Dipstick oil spray !

[Jake]

Just finished fitting new shiny Edelbrock rocker covers and oval air filter to the RV8 and today I started the engine for first time since it was all changed. After a short run out I checked under the bonnet and oil is bubbling up the dipstick tube (not quite spraying). Oil is then burning on exhaust manifolds and generally creating a bl**dy mess. Before I changed the parts there were no problems at all, the engine only used a little oil from day one but no more than you would expect from an RV8 (complete rebuild engine). Both rocker covers are vented through Edelbrock breathers to the air filter pan as was the case before they were changed. Engine sounds and runs as sweet as a nut . I've read many posts about fitting PCV valves and maybe this is the problem although it wasn't previously a problem. If I do need to fit a PCV where would it be connected to as I am using the vacuum on the Weber carb for the brake servo.

Any help would be appreciated as the MOT is on Saturday and the weather is looking reasonable.

Cheers

[mylesdw]

I can't see why it should suddenly need PCV when it didn't before. I would look to the new breathers and what might have changed. To push oil up the dipstick tube means there is quite some positive pressure in the crankcase. Are the new breathers more restricted than the old ones? Some of the square dragster style ones that sit on top of the rocker boxes had quite a bad reputation for being more show than go; they are too restrictive. Can't think of much else.

[TINKA]

It would indicate from your new setup that there is pressure building up in your engine now. No idea why this should occur now but I would check if the breathers are blocked or not.

On the subject of a PCV you do defiantly need one, the RV8 works at it's best when their is a slight negative pressure in the engine, this also helps clear out some of the fumes that build up in engines due to things like blow by.Your carburettor should have 2 ports at the base one for the PCV and the other for a servo, if my memory serves me correctly i thought it was specified which was which. Is there not a place on the inlet manifold for the servo, this would make things easier.

[Happy Jim]

Is there a seal on the dipstick? (Can't remember) might be worth checking that it's not got lost or nicked during the rebuild.

Jim

[slogger]

Hi Keith,

As stated by others (memory shot today) it does sound like crankcase pressure build up. The RV8 fitted with SU carbs had a hose with Y piece on one of the rocker boxes which was then connected by two hoses to a large port on each SU. No valves just direct. On the opposite rocker box to this take off, there was a small inlet port with in many cases an inline filter.

Unless the engine has been standing for a long time I would say the breathers and pluming are at fault. On the other hand if your engine has stood for a while you may have a stuck piston ring. Has been known with these motors. If so it could free itself or a helping hand from a dose of Redx should do it.

[Jake]

Thanks for all the suggestions guys, it would seem that the plumbing / breathers may be the problem and I will check that later today.
The engine has only been stood for about 6 weeks so I would hope it wouldn't be a piston ring
There is an O-ring seal on the dipstick and I plan on changing it just in case

Martin: I had planned on fitting a PCV connected to the manifold vacuum but I've never been able to find a fitting for the manifold that would allow me to connect the pipe, any ideas ?

Cheers 4 now

[kdavies3]

If you have an Edelbrock carb you should have two or three Vacuum ports on the front of the carb.
One of them should be connected to the PCV, can't remember which one off hand. It does matter which one or you can get too much vacuum. One of them also goes to the vac on the dizzy.

[chesterak]

I had a similar problem with the std SD1 tube and stick - the inverted bell cover did not seal. My engine is built as new so there is (should not be) no blow by, it seems a characteristic of the RV8 that the cranc case pressure will push oil up the tube. I have fitted a Discivery tube and stick - no more oil leaks - at least not from there!!! BTW, I have fitted a PCV on one rocker cover, seems to work OK.

[Jake]

Ordered PCV which will hopefully sort the problem out, watch this space

Thanks again