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High oil pressure and this puddle...

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You probably already know this but these ngines dont have an oil seal on the rear end of the crankshaft.
There is a "thread" which winds the oil back in as the crank revolves.

This is why its important that the crankcase does not get pressurised or the scroll-seal will be overwhelmed
and oil will get into the bell-housing.
 
OK for the PCV valve installation, do I need a stainless steel hose barb fitting to connect to the manifold or can it be brass? My gut says it should be stainless, but brass is easier to come by.

Also, how close can the valve sit to the manifold? Will the heat mess it up if it's too close?
 
I wouldn't be afraid to use brass. Don't know about interaction of the two metals but a little anti seize couldn't hurt.
Merlins picture shows the original placement of the valve on a 4A with a bracket off the rear manifold stud which would alleviate heat issues and be simple to fabricate.
 
The original fit of the PCV used a steel strip about 2-3 in long with one end under the rear-most manifold stud and the other on on the hole through the PCV.

The PCV flat disc area then sits horizontal between the carb and the rocker-cover. Th inlet points towards the rocker and the outlet to a tapping in the manifold.

Originally these tappings are just ordinary mild-steel. I wouldn't mind using brass myself.

Al.
 
OK time for an update: PCV is installed, took the car for a drive, same problem. Oil is leaking pretty well from the rear of the engine. I'm not sure it's the rear engine seal necessarily. May be the sump. I need to crawl under there this weekend to try and figure it, but regardless, I think I have bigger a problem.

There's no emulsion on the dipstick but my oil level isn't going down and might actually be going up. I suspect the coolant level is dropping, but I had to siphon a bit out to do the block test, and refilled it afterwards so I'm not entirely sure. I'm taking it to a shop next week but I think the head may have to come off...
 
Over here we are of the opinion that the sealants used originally for things like sumps are inferior to more recent methods.

This is one of our favorites:

https://www.loctite.co.uk/fullprodu...redDotUID=productfinder&redDotUID=1000000IXJA

Stuff like this does not need the traditional fibre gaskets which is also a big help.

The UK Register ran a thread on using this on the diff cover recently. The guys most into this are the hill-climbers and racers who are of course getting the most repairs to do.
 
I say you should re-torque the head ASAP, a fresh motor needs this, and the signs are loss of oil
at the rear of the motor/loss of coolant.Dude ya got both.......
MD(mad dog)
 
Got a bit of good news to share. I took the car for a leak-down test and had them re-torque the head while they were at it. The leak-down test was "good as new" and only a couple bolts needed a slight bit of torquing. I'm feeling much more confident in the quality of the engine rebuild.

Now, I've driven it a few times since that first picture of the oil, and while it still leaks, it doesn't look emulsified like it did in that picture. I'm pretty sure it still needs better crankcase ventilation and am working on getting the PCV cleaned up and ordered a new rubber diaphragm. Time to put this thread to rest.
 
I just used "the Right Stuff" on my oil pan and timing cover. It seems like great stuff - I have high hopes for no more (or few) oil leaks. Will be reporting the results within a week.
 
OK one more question: my current oil fill cap is completely sealed. Is that correct with a 4a PCV setup? If not, do I need to buy a vented cap or can I just drill a hole in the top? How big?
 
Your photo show the same cap as my 4A which came with stock PVC. No vent although there is a small hole in the underneath brass plate. I don't think you want a vent in a closed system. Vented cap from earlier 4's and 3's won't fit your cover.
 
I'm fairly certain the TR4A with PCV uses a vented oil filled cap. Mine does. That's how fresh air is allowed to enter the crankcase and displace the blow by gasses.

Bob
 
RJS said:
I'm fairly certain the TR4A with PCV uses a vented oil filled cap. Mine does. That's how fresh air is allowed to enter the crankcase and displace the blow by gasses.

Bob
Click to expand...

Is your cap different than Scott's?
 
What I can find out is that there are three kinds of caps, one for the breather tube type ventilation, one for TR4 with closed circuit breather system, and one for the TR4A according to TRF:

https://trf.zeni.net/TR4-GB/index.php?page=24

So it there are two different kinds of vented caps it looks like and no one sells the TR4A type that I can find.
 
sail said:
Is your cap different than Scott's?
Click to expand...

Just to confuse Scott's. :smile:

My second TR4A still has the original setup which has a cap like Scott's with the PCV. I converted my original TR4A to the TR4 style crankcase ventilation with the tube, a TR4 valve cover and the oil filed cap and a late TR4 intake which is the same as the TR4A except not being drilled for the PCV connection.

Scott

Scott
 
Yes, the one I am refering to and have on my car is PN 143393 in the link above. That is correct for TR4A with the PCV.

Bob
 
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