G60 Cylinder head questions

[kjkg60]

Hi lads,

I have a few questions,

I have a jabba sport ported head on the bench at the minute. It has cracked between the inlet and the exhaust valve on cylinder 1 and the crack has strected into the exhaust valve port. It failed a pressure test

I also see a crack in the same place in cylinder 2 but that didnt fail pressure test.

Are these cracks common to G60 heads? anyone have one out they can check.

Next question, does anyone know the Grade of aluminium that the heads are made from?

Last question, could i use a ported 8v GTi head? as far as i know the only difference is the g60 one is heat treated?

Cheers
Kieran

[JBETZ]

Hi lads,

I have a few questions,

I have a jabba sport ported head on the bench at the minute. It has cracked between the inlet and the exhaust valve on cylinder 1 and the crack has strected into the exhaust valve port. It failed a pressure test

I also see a crack in the same place in cylinder 2 but that didnt fail pressure test.

Are these cracks common to G60 heads? anyone have one out they can check.

Next question, does anyone know the Grade of aluminium that the heads are made from?

Last question, could i use a ported 8v GTi head? as far as i know the only difference is the g60 one is heat treated?

Cheers
Kieran

this can happen when the engine over heats...and then it also detonates.
i would imagine that this could maybe happen from just detonation, most likely just over heating. it could also happen from the coolant freezing up on a cold winter day.
yes, the gti head will work.
not sure on the blend of aluminum vw used for these heads.

[kjkg60]

Thanks for the reply

Hmm i see i think the car it came out of was running lean which would have caused raised temperatures in the cylinders.

The cast numbers on the head what good are these numbers will this tell you the grade are they individual stamps or are they batch number?

[petethepug]

Thanks for the reply

Hmm i see i think the car it came out of was running lean which would have caused raised temperatures in the cylinders.

The cast numbers on the head what good are these numbers will this tell you the grade are they individual stamps or are they batch number?

What you're explaining is why I had my intake opened up and port matched, flowed and balanced at Scientific Rabbit. This sounds like the dreaded run lean on #1 Cyl issue that can occur.

It's been over 300K on the factory block and 250K on a reman stock G60 head. I purchased my G60 new. It has a Feb '90 build date. It's been running an Autotech Stg III kit since 2000 with a TEC GT-1. This set up makes a decent amount of semi reliable HP.

Every other year Calif cars get emissions tested. Even with a healthy tune the motor barely passed CA emissions last year. I've been picking the meat off of recently deceased Corrado carcasses from the classifieds. I found a port matched PG head, exhaust and intake in really good condition. Between the 1.9L short block I found and the port matched top end I could still budget getting the top end flowed and upgrade to a TT (kit # 109910T) 40x33 (7mm) valve upgrade kit w/ Ti retainers. They installed a TT 270 cam too.

The already port matched top end was sent off to Scientific Rabbit. The head flowed pretty good but still had room for improvement. SF got the numbers right where they said they would. Stock G60 flow numbers are below:


Originally Posted by SSj4G60
stock G60
Intake
Valve Lift----Oricifice------% of Flow-----Leakage-----CFM
.05------------56------------64----------------0-----------35.84
.1-------------75.5----------72.5-------------0------------54.7
.15-----------148-----------48----------------0------------71
.2-------------148----------63----------------0------------93.2
.25------------148----------72----------------0-----------106.5
.3-------------148-----------76----------------0-----------112.5
.35------------148-----------79---------------0------------116.9
.4-------------148----------80---------------0--------------118.4
Exhaust
Valve Lift-----Oricifice------% of Flow-----Leakage-----CFM
.05------------60.4------------66.5------------9.3-----------30.8
.1--------------81.4------------59.5------------9.3-----------39.1
.15-------------81.4----------- 83------------9.3-----------58.3
.2------------159.5------------50------------9.3-----------70.45
.25----------159.5------------51------------9.3------------72
.3------------159.5------------58------------9.3-----------83
.35----------159.5------------60------------9.3------------86.4
.4------------159.5------------61---------9.3------------87.9

Intake/Exhaust % Ratio
Valve Lift-------%Ratio
.05-------------------85%
.1--------------------71%
.15-------------------82%
.2---------------------75%
.25-------------------68%
.3---------------------74%
.35--------------------74%
.4----------------------74%

The ported and polished head I got from the clasified is listed below (Begin CFM) . The 2nd set (final CFM) of numbers below shows how SR improved the flow even more using a flow bench.




The head and intake came back tanked and media cleaned on exterior surfaces. I opted for a Stg III intake from SR. It balanced the fuel delivery and eliminates that dreaded run lean on # 1. I'll post some pics of it later. The ported exhaust and TT s/s downpipe are getting JetCoat right now.

The intake and exhaust are back from getting coated. The tt s/s down pipe had a flaw in the coating so it's getting redone. There's nothing exciting about the jet coat on the exhaust manifold. I had the option of black or silver. I chose black since it will stay that color and it was rated for an extra 200* beyond the silver.

I didn't like the bead on the OE intake after it had it's surgery from being ported. As much as I like polished intakes I wasn't ready to invest my time or pay to have it ground down, sanded and polished. I had the shop grind the welds down and powder coat the Scientific Rabbit intake. This is going to test the limit of standard powder coat thermal rating The visible portion of the intake should stay unblemished and that's all I care about.

I can't wait to throw an ir temp gauge on the intake. I'm anxious to see what the results are of potential heat soak are over a standard (uncoated) intake.



You can see the Stg III port on another Corrado after completion (below). It has the scar from it's plastic surgery. My intake was at the shop with the rest of the parts. It was just too convenient not to throw in the oven with everything else.



BBM was was cool enough to fab this CO bung for their AWIC setup I was missing. I bought a dude who didn't complete his AWIC Lysholm project. I got everything from him except this 90.

[kjkg60]

some great info there.

Im little confused with flowing the manifold as u say above you will increase the volume of air entering cyl 1, which means you would have the danger of running leaner.

Cyl 1 is furthest from the throttle body also.

Can you explain how cyl 1 rather than cyl 4 can run leaner? the injection quantites are surely the same no?

[JBETZ]

pete ur awesome! how is that vwms g-lader treating you

[petethepug]

some great info there.

I'm little confused with flowing the manifold as u say above you will increase the volume of air entering cyl 1, which means you would have the danger of running leaner.

Cyl 1 is furthest from the throttle body also.

Can you explain how cyl 1 rather than cyl 4 can run leaner? the injection quantities are surely the same no?

That's exactly why it runs lean. "Cyl 1 is furthest". Look at it like where your vacuum would gather the most dust (fuel ), #1 (furthest away?) or #4 (closest to it).

The Group "N" charger is still sitting on the bench in the garage. It just didn't seem like a good idea to install it in the car until I sourced the fuel leaks. A chick hitting the car while texting (almost totaled it) set me back even further. I would of been really bummed to have that G Ladder sitting in the car while at the shop for about forty days.

Oh yea ... didn't wanna type when on the phone about Positive displacement.

[ny_fam]

Right More air in one cylinder will make that one cylinder run lean - one of the issues with the G60 manifold design is that the flow between each runner is not balanced. So this condition exists. What the ported intake does is balance the flow between each runner much better than the factory. When you modify the stock G60 for more power, its important to do what's ever necessary to make sure that each cylinder is getting the proper fuel it needs ( reading plugs, running a little more rich, etc..)

[kjkg60]

makes sense now sorry when i think about it. Thats a shame now i have two heads here cracked off two different engines which were both running small pulleys and ported head both running green injectors.

They shoud have been running red tops at least anyway.

I only coped i was lean when i bought a innovate lm2 and its the reason i got curious about the engine and had a look at the heads.

Im sure there is plenty of heads like this just waiting to fail.

Can these be fixed. as in remove the valve seat cut out the crack section weld in a new material and machine out the seat to recieve its insert again?

[petethepug]

Send Derek a pm and see what he says. He usually gets back in a day or two (ny_fam private Message).

If you already have money into the heads it may be worth it to have them repaired. Make sure to send him some pics with the cracks exaggerated by something like a sharpie marker.