Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Crank case ventillation hose

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
Crank case ventillation hose  Rating:  Rating
AuthorPost
 Posted: 05-15-2013 03:59 pm
  PM Quote Reply
1st Post
Cac41155
Member
 

Joined: 09-13-2010
Location:  
Posts: 9
Status: 
Offline
Reading the blogs on the crank case vent back to the carbs, is there any reason why I couldn't install a catch can off the crank case vent and then vent it to the vacuum port on the intake manifold so I don't have to go through the carbs; when I connect the line to the carbs the engine drops in RPMs and runs rough.

Any comments will be appreciated

Angelo 

Back To Top PM Quote Reply  

 Posted: 05-15-2013 10:51 pm
  PM Quote Reply
2nd Post
Jim Ketcham
Member
 

Joined: 03-13-2005
Location: Salt Point, New York USA
Posts: 208
Status: 
Offline
The original design had the crankcase vent going to the "air box" at it's bottom where heavy vapors could condense and flow back to the crankcase and only light end vapors got sucked through the carbs and burned. I do not know your setup but if you have so much condensate going through your carbs that it affects engine operation you may have other issues going on. I think trying a condensate catch can without hooking to the intake or carbs, just vented to atmosphere with drain back to the crankcase similar to the early 1973 JHs would work.

Back To Top PM Quote Reply

 Posted: 05-15-2013 11:07 pm
  PM Quote Reply
3rd Post
Cac41155
Member
 

Joined: 09-13-2010
Location:  
Posts: 9
Status: 
Offline
Thanks for the response Jim, I'll try that. Is there a way to tell if the rings are shot, I imagine a compression test won't be conclusive. Is there a normal range of pressure that should be seen on the vent line (inches wc).

Angelo

Back To Top PM Quote Reply  

 Posted: 05-16-2013 12:31 am
  PM Quote Reply
4th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Before my engine rebuild I fabricated a catch can with 5 or 6 layers of 1/8" screen inside to reduce the amount of oil entering the air box. This didn't work very well due to the volume of blow-by.

I'm sure a better oil separator could be designed.

I have no issues since the rebuild.

Kurt

Back To Top PM Quote Reply

 Posted: 05-16-2013 02:22 pm
  PM Quote Reply
5th Post
Brett Gibson JH5 20497
Member
 

Joined: 03-17-2005
Location: Hilton, New York USA
Posts: 798
Status: 
Offline
To check if the rings are shot you need to do a compression check, make sure though that the carbs are fully open otherwise you may get a bogus reading.

hopefully all the cylinders are better than 100lb's,

Now do a compression check again but sqiurt some engine oil in the cylinder just before doing each one, if the reading is much higher the rings are allowing bypass, (the oil creates a seal) if the reading stay's the same and its low then you have a head issue.

Brett

Back To Top PM Quote Reply  

 Posted: 05-16-2013 02:58 pm
  PM Quote Reply
6th Post
Cac41155
Member
 

Joined: 09-13-2010
Location:  
Posts: 9
Status: 
Offline
Thanks Brett - I'll give that a try.

Back To Top PM Quote Reply

Current time is 04:45 pm  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Crank case ventillation hose Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems