• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
  • When posting a classified ad, you MUST select a prefix from the drop-down next to the subject line. If you don't you will get an error and your ad will not be posted!
Tips
Tips

TR4/4A Better TR4 Valve Cover Replacement?

Share this page

J

jimitro

Senior Member
Country flag
Offline
I am going to replace my stock early TR4 valve cover with an new alloy
cover. Is there any advantage going to a cover with a breather outlet vs. my non-breather cover?
If so, most breather covers seem to outlet them thru the air cleaners.
Any other thoughts on this?
Cheers
 
The crankcase absolutely has to be vented some place, otherwise it is going to blow oil out everywhere (mostly the rear seal).

But your early TR4 should have a road draft tube on the side of the engine, and a vented cap on the rocker cover. The 'sealed' system with the tube to the carbs did not come in until CT23594.

In theory, the vented cap helps keep the oil cleaner; at speed the air rushing past the road draft tube pulls fresh air in through the vented cap, thereby dispelling the blowby gases that could later condense to form acids and sludge. In practice, I'm not sure how much difference it actually makes.

But, since pressure buildup in the crankcase is a primary cause of blowing oil out the rear seal, it seems like a good idea to me to keep some sort of vent on the rocker cover.

Hooking it up to the air filters might help reduce pollution, but IMO isn't going to help the engine at all. I would just use an ordinary filter:
https://www.google.com/#q=rocker+breather...2289185d5cea093
 
thanks for the advice. My engine does have the draft tube and original
valve cover cap. I've been having some oil leaking from the rear seal.
Maybe this will cut it back some.
This may be a dumb question though, Can the engine breathe too much,
meaning, should the side draft tube now be plugged if I go with a
valve cover with a breather outlet?
Cheers
 
I would say no.

IMO the breather as used on the TR4 valve cover is inadequate to do the job on it's own. I added a road draft tube to my late TR4 and it really lessened my oil oozing/leaking.
 
Thanks for your feedback.
I will be ordering an alloy valve cover with a breather outlet.
Only problem is, will not be able to test out until Spring!
My 4 is now in storage in Upstate NY (New Harford/Utica).
Cheers
 
I welded an alloy pipe to the aftermarket alluminum cover and used the original breather oil cap. Works as it should and looks right.
 
Back
Top