Everything affects everything, but I consider 18@6500 high.

That is a pretty aggressive timing at peak torque. Usually its the other way around being lower at peak torque and increasing to redline. Hopefully you get this car back together soon and test out this hks gasket.

amsrn13 said:

happened to that turbo. The damage looks like something was ejected from the exhaust and hit the wheel. Thats impressive

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Too much back pressure. I was on a .55 BEP housing, after doing that TWICE, I went to a T3 .70 setup. I completely SNAPPED the shaft at the exducer on the other HX40.
Vegas, you are all welcome to ride in the "beast". I don't hide, sorry I disappointed you. If you show up here in my home town, just ask at any parts store, they will point you to my place .

bastarddsm said:

Everything affects everything, but I consider 18@6500 high.

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As do I. I like low single digits at peak torque, and I wouldn't be running 18* anywhere at 38psi.

With that 62mm I would start with 2* at peak torque and 10-12* at 9000 with a smooth ramp between the two.

You can always work up with the timing, but working down requires parts.

Are you using just the factory knock circuit to tune? 18 degrees of timing is quite aggressive.

That timing seems too high. I wish tone could be expressed through text as I don't mean at all to sound like an a-hole with what I am about to say next: Based on my experience and the advice of other successful DSMer's I have received over the years, BOOST is not your issue. TIMING causes far more problems.

I may have totally missed it, but what is your comp ratio? On my 10.5:1 I had to run stupid rich AFR's and timing at like 3-5deg at peak torque ramping up to 13deg or so up top. I was running 35psi+. Composite gasket. Even on my 8.5 motor that I pounded on for years at 30-35psi and trapped 130.75 in, my timing was not as high as what you referenced above.

I would venture to guess timing is your issue. If that is indeed the case, that is exactly why I run composite gaskets. If I do something I shouldn't have, i.e. run too much timing, I would hope the HG would blow out instead of toasting an entire motor. IF timing IS your issue, and you put an MLS on there and don't change the tune, you may be saying bye bye to your engine.

What everyone is failing to miss even with calling his timing too high, is his total timing if the base timing is set correctly is actually 23*. Wrap your head around that and think why the head gasket can't take non stop abuse.

Yuuup. Always base + whatever advance is electronically commanded.

Put a light on a car while it's running. The 5* is accounted for in the ecu.

The reason base timing is set at 5* advanced is for starting the car. During cranking the ptu is basically hard wired to the cas, you cannot change cranking timing advance without moving the cas.

Ive ran my old dsm at 18 deg up top. It ran fine for me. (550hp)
Just know, they hate us because they aint us.

Though that was ok with e85, and boys....... this time it's coming down. I'm still learning guys, if that's what's causing it then why does my headgasket look new? Nothing was burnt or appeared to be caused by detonation? Or is it causing elevated pressure in the head and the gasket can seal it?

wishihadatalon said:

Are you using just the factory knock circuit to tune? 18 degrees of timing is quite aggressive.

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???????

Kapok6 said:

That timing seems too high. I wish tone could be expressed through text as I don't mean at all to sound like an a-hole with what I am about to say next: Based on my experience and the advice of other successful DSMer's I have received over the years, BOOST is not your issue. TIMING causes far more problems.

I may have totally missed it, but what is your comp ratio? On my 10.5:1 I had to run stupid rich AFR's and timing at like 3-5deg at peak torque ramping up to 13deg or so up top. I was running 35psi+. Composite gasket. Even on my 8.5 motor that I pounded on for years at 30-35psi and trapped 130.75 in, my timing was not as high as what you referenced above.

I would venture to guess timing is your issue. If that is indeed the case, that is exactly why I run composite gaskets. If I do something I shouldn't have, i.e. run too much timing, I would hope the HG would blow out instead of toasting an entire motor. IF timing IS your issue, and you put an MLS on there and don't change the tune, you may be saying bye bye to your engine.

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Compression is in the low 8s 8.3:1? I was actually going to make a thread about this. What is better? Higher compression less boost or lower compression high boost? Technically speaking by compressing air and forcing it into an engine you are increasing compression? For instance a Diesel engine has a very high static compression which ignites the fuel. On a fi engine you are forcing compressed air into the cylinder. More air + more fuel= more power. Now by using e85 or race gas you are trying to prevent pre ignition of the fuel as it get to tdc. What I'm saying is -say you start out at 10:1 static compression your knock threshold will be lower so technically you run less boost. However you don't require as much boost because of that static increase. It seems to me that having more compression and less boost is a good thing. your not pushing the turbo as hard and the engine will be more responsive. I'm debating bumping my compression on the new motor to 10:1

wishihadatalon said:

???????

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Yes

amsrn13 said:

Compression is in the low 8s 8.3:1? I was actually going to make a thread about this. What is better? Higher compression less boost or lower compression high boost? Technically speaking by compressing air and forcing it into an engine you are increasing compression? For instance a Diesel engine has a very high static compression which ignites the fuel. On a fi engine you are forcing compressed air into the cylinder. More air + more fuel= more power. Now by using e85 or race gas you are trying to prevent pre ignition of the fuel as it get to tdc. What I'm saying is -say you start out at 10:1 static compression your knock threshold will be lower so technically you run less boost. However you don't require as much boost because of that static increase. It seems to me that having more compression and less boost is a good thing. your not pushing the turbo as hard and the engine will be more responsive. I'm debating bumping my compression on the new motor to 10:1

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I doubt I'll ever build a high comp 4g63 again. Your already narrow tuning window gets even more narrow, and the gains imo are more negligible. Yes, the throttle *seemed* slightly more responsive, but on my personal car, I certainly was not any faster with 10.5 than I was with 8.3 and I even ran more boost on the 10.5.

Kapok6 said:

I doubt I'll ever build a high comp 4g63 again. Your already narrow tuning window gets even more narrow, and the gains imo are more negligible. Yes, the throttle *seemed* slightly more responsive, but on my personal car, I certainly was not any faster with 10.5 than I was with 8.3 and I even ran more boost on the 10.5.

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Even Kevin at kiggly racing said he saw no gains after 9:1.

The cylinder pressures on high compression setups are ridiculous and that is why few 4g63 guys have huge success with them. You are exactly right. You have a giant compression maker hanging off the front of the motor. Use it. If it is not enough, go to the next desired size.

A local I helped a lot with tried to go the stroker high conpression route. Once he went to a serious turbo his troubles really began. It still would not spool and still took just as much rpm as a regular 2.0L. After two sets of bearings he finally have up and went back to a 2.0L. I then proceeded to make 950whp in his car and his motor issues were gone after that. Not to mention the tuning was much smoother for him than with the stroker.

amsrn13 said:

Though that was ok with e85, and boys....... this time it's coming down. I'm still learning guys, if that's what's causing it then why does my headgasket look new? Nothing was burnt or appeared to be caused by detonation? Or is it causing elevated pressure in the head and the gasket can seal it?

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You need to get into the mindset that at this point, your build is completely unique, and will require a tune tailored specifically for your car and nobody else's. I'm running 18* peak on a 68HTA....But that's absolutely not going to work for somebody moving twice as much air.

Like Donnie said, start with very conservative timing, and work your way up. If you do it the opposite way, you'll likely be replacing hard parts the next go around.

Maybe some of these questions have been answered, but you've got so many threads with so many posts in them, I've lost track...Have you ever checked the block and head deck surfaces with a machinist's edge? How many times have those ARP studs been torqued? Have you ever measured them to see if they're stretched?

Based on what I've seen in many of your logs, and the pics of the gasket, your hot timing table probably isn't to blame for your HG issues. I'd put my money on poor sealing surfaces, or possibly issues with the fasteners.

I'm only chiming in because I read all of this long ass thread and now feel obligated. I'm no real mechanic or machinist by any means, but it seems totally obvious to me that the head is the issue and has always been the issue. I would have lost my mind at this point. After one HG failure with your reused head and I would have picked up a used head, taken it to my local shop for hot tank, resurfacing, valve job, etc, and the $400-500 I'd be out would be worth it over the pain and aggravation. Worst case if it didn't work is at least you have a spare head.

PlanZero said:

I'm only chiming in because I read all of this long ass thread and now feel obligated. I'm no real mechanic or machinist by any means, but it seems totally obvious to me that the head is the issue and has always been the issue. I would have lost my mind at this point. After one HG failure with your reused head and I would have picked up a used head, taken it to my local shop for hot tank, resurfacing, valve job, etc, and the $400-500 I'd be out would be worth it over the pain and aggravation. Worst case if it didn't work is at least you have a spare head.

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The head that I used was off a low mileage engine, was dropped off at a machinist, hot tanked, pressure checked and milled flat. So your guess is good as mine. I have 3 heads for the record. I just took a trip to rrt, I'm having my block machined for orings and having the head castings welded shut. He did however mention that my ignition timing is too high. He has the fastest Evo in the country so I take his word seriously. He says that running really high timing is not necessary and can be made in our ways. So I installed a new head with an gasket. I'm gunna lower my timing significantly and go from there.

GST with PSI said:

You need to get into the mindset that at this point, your build is completely unique, and will require a tune tailored specifically for your car and nobody else's. I'm running 18* peak on a 68HTA....But that's absolutely not going to work for somebody moving twice as much air.

Like Donnie said, start with very conservative timing, and work your way up. If you do it the opposite way, you'll likely be replacing hard parts the next go around.

Maybe some of these questions have been answered, but you've got so many threads with so many posts in them, I've lost track...Have you ever checked the block and head deck surfaces with a machinist's edge? How many times have those ARP studs been torqued? Have you ever measured them to see if they're stretched?

Based on what I've seen in many of your logs, and the pics of the gasket, your hot timing table probably isn't to blame for your HG issues. I'd put my money on poor sealing surfaces, or possibly issues with the fasteners.

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More great new guys.......The new head I purchased from ebay from a seller mitsubishirestoration which I thought was good is not what I thought it was. 5 exhaust studs were stripped and repaired incorrectly so I had the honor of repairing them myself. Just another example of why im starting to hate this platform. All the parts are getting old and abused. Id give anything to buy a new head. Good news is the engine is together and ready to rock and roll. The only was this engine is coming out is in pieces.......Im going for all or nothing.

I have a brand new head in the mitsu box on the shelf.

bastarddsm said:

I have a brand new head in the mitsu box on the shelf.

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6-7 bolt? how the hell did u get that

6 bolt bought it new. Make an offer I can't refuse.

bastarddsm said:

6 bolt bought it new. Make an offer I can't refuse.

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how long ago did you purchase that? I was looking everywere

I don't even know what I would offer.....is it just a bare core?

It's a full assembled head new in box. No cams rockers or lifters. I'm not looking to sell it, but for the right offer (a lot) I might. I plan on building a billet crank 2.2 in a couple years and this head is for that

Has anyone tried chamfering the head bolt holes in the block. When the head is torqued down, the threads in the block exert enough pressure to distort the cast iron around the bolt holes and raise it slightly. This can lower the clamping force and lead to the head gasket leaking.
http://www.federalmogulmp.com/en-US/Technical/Documents/Head Gasket Installation.pdf

This is common on V8 racing engines but I've never seen it mentioned for a 4G63 build. Do a Google search for "chamfered head bolt holes" for more info. There's even a YouTube video.

Jim

amsrn13 said:

Yes

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You need to start reading plugs.