The V8 Owners Forum -

Well back in January I got my RV8 with a Wade RO34 running
Thread: http://www.v-8.org.uk/forum/viewtopic.php?t=556
but since then have managed about 25 miles with problem after problem

- Wouldn't idle right at all, found the Holley 600 has a whopping big crack. On advice bought a new 390 VacSec into which I popped larger jets - solved.
- Exhaust blew to bits on the 4 into 1 welds on both sides. Custom build S/S headers & front pipes - solved
- Burned out a valve & damaged head. Bought set of ported 3.9 RRover heads - solved
- Snapped half shaft. Welded, sleeved to re-enforce & deliberately snapped & did same to other side - solved

Now it runs but I am having major problem with escaping fumes from every orifice under load, I assume due to the extra pressure inside the engine. At first they were escaping from the oil filler cap so we plugged the vents in the cap & conected a breather pipe to the breather pipe from the other rocker cover.

Then they popped the cap from the vent at the back of the block near the heater inlet/outlet pipes & the fumes are entering the car & oil spraying down over the bellhousing, this can obviously be blocked up properly again but am hesitant to do so just yet. Also it is popping the dipstick out and ejecting fumes and oil over the headers on that side of the engine.

My question is - has anyone else who has fitted a blower to a RV8 had any similar kind of problem with aparent build up of pressure inside the engine causing so much oil and fumes to escape. It doesn't happen when coasting or idling, only when accelerating or giving it foot to the floor (all 4 barrels of the carb opened up). - any suggestions at all? I am in over my head a bit now.

The crankcase will need venting, blocking the vents up won't help at all.

You really need to connect some of the vents to the air intake so the fumes get burned rather than vent to the atmosphere.

Chris.

Aye I have both vents from the rocker covers being piped back into the air intake. However I am a bit hesitant about piping the rear vent in aswell due to the amount of oil that pisses out of it which I wouldn't imagine would be much use getting into the combustion chambers?

Mind you with that and a decent seal on the dipstick would that just force the majority of gasses out through the rocker cover vents and therefore back into the air intake?

I am assuming other than that it is quite normal then to have so much additional air pressure inside the crank case as a result of having the blower?

Well Rovers are known to be a bit oily apparently. My old engine spewed its guts out once under load, but turned out to be fuel contamination. How bad is it?

if its bad then I think you need to check your compression which should tell you if the rings are ok or not. FI will need good piston ring sealing or the extra pressure will just blow by causing what you seem to have just now. The back vents should actually let air into the engine by the way not out.

Compression is good, we did a compression test when the valve burned out to find out why & where it was mis-firing in the first place. Replaced the heads with ported rebuild 3.9 heads & copper head gaskets and re-tested the compression which was all good. Rings should be OK anyway as the motor's only done about 6000 miles since a rebuild, we let it run in a bit before fitting the blower.

The little vent at the back of the crank case was previously blocked with a little yellow plug but I imagine this was blown out - maybe a safety valve or something? From web research it looks like it is a breather pipe which was replaced with a core plug on later models (My block is from a Rover P6).

It's hard to say how bad it actually is to be honest. Until I can source a replacement dipstick with a good tight fit it's hard to see how much oil is being vented from the pipe as it just sprays everywhere when you're standing underneath the car & it's being revved - need to get goggles I think.

Here's how I did it....


On the right side of the pic you'll see the left valvecover with on the back a PCV valve or flame trap. I modifiet the valve cover to fit this Ford style PCV valve with a gromned. From there goes a hose to the alloy catchcan on the lft side of the pic ( rightside innerwell ).
From the catchcan there goes a hose to the PCV connection on the throttle plate of the Holley.

Next is the K&N breather filter on front of the rightside valve cover ( left side of the pic ).

With this I'll have a positive carter ventilation system while the oil will not sucked back in to the engine ( its catched in the can ). I'll have no fumes at all and is working great.
The can has a drain on the bottom.
After some discusion with Nigel from UKblowers we came to the conclusion that this is the way to go on a street engine.

JP - Brilliant, I owe you one, thanks very much. Not sure where I will be able to put a catch can in mine though (had a job finidng somewhere to put the winscreen washer bottle) but I'll fit one somewhere. Yours looks like a Capri engine bay? Nice and big.

Just one query, have you had any trouble with that vent at the rear of the crank case I mentioned or is that just securely plugged on your motor?

Positive crankcase ventilation works as follows....... there needs to be an hole at one side of the engine where fresh air can be sucked in and on the other side of the engine there needs to be a hole where it can sucked out. I modifiet both valve covers a bit to accept a normal style breather & PCV valve as I always found that sucktion pipe on the back of the valve cover to small for a performance engine that runs 6000+ rpm.
I modifiet that canister thing on the other valvecover to accept a normal US style breather.

At the moment I replaced heads for the Merlin F85's and my PCV system is vice versa now...

Hoses aint connected yet but the left hise will be cut ant mounted to the catchcan.

You haven't connected the breathers to the pressurised side of the intake have you?

Jeff