Heron Motor (Carb v KJet)

[Retired]

Afternoon chaps and chapettes,

Ok so the decision has been made for my project, it will be a 1.6 Heron motor out of the early Mk1 GTI's running a 5sp manual box.

The head has apparently got a little work to it (to be confirmed exactly what) and I want to run a mild cam for some nice mid range torque and power.

The question now is....

Do I run KJET or Weber Carbs?

I will be buying an early Cabby parts car so has all the lines, cabby fuel tank and engine/box. This will make it easier to go to the KJET route esp as its all there but I still would love to have carbs as they just sound so damn TOUGH! My thing with the carbs is that the carb will be sitting at the rear so will only be sucking in hot air and when we move back to the gold coast it will be hot MOIST air.. prob not too good an idea.

What are you peoples opinions on this? Am I just trying to convince myself or what?

[Jarred]

Kjet, that way it's closer to GTI spec!

carbs are generally never ending fiddling. + they look better on cross flow heads..

[Preen59]

Kjet is (within reason) a one off tune. Get it fitted, get it tuned by someone competent and forget about it. Very simple. Good fuel economy etc etc...

I'd probably just do the Kjet thing, messy as it is. Far simpler if you have a complete dressed engine.

You'll be a bit annoyed with carbies if you're not used to them. Injection is better for a daily driver, in my opinion.

[roccodingo]

Would go K jet, stays in tune as Preeny commented, and better milage for the power delivered. ( less fiddle time, more time behind the wheel )

Have you a 1.6 heron engine or just the head ?

Got about 3 of them here but they all need new pistons ( oversize ) you can get them from Wossner i believe.

Valves are slightly longer from std 1.6 items as well from memory.

Have most of the fuel system as well ( several sets)

In hot weather, K jet can have fuel evaporation probs as well ( inlet being directly above the exhaust as you well know..) but there is a pretty easy fix for this...

pix....

[Golf Loon]

I have a few Heron motors and heads too if you feel the need.

[Retired]

Would go K jet, stays in tune as Preeny commented, and better milage for the power delivered. ( less fiddle time, more time behind the wheel )

Have you a 1.6 heron engine or just the head ?

Got about 3 of them here but they all need new pistons ( oversize ) you can get them from Wossner i believe.

Valves are slightly longer from std 1.6 items as well from memory.

Have most of the fuel system as well ( several sets)

In hot weather, K jet can have fuel evaporation probs as well ( inlet being directly above the exhaust as you well know..) but there is a pretty easy fix for this...

pix....

Hey mate, have not got it yet but hopefully I will soon.

It is in a Cabby GLI with full GTI running gear so should be good fun

[WABIT]

hey dude, all GLI and GTI cabbys came out 1.8lt.... im alsoo pretty sure they didnt comeout as a herron engine

dom

[Peter Jones]

I'd say K-Jet for the street for all the reasons above.

K-Jet actually makes good horsepower if it's all setup properly.

Carbs are great and will probably make a little more horsepower but at the cost of noise, fuel, starting issues, non standard aircleaners etc etc.

I've run both on the road and on the track, I'd say the carbs, professionally rebuilt and dyno tuned are better than my home tuned but functional K-Jet provided you can put up with all that goes with them.YMMV.

On a fairly stock Herron 1600 either will go pretty hard IMHO.

Every thing's a trade off.

In your case I'd probably just go with whatever's more convenient to source and install.

Pete

[Retired]

Well, it comes with KJET and all the lines and cabby tank so will prob be a pretty easy conversion.

The Cabby tank is a pretty easy swap I take it?

Dom: Not sure what the go is but I was told it is a Heron engine?

[roccodingo]

have a look at the front of the head, if the top coolant flange from the radiator goes between #3 & #4 Cyl its a 1.8 ( not heron head )

In the pic above the engine is a 1.8 Inj + 0.5 overbore.

If its between #1 & #2 then it could be a heron head or std type inj head.( or carb as in this case)



heron head, note NO combustion chamber ..



Thats because the combustion chamber is infact the bowl in the crown of the piston...



Hope that gets you on the right track..

You may need to check what fuel tank the cabby ( donor) has, as the later cars had a larger tank than the earlier models..( Think the stiffener across the front of the spare wheel tub interferes with the latter type tanks, anyone confirm this ??)

[Retired]

Thanks mate, great post! Glad there are still SOME decent people on this forum

[twin eng, twin turbs]

I have run a few different set ups over the years, KJET with a modified air box and big bore induction piping, Twin downdraught 40mm webbers, Twin sidedraught 40mm webbers. You will make slightly more with the webbers compared to KJET, though tuning the webbers i found was tricky and even with them running sweet the spark plugs still carboned up. KJET for the street is the go, good power, good fuel economy, but even saying that webbers sound sooooo awesome at 7000rpm

[Retired]

Hey Grant, pretty sure the cabby is an earlier one, early 80s I am guessing as it still has the plastic later bumpers not clipper kit and so on. These are the tanks to use right?


I bought that 274 Speco cam off ebay and am going to buy some stiffer valve springs, a adj cam gear and shaft pully so it should give it a little more go. I have decided on K-Jet btw

[gtimk5]

Its an 81 model, goes well, I would try it first Cam.
Its a biggish job changing the cam with the shim adjustment.
Andrew

[DubSteve]

Cam is this car a wreck that you are going to buy?