Intake ports black?

[Grimmy 312]

So I started pulling down my old engine today and I noticed that #1&6 intake ports are near black , while the rest are perfectly clean . Any one know what would cause this ?

[Tyler06 266]

Valves not closing completely and firing into the intake runners?

[slydog 7,873]

Nope uneven cyl fill is all.You can try moving the carb or go webbers or EFI or other means.

 

I know which way Im going.

[gerg 10,871]

Does the discolouration occur further up into the inlet manifold? If so, how far up? It's not something funny going on with the EGR gases is it?

[slydog 7,873]

It's all in the head and reversion and extra flow on 1-6 ports due to vacuum.It's unburnt fuel caused by the POS manifold hanging off a xflow head trying to feed 6cyls.Which is why a xflow head flows like poo cos you go and fit a POS manifold to it.If it had a straight throttle body or Webbers well no issues but anything less than that or boost will suffer.Common sense tells you that...1 carb with 2-4 barrels feeding 6cyls with different length runners and different flow rates? Please come on?

 

OK that said if used for wide open constant RPM it would be fine but up and down everyday driving IS NEVER going to be your friend.

 

Again I think you have my number if you want to talk about it bro please ring and I will try to help as best I can...I know Jase had good results moving the carb but I don't know your limits or intentions either but will try to help if I can.

 

Rob 

[gerg 10,871]

Well there you have it. I always looked at my Redline Torker and thought it looked bad, particularly at 1 & 6. However it did the job on a mild LPG motor, but ran out of puff at 4500.

 

I quite like the manifold on the single point EA. It looks like they actually made some effort to make the runners simlar in length. I've seen one welded to a cross-flow flange, and I wonder how much better that would be over stock.

[slydog 7,873]

Speedway boys use/like the EA manifolds for that reason bro...Even Holden 6cyl manifolds have different port sizes shapes to try to create more even flow into the head.We basically have a very poo manifold to deal with and the OHC engines really sorted that with there EFI set-up but as for us with carbies you have some trouble.As good as the A0016 Aussispeed 4 barrel is it's just the best of whats available really.It will make awesome HP and is cheap for what it is but it cannot be tuned liked a individual throat/TB per port can.

 

I know "some" people think otherwise but after all this time and still praising the single 4 barrel on a x-flow amazes me.Marks manifold is very good and maybe too good on 1-6 and I know Jase had good success moving the carby on his Cain sytle manifold to help fix the issue but thats beyond what most are willing to or want to do with there's.

 

I can show people mine when it's done that is VERY left of field and VERY custom but it could be done in soo many different and cheaper ways it's not funny.It really makes me wonder why it hasn't been done before or maybe we just havn't seen it or looked hard enough or didn't pay attention?

 

Webbys Webbers make the point loud and proud and it's easy to see why when we open our eyes...

[gerg 10,871]

I'd like to see your work Slydog, no I'm not going to copy it (I don't have a Crossy any more). Although my brother's using my old one to build a 200 turbo EFI Donk for his XP ute.

 

The stock manifold does the job on a stock engine, but yes it is poo for anything more than stock. I'm sure that the Ford engineers would never in a million years think that somebody, somewhere would try and get better performance out of a Crossy. It's ridiculously reliable, torquey, and resembles a scaled-down truck engine. All I can say is hats off to the folks that squeeze the amounts of power out of them that they do.

 

I always wondered how a twin carb setup would go, one feeding 1-2-3, the other 4-5-6. Some Jags were like this. Much better balanced that's for sure.

[slydog 7,873]

I could do 1 but have found 2 very competent and keen fabricators to do the job for me instead.Still the basic idea is there for 1 throat/tb per inlet port.Taking that thinking it's easy to sort many combo's that could fit that bill.The chosen fabricator has ALOT of V8 supercar experience so has had to work within alot of restraints which gears one for problem solving via different means out side the normal.Braddy had 3 XF webbers or strombergs??? on a custom manifold that appeared to work on a stockish engine.Not hard to improve on it...  

 

That only leaves the exhaust as your weak link and as mine is getting custom merge collectors and a twin 2.5 exhaust I feel that is covered now aswell.Again not everyone's idea of what should or will work but after talking to the right exhaust shop and head porter/fabricator it seems it is going in the right way.Issue here is mine will be very very far from a daily but if reworked via smaller camshaft (even hyd),less compression and petrol and a rethink of the exhaust to quieten it down I bet it would run very good numbers and be happy as a daily aswell albeit a tad thirsty as you would still spank other streeters on the way to work for fun...LOL 

 

If we remove the "it can only be this way" thoughts from peoples minds we can achieve much more all while seeing the issues raised as simple engineering/mechanical problems like we solve in other areas of our lives on a daily basis.We just have to aim for higher efficiency with every single aspect of what we do in modified engines or stick with what some claim is the only way and watch the rest go ahead.

 

A boosted engine is much softer on engine components other than pistons and valves springs then a NAT ASP engine is due to the constant pressure on the rotating assembly acting as a cushion if you will.Where as a NAT ASP is continuously loaded and un-loaded on every stroke which is why we see certain conrods last in boosted combo's that can't in a NAT ASP deal.NAT ASP is HARD on a engine thats near the limit yet boosted engines just swallow more and more.They always have a safety window ready to go like a head gasket where as on a NAT ASP combo it will be a conrod out the block or such.Tuning is the key to reliable boosted combo's,even NAT ASP really.

 

The factory BBM manifold off a E series seems to be the go for boosted x-flows but even the stock unit can make REAL numbers judging by that green one that came from down south that young fella did.Boost will flow anywhere but vacuum needs help to flow well and be efficient...       

[Clevo120Y 815]

Back to the original question, Sly is correct the ports are bad for reversion during the overlap period because of the imbalance between the intake and exhaust flow. The crossy needs both a better intake and exhaust to correct the issue.

Can't wait to see your custom work Sly.

[Clevo120Y 815]

Also the valve seat setup can minimize reversion too