Vacuum 292 y block with holley 2300

[UrbanT]

Hi all
Im from Sweden, so My english is bad.
Some questions,
What Vacuum level should i have?
Where should i measure the Vacuum?
Can i measure Vacuum on the hose to the wiper motor?

The problem i have is that the wiper motor cant pull the wipers. I have cleaned and lubricated the motor, but i couldnt find a repair kit for it.

Br Urban

[rotorwrench]

Manifold pressure varies with elevation too much to really say. If the engine runs well at idle then it will operate the vacuum motor. Here may be leaks in the valve mechanism, bowl gaskets, or the old flapper (paddle) seals are not sealing up well.

There are a few shops that rebuild the Trico vacuum motors over here in the US but I don't know if they reproduce the old Trico repair kits for sale or not. A person needs to know the model number if possible and how wide the bowl is to get the parts. Some folks fabricate their own gaskets & flapper seals.

[UrbanT]

Originally Posted by rotorwrench

Manifold pressure varies with elevation too much to really say. If the engine runs well at idle then it will operate the vacuum motor. Here may be leaks in the valve mechanism, bowl gaskets, or the old flapper (paddle) seals are not sealing up well.

There are a few shops that rebuild the Trico vacuum motors over here in the US but I don't know if they reproduce the old Trico repair kits for sale or not. A person needs to know the model number if possible and how wide the bowl is to get the parts. Some folks fabricate their own gaskets & flapper seals.

Thanks for the answer.
I suspect that the bowl is worn out. But what can i use as flapper seals? They looks and feels like plastic now.
The engine runs well at idle, but some times it's missing When i give a fast trottle.

[triumphleroy]

When I was younger Used to pull vacuum line off of manifold and inject a little motor oil into the vacuum line and move the wiper arm back and forth to pull the oil into the vacuum motor. that sometimes softened the seals and put enough oil into the motor to keep wipers working awhile. Leave it sitting for awhile and the old leather seals would soak up the oil
Have been considering the various 12 volt vacuum motors that are available nowadays and an vacuum canister to help with vacuum motors !
They appear to be using these for power brake boosters so I don't know why they wouldn't work in this application ?
Anyone out there tried that successfully?

[Crankster]

Make sure the engine is tuned properly, it will not have good manifold vacuum otherwise. Ignition timing is one possible culprit. It is common for the vibration absorber (damper) steel outer inertia weight ring to slip off axis, making the timing marks inaccurate. Rotate engine so #1 piston is at TDC on the compression stroke. The "0" mark on the damper should line up on the pointer. A stock engine in good condition should pull a steady needle of 18" to 20" at around 600 RPM at Sea level. Subtract 1" for roughly every 1000' above sea level for a corrected figure. Another factor that can contribute to poor engine manifold vacuum is incorrect valve lash, the Y blocks have solid lifters, these require periodic adjustment.

[rotorwrench]

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Originally Posted by UrbanT

Thanks for the answer.
I suspect that the bowl is worn out. But what can i use as flapper seals? They looks and feels like plastic now.
The engine runs well at idle, but some times it's missing When i give a fast trottle.

The flapper or paddle was sold with a rebuild kit in complete form. You might find some examples on e-bay. The paddle can be disassembled to replace the seal material if a person is familiar with riveting processes and removing rivets. They used different materials over the years so a person would have to take it apart to get a sample of the material to work with. Leather was used on the old ones but synthetic materials were used later. If your bowl shows signs of excessive wear or scoring in the bottom then you will need a better core for rebuild.

This fellow is the best known rebuilder of Trico units in the USA.
http://p15-d24.com/links/link/67-ficken-wiper-service/

He doesn't supply kits. He will only rebuild a complete unit that has a good core.

Your off idle stumbles may be due to a problem with the accelerator pump in the carburetor not functioning as it should.

[Ole Don]

I have used a vacuum can for the wipers on a 312 with a wild cam. It worked very well. The best vacuum that engine ever pulled at idle was eleven inches.

[Crankster]

I remember my dad mentioned that vacuum wipers had a hair shirt element to them. Passing someone in the rain being a dicey proposition, lol. Was this a problem from the factory, or simply an indication of a poor engine tune?

[Ole Don]

Hair shirt element??? Never heard that before. What does it mean?

[40cpe]

I have not heard it, either. Maybe the same as "hair raising experience".

[Crankster]

"Uncomfortable" would be one way to put it.

Was it pretty much SOP for vacuum wipers in general to fail when trying to pass someone on the highway?

[dmsfrr]

Originally Posted by Crankster

.....Was it pretty much SOP for vacuum wipers in general to fail when trying to pass someone on the highway?

Any extra foot pressure on the gas pedal makes the vacuum drop, and the wipers slow or quit.
The dual diaphragm/vacuum booster fuel pump was an attempted fix for the problem.

.

[dmsfrr]

Originally Posted by Ole Don

Hair shirt element??? Never heard that before. What does it mean?

I had to look it up too, just to make sure.

'Something done to punish yourself.'

https://www.collinsdictionary.com/us...ish/hair-shirt

.

[Crankster]

Originally Posted by dmsfrr

Any extra foot pressure on the gas pedal makes the vacuum drop, and the wipers slow or quit.

Well sure, but I can't believe this was considered acceptable, even by the standards of the day. Maybe passing in the rain on two lanes is overrated anyway.

[50fordcoupeman]

Well it was a step up from reaching up and moving the wiper blade back and forth with a little handle that stuck thru the cab above the windshield.
Really didn't work in the snow )

[Crankster]

LOL! Yeah I guess so... perspective is everything

[50fordcoupeman]

Yes sir..............when dad said wipe the windshield we thought we were big cheeses to get to operate it!! What did we know at 6 yrs old? Sometimes miss those days but not very much........lol!!

[rotorwrench]

The high end cars of from 1949 up like the Mercury & Lincoln cars sometimes had the dual diaphragm type fuel pump that also had a vacuum pump to boost the vacuum during times when manifold pressure was high (low vacuum). Running at a normal highway speed even had a tendency to slow the old wipers way down unless you had a booster pump. I remember many times I'd have to let off the throttle just to get a good wipe when driving in the rain or snow. Both of my 1951 Mercury cars had standard fuel pumps since they were built for duty in Kansas, Colorado, and New Mexico where it doesn't rain as much.

[Alaska Jim]

My '51 Merc. has the dual diaphragm fuel pump. even with this ( new pump ) the wipers will still come to a stop if going up a hill or hard acceleration. the wipers work well on flat ground. It could be that my wiper motor is weak, since it is the original and has never been rebuilt to my knowledge.