened,
> and I am not running it since. I fished around the cylinder and
> couldn't find or hear anything that seemed to be laying in the
> cylinder, but I am sure that this could be misleading.
>
> I will check on the head numbers and get back. Thanks.
>
> Frank,
>
> Didn't know about the difference in ignition systems and pulling a
> plug wire. Thanks for that. Guess I should have pulled the coil
> wire to the distributor when I cranked the engine for the
> compression test.
>
> When you refer to deep seats being costly, is this the proper
> repair to the valve seats? Cost? Probably best to do all on the
> head since it is out. Thanks.
>
> Bryan,
>
> Understand now from the comments from all three of you that it is
> important to know what heads are on there since there were
> differences in the late models, which I did not know, and it is
> necessary to confirm which ones are on there.
>
> Does using a probe on the wire and grounding the cylinder reroute
> the charge from the distributor to ground to prevent spark? Thanks.
>
>
> I am learning so much. Thanks.
>
> Remember "Young men try to outdo. Middle aged men try to make do.
> Mature men help others to do."
>
> Dan
>
>
> -----Original Message-----
> From: Bob Marshall via Novacc-list <novacc-list at corvair.org>
> To: novacc-list <novacc-list at corvair.org>
> Cc: ram0672 <ram0672 at verizon.net>
> Sent: Fri, Mar 3, 2017 5:19 pm
> Subject: Re: [NoVa-Corvairs] Noob May Need a Good Used Head
>
> Just my two cents.
>
> Keep the old head if it is a 69 part number 3880707/3880708.
> Damage can be fixed by a shop that knows how to correctly work on
> aluminum heads.
>
> If it is a valve seat don't run it anymore to minimize the
> damage. We had a member that drove his car about 40 miles after a
> seat let go and he now is facing a $5000 rebuild.
>
> Bob
> On 03/03/17, Frank DuVal via Novacc-list<novacc-list at corvair.org
> <mailto:list at corvair.org>> wrote:
> Where to start.
>
> 69 110 HP originally had open chamber heads. Different than 64 to
> 67 design. As Bryan says, get head numbers. Who knows who did what
> in 40 years.
>
> All used heads are unknown, unless YOU know how they were used for
> the last 50 years. Clarks "good" just means seats, etc. are still
> there. They have no history usually.
>
> Yes, deep seats cost money, but better than doing it again later
> with piston damage.
>
> The electronics of electronic ignition do not like the spikes
> created when spark plug wires are remov d with the engine running.
> Good chance of replacing the electronics when you do that. Spark
> plug wire pulling great diagnosis technique with points system,
> bad with electronics.
>
> Turn engine either way. But camshaft turns half with each
> crankshaft rotation (four stroke engine). So just because timing
> mark is on 0 does not mean cylinder is on compression stroke.
>
> Frank DuVal
>
> On Mar 3, 2017, at 1:09 PM, Dan Weiss via Novacc-list
> <novacc-list at corvair.org <mailto:novacc-list at corvair.org>> wrote:
>
> Bryan,
>
> Thank you for your input.
>
> If I understand your first point, I may need to rotate the nut
> on the harmonic balancer until the rotor comes back around to
> the position for the second cylinder. Had not thought of
> that. I have been turning the nut clockwise. Should manual
> advancing of the crank be done in only one direction
> regardless of which one? I read somewhere that if you go over
> where you want timing marks to meet, you should not go
> backward, but make another rotation. I know that the timing
> marks are only for cyl #1.
>
> Yes, it has electronic ignition. Everything in your middle
> point flew over my head ;-}, but the above is pretty much all
> moot as to diagnostics in this instance but great for my
> edification on corvairs.
>
> I would be reluctant to go through all the work with one of
> "unknown history." Clarks quoted $150 for good used heads,
> which several have said is really high. Any idea what it
> should cost to rebuild a head and where to go? One vendor
> quoted $1500 to rebuild both heads. Does "if it ain't broke,
> don't fix it" apply to the other head, or should both be
> rebuilt at the same time?
>
> Apologies for all the questions, but really at the start of
> the learning curve with this.
>
> Dan
>
>
>
>
> -----Original Message-----
> From: Bryan Blackwell via Novacc-list <novacc-list at corvair.org
> <mailto:novacc-list at corvair.org>>
> To: Northern Va Corvair Club <novacc-list at corvair.org
> <mailto:novacc-list at corvair.org>>
> Cc: Bryan Blackwell <bryan at skiblack.com
> <mailto:bryan at skiblack.com>>
> Sent: Fri, Mar 3, 2017 12:21 pm
> Subject: Re: [NoVa-Corvairs] Noob May Need a Good Used Head
>
> Hi Dan,
>
> A couple of thoughts:
>
> First, you're right, the head has to come off. The compression
> check shows zero. On the leakdown test, it may just be you had
> it on the overlap instead of compression, don't forget it's
> two engine revolutions per cycle.
>
> One other bit - as I recall you have an electronic ignition.
> On those you don't want to pull plug wires for the test, it's
> better to sneak a probe down the boot on each distributor wire
> and ground the cylinders one at a time.
>
> Finally, I've reached the point that I don't trust used
> unknown history heads. IMHO, if the head is coming off, I want
> to put a rebuilt one with fresh seats in it's place. In any
> case, you should verify which casting numbers are on the
> engine so both sides match.
>
> --Bryan
>
> > On Mar 3, 2017, at 12:04 AM, Dan Weiss via Novacc-list
> <novacc-list at corvair.org <mailto:list at corvair.org>> wrote:
> >
> > Pulling one plug wire at a time, removing the wire for #2
> Cyl produced no difference, so it seemed the problem was the
> same cylinder the Ranch found in need of some attention.
> >
> > Compression test was done on each cylinder. First test was
> without having throttle open (forgot about that); second test
> was with throttle open for each cylinder. Open throttle
> produced a range of 2 to 7 additional PSI of compression.
> >
> > Here are readings:
> >
> > CYLINDER FIRST TEST SECOND TEST
> > 2 0 0
> > 4 143 145
> > 6 150 157
> > 1 140 143
> > 3 157 164
> > 5 151 156
> >
> > Onto the leak down test.
> >
> > Did the best I could to get cyl #2 to TDC by aligning the
> rotor under the cap with the #2 contact. First attempts read
> close to 100%. Further adjustment seemed to tighten things up
> and tests consistently read right on the yellow and red
> section divider at about 71% cylinder leakage. I made sure to
> turn the regulator so the gauge read 0% before connecting it
> to the cylinder. The gauge immediately read 71% leakage and
> stayed right there. I turned the regulator clockwise to allow
> for airflow from the compressor, and the air was flowing out
> the exhaust pipe. What surprised me was that if I did achieve
> TDC, with the air leaking out the exhaust, I thought the
> rocker arm in the pic would have been with the exhaust valve,
> but as you all already know, that is the intake valve.
> >
> > Does it seem that the leak down test was done correctly?
> >
> > Obviously, regardless of the leak down test, the head has to
> come off to be replaced or repaired. I plan to pull the valve
> cover off to see what may be going on under there tomorrow or
> Saturday..
> >
>
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