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Re: Secondary Carb Leak
Posted by: JimBrandberg ()
Date: July 27, 2022 04:49AM

After a while I realized this was an old post and then I saw one from Bob Helt himself. He was a good guy.

Jim Brandberg
Isanti, MN
CorvairRepair.com



Re: Secondary Carb Leak
Posted by: joelsplace ()
Date: July 27, 2022 09:32AM

Saxon revived it with a related question. I was answering him.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

Re: Secondary Carb Leak
Posted by: Saxon ()
Date: July 27, 2022 02:31PM

Joelspace asked if I deflashed the head or cover the air hose intake:

Yes, deflashed heads.

No, the air intake hose is still attached.

I did not know Bob Helt is no longer with us. I am fortunate to have learned from his book and come across his past response.

Northern CA
66 Monza Coupe 4-spd 140

Re: Secondary Carb Leak
Posted by: Frank DuVal ()
Date: July 27, 2022 07:06PM

Take off the adapter from the hose to the upper shroud, cut a piece of metal to size, even a soda can will work, punch the three holes for the mounting screws and slide that blank between the upper shroud and the hose adapter. Looks stock, no more cooling air going to where it is not needed for engine cooling.

Frank DuVal

Fredericksburg, VA

Re: Secondary Carb Leak
Posted by: Saxon ()
Date: July 27, 2022 10:00PM

OK, I have some sheet aluminium I can use.

I plan to pull the upper shroud to retrieve a melting aersol straw. I was spraying engine degreaser past the fan. Why, because I accidentally left the oil cap off and took it for a spin.

Looks like a lost a quart of synthetic all through engine bay. My dip stick is difficult to read, but I put a quart back in.

Where does the engine oil go if I go beyond 4 qts and drive it. I ask because I heard some strange gurgling sounds from my engine this evening after I pulled in.

Northern CA
66 Monza Coupe 4-spd 140

Re: Secondary Carb Leak
Posted by: joelsplace ()
Date: July 27, 2022 10:38PM

They hold 4.5 and I always put in 5. Never an issue for me.

Joel
Northlake, TX
5 Ultravans, 138 Corvairs and counting...

Re: Secondary Carb Leak
Posted by: Saxon ()
Date: August 02, 2022 06:43PM

Wanted to add some closure to this thread.

My gas does not dribble any more after engine shutoff. I set my floats at 1.5" inches instead of the 1 3/16".

I drain my 5 quarts of oil out since it was making some strange gurgling noises after engine shutoff.

The block off plate resulted in the temp/light coming on after a 20 min. drive on local suburb streets. I cooled it in the shade and headed home when it came on again after 10 minutes of driving.

I removed it and the temp pressure light does not come on anymore during drives.

Northern CA
66 Monza Coupe 4-spd 140

Re: Secondary Carb Leak
Posted by: Paulsgt ()
Date: August 03, 2022 08:05AM

Having the fresh air hose blocked should not cause your car to overheat. Sounds like maybe your cooling air exhaust doors are not opening.

There is some disagreement as to the function of the hose from the top shroud of the engine. I really don't think it is necessary but on my 65 convertible I did mount a K&N filter on the heater box where that hose enters the heater box so the HVAC system can get fresh air.

Your results may vary.

Enjoy the Corvair!

Paul Sergeant
CORSA Central Division Director / CORSA Treasurer
Lee's Summit, MO
CORSA since 1975
Member – HACOA, Corvair Minnesota, CORSA, Little Indians, POCI


Re: Secondary Carb Leak
Posted by: Frank DuVal ()
Date: August 03, 2022 10:09AM

Quote
Saxon
The block off plate resulted in the temp/light coming on after a 20 min. drive on local suburb streets. I cooled it in the shade and headed home when it came on again after 10 minutes of driving.

I removed it and the temp pressure light does not come on anymore during drives.

Something REALLY wrong here. Maybe nomenclature and you blocked the wrong part? I have done maybe a hundred of these block offs of the fresh air hose, no issues.

Frank DuVal

Fredericksburg, VA

Re: Secondary Carb Leak
Posted by: Saxon ()
Date: August 04, 2022 07:23AM

Possibly..., am all ears.

I read about this modification so fashioned one from a thin sheet of aluminium.

Disconnected flexible hose at shroud end. Used the upper shroud's short duct to make a template block.

Inserted the sheet between the metal duct and circular opening in shroud.

Secured flexible hose back in and checked to make there were no gaps or tears.

When the temp/press light came on about 20 minutes later, I pulled in under the shade of a park tree to shut down the engine. I wondered if the damper doors were inoperative, the the left one was fully horizontal and the right one almost horizontal.

I read different things about the purpose of this modification. I like the idea of pressurizing the cooling area further by covering the hole. But after a head scratch, I looked further at the shop manual diagram and read the description. It seems reasonable that I should maintain a source of cooler air from an area away from the heat of the engine.

Northern CA
66 Monza Coupe 4-spd 140

Re: Secondary Carb Leak
Posted by: Frank DuVal ()
Date: August 04, 2022 09:32AM

The hose is on the output of the fan pressure. The fan inlet is only the large round opening above the fins. This small hose supplies "fresh" aka unheated air to the heating system, not the other way around.

You made and installed the blank plate just fine.

And your observation of the damper doors shows they are working right also.

I am confused as you are.

Is the timing set right?

Take a borescope and look around under the top shroud for any blockage. Ahh, another tool to buy.thumbs up

Frank DuVal

Fredericksburg, VA



Edited 1 time(s). Last edit at 08/04/2022 09:33AM by Frank DuVal.

Re: Secondary Carb Leak
Posted by: Saxon ()
Date: August 04, 2022 06:39PM

The timing was at 8 degrees to prevent pinging in 3rd and 4th gear WOT. 91 octane pump gas.

Coincidentally, I am experimenting with some timing now but not during this temp/press incident.

Shop manual specs 18 degrees, but my gut told me to set it at 16. It pinged slight to moderate at WOT in 3rd and 4th. Same result for 12 degrees. For sure I know there is carbon buildup in the cylinder as I have vacuumed some of it out or seen it sprayed on the driveway at start up. No black smoke though.

I recently took off the upper shroud twice to clean up an errant spray straw and oil spatter. Surprised the WD40 straw was sitting on the fins unmelted despite some freeway runs.

Northern CA
66 Monza Coupe 4-spd 140

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