Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Walnut Blasting GDI Engine

One hopes that the walnut blasting does not microscopically etch into the metal surface, giving carbon particles a better grip in the future! Only time will tell.
I would be diverting the breather without delay!

That's a top job done. That may be the way to go for me next time, if there is a next time?
Hopefully the catch can will do it's job so there will not be a next time.

That's some improvement!! .... back in the day cars just had the sump breather pipe clipped pointing down at the road .... so I doubt letting it vent to air out of the way will be an issue if you fancy a drive before the catch-tank kit appears.

I made one in the past out of a cheap alloy cyclists drink bottle, just drilled a hole to hold the pipe on the plastic top and a ring of small vent holes round the top shoulder, even came with a holder for about a fiver ... looked fine and did the job

K

Sorry, I thought I posted this a hour or so ago, so may be repeating some of that which has already been typed... Duh..!!

Interesting thread on inlet tract fouling caused by the need to cut down on emissions due to the requirement to vent crankcase pressure and any contaminants contained therein back into the combustion chamber.

In times past the crankcase could be vented via an open pipe on the side of the engine that pointed downward to the road surface thus venting to atmosphere. as things "progressed" it was usual to find a tube connecting the rocker cover to the air filter to vent crankcase pressure back into the intake system...A sure sign that an engine was worn, would be the air filter becoming partly clogged with oil from the rocker cover vent..

It seems the introduction of direct fuel injection (D.F.I.) of the fuel into the combustion chamber increased efficiency and may have cut down on emissions in the process, but this equated to no fuel passing through the induction system part of which obviously includes the back of the valves, which would benefit to some degree in being washed with fuel to some degree..

With ever advancing technology, emission regulation, and the introduction of on-board digital management systems, there was a need to modify the system of discharging crankcase contaminants directly into the inlet tract to cut down on fouling of the inlet tract which had potentially increased due to the effects of D.F.I. thus Positive Crankcase Valves (PCV) were introduced in the hope of them catching the heavier contaminants and cutting down on the sludge build up in the inlet tract..

All of which seems better for the planet...? Perhaps not so for the volumetric efficiency of the engines or their max potential power output...?

I think I read somewhere that Mazda had introduced an extra injector into the inlet manifold of one of their D.F.I. engines in an attempt to minimise build up of sludge.. though that seems not to have been universally adopted..?

As to just how much it might be worth to have an engine inlet tract/valves etc cleaned I know not in terms of either MPG or actual power output improvement, though I suspect engines that are used mostly in slow traffic and for short runs, as ever seem more likely to foul up more than those that spend time being driven in a more sporting manner...? (-:

Also the more an engine wears chances are that build up in the inlet tract may increase.... piston ring blow by creating increased pressure in the crankcase and valve guide or seal wear creating more build up on the backs of the valves...?

As for thinking to solve the issue on a modern engine by just venting to atmosphere.... Hmm..? Dependant on when the vehicle was first registered I guess a wide awake MOT inspector might fail a machine with such a modification. Also worth considering is that other than Morgan (?) modern vehicles may have adaptive systems that monitor the emissions, crank case pressures etc.etc.etc. and may create an alarm relative to your crankcase modification....?

Just passing time thinking in type.. (-:

Further to George’s missive above, it’s not only Mazda who have gone for port injection combined with cylinder injection. Thankfully, the new 3 cylinder Ford Dragon engine fitted to the Morgan Super 3 has that feature, so manufacturers have soon realised their folly in producing GDI engines.
Pity for those who became the test bed for ill conceived technology!

That last sentence is a hard swallow for us Morgan owners!

The only way I could get my old 1970s plus 8 through the MOT back in the 90s was to disconnect the top (rocker) hose from the inlet manifold. Smoke would come from it ( I just used to pull it off the rocker leaving everything else in place) and my friendly MOT man used to say.. I'm measuring at the exhaust pipe not under the bonnet. More flexible days.....

I think walnut shell blasting is one of the least invasive and damaging of the various blasting mediums Doug. It's particularly suitable for softer materials such as aluminium, GRP gel coat and even some woods. The medium has friability (new word for me) meaning it degrades on impact into powder/dust. First came across it during the vintage Lister diesel rebuild for my narrowboat propulsion. It was used to clean out cylinder heads without damaging mating surfaces.

DFI Morgans have it a tad easier than Porsche 911 derivatives with DFI, as their engines require to be dropped to remove the inlet manifolds if nut blasting is thought desirable..

Touching wood as I type that my mid 80`s +8 has passed it`s MOT and without advisories in the 20+ years I have owned it....(-:

Thanks for that Richard; quite re-assuring.

These were my thoughts when I was pleasantly surprised at the level of deposits on my valves after 20K miles.