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CaptainDan, if you've already replaced your stock pistons with 8.5:1 GTE spec pistons then you'll want to use an OEM 2JZGTE head gasket (the 1.6mm?). 2.0mm (or 2.4mm) head gaskets are more for short blocks with stock 10.0:1 compression pistons.
lexforlife, if he uses a GE thickness head gasket shouldn't he use an aftermarket one with the same stronger metal matrix as a GTE gasket? I was under the impression the GE gasket material was not as strong regardless of it being much thinner.
CaptainDan, if you've already replaced your stock pistons with 8.5:1 GTE spec pistons then you'll want to use an OEM 2JZGTE head gasket (the 1.6mm?). 2.0mm (or 2.4mm) head gaskets are more for short blocks with stock 10.0:1 compression pistons.
lexforlife, if he uses a GE thickness head gasket shouldn't he use an aftermarket one with the same stronger metal matrix as a GTE gasket? I was under the impression the GE gasket material was not as strong regardless of it being much thinner.
if using a gte styled/dished piston , you should be using the non vvti ge metal headgasket to mainitn proper squish and quench factors .. the ge matal hg is made of same materiel as gte , just thinner .. many have used the gte piston with ge hg running upwards of 36 psi of boost with no ill effects, i would however suggest using the arp 625 headstuds with oem washers and trq to around 94 ft lbs
if you are staying with ge pistons then keep it simple , just use gte hg
well Ive got three different headgaskets in my possession... oem ge, oem gte, and tomei 2mm. block is .020 over. Im feeling most comfortable (personally) running the oem ge (.3mm), but thats just me. Keep in mind, Im only planning on running around 20psi on pump gas. Ill turni it up as much as I can given my injector size on q16. Ive gotta make this setup last me a while.
also, i was out in the garage tinkering around and noticed that the pistons actually come up higher than the deck of the block on the exhaust side...by a very marginal amount, but enough to visibly see... as you rotate the crank. This was not the case with the bottom end when it was stock. My question is... should this be happening??? Im no moron when it comes to engine building but this is my first 2jz, and im probably a little too ocd for my own good. Any input here would help. it looks like the piston protrudes roughly the thickess of the gte headgasket past the deck of the block...only on the exhaust side.
I dont really trust the shop that assembled the block/head for me at the moment considering the careless mistake they made with my cylinder head and getting a piece of trash stuck in one of my cam journals on the intake side then torquing the cam and rotating it (scarring the cam and inbedding a shard of steel in the head-side of the journal)... I wont be naming names at this moment, but if I do run into issues, I will do so just so people know to look out.
Man, I hate to hear about the head but even very successful shops have made mistakes, it happens. What's important is that they are backing up their work and getting it worked out free of charge, not all is lost.. I'm subscribed for the road ahead. Great build so far man!
I started doing research on the thole "my pistons come up past the deck of my block" topic and talked to a few of my trusted friends who build engines on a regular basis. I was advised to do a Piston-to-Deck clearance check, So I rigged up my dial indicator and did some measuring...
I also came across this SUPER helpful thread on supraforums regarding compression ratios and combustion chamber squish calculations: http://www.supraforums.com/forum/sho...fferences.PICS
Anyways, from what Ive been able to find, piston to deck clearance spec is supposed to be around .005in below the deck of the block. I wasnt able to find an exact specification through alldata or mitchell repair software, and dont have an FSM (i need to get one).
Here is my engine:
This is cyl#4, which measures just over .020in PAST the deck of the block on the exhaust side.
This is cyl#4 again, intake side this time, measures .005in PAST the deck of the block.
I was instructed to add both measurements together, and divide by 2, this giving total average Piston-to-Deck clearance which comes to .0125in PAST the deck of the block, or .0175 over specification. I measured all 6 cylinders, but #'s 3 and 4 were the worst ones by a marginal amount, all of them sitting higher on the exhaust side.
BY THE WAY: I know that a Bridge Gauge is supposed to be used when checking piston to deck clearance, but I dont have one. I double checked zero after every measurement and it never fluctuated more than .003in off of the initial zeroing before the measurement, so I feel pretty confident in what I came up with.
I dont know wether they decked the block too much, or mounted it on the machine wrong before it was decked resulting in a sloped deck, or if its a defective set of pistons, defective set of rods, or if the block was assembled improperly... all I know is that im fairly positive that if I put this motor together that the pistons would be hitting the top bottom of the head... Looks like Ill be taking it back to the shop that built it for me
This is the reason I don't trust machine shop local to me, the only person that builds or will ever , I mean ever build a motor for me or my friends is Donald Summerton At Accelerated performance in Toledo OH.
He did for me turn around time was 3 days and done right.
This is a very expensive mistake, this is a machine shop they should not be making these types of mistakes...This is why I've never bothered with built motor until I found the right guy for the job.
As for the feed line do to tap the block for it, just tap the banjo bolt on the oil filter housing and get your feed from there.
That galley is not open you must drill through the block to do that and that's not a great idea...GTE block were drilled from the factory.
Yeah you need to do a straight edge check along the deck surface with feeler gauges to give you an idea of where the dips might be. As for the pistons you can take a depth mic measure all of the piston dishes and see if there are any big differences in the set. In the machining world decking a head is straight forward, but machining piston sets there's room for variation especially if the operators aren't doing their job correctly.
So I ended up taking the motor apart, checking it all out, measuring piston wall height, blah blah blah... turns out the pistons were a hair tall... decided to put it back together and will run a GTE headgasket to compensate. .008 was machined off the head to make it flat, leaving .022 recess. considering my piston to deck was .020 over deck, and the compressed height of the GTE headgasket is .050 im looking at a squish of about .048 ballpark. A little tall, and compression will be a little down compared to what Id hoped for but all in all I think itll run just fine, and Ill just run a bit more boost. I bought a snapon tool box for work that killed me financially for several weeks, but I paid it off this past week, so Im going back on this build full steam ahead here shortly. WIll update as progess is made.
I got everything sorted out with the rotating assembly and slapped the long block together over the last couple days... for the amount of headache this thing caused me over the last few months, it went together like butter. Its such a relief to see some forward moving progress in this build after such a delay.
Im getting about 65psi compression just turning it over by hand with a 1/2" breaker bar, and about 3% leakdown across all six. So far, this is the tightest engine ive put together, hopefully itll run as good as im hoping it will. ordering a cam-degreeing kit after the new year along with the intake mani, fuel rail, and turbo manifold.
anyone here have any experience with CX-Racing's new equal-lenth manifold they designed for the SC300? It looks like a damn tarantula but im considering giving it a try. Only concern id have is heat-soaking the engine bay considering its so damn big.
She's coming together Dan, hopefully everything will be smooth from here. Sorry about the past hiccup...way to recover! Keep us posted, thx for sharing.
^ Ive got a couple friends running a twin scroll turbo on an undivided manifold flange, one is a GTE making really good power for 3+ years and no ill effects.
I havent decided on what Im going to do for fuel feed yet.. Going to be using a Driftmotion rail which has -8 ends and -6 center return... thinking of stepping down to -6 dual feeds and using the -6 return.... but im not opposed to running a single -8 feed then stepping down the other end for a -6 return... Id be saving about a hundred bucks in AN like and fittings running a single feed... Ill cross that bridge when i get there
10-05-14, 10:37 AM
