Bristol Cars - Owners and Enthusiasts Forum  

Go Back   Bristol Cars - Owners and Enthusiasts Forum > Bristol Forums > 6 cyl Bristol cars

6 cyl Bristol cars Type 400 to 406 - restoration, repair, maintenance etc

Type 85A engine breather

Reply
 
Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 08-06-24, 07:24 AM
Member
 
Join Date: Oct 2010
Location: gold coast, australia
Posts: 22
Default Type 85A engine breather

The type 85A engine breather is situated on the front unit of the inlet rocker box cover & connected by short hose to the air filter.
Can anyone please tell me how the bypass combustion gases get from the crankcase to the inlet rocker cover.
The path taken by the gases is not obvious on examining a sectional view of the engine. Thank you.
Attached Images
File Type: png Type 85A.png (1.54 MB, 17 views)
Reply With Quote
  #2 (permalink)  
Old 08-06-24, 07:42 AM
Member
 
Join Date: Jun 2010
Posts: 36
Default

Via the vertical pushrod “wells “ on distributor side that go from camshaft tappets /followers to the rocker arms in cylinder head.( you can see this if you take tappet/ pushrod long cover off on distributor tower side.
I’ve an engine in bits atm so will try to send a picture.
There’s also oil return to sump from cylinder head at rear.
The breathing on exhaust side not that great if you use high revs.
Now you know what you are looking for you can just make out the vertical pushrods in your diagram.
Graham

Last edited by flyinghorse1; 09-06-24 at 08:28 AM.
Reply With Quote
  #3 (permalink)  
Old 10-06-24, 04:08 AM
Member
 
Join Date: Oct 2010
Location: gold coast, australia
Posts: 22
Default

thank you Graham.
Any idea if the movement of the gases is bidirectional - could the crankcase ingest atmospheric contaminants during piston upstroke? i.e. if the crankcase gases are routed directly into a downpipe (as when individual Vokes pancake filters are used) instead of being returned to the Bristol factory air manifold. Thanks.
Reply With Quote
  #4 (permalink)  
Old 10-06-24, 07:47 AM
Member
 
Join Date: Jun 2010
Posts: 36
Default

I don’t see why not. On the Volkes air filter cars there’s an alloy breather on the side of block going to a catch tank.
I stand to be corrected but having thought about it:
As that’s all at atmospheric conditions the volumes would be much lower than any combustion blow by ( pistons/ rings ) and the pipe / catch tank arrangement would make it hard for any ingress of large particles.
Graham
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


All times are GMT. The time now is 05:45 AM.


This is the live site

Search Engine Friendly URLs by vBSEO 3.6.0 PL2