Cross flow breathing

[jpa]

What is the best set up for crank case and rocker cover breathing on the crossflow engine?

Is the norm to leave the crankcase venting to the inlet manifold via a PCV and the rocker to atmosphere or a tank?

I can't seem to find a good set up where oil does not try and vent itself through the dipstick tube or cap. My engine has an aftermarket alloy rocker cover as the original is a bar-steward to get to seal!

Any recommendations / ideas? Or is the fact my engine is 'blowing by' an indication that a rebuild is imminent.

Cheers
Paul.

[Slow M]

Checked compression?

B

[jpa]

heightswitch said:

Remove PCV valve and fit a alloy 90 degree elbow to the hole (2 types available dependant on year of block from burtons) Drill and tap the top of your rocker cover at the rear to take another 90 degree elbow. Connect both elbows to a Mocal 1 or 2 litre carch tank with sight glass drain and vented lid / filter lid. (You can buy twin entry left or right handed tanks)
You will also need to remove the old elbow that the PCV valve was connected to on your

Thanks gents. This is the set up I have now got but when I had it venting through a filter oil was spitting from the filter a bit - could be my tank is not the greatest.

I had tried the original rocker cover with a 'fiesta' vented cap but the cover leaked too much (they are useless I believe). Hence I drilled the alloy cover and have this going to the tank now instead.

Just wondered if there were any other tricks I was missing.

[nwarner]

jpa said:

I can't seem to find a good set up where oil does not try and vent itself through the dipstick tube or cap. My engine has an aftermarket alloy rocker cover as the original is a bar-steward to get to seal!

My engine had an aftermarket alloy rocker cover and with this fitted it blows oil out of the dipstick but with the factory rocker cover this doesn't happen so I think the problem is down to the filler cap on the alloy cover not venting properly. I tried making the hole in the cap a bit larger but this doesn't make much difference.

Regards

Nige

[kabaman]

If it's puffing it is quite likely the result of a compression problem not the breather system itself. I used to run an open breather sysetm on my corssflows including Vixen and 1600M, Anglia 105Es. One time on my 1760cc x/flow Anglia it started puffing blue smoke from the breather and I'd broken a piston ring. I'm not suggesting that your problem has to be quite as drastic as that but I would tend to think that a compression test is in order.

Neil

[jpa]

Done a test today, this was done with the engine cold (is this right or should it be warmed first??). Anyway, the reading was 160 psi on all 4 cylinders. They were all very close and seem not too far from the 168 that my haynes manual states they should be.

So does this suggest the engine is in not too bad nick?

[heightswitch]

jpa said:

Done a test today, this was done with the engine cold (is this right or should it be warmed first??). Anyway, the reading was 160 psi on all 4 cylinders. They were all very close and seem not too far from the 168 that my haynes manual states they should be.

So does this suggest the engine is in not too bad nick?

160 is ok if they are all within plus / minus 10 psi then thats OK.

You could have valve guide wear and or those horrible cheap rocker covers and caps that need drilling and tapping like my previous post.

Neil.

[Loubaruch]

Presumably you are using an electric fuel pump. If so did you use a baffle plate when blanking off the mechanical fuel pump aperture on the block. I had oil everywhere on a 1700cc Westfield until inserting the baffle, it would collect about 1/2 pint per 50 miles in the catch tank as well.
Burton sell the blanking plates complete with baffle, solved my problem immediately.

[jpa]

Loubaruch said:

I had oil everywhere on a 1700cc Westfield until inserting the baffle,

That's interesting. I never heard of that one before so I will have to take off the blanking plate to check. Where did it 'chuck' the oil on your engine before you fitted it the baffle version?

Neil - With regard to my alloy cover, I have drilled and fitted a union to it which runs to the catch tank but am still getting weeping round the cap. I thought my guides might have gone but would the compression test not show this? The compression figures were all virtually identical.

[Loubaruch]

From memory the cam shaft threw oil straight into the breather that vented into a catch tank on the bulkhead.Of course with the old mechanical pump in situ this would not happen. The horozontal baffle simply stops the cam hurling lubricant upwards. Certainly worked for me.

[Slow M]

Do these engines have valve seals? If so, it may be time to replace them. You'd be surprised at how pressurised gasses escape past the guides when they're a little worn.

[TVR_owner]

It needs pulling apart and putting back together with new parts...after its rebore and head rebuild - its knackered. Thoughts of balnking plates to cure the problem are crazy - its tired and wants money sepnding on it.

Questions, how many miles has it done since its last build, what temperature did it run at before it started to wheeze. What CR ratio is it - nice to know when folk tell you the compression test readings are fine...

Spend some money on it...its probably time.

Edited by TVR_owner on Tuesday 22 September 21:20

[Loubaruch]

TVR_owner said:

It needs pulling apart and putting back together with new parts...after its rebore and head rebuild - its knackered. Thoughts of balnking plates to cure the problem are crazy - its tired and wants money sepnding on it.

The blanking plate is intended to prevent excess oil being thrown up the vent pipe I was not suggesting it would cure a worn out engine. Burton know what they are about and surprising the number of racers who are not aware of this simple fix to prevent excess oil in the catch tank.

[jpa]

[quote=heightswitchJohn has lots of money to play with and would have the mutha of all 1600 engines.
[/quote]

I'm assuming John is TVR_Owner........ nice attitude!

Anyway, thanks for the advice Neil / Loubaruch. I am due to rebuild engine this winter anyway as am doing a full body off chassis / drivetrain rebuild too (don't worry, funds should just about cover it).

It's just the engine has been running pretty sweetly, and the suggestion is it is not on its last legs just yet. Some of us like to investigate and solve problems if possible and not just throw money at it at the first sign of an issue. From what you say Neil it could be that my catch tank is not the greatest as the vent tube is the same size as the inlets, and so may not be venting adequately.

I will check that blanking plate out of curiosity (as I see what you mean from the Burton site).

Cheers

[TVR_owner]

jpa said:

I'm assuming John is TVR_Owner........ nice attitude!

It's just the engine has been running pretty sweetly, and the suggestion is it is not on its last legs just yet. Some of us like to investigate and solve problems if possible and not just throw money at it at the first sign of an issue.

Didn't think there was anything wrong with my attitude. Engines normally breath heavily because there's a problem with them.

I also like to investigate problems and rarely just throw money at problems, I'm an Engineer and need to understand failure and cause - then I like to resolve. In the case of my TVRs that involves resolving via a cost effective solution that will provide optimum preformance with reliability (Sadly something that rarely has an Aldi price tag).

Good luck with it anyway and I hope it is only something simple.