MYTMK3 6th times a charm HG thread

[mytmk3]

righto after latest round of tuning it has become apparent that my HG is leaking under heavy load. normal driving conditions normal.

So stating up this thread to gain opinions to settle this once and for all head will being pulled off as soon as the new gasket turns up from driftmotion will take a couple weeks id say.

Will be putting up photos to try diagnose why its happened.

Here is my headgasket story

1. just bought car was probly already blown lasted 6 days blew big time
2. did full rebuild no research reused stock bolts was all good till upped the boost and blew
3. Used Arp gear stock HG never blew
4. Went for forged bottom end so changed to a cometic HG didn't even start the car only cranked and filled the sump with coolant the dowels in the block looked rubbish
5. Got another brand new cometic HG changed dowels (this is current HG) been driving for 2 years on the track it got hot really quick and on hills would push coolant got retuned for more power and it cant handle the incresed boost low boost still fine just under heavy load it leaks

At the time I went to MHG head and block were machined to an RA of less than 20 were the instructions I gave to the shop and the front cover was machined too

ARP studs with ARP lube used
But on the latest one it looks like the shop that put my head on may have used copper spray on the new cometic HG maybe that is my issue

Head was hardness checked at HG no 2 and no 3 will be getting it checked again once I pulled the head this will be a semi slow moving thread but Ive had enough of HG's and want to enjoy the power of my new tune 422rwkw would have been more but had to stop as the HG problem becoming obvious previously it was a hunch

 

[Turbo Habanero]

I thought it had to be a RA of less then 12

 

[mytmk3]

I thought it had to be a RA of less then 12

Different for different brands hks is the fussiest I have cometic

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[suprarx7nut]

I thought it had to be a RA of less then 12

Cometic states an RA of under 50 is generally required. RA of 12 is extremely smooth and most shop equipment wont get cast iron to that smoothness no matter how hard they try.

At my work, we deal with stainless castings all the time. To guarantee an RA better than 15 we can't use anything cast. We use all billet or extruded material which is polished by drill and then electro-polished.

What surface finish is required to us an MLS head gasket?
A surface finish of 50 RA (roughness average) or finer, is recommended for a proper gasket seal. Anything rougher may conflict with the gasket design.

 

[mytmk3]

Well thamks to driftmotion my parts are here already so should start stripping it tonight

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[mytmk3]

heads off going to get it checked tomorrow. nothing seemed obvious to me but I aint no mechanic.

I know your ment to get the lower timing cover machined with the block (was done and just double checked) but what about the upper cover (one thats behind the cam gears) that actualy sits lower than the head at the moment

 

[IJ.]

6x you're doing it wrong :runaway:

 

[mytmk3]

plugs were like this on 3-4

like this on the others

 

[mytmk3]

6x you're doing it wrong :runaway:

Ive been paying people to do it wrong

 

[IJ.]

Ive been paying people to do it wrong

Should pay someone to do it right then

 

[mytmk3]

Should pay someone to do it right then

I hope it is this time round seen as you online IJ whats your thoughts on this?

I know your ment to get the lower timing cover machined with the block (was done and just double checked) but what about the upper cover (one thats behind the cam gears) that actualy sits lower than the head at the moment

 

[IJ.]

The Tin plate??

If so it's just a cover, doesn't need to be touched.

 

[mytmk3]

Yup thats the one.

Head has been checked out to be ok getting cleaned up then see how we go.

Head gasket was definitely sprayed with copper spray so dunno if that affected the vilton on the gasket or what

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[hvyman]

Not supposed to spray copper head gasket sealer on a new hg.

 

[mytmk3]

Not supposed to spray copper head gasket sealer on a new hg.

I had read that I didnt ask for it to be done either just discovered it had. its not going on this time

 

[suprarx7nut]

Not supposed to spray copper head gasket sealer on a new hg.

I had read that I didnt ask for it to be done either just discovered it had. its not going on this time

I've always sprayed my composite gaskets with good luck. :dunno:

Although I realize its not called for in the tsrm.

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[super51fan]

Why not try an HKS head gasket? After making sure you have no warpage on head or block. They were one of the first MLS gaskets. I would only use a HKS gasket. I think 80 to 85 lbs torque is the best. Just my two cents. Good luck.

 

[Backlash2032]

There's nothing wrong with a cometic/Titan gasket. Its what I'm using with no problems at all.

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[mytmk3]

well rather than another thread seen as its in the same job HG was replaced everything all plugged back in started it ran pretty ruff and stalled saw figured timing was prob a little off there was a leak from my turbo drain so had enough for one day pushed it into the garage and went to work.

Next day fix turbo drain try to start no go looked at match marks at TDC and cams seemed a little off (was re-assembled to match marks I had drawn on the cams/crank/belt) so mucked about getting the cams to line up better (were what looked to me at TDC on the cams when the Crank was at 5deg) looked at pictures of how to set CPS got it started again running on 3 (at a guess) stalled tweeked CPS ran on what felt like 5 tryed tweeking a little and didn't help was late so left it.

Skip to today got a mate to come over and bring a compression tester and timing light to help out. To start timing light didnt work haha so that was already a bad start. so tried starting - no go got him to double check CPS cam geats and crank to make sure im not crazy.

After a bit more mucking around checked cold compression was the same on 1-2 both around 155

got it started again ruff as again checked temp on exhaust runners 1-3 cold 4-5-6 warm/hot (wasnt running long)

checked spark on no1 was there checked both fuel pumps there both working

to change the head I removed the oil pressure sensor wire, water temp wire, injector plugs, CPS plug, coil Plug and one earth off the mainifold (aftermarket ecu/loom) and they are all back on im very tiered and most likley missing something silly so some suggestions would be fantastic and below should be some pics of the current positions of the cam gears, crank pully and CPS