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[Jim G]

Hi all,

I've recently acquired a 65 TR4 (CT25510L). I'm getting a little oil splashing up through the oil filler cap. The air filter set up appears to be non-original in that its got black air filter covers and no connection back to the valve cover for oil vapors. The previous owner did supply a pair of what look to me like original filters with the tube that goes to a port in the valve cover as spares. He tells me that a mechanic had advised him to fit a non-ported valve cover to stop a rear main oil leak? Doesn't make too much sense to me.
I'm thinking of fitting the original looking filters (chrome, smaller) and connecting up the valve cover port (also supplied as a spare).
I've tried researching this a bit but I'm kinda confused on the closed vs. open systems I've seen mentioned on Moss etc.
Question - does my thought of returning to a 'vented through the air filters' type set-up make sense? Is that likely to cure the splash up through the filler cap? Should the filler cap be a lock down type one (its not currently)?
Thanks in advance...


Jim.

[charley fitch]

Assuming that you still have the original engine, you SHOULD HAVE the closed system valve cover.  This change was made with engine number CT23594E.  One further piece of evidence is that you would NOT have a breather tube on  the lower left rear or drivers side of the engine.  This would be found right next to the clutch slave cylinder.  Without the breather tube the engine would in fact be pushing a lot of pressure (and possibly oil) out of the lone breather, which is now the oil filler cap. The original system used the outlet found in the right side of the valve cover to vent into the air cleaners and the combustion chambers. If you have the correct valve cover you would then have a cap that looks like a radiator cap on top of the valve cover.

Hope this helps.
Charley Fitch 

[TomMull]

Charlie is right about this and I think the mechanic who made the change was wrong. Even though the earlier setup with two vents (filler cap and crankcase pipe) would seem to be belt and suspenders, with the slightest blow-by you would see an oil film under the cap and a drip or two from the pipe after hard running. With moderate blow by, the film under the cap could get quite nasty. Without the pipe to share the venting, the problem would be doubled, which it would seem to be in your case (and very a unlikely cure for a rear main seal leak). The later style, with the single vent going to the air cleaners would have the venting aided by the slight intake vacuum at the air filters and I don't think would be any less effective than the two vent original system and I would think, more effective than your single vent.
I'd go back to the original system, although it sounds like you'll need a different valve cover. Run a compression check first though. If you do have excessive blow-by, then this will be an endless battle until that is fixed.

[Jim G]

Charlie / Tom - thanks very much. There's no breather pipe in the lower rear of the engine . And I do in fact have a vented valve cover that came in the trunk of the car along with the air filter set up to vent it.  So I will (re) fit all this and see if that does the trick - compression is ok.

Jim

[charley fitch]

Just to let you know how some others remedy the problems.  I have a friend with at TR6, which uses a similar setup. He was frustrated with the amount of oil and grunge that collected on the air cleaners from this recovery setup.  So he put a "T" in the line between the valve cover and the air cleaners and ran a tube down to the bottom of the engine compartment.  He solved the problem as far as he was concerned  and his air cleaners no longer collected the oil and grunge.  I have also seen such where a guy did the same thing and ran the tube into a empty beer can.
You may have to vary what you do depending on your smog control laws.
Charley