EVOizmm

iTrader: (10)

Lifting a head can be caused by many other things besides the tune. Our issue at SLB was not tune related.

LetsGetThisDone

iTrader: (1)

Didn't mean yours was tune related, sorry if it came across that way.

Yes there are lots of factors. But a billet block isn't really necessary. The 4g63 and 4g64 do well at 700-800whp with keeping the head on.

English Racing keeps the head on at 1400whp without a billet block... Just some head gasket and oring trickery..

Dallas J

iTrader: (1)

Not to mention, Aaron at ER has a ton of experience getting these things to be happy at high cylinder pressures. There was a time he was pushing something like 700+ on pump gas just to do it. He might still hold some sort of record with that. I like to play with suspension but will never pretend to know even close to what he does in making these motors work.

And Im not just a fanboi, Ive known Aaron since he was schwab tech and Lucas worked out of his 2-car garage. Its super impressive to me how far theyve come with the 4G motor along with the X and GTR motors.

Balrok

iTrader: (15)

Agreed, loved his vid too.

For general reference on the topic:

wanabgts

Is the block at least half-filled? Sorry I'm late to the party.

Zack

MinusPrevious

iTrader: (3)

There will be no filling of blocks in our sacred road course forum

wanabgts

I wouldn't hesitate for a minute to do a half fill on a Time attack build. But from the sounds of it there is a lot more that could be done to prevent HG failure anyway on this car as well as others. But what do I know....

LetsGetThisDone

iTrader: (1)

Go back to your silly Subaru's, Zack...

wanabgts

Fine, those hold 60psi without HG failure also....

hahahahaha

Zack

MinusPrevious

iTrader: (3)

Just messing w/ya . Hey, just thought the block fillers were strictly 1/4 milers? Seems like O-ringing the block is the next step?

LetsGetThisDone

iTrader: (1)

And ER is doing 1400 with 11mm head studs still hahaha

A 1/2 full would be fine. Not much heat towards the bottom of the cylinders.

wanabgts

I have given advice to many people on this subject, and no one yet has actually done it all. I believe that the reliability we have achieved (er included) stems from an entire process, not just a singular modification. I tried explaining this to a certain Subaru team that suffered the same fate as this car this year, and none of the advice was heeded.

I will lay it out, take it or leave. If you want this stuff done right, have a shop or machine shop with the proper tooling do it. If you are doing one or two engines buying everything is not gonna be worthwhile.

1- You need FLAT surfaces. Machine shop decking is NOT FLAT. We use a 250lb slab of granite to cut the block and head down to flat, starting with 400 grit and finishing at 1500. You need to have somewhere around 10RA finish.

2- Orings, Stainless Steel, IN THE CYLINDER HEAD. I have done every combination of block based oring setups and none have yielded the same results. The protrusion used should be dictated by the block material and gasket thickness.

3- The gasket. I have ran nothing but OEM headgaskets on everything that makes between 700 and 2000whp for the last 5 years. THINNER is better. As you add layers it becomes easier for things to shift and the gasket to be compromised, you simply need more clamping load to hold it. If you do not have enough piston to cylinder head clearance CUT THE PISTON. On the subarus I run .022 thick oem STI gaskets, at 58 lbs and 1000whp. The Evo's I did were also on stock gaskets, so were the 2k+ GTR's.

4- Cylinder head clamping. Countersunk steel washers should be installed in the head. These are double step washers that support the upper part of the stud, and provide a pressed-in steel seat for the headstud nuts to clamp on. The ones I install on the subaru come from arp and are made for top-alcohol cars. They are BEEF. This helps you torque the stud more accurately because the friction of the aluminum is much higher, and the head will not longer compress under the studs. The suface of the washer that meets the washer of the headstud kit should also be flat sanded to 1500g.

The head stud washers, and nuts should also be flat sanded. ARP or any other washer is punched out, and NOT flat. This will give you the best shot at maintaining your clamping loads.

Larger studs help, but not as much as any of these other things will. Sometimes the elasticity of the smaller studs can actually help maintain a seal, this is normally true when the block and everything is being stressed to the max. Everything can move as one instead of resisting movement to a point, and then yielding all at once. Engines at these power levels deform, swell, bend, twist, all sorts of stuff. Sometimes its smart to resist the movement, and sometimes its best to plan for it.

5- The blocks deck rigidity is important, that is why I believe in sleeved cases on subarus, and doing anything you can to increase the deck strength. IE filling, welling etc.

6- Coolant pressure, monitor, use it as a safety, and you will never torch another block and head combo.

Using this as a guideline, I have not witnessed a HG failure on any of the cars utilizing this system in over 5 years. That failure was linked directly to running out of fuel supply on a -1500ftda day!

Hope that helps, if not, whatever I'll just keep doing it.

EDIT: I also think its a mistake to build this like a "road racing" engine. What these types of cars need is a drag racing engine, that can run 10 minutes.......with siginificant oiling challenges haha

Zack

Dallas J

iTrader: (1)

Out of curiosity, adding these details to a standard build, what are you looking at for hours added? Are we talking 1g or several more for these details? Im just curious to see what keeps a suby sealed cause even in what we do the top level guys often seem to either run lower power or struggle with pushing coolant.

Obviously I can appreciate time is money in this game as I sit here at 9pm machining uprights. I just think it helps people understand what should be done at various levels of racing.

wanabgts

O-ringing is usually around 350bucks or so. If you don't have a plate or cutter you will be in over a grand just to get the tooling etc.

Lapping of the head and deck surface is usually between 60-90 dollars. A flat block big enough to do an inline 4 cyl is gonna run 600 bucks or so.

Installation of the centering washers probably 150 bucks.

Yes it takes a good amount of time to get it all right on assembly, probably an extra 4 hours or so. But its all a drop in the bucket compared to wasting a head and sometimes even block to a blow torch job.

So all and all, yeah probably a grand to 1500 bucks to do it right. As a percentage of the cost to build these cars, or even replace the parts that go bad if it fails, its pretty low.

Zack