TR4/4A TR4 Upgraded inlet manifold/valve cover question

[jimitro]

I upgraded my '62 TR4 with a TR4A long tube manifold and aftermarket valve cover which has the PCV valve outlet. Do I need to connect a PCV valve to this and then connect to the manifold or should I just run a hose from the valve cover to the inlet manifold? Any other ideas on either blocking off or
different connections?
Thanks

 

[JerryVV]

You should not make a direct connection. There should be some sort of PCV Valve in that system. Or block off the manifold hole completely and run a hose away and down from the valve cover. Best is the use of a PCV device.

 

[sail]

On my 4A I put one of these on the valve cover and plugged the manifold with a bolt.

 

[Geo Hahn]

Later TR4 air filters have a fitting for a tube from the valve cover vent. No PCV valve on that set-up (just a flame trap I think). Not particularly effective either I'll admit -- but perhaps closer to a TR4 look than some other options.

 

[TR3driver]

If you are going to implement any of the PCV options; then you'll also want to remove the road draft tube and plug the hole. Otherwise, you'll be sucking dirt up off the road surface and into the crankcase.

Since that may be kind of a pain, an easier option would be to find something like this:
https://www.amazon.com/Spectre-3998-Cotton-Filter-Breather/dp/B00062ZING

to fit the fitting on your new valve cover and let it go at that.

 

[jimitro]

Thanks for all the fast suggestions.
I think I'll try the crankcase vent filter option and plug my manifold outlet.
Cheers

 

[doughairfield]

Did you have any issues getting the throttle linkage reconnected to your carbs after installing the TR4A intake? I'm getting ready to change the stock intake out on my TR4 for one like you have done and was wondering if the longer tubes moved the carbs out towards the fender to much for the linkage to reach.

Any noticeable performance improvements?

 

[richie]

Hey all,

I've just recently bypassed my PCV on my TR4a. I plugged my inlet manifold and put a breather on my valve cover. I am experiencing severe blow-by to the extent that oil is bleeding out of the holes for the studs which hold down the valve cover.

I am curious if others have experienced this and whether or not this is somewhat acceptable for these old engines or whether or not my rings are already showing signs of wear (rebuild is under 15k miles). Perhaps a valve cover with baffling might resolve this issue?

Thanks!

 

[HerronScott]

Richie,

You need to install the breather pipe assembly on the driver's side of the engine block from an earlier TR3/TR4 engine. On the later TR4 and the TR4A engines, this is blocked off with a plug that needs to be removed.

Scott

 

[richie]

Hey Scott,

Are you referring to the "road draft tube" ?

 

[sail]

One of these. But I think mine went for around $25.
How to pull plug which is harder than it looks.

 

[HerronScott]

Richie,

Right and Richard sent you a link to what one looks like on eBay (but also ouch on the price).

The prior owner on my first TR4A had removed the PCV but had not done any of the other work so when I restored the car, I did the full reverse conversion and installed the tube, a TR4 valve cover and oil filler cap, and a TR4 intake manifold so it all looks stock. Used parts were a lot cheaper and plentiful then.

Scott

 

[RJS]

I ran a stock PCV system on my 4A for years. No issues. Then I started getting massive oil leaks everywhere. After a long time I traced it back to a failed PCV (I think the little spring inside the unit failed allowing it to close prematurely). I even suspected excessive blowby (rebuild 10K miles ago). I was doing compression tests, leak down tests, etc.

I then ordered various replacement units from eBay and one of the big three but, still, none of them appeared to work properly. Not to mention, each one looked slightly different.

At this point, I have the inlet on the intake manifold blocked with a rubber plug and run a long 1/2" hose off the valve cover. It's routed over the carbs and down low - just poking beneath the chassis where it runs in the free air beneath the car. It works pretty well but, I suspect the engine could use additional venting.

Ideal crankcase vacuum to scavenge the gases is 8"-10"Hg which is roughly equivalent to 4-5 PSI. That would also prevent most oil leaks.

From what I could find, the Triumph PCV valve never worked entirely well. I think it was a stop-gap measure to new laws in the U.S. and was poorly designed. I've actually been keeping my eyes open for a replacement or aftermarket PCV which I could use in it's place. Many are designed to feed crankcase air into the air cleaners. The TR4A set up requires one designed to vent into the intake manifold.

Bob

 

[martx-5]

Here is a link to Paul Teglerizer's site that shows what he went through to get a good working PCV system. It took five tries, but the end result is great. I've got it in the back of my mind to adapt such a system for my TR3.

 

[Willie_P]

early TR4's (such as my '62) - dont have the PCV system..correct?

I know I do have the road draft tube on my car for sure.

 

[sail]

I believe the early cars had a valve cover without a vent but a fatter vented cap to compliment the road draft tube, so no. I'd guess Geo's set up above was among the first attempt to close the system. His filler cap is not vented and vapors just go thru the carbs again. The 4A added the PVC valve off the vent to the intake manifold with the closed cap and no road draft tube.

 

[F1LOCO]

So, can someone tell me what I have? Allegedly a '64 TR4 engine, but I don't see a road tube, I don't see a plug on the passenger side? Have blow out through the breather cap currently installed...suggestions? Do I get a new valve cover with an out pipe and put a filter on it and/or run a hose to below the vehicle in conjunction with the current breather cap??

Getting ready to redo the lower sump gasket and valve cover gasket...hate to do it if it fixed as it will only happen once again most likely.

 

[DNK]

You getting to much pressure in the motor?

 

[F1LOCO]

Have no idea, but I am getting oil blowing out from the breather cap on more than in city putting...

 

[TR3driver]

Looks to me like you have an earlier rocker cover on a 4A motor. The PCV valve has been removed, and the manifold port plugged. Now any combustion gases that leak past the rings have to exit out the vents in the cap, carrying along oil spray from the rocker shaft and making a mess.

Two ways to fix it:
1) Source the proper rocker cover, cap, PCV valve and associated plumbing.

or

2) Remove the plug and install a road draft tube from an earlier TR.

Just as a side comment, it is usually better to start a new thread rather than tacking onto an existing thread. You'll get more readers that way, and some of them might have a better solution to the problem. Lots of folks may have already decided that they had nothing to contribute to jimitros problem and so won't read any additional posts to this thread.