Very good video on this. You make it easy to understand and apply. So important to make sure you don’t have a leak or like me, and so many people, you will be replacing an air box. Thanks.
Hello, nice video! Wouldn't it be also possible to "inject" the smoke in front of the car, where the brake booster line gets to the brake booster? Maybe for ease of process it would be first also enough to just seal the inlet of the airbox (I have no pop-up valve and are most concerned about the lines, not so much the box itself). Thanks
This is possible. I would argue this might be a good way to find a vacuum leak closer to the booster. That small elbow from the booster to the hard line in the body is usually pretty stiff rubber so it may need to be replaced after disturbing it.
@@JoeEngineer Hello, so I did it "my" way and it worked quite well. It is a bit complicated to get the airbox air tight and I always had smoke coming out from there. But I found also other leaks (around injection valves and on the cap of the oil tank) so I'm happy with the procedure.
Now that’s a great and easy to follow along video. I just did a smoke test and believe it or not but I only seem to have one major leak and it’s the seal in the pop off relief valve. Do you know what to live this with for optimal sealing? The spring feels pretty firm so hoping it’s just the o-ring that’s bad/dry. Also at the back of the rubber manifold boot the crank house vent is plugged and the hose is missing on my 1978 911sc. Seems fishy.. 1
I grease the o-ring with silicone grease every year or so. Honestly the seal that comes in the pop off valve is not that great quality. Once I find a better equivalent on McMaster I'll post the P/N.
Great video on this very important test. CIS at air boxes are expensive and a bit of a pain to replace so fixing those leaks is a must. How do I know this ?
Great video --- thanks for posting and sharing the knowledge. I built a DIY smoke generator and will be tackling vacuum leak test. Your video is very helpful for me to plan and understand what to do. Your engine bay is looks so empty, simple! No A/C, no heater fan or ducts getting in the way. No cruise control? Did you remove all those systems or that was how your car was equipped? My 83 SC has everything A/C (that doesn't really work well), heater fan, and cruise control. It is so crowded in there. Just thinking about removing the rubber boot behind the airbox, disconnecting the hoses in the back --- so many things I need to remove just to get to it.
I would say the booster line is worth testing since it runs all the way to the front and is safety critical. The oil breather lines are cheap and easy enough to just replace if you suspect they are getting old and cracked.
Thanks. Your videos are absolutely fantastic, btw. My car just underwent a top end and CIS rebuild. The shop did ok with those, but they weren't very thorough with the last process. They got the car running -- it starts ok, but not immediately every time. And on cold starts, it idles at around 2k and is perfectly content to sit there. But when it warms up and the idle settles, I get a pretty significant amount of idle surge. Like it will oscillate between like 400 and 1400 RPM. You basically have to stay a little in the gas when standing at a traffic light in order to smooth it out. I suspect a vacuum leak, which is why I'm starting there. But the car is definitely running inefficiently. I'm getting about 10MPG, which in a way seems like it's running rich. Not sure...have a lot of tests to run here to try and isolate it.@@JoeEngineer
@@JoeEngineer thanks I've been searching the web on the size of that O ring. My understanding is O rings are numbered. About 6 months ago I found a post but did not bookmark I think the size as I recall was something like 372 or 376. Not sure if you know the size or a source to get those O rings.
Unrelated to the smoke test, you have a heat sink on the oil filter. Does it really do anything? It seems that the surface area and air flow would not be sufficient to add measurable cooling.
Great Video.. I put smoke into the Dizzy Retard line into front bottom of the Throttle valve, Plugged everything as you did, No smoke up top but I get smoke under the engine very close to the oil cooler, What could this be??? I've been using a lot of your video's and web site... Thanks
@@JoeEngineer Thanks for the reply Joe, Another question: Does smoke make its way into the crank case? I put mine back together and it runs awesome, but now I have a NASTY oil leak, when running, approx where engine and trans meet. I'm thinking main crank oil seal, flywheel seal, but wondering if it's related to my smoke underneath i never found, oddly the oil leak and smoke leak were in the same area???
Excellent video. Is your air box stock? I notice it doesn’t have the ribs where the pop off valve is installed. It also looks light gray in color vs black. Just curious.
Wow, that's pretty slick. I also had a 6 year old Porsche master tech, but she's 18 now. I sure miss those days. Thanks for the effort you put into your videos and blog. They're indispensable. @@JoeEngineer
![Lp. Сердце Вселенной #1 НАЧАЛО ПУТЕШЕСТВИЯ [Новый сезон] • Майнкрафт](http://i.ytimg.com/vi/380Q7gLWGvk/mqdefault.jpg)
All the years of watching utube videos on fixing my cars, your the best instructor. The oil cap off was something I didn’t know.
Very good video on this. You make it easy to understand and apply. So important to make sure you don’t have a leak or like me, and so many people, you will be replacing an air box. Thanks.
Good wark bro 👍
Hello, nice video! Wouldn't it be also possible to "inject" the smoke in front of the car, where the brake booster line gets to the brake booster? Maybe for ease of process it would be first also enough to just seal the inlet of the airbox (I have no pop-up valve and are most concerned about the lines, not so much the box itself). Thanks
This is possible. I would argue this might be a good way to find a vacuum leak closer to the booster. That small elbow from the booster to the hard line in the body is usually pretty stiff rubber so it may need to be replaced after disturbing it.
@@JoeEngineer Hello, so I did it "my" way and it worked quite well. It is a bit complicated to get the airbox air tight and I always had smoke coming out from there. But I found also other leaks (around injection valves and on the cap of the oil tank) so I'm happy with the procedure.
Now that’s a great and easy to follow along video. I just did a smoke test and believe it or not but I only seem to have one major leak and it’s the seal in the pop off relief valve. Do you know what to live this with for optimal sealing? The spring feels pretty firm so hoping it’s just the o-ring that’s bad/dry.
Also at the back of the rubber manifold boot the crank house vent is plugged and the hose is missing on my 1978 911sc. Seems fishy.. 1
I grease the o-ring with silicone grease every year or so. Honestly the seal that comes in the pop off valve is not that great quality. Once I find a better equivalent on McMaster I'll post the P/N.
@@JoeEngineer awesome thanks man
Great video on this very important test. CIS at air boxes are expensive and a bit of a pain to replace so fixing those leaks is a must. How do I know this ?
Great video! If one doesn’t have a vacuum port for power steering, where else would you attach the smoke tester, top of the WUR perhaps?
Thanks
Throttle body connections should work as long as you seal the top of the TB.
Great video --- thanks for posting and sharing the knowledge. I built a DIY smoke generator and will be tackling vacuum leak test. Your video is very helpful for me to plan and understand what to do. Your engine bay is looks so empty, simple! No A/C, no heater fan or ducts getting in the way. No cruise control? Did you remove all those systems or that was how your car was equipped? My 83 SC has everything A/C (that doesn't really work well), heater fan, and cruise control. It is so crowded in there. Just thinking about removing the rubber boot behind the airbox, disconnecting the hoses in the back --- so many things I need to remove just to get to it.
I did a heater backdate and AC delete myself. CC was already gone before my ownership.
So this doesn't test the oil breather lines or the brake booster line. Is it worth testing those by connecting the tester in those directions as well?
I would say the booster line is worth testing since it runs all the way to the front and is safety critical. The oil breather lines are cheap and easy enough to just replace if you suspect they are getting old and cracked.
Thanks. Your videos are absolutely fantastic, btw. My car just underwent a top end and CIS rebuild. The shop did ok with those, but they weren't very thorough with the last process. They got the car running -- it starts ok, but not immediately every time. And on cold starts, it idles at around 2k and is perfectly content to sit there. But when it warms up and the idle settles, I get a pretty significant amount of idle surge. Like it will oscillate between like 400 and 1400 RPM. You basically have to stay a little in the gas when standing at a traffic light in order to smooth it out. I suspect a vacuum leak, which is why I'm starting there. But the car is definitely running inefficiently. I'm getting about 10MPG, which in a way seems like it's running rich. Not sure...have a lot of tests to run here to try and isolate it.@@JoeEngineer
Did the smoke test. Discovered my pop off valve rubber O ring is leaking. Does anyone have a source or O ring size they can share?
Happens to me too. New video incoming.
@@JoeEngineer thanks I've been searching the web on the size of that O ring. My understanding is O rings are numbered. About 6 months ago I found a post but did not bookmark I think the size as I recall was something like 372 or 376. Not sure if you know the size or a source to get those O rings.
Unrelated to the smoke test, you have a heat sink on the oil filter. Does it really do anything? It seems that the surface area and air flow would not be sufficient to add measurable cooling.
Anecdotally, I think it does help cool a few degrees (not much) but I don't have any formal test data. Might be a good topic for a future video!
Great Video.. I put smoke into the Dizzy Retard line into front bottom of the Throttle valve, Plugged everything as you did, No smoke up top but I get smoke under the engine very close to the oil cooler, What could this be??? I've been using a lot of your video's and web site... Thanks
Maybe one of the rubber lines between the airflow meter and the firewall. Stick a phone behind there and take a photo.
@@JoeEngineer Thanks for the reply Joe, Another question: Does smoke make its way into the crank case? I put mine back together and it runs awesome, but now I have a NASTY oil leak, when running, approx where engine and trans meet. I'm thinking main crank oil seal, flywheel seal, but wondering if it's related to my smoke underneath i never found, oddly the oil leak and smoke leak were in the same area???
Excellent video. Is your air box stock? I notice it doesn’t have the ribs where the pop off valve is installed. It also looks light gray in color vs black. Just curious.
Aftermarket cast aluminium box
Wow, that's pretty slick. I also had a 6 year old Porsche master tech, but she's 18 now. I sure miss those days. Thanks for the effort you put into your videos and blog. They're indispensable. @@JoeEngineer