The V8 Owners Forum -

With the old carb 3.5. there is a hole at the back of the block with a filter on it that allows filtered air to flow into the crankcase. Each of the rocker covers have an outlet that goes to the base of each carb where the fumes are sucked into the inlet manifold.

On the 4.0/4.6 blocks with a Thor Manifold, there is no hole at the rear of the block. Like the 3.5 both rockers have a pipe in them to allow air in/out of the engine. The passenger (RHD) side rocker cover is the inlet with filtered air being sucked into just before the throttle body - it is normal filtered air that is going into the engine. The sucker side is on the drivers side rocker cover and goes into the end of the cross section of the Thor plenum next the the brake booster vacuum pipe.

Now I have a 4.6 block with 3.5 carbs and inlet manifold and as such do not have the hole and filter arrangement at the back of the engine. As a result one of the rocker cover pipes needs to be the air inlet for the crankcase and the other rocker cover pipe needs to be the sucker and go to one or both of the carbs.

My thought is that I will run a pipe from the passenger side rocker cover pipe to the engine inlet piping between the air filter and the carbs so that filtered air can get into the engine. On the suck side I though of running a single pipe with flame blocker, then splitting into two pipes to the base of each - that way both sides of the inlet manifold will get equal amount of air.

So what do you think - will this provide adequate crankcase ventilation or is there a better way?

Thanks

Garry

quote=garrycol post_id=119876 time=1622126429 user_id=4443] My thought is that I will run a pipe from the passenger side rocker cover pipe to the engine inlet piping between the air filter and the carbs so that filtered air can get into the engine. [/quote]

Should work ok at tickover as the pressure will be lower at the engine side of the throttle butterfly than between the air filter and carb, but at cruise there won't be much difference and air won't move. I just used a small air filter on the N/S rocker cover so the air would be at atmospheric all of the time.

I may have a piccy somewhere.

Found it - ok it's on the O/S now but this is what I did

Thanks for the pics - what is the filter off?

Just a cheapy from ebay, like this -

https://www.ebay.co.uk/itm/174455348494 ... Swk-Ne6x8E

Thanks for that - much appreciated.

Cheers

Garry