Vacuum Leak? Vacuum gauge showing 12 mercury from intake. (1 Viewer)

[Beehanger]

Hi all,
Trying to tune the 60 but its proving difficult doing the lean drop with this aftermarket chinese carb I'm running with. Using a line from the intake I get 12 mercury, but i know the ideal range is 15-20. will this increase as I get closer in tuning this, or do I have vacuum leak?

Im leaning towards vacuum leak because If I hook up any of my other vac lines to this gauge it shows 0 mercury (no pressure, obviously). All vac lines should have roughly equal vacuum running through them, right?


I ran desmg, and there's a chance I hooked up something incorrectly, but I assure you all vac lines are plugged in, so not sure why a misplaced line would create a leak if its plugged.

Thanks,
Beehanger

 

[OSS]

12 inHg vacuum is very low. - unless you’re above 6000 ft elevation
Not all the vacuum hoses carry full vacuum all the time.
Connect the vacuum gauge to the small pipe jutting off of the brake booster manifold fitting.

 

[Beehanger]

12 inHg vacuum is very low. - unless you’re above 6000 ft elevation
Not all the vacuum hoses carry full vacuum all the time.
Connect the vacuum gauge to the small pipe jutting off of the brake booster manifold fitting.

im at 5200 feet elevation

 

[bcolvin]

Most of the well tuned cruisers around here pull around 15-16. I’m at 6k in Colorado. 12 seems low.

 

[cps432]

Some of those Chinese carbs are hit or miss. Some people have dropped them straight into the truck and they work perfectly. Others seem to have better luck replacing all the gaskets and seals with Japanese components.

Further more, some of the mating surfaces could be uneven and not making a seal internally. You could have a leak inside the carb. There could be gunk from the manufacturing process left inside. You might need to adjust the float to keep the correct amount of fuel in the bowl.

 

[CruiserTrash]

im at 5200 feet elevation

I’m at 5200’ elevation and depending on the weather, my vacuum is at 16-17 at idle after the engine warms up. Just throwing that out as a reference point. I will agree with others that 12 is low.

As a general rule of thumb you’ll see a 1inHg drop in vacuum for every 1000’ above sea level. The actual math is a little more exact than that but the 1:1000 rule is in the ballpark. I think at 5000’ it’s actually 82% of sea level vacuum. Since sea level is used as a reference point (21-22inHg at sea level is ideal), you can take your vac reading (12) and DIVIDE by 0.82 to find out your theoretical sea level vacuum: 14.6. Low.

In my case, let’s take my average (16.5) and divide by 0.82 to find theoretical sea level vacuum: 20.1inHg. In the ballpark, maybe a touch low. It’s a never-rebuilt 42 year old motor though.

 

[salvage60]

I was just chasing what I thought was a vacuum leak and it turned out to be out of adjustment valves, worth the check before you start pulling a bunch of stuff apart...

 

[WILLD420]

Have you checked your timing yet? Faulty timing, bad wires, misfires, too low rpm etc will do that. Try pinching off the vacuum booster hose, see if that fixes it. Same can be done with all the other hoses that you see coming off the intake. Otherwise, suspect the gasket under the carb. I got bit by that one a few years back.

 

[cps432]

I was just chasing what I thought was a vacuum leak and it turned out to be out of adjustment valves, worth the check before you start pulling a bunch of stuff apart...

I agree. This engine was just rebuilt and he’s just getting it back together. I know he was having some issues setting the initial valve timing a few months back. That very well could be the issue.

@Beehanger get the engine up to operating temperatures and then stop the engine and check the valve lash. It’s better to be a little loose than too tight. Having valves that don’t open all the way cause restriction in the flow of air and the combustion process can get disrupted. It’ll cause loss of power which may explain the low vaccum.

Also, go get yourself a set of go-no go feeler gauges. Look them up and how to use them. They are a game changer when setting valve lash. Totally worth the ten bucks.

 

[Michael Hanson]

Get rid of the communist crap.

 

[Beehanger]

I agree. This engine was just rebuilt and he’s just getting it back together. I know he was having some issues setting the initial valve timing a few months back. That very well could be the issue.

@Beehanger get the engine up to operating temperatures and then stop the engine and check the valve lash. It’s better to be a little loose than too tight. Having valves that don’t open all the way cause restriction in the flow of air and the combustion process can get disrupted. It’ll cause loss of power which may explain the low vaccum.

Also, go get yourself a set of go-no go feeler gauges. Look them up and how to use them. They are a game changer when setting valve lash. Totally worth the ten bucks.

are these any different than standard feeler gauges? i've got some old school ones here they look like this

 

[Beehanger]

Have you checked your timing yet? Faulty timing, bad wires, misfires, too low rpm etc will do that. Try pinching off the vacuum booster hose, see if that fixes it. Same can be done with all the other hoses that you see coming off the intake. Otherwise, suspect the gasket under the carb. I got bit by that one a few years back.

There's no gasket currently underneath my carb... bought a new carberator insulator from @ToyotaMatt and figured it goes directly on that soft surface.

Maybe this is my issue,...?

 

[Beehanger]

I was just chasing what I thought was a vacuum leak and it turned out to be out of adjustment valves, worth the check before you start pulling a bunch of stuff apart...

Just tested sael on the intake gasket last night with some break cleaner and it revved.... fkn dammit. Gunna have to pull that off eventually, but hoping I can drive it before I invest in headers. The brake cleaner check didn't rev the engine anymore when I got it to operating temp though, so am I valid to drive the thing if I can tune it?? Also double checking torque specs on the studs nuts ight now.


:Little backkwoledge, my exhaust manifold didn't looked that laterally warped (it was pretty straight to the block (intake looked good also ), but dont recall it being that bad off. I had to put on the intake and exaust sperately though because I couldn't get them to mate to the block otherwise (put on exhaust manifold first, the put the intake on top.) so if this helps at context there it is.

I was gunna go the header route eventually, just wondering if im gnna break something driving with an intermittent intake leak.

Dan

 

[Beehanger]

Just tested sael on the intake gasket last night with some break cleaner and it revved.... fkn dammit. Gunna have to pull that off eventually, but hoping I can drive it before I invest in headers. The brake cleaner check didn't rev the engine anymore when I got it to operating temp though, so am I valid to drive the thing if I can tune it?? Also double checking torque specs on the studs nuts ight now.


:Little backkwoledge, my exhaust manifold didn't looked that laterally warped (it was pretty straight to the block (intake looked good also ), but dont recall it being that bad off. I had to put on the intake and exaust sperately though because I couldn't get them to mate to the block otherwise (put on exhaust manifold first, the put the intake on top.) so if this helps at context there it is.

I was gunna go the header route eventually, just wondering if im gnna break something driving with an intermittent intake leak.

Dan

There's no gasket currently underneath my carb... bought a new carberator insulator from @ToyotaMatt and figured it goes directly on that soft surface.

Maybe this is my issue,...?

@ToyotaMatt does this carb insulator require a gasket to mate to the carb?

 

[ToyotaMatt]

@ToyotaMatt does this carb insulator require a gasket to mate to the carb?

as you can see , there are TAN color OEM gaskets molded into the insulator plate on both sides


, your good on the gaskets topic

 

[Beehanger]

as you can see , there are TAN color OEM gaskets molded into the insulator plate on both sides


, your good on the gaskets topic

View attachment 3436217​

are these reusable if I pull the carb off? and if fuel is spilt or some other gunk how can one replace these?

Thanks
Dan

 

[ToyotaMatt]

are these reusable if I pull the carb off? and if fuel is spilt or some other gunk how can one replace these?

Thanks
Dan

Trying to tune the 60 but its proving difficult doing the lean drop with this aftermarket chinese carb I'm running with. Using a line from the intake I get 12 mercury, but i know the ideal range is 15-20. will this increase as I get closer in tuning this, or do I have vacuum leak?

Im leaning towards vacuum leak because If I hook up any of my other vac lines to this gauge it shows 0 mercury (no pressure, obviously). All vac lines should have roughly equal vacuum running through them, right?


I ran desmg, and there's a chance I hooked up something incorrectly, but I assure you all vac lines are plugged in, so not sure why a misplaced line would create a leak if its plugged.

Thanks,
Beehanger

=

Get rid of the communist crap.

I agree. This engine was just rebuilt and he’s just getting it back together. I know he was having some issues setting the initial valve timing a few months back. That very well could be the issue.

@Beehanger get the engine up to operating temperatures and then stop the engine and check the valve lash. It’s better to be a little loose than too tight. Having valves that don’t open all the way cause restriction in the flow of air and the combustion process can get disrupted. It’ll cause loss of power which may explain the low vaccum.

Also, go get yourself a set of go-no go feeler gauges. Look them up and how to use them. They are a game changer when setting valve lash. Totally worth the ten bucks.

12 inHg vacuum is very low. - unless you’re above 6000 ft elevation
Not all the vacuum hoses carry full vacuum all the time.
Connect the vacuum gauge to the small pipe jutting off of the brake booster manifold fitting.

Have you checked your timing yet? Faulty timing, bad wires, misfires, too low rpm etc will do that. Try pinching off the vacuum booster hose, see if that fixes it. Same can be done with all the other hoses that you see coming off the intake. Otherwise, suspect the gasket under the carb. I got bit by that one a few years back.

Most of the well tuned cruisers around here pull around 15-16. I’m at 6k in Colorado. 12 seems low.

I was just chasing what I thought was a vacuum leak and it turned out to be out of adjustment valves, worth the check before you start pulling a bunch of stuff apart...

Good morning Dan .....

- Excellent question here , and thread topic as whole .

- thumbing through the TAN 2F paper print media FSM i have in-hand , there is ZERO mention of the insulator plate ?

- but i clearly recall seeing and reading a TOYOTA image somewhere in my past - current TOYOTA anything life ?

- ill find it and post it here , i possess 100% of the usa-spec. T.S.B. 's on the LAND CRUISER modle starting from 1972 - mid 1994's ish , i think perhaps that is what is a foggy YES in my mind here ........

- i have a vested interest in helping Dan get to the finish line here from a unique perspective , he reached out to me for parts and Service Technical consultation from the onset of his current FJ60 Pjct.

- i recent memory , i don't recall a more driven , and passionate person doing a re-build / re-fresh at a level he now is ...................

- this is not some no normal it sadly seams and in-deed sucks " Bring-A-Trailer " get quickie rich cash fast in hand scheme he is trying to pull off .......no no no


- Dan is actually a real live example of a type or " classification " of current Land Cruiser owner operator i now am seeing less and less of now , as i have a unique way that i can factually say is 100% real and legit in our community as a whole

- Has has always wanted a 60 series Land Cruiser for longer then most even make that point anymore at all , and now he has his personal pipe dream , he got it now and i know he is the LAST person on Earth to throw in the Towel here for any reason , because he stays late at his Job during the weekdays , thay have a shop and lift he can take full advantage of , and also is there every Saturday and Sunday , sometimes he Text's me for a TECH. or Parts inquire long after i hit the Couch and bed time for sure !


- That is how i was during my age 16 high school years and long after T-TEN school too , perhaps i still have some of that " Nothing Else Matters in LIFE Except Land Cruiser Anything " ...

- keep up the steam Dan , your in the last 7.4% to the finish line now , know that your going to finish , because i know you will , and that's all that matters ...



- on the FLIP-SIDE , it is on-my-topic here to note : The fastest growing of my Professionally stated " Classifications " of new ' ish Land Cruiser owner operators 1997- Older are our fellow Female Owner Operators , this is a super key point here , because in my Vintage Toyota Land Cruiser & Service Technical professional Concierge service and parts topics i offer blended together in my own unique format .....

- Both all of them and Dan come to the table possessing 99.3% of everything i outline above , a mission to fulfill there Land Cruiser pipe dream's at various levels , and that alone is why i say what i say here and why i say it now in the way i do ............


- oh ?

- the original topic at hand , how bad bad of me here this morning , shame on me to get off topic here .

-

- the gaskets on the insulator plate are designed to withstand gasoline , unless physical damage in someway here dan , you just treat it like a new gasket again .....


- if you have been told or are told to apply any form of liquid sealer or a 2nd set of gaskets the 2nd use time rodeo here , ?

- your being lied to , so don't listen to that non sence , te tan OEM gasket material there in that space-age insulator resistes Memory , hence it will bounce back ikn a YOUNG time era like yours is ....


- if you have already applied a liquid gasket or some Bull S#it permitted product to either side , now os the time to come clean , so i can advise you correctly how to remove it , and NOT hurt the TAN factory applied Moon Lander gaskets at the same time


- THIS IS THE WAY ...........

 

[cps432]

Get rid of the communist crap.

Japanese Imperialism is the only way…

 

[BigHighBlue]

are these reusable if I pull the carb off? and if fuel is spilt or some other gunk how can one replace these?

Thanks
Dan

Might be an unpopular opinion but I run gaskets even with the ones on the insulator. If nothing else it makes me feel better about not having leaks. There are two, one that goes between the carb and the insulator with 2 holes for the primary/secondary and a second that goes between the insulator and the intake manifold with one oval hole. I think City Racer may have them and I know Spector has them.

 

[Paullus]

If I recall correctly I had to lightly sand the top off my insulator because the tan molded on gasket was looking pretty bad. I then added a gasket that I made from a sheet of fuel resistant gasket material.

In your other post you mentioned low fuel in the fuel bowl. You should check your float height and needle valve in the air horn. I think what cps432 said about valve lash is worth checking out.