"Heron Head" 1600 GTi questions

Hey guys…Yank here that needs some help!

I have assembled a Heron head GTi motor here, something that we never got.   A friend had brought with him several heads and sets of pistons from Germany after he got out of the US Army and I talked him into selling me the matched set of pistons and head so I could build one of these cool 1600 motors.

It was my understanding that these engines were high compression motors, like 10:1 compression, is this true?   Once we assembled the motor, we are only seeing 125 psi compression in each cyl, which is more like 8.5-9:1 compression.  This is with new rings and a light hone on the cyl walls (the block was in excellent shape).

The pistons and the head are the only thing different on the GTi motors vs the regular 1600s, yes?  (The head way different to me, and the pistons have a large dish in them.)  I used a US 1600 block with US 1600 crank, which I was told was identical to what you guys have.

Also, on the 1600 GTi motor, how far from the top of the block are the pistons supposed to come up to?  When we assembled this, we found that the pistons only came up to within 3mm of the top of the block.

Oh, and ignition timing…is it just like any other 8v and should be set at 6 BTDC?

Thanks in advance for your thoughts here, we are thinking something isn't right with what we assembled, and your responses here will help us understand what could be at fault.

OI!  22 views, no responses?  Come on mates, help a poor guy out!

Found out a few things from various sources:  Motor should be 9.5:1, and stroke of the piston is correct (a friend with a fully assembled EG code motor pulled the head and checked for me, his piston came within 4mm from the top of the bock).

Well, I am off to actually DRIVE the thing here in a few minutes…we'll see if I am happy or not with the power…going from a 2.0 8V (3A code from audi 80) to this motor should be interesting.

update:  Bumped the cam timing one tooth advanced, now have 160 psi a cyl, this is good, well within what a 9.5:1 motor should be seeing.

Its slow as molassas though, can barely maintain 80 mph, feels like it can't breath.  Slight miss under load.  Maybe making 60-70 hp.  

Well - Something is not right!

Not sure of the technical details you posted, but the car should see 80MPH no problem and should still be pulling hard!

can u post some pictures of the pistons and block and bottom of the head ie valve seat side, of your originals and of the new stuff, if we can see what u have it may be something odvious.

sounds like you've got the cam timing sorted now

have you checked the ignition timing and the air fuel ratio what fuel are you running ?

Stu

Wellllll then…so, something retarted about the car I installed the motor in bit me in the ass.  The VW Fox was a super cheap VW of the late 80s and early 90s here, VW of America didn't want them being faster than the Golfs and the  Jettas of the time, so they stuck a goddamn restrictor in the exhaust..choked it down to 1" or less right before the cat converter.  Removed the exhaust restrictor and its finally fun to drive…have more to go, but just picked up an easy 20 hp with that alone…things are looking up!

Guys, since I don't have access to repair books that cover this motor, can you please tell me a couple of things?

Ignition timing, 6 degrees BDTC?  Or does it want more advance?

What spark plug is recommended for this motor?

Well, thanks for nothing guys.  

   :evil:

hello mate i'm nto really that good mechanicaly but try this site

http://www.sciroccoregister.co.uk/phpbb/phpBB2/index.php

After a bit or research through some very dusty books I can offer the following information:
Spark plug type: Champion N6YYC or N6YC
with electrode gap 0f .75 - .85mm (.029 - .033in)

Stroke of 80.0mm (3.15in)
Compression ratio 9.5:1
Timing:
inlet opens 6 deg btdc
inlet closes 43 deg abdc
exhaust opens 47 deg bbdc
exhaust closes 3 deg atdc

Goy a bit more info on this engine so if there's anything else give us a shout.
Hope you find this usefull
Cheers

ew said

After a bit or research through some very dusty books I can offer the following information:
Spark plug type: Champion N6YYC or N6YC
with electrode gap 0f .75 - .85mm (.029 - .033in)

Stroke of 80.0mm (3.15in)
Compression ratio 9.5:1
Timing:
inlet opens 6 deg btdc
inlet closes 43 deg abdc
exhaust opens 47 deg bbdc
exhaust closes 3 deg atdc

Goy a bit more info on this engine so if there's anything else give us a shout.
Hope you find this usefull
Cheers

Thanks mate!  I appreciate it!