02-26-2010, 03:10 AM | #1 |
3" Exhaust
Join Date: Nov 2009
Location: cocoa
Posts: 64
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Best questions ever. could really use awnsers lol.
putting the head back on my turbo supra, could use a couple of pointers..
ill get pics up soon im a new tech a tire kingdom makin good money so the supra is gettin the attion it needs finally. i bought a non turbo head, its at the machine shop now gettin re-surfaced and new valve seals then ill measure the valve cover to deck clearence and take it away from stock. wait.... what is the stock distance? and do i have to make it up ina gasket or can i run higher compression? and whats the tourqe for arp head bolts etc. and whats better turbo cams or na cams i have both and there going in a turbo car. any pointers on putting this thing back togeather is GREATLY apprechated. Thank you guys i miss my car.. just want it back.
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88, targa top, 5 speed turbo, tein coilovers, 4 inch hks exhaust, ebay front mount, hks turbo timer. |
02-26-2010, 03:18 AM | #2 |
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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The machine shop should be able to tell you what they removed, but as the head may have been worked on previously, yes, an absolute measurement is best.... I'll look it up and get back to you on it.
Stick with the GTE cams in a GTE. Just follow the TSRM to the T... and DON'T FORGET THE RTV at the block to lower timing plate union!!!!
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02-26-2010, 04:06 AM | #3 |
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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Oh, and the stock HG thickness is 1.37mm compressed. It's better to run stock compression or, if you're increasing the boost, an even lower compression; That's only possible with a metal head gasket though and the block deck MUST be resurfaced and both head and block must be SMOOTH. MHG's require a smoother finish than you want with a composite HG.
Don't forget that when you swap the cams you'll have to reshim for proper clearances... do both intake and exhaust. The intake cam is the only one that's different between the GE and GTE; The Exhaust cams are the same.
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02-27-2010, 03:15 AM | #4 |
3" Exhaust
Join Date: Nov 2009
Location: cocoa
Posts: 64
|
jesus christ!?
the head is resurfaced but i was just gonna take a cookie pad to the block. dude this is insane thats all i did on the 351 and the ka and worked fine.. ill take you word for it thoe. since the block is in the car cre, how do i resurface it???
And why do they make a gasket thinner than 1.3? and if the stock is 1.3 then do i buy a 1.4 (just a example) and should i buy a stopper or bead type? the over 300 bucks if its more then 1.2 fuck. man i need help bad.. wtf is shim the cams? ive never heard of that just lube the seat and do the rotation just like the head.. fuck man i really need help. im sorry for so many questions but this is rediclous. im buildin it for boost its a turbo originally man.... fuck. depressed as hell.
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88, targa top, 5 speed turbo, tein coilovers, 4 inch hks exhaust, ebay front mount, hks turbo timer. |
02-27-2010, 04:49 AM | #5 |
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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First and foremost: RELAX
The short and direct answer is that the factory finish wasn't smooth enough, why would a 20yo deck which has in most specimens warped enough to be out of spec for a composite HG be suitable? Also, from what I recall it's also got thinner cylinder walls than the 351... dunno about the KA. You can try to get away without having the deck cut but it usually doesn't turn out well. Get a machinist's straight edge and check the block for flatness as per Toyota's specs. If there is ANY pitting, I'd flat out forget it and just pull the engine. Then, if it is truly flat, hit it with a precision lapping plate and various grades of diamond lapping paste until it's smooth like glass; Lap it until you can't feel anything with your fingernails and then continue to lap for another day. Doing it this way I wouldn't trust the finish to be smooth enough to use a Stopper HG... Per HKS you need a RA of 20 or less and for some reason a lot of shops have a hard time managing that. If you go this route I would go with a MHG from Cometic... they seem to be the most forgiving and should work quite well. YOu also need to make sure the head is VERY smooth. With a composite HG like the stocker you actually want texture, not the case with a MHG. There are a couple reasons for going with a thinner HG than stock and a couple I'd speculate on. The most common is it's a cheap (but very ill advised) way of increasing an engine's compression... Another situation where I've heard of them being used is where you want as few layers as possible (the thicker the HG the more layers it has) and then the compression is brought down with different pistons.... Then there's also the situation where the head's volume has been increased and you want to bring the CR back up. Yes, shims. The valves are opened buy the cams pressing down on the lifters or buckets... on top of the bucket are shims which are used to adjust the amount of space between the bucket and the cams. Too much space and the valve doesn't open as much as it could nor does it open for its full duration; Too little and the valve may not close completely. In the extreme in either case you risk the cam lobes coming into contact with the shim. You also need to measure the cams... or at least measure the lobes. The details of all of this are in the Toyota Service and Repair Manual; I STRONGLY recommend you buy a copy. For now, you'll find an online copy here: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/
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02-27-2010, 05:15 AM | #6 |
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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Factory head thickness (from the valve cover landing to the base) is 116mm.
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02-27-2010, 10:26 PM | #7 |
3" Exhaust
Join Date: Nov 2009
Location: cocoa
Posts: 64
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Wow
Ridicousily hard to relax but that helped.. the head is getting a glass like resurfaceing at the machine shop now. i called and the final spec should be about 116.1 or 115.8 give or take. so i would love more compression and less layers and not to blow 3 houndred ona head gasket.. is 1.2-1.3 good for me? if not what it..
So i guess im going with a bead type from cometic.. thank you VERY VERY MUCH. So.. the blocks is cast steel or cast iron, unless were in nascar and running aluminum machine shop says chances of it warping are slim and the block has 0 pitting... But i will check it with a real stright edge and a bright light on one side to see if i see any light but what if there is like minascewel/really redicously small peaks of light...? am i fucked and need to pull it? now onto lapping i would love to learn wtf it is and were do i get it/borrow it and how to use it.. i really want this to run right, strong and round 10 psi.. give or take. thats it man. and Cre, couldnt be happier that your helping me right now means the world really.
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88, targa top, 5 speed turbo, tein coilovers, 4 inch hks exhaust, ebay front mount, hks turbo timer. |
02-28-2010, 12:08 AM | #8 | ||||
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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Quote:
Higher compression on a turbo is not generally considered a good thing. Get a gasket sized to keep the stock CR or thicker and add more boost... the minor bump in CR isn't going to gain you any noticeable increase in power, but the 5 extra psi of boost you'd otherwise have room for would. Quote:
Quote:
Quote:
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02-28-2010, 01:03 AM | #9 |
3" Exhaust
Join Date: Nov 2009
Location: cocoa
Posts: 64
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damn... im sorry man. after seeing what you quoted i sound like a kid with a car he has no intent for.
im not thick headed just ina case were i wanna hear it'l be okay.. its a remorse issue but i want to apoligize. ive seen you help out alot of people and for you to go out of your way for me right now is nothing but godly. i think ill just go with a nice composite thats good and thick and arp suds or bolts.. what ever you prefer. And i will listen and not backfire everything you say.. im sorry man.
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88, targa top, 5 speed turbo, tein coilovers, 4 inch hks exhaust, ebay front mount, hks turbo timer. |
02-28-2010, 04:22 AM | #10 |
Toyota Racing Development Join Date: Apr 2007
Posts: 5,038
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Meh, if you don't trust something that's all good.... I'm just touchy from time to time; My wife and my father in law both have this crap habit of asking advice and then immediately replying with reasons why they can't do it or it won't work or they already got the answer from someone else and it was the opposite... Bugs the shit out of me... if you're sure you know what's up, don't ask.
Anyway, if the block is within specs a good lapping will bring it closer and get the finish where you need for a Cometic... If you're going to try this I recommend using studs over bolts, you get more accurate torque and more clamping force... actually, for the extra $20 studs are generally the better choice, but you'll need to remove the car's hood to drop the head down over them. And make sure you don't forget to chase the threads in the block with a tap!!!! And as mentioned before, the RTV at the lower timing plate/block union!!! A precision lapping plate is a thick, HEAVY plate of steel that's been machined within very tight standards. Many have two serviceable sides; one is smooth while the other has a cross hatch pattern cut into it. The smooth side is used for fine finishing and the cut side for quickly taking down material. When lapping you simply rub some of the lapping compound into the plate, then set the plate down on the deck. You move the plate in small figure 8's as you move from the front of the block to the back, make sure to move at a consistent pace and not to over work any one area. Let the block move a couple inches past the edge of the block when you reach the ends to avoid creating a concave surface. DO NOT PUSH DOWN ON THE PLATE!!! You'll get warn out enough from sliding the pate around as it is and pressing on the plate just increases the likeliness of making things uneven... let the plate own weight do the work. Do prevent the abrasive compound from entering the engine move the crankshaft so none of the pistons are at the top; now fill them up with Crisco (no, I'm not joking). Then take a LOT of foam ear plugs and use a sewing needle to add a pull string to each. Insert the ear plugs into the oil and water passages so there's about 1/8" to 1/4" of space above them and add a little Crisco to fill the top there too. Now, you may lap away and the Crisco will collect the detritus and spent compound... It'll help lubricate the plate a little too, but you'll still want to add a little lightweight oil here and there while lapping. I've heard from people I really trust that it's best to bed the compound into the plate by rubbing it in with some stiff cardboard first. I'll have to look up the grits that are recommended for what you're doing, but it's going to vary a bit depending on how off the deck is. Oh, also the larger the plate the closer to flat it will cut the deck. One thing you need to remember to do is keep checking the deck with a flat edge!!!! I think you can get a 12" x 12" for around $100... check McMaster Carr. Should I add that to the FAQ?
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