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[zirk]

Need to rip the Inlet manifolds of soon to start the LPG conversion on one of the 3.0 MV6's, so it would make sense to do some porting and any polishing at this point.

Its been a while since Ive done this, and certainly not on any injection engines, in the old days we would grind, port and polish just about anything that was polishable.

Talking to some old friends about this now, there seems to be mixed feelings on this with modern engines, some saying polish what ever you can get to, to dont polish past the petrol injecter points (injecters to valves) and others saying dont polish at all past the throttle bodies?

Any thoughts on this anyone?

Plus any tips on the 3.0 porting would be good.

Thanks Chris 

[zirk]

Anyone?

[Marks DTM Calib]

Are you removing the heads or just the inlets?

[zirk]

No wasnt planing to unless its worth it, thinking your going tell me now its worth porting the head inlet to the inlet manifold?

[Marks DTM Calib]

Well, as the key limitation on any engine is generally around the port then thats the bit that gets the best results.

No harm in porting the inlet though but, dont make it larger than the plastic bridge piece.

And it needs to be slightly rough in order to creat some turbulance to aid fuel atomisation

[Martin_1962]

And you end up with the fastest 2.6 on the forum (Mikes) and 2.6 auto mine!

[zirk]

Thanks Mark, Ill have a look at the head thing when I take it apart, we did manage to port a 2.9 cosworth head without taken the heads off (please dont shout at me) I made a small spindle with a small cup and some aerial riggers rubber to seal past the inlet hole to catch all the crap, risky and all a bit tight but it worked,

[Marks DTM Calib]

Thanks Mark, Ill have a look at the head thing when I take it apart, we did manage to port a 2.9 cosworth head without taken the heads off (please dont shout at me) I made a small spindle with a small cup and some aerial riggers rubber to seal past the inlet hole to catch all the crap, risky and all a bit tight but it worked,

You cant do them very well fitted as the key area is where the valve seat meets the casting, here you need to smooth out the imperfections and raised casting flash.

You could match the lower inlet though (normaly worse around the injector port sections and lower opening)

[zirk]

Well, as the key limitation on any engine is generally around the port then thats the bit that gets the best results.

No harm in porting the inlet though but, dont make it larger than the plastic bridge piece.

And it needs to be slightly rough in order to creat some turbulance to aid fuel atomisation

Ok, that sort of answers the "dont polish past the Injector points" bit. 

[zirk]

Thanks Mark, Ill have a look at the head thing when I take it apart, we did manage to port a 2.9 cosworth head without taken the heads off (please dont shout at me) I made a small spindle with a small cup and some aerial riggers rubber to seal past the inlet hole to catch all the crap, risky and all a bit tight but it worked,

You cant do them very well fitted as the key area is where the valve seat meets the casting, here you need to smooth out the imperfections and raised casting flash.

You could match the lower inlet though (normaly worse around the injector port sections and lower opening)

Thanks again Mark, sounds like you've done all this before, dont suppose you took any pictures?

Chris.

[zirk]

And you end up with the fastest 2.6 on the forum (Mikes) and 2.6 auto mine!

That would be nice Martin, but mines a 3.0

[Marks DTM Calib]

Best I have are:



and

[zirk]

Ok, Thanks, first picture, looks like you've ported the metal to match the plastic without messing with the plastic  , second picture, yea, understand the heads off bit now (valve seats)  .

Debating now about taking heads off  :-/, thanks.

[deviator]

Well I had prepared a wonderful post including pictures and everything. But that was last night and in the time it took me to write it, the server had gone off line.

So no pics and the moment, will try and do it tonight if I get chance.

My 2 pence worth.....

Take the heads off! The amount of fillings created during this process mean that if you don't remove the head, you run the risk of killing you engine. On my practise head, I chopped the bottom of the valve guide off to aid flow and also removed the lump on the exhaust ports, (only really useful if using tubular manifolds).

You will probably need to re-grind the valves after as I did catch the valve seats a little. Once done, I recommend you spend many hours cleaning the crap out. The oil jets around the camshaft seats can be removed and I think there are other none jet bolts that allow access to the oilways. I would use a compressor and petrol to clean there out as best as possible.

[deviator]

OK this is last nights post......

OK here was my first attempt (never tried, just an exercise)....

Inlets...



Outlets.....



As you can see they are far from perfect! But I wanted to see what was possible. I cleared out the value guides on both sides. Also on the exhaust side, I removed the lump with the hole in, but can't find the pics. This may not help, and in fact may hinder unless you have larger fanimolds.

Hope they help.