1.8 8v clipper converting to crossflow head

o.k. so I have started to get a pile of parts together to do a crossflow head conversion on my 1.8 8v clipper so I can run my twin 40's and get maximum benefit from the carbs being front mounted…
here's the question has anyone else done this already and what do I need to get done to the crossflow head, it looks very close to the old 1.8 8v but some of the return oil ways are a bit different in their location… any pointers would be appreciated!

sorry cant help that much but have you seen this thread

http://www.clubgti.com/showthread.php?269246-2L-cross-flow-conversion-twin-45-carbs

kinda… not really relevant to what I am doing tho, I already have all the parts minus the wider mk3 crankpulley and waterpump pulley, and inlet manifold….. all the mounting hardwear for the PAS and ALT I picked up from the scrapyard a couple of days ago, my main info required is the the oil ways slightly vary between the 1.8 8v mk1 block and the 1.6 8v mk4 head and I am wondering how to go about rectifying this issue because once that's done I am thinking it's almost plug n play stuff thankfully!

i think they have the head welded up to suit the early block

yup figured that one out just need to find someone that's able to take car of that for me…. another issue I think it's going to have is the coolant pipes from the front of the old 8v head the one with all the sensors in it is not obviously there on the new 8v head but on the side and there are less sensor holes so aint 100% sure what to do there??? Hmmmm

have you tried jmr who helped with the build of tht engine

dik-van-dub said

have you tried jmr who helped with the build of tht engine

I havn't yet as I am captain skint bloke and trying to do the lions share myself to save on costs but jmr are only about a 40ish min drive away from me so I expect I will be paying a visit to 'em in the not too distant!
may get them to do the head bolt rebore and oilway modification and porting on it once I have it all cleaned up etc

what are you gonna do about the ignition system? keep the vacuum dizzy or fit some kind of ecu?

rubjonny said

what are you gonna do about the ignition system? keep the vacuum dizzy or fit some kind of ecu?

dunno man, depends on cash flow when I get nearer to the point of getting the head on the car… if I am doing o.k. at that point I will have a standalone ecu summat like the nodiz system but if I am still skint bloke who knows…. any suggestions?? would the dizzy from a mk3 work??

reason I ask is it determines which sensor(s) you need for your build. for a standalone type ecu that can be calibrated for any sensor use a mk3 golf 4 pin coolant temp sensor in your side flange, use 2 pins for dash and 2 pins for ecu. if you use just the vac advance 8v dizzy you dont need a sensor for that so just a 2 pin black mk2 golf dash sensor is needed. if you wanted a mk2 16v ecu then you would need 2 dash sensors, the mk3 4 pin is no good as the ecu sensor is wrong rating.

I'm assumign there is no sensor hoel in the front flange right, just the one in the side flange right?

rubjonny said

reason I ask is it determines which sensor(s) you need for your build. for a standalone type ecu that can be calibrated for any sensor use a mk3 golf 4 pin coolant temp sensor in your side flange, use 2 pins for dash and 2 pins for ecu. if you use just the vac advance 8v dizzy you dont need a sensor for that so just a 2 pin black mk2 golf dash sensor is needed. if you wanted a mk2 16v ecu then you would need 2 dash sensors, the mk3 4 pin is no good as the ecu sensor is wrong rating.

I'm assumign there is no sensor hoel in the front flange right, just the one in the side flange right?

lol….. way too technical for me! this is the first time I have done any modification work on any of the cars I've owned!
this is a picky of the side of the crossflow head I picked up the other day (AKL from a 1.6 8v mk4)


I was wondering the sensor thing the other day as the coolant flange that comes out the front of the standard clipper head has three plugs on it and this head only has one sensor hole on the coolant flange coming out the side!!

You wont need 2 of the clipper sensors, these are the thermoswitches for carb and inlet heater. the 3rd black one is the temp sensor for your dash and will drop into the hole in the side of your new head.

However this may not be enough depending on what ignition system you go for. So if you have an aftermarket unit which needs a temp sensor input, and this input can be tuned to match any temp sensor in the software say megasquirt or megajolt, then you could use a 4 pin mk3 temp sensor. 2 of the pins for your dash, 2 of them for the spark ecu.

if you just use the basic vacuum advance dizzy, this doesnt need temp sensor so you just use your old clipper one.

if you wanted to use a kr ecu, then this needs a black temp sensor so you would need to add another somewhere. I've not seen many people use a 16v ecu on an 8v though so I assume you wont be doing that. it would work, just a case of would the ignition map be any good…

Crossflow heads are a good conversion but there is a lot to sort.

The oil return in the head needs welding up when used on 1800 blocks..easy enough..then re shaping with a die grinder to line up with the gasket..again simple enough. 

However the 1600 isn't the best head to use as it needs a lot of porting to make it flow. The 2ltr versions however flow brilliantly in std form and are a much better base. I've used them on a basically std 1800 bottom end with detail work only, a 272 newman cam and throttle bodies making 165hp…140 at the wheels. The head just had 3 angle seats and some mild throat work…no port opening as they're big enough in std form. .the 1600 version ports are too small.

The above engine flys to 7,400rpm in a full trim tin top on std gearing. I've also done a full race 2ltr using the 2ltr head but with more porting work. .that makes 197hp. .167 at the wheels. .so they work quite well. 

The radiator also needs re locating as it sits right in front of the carbs or itb's. .a big "no no" in terms of drawing in warm air.

Both customers float around on the JMR forum (access through the website home page) and would be happy to help with plumbing and install advice..Tim Moll has the 2ltr race car and "dumma" (Adam Phillips) the mint red road install…both are mega helpfull…Tim is around on the forum more than Adam tho.