Throwing on a Driftmotion CT2657trim - Headgasket First??

[755hp]

Dropped my engine head off this morning to the machine shop. I wish I had brought them my exhaust manifold stud/heli coil kit from DM (some were stripped out) but ohh well. They'll deck the head, vacuum pressure test (valve sealing) and clean up the head little for me as well. Also, they'll bead-blast my exhaust manifold then I'll just paint it over it with some high temp black spray paint.

Also, I cleaned up some parts with brake cleaner and a red scuff pad. Decided to paint them giving it a freshened new look (valve cover lines are done in dark ford blue and everything else was silver); also painted my exhaust manifold heat shields (not shown in pics).











Also, here's the surface/deck of my block. I used a gasket scrapper and even a razor blade to scrap off the gasket material on the surface. However, I'm not too confident in the "finished" look/feel. I know its hard to tell with pictures but how does this surface look?? I'm thinking to block sand (VERY LIGHTLY) to get the surface gasket/crap off. Should I try that?? Or should I use some brake/carb cleaner on the surface and keep scrapping lightly with the razor blade?? Any suggestions?? I've never gone this far ever with an engine.

 

[vCo2v]

Read and watch some video on YouTube about sanding the block. I'm going to attempt the same thing. The machine shop I sent my head to said they are getting my head to about 20 ra. So I'm thinking about sanding my block and slapping on a metal head gasket instead of the oem

 

[755hp]

Read and watch some video on YouTube about sanding the block. I'm going to attempt the same thing. The machine shop I sent my head to said they are getting my head to about 20 ra. So I'm thinking about sanding my block and slapping on a metal head gasket instead of the oem

Yea, I've watched a couple here/there; that's where I got the idea from. Also, I saw photos/threads about HG changing on a UK Supra forums site where this dude took a block sander to his 7M bottom end surface. I'm a little worried about keeping those metal shaving under control though.

That's great that there able to get the head resurface to 20 RA however, I would suggest sticking with the OEM HG cause it will conform to the uneven surface of the block. Unless the block is being decked, a MHG is not going to have a proper sealing surface. If anything, I'd say go with a Cometic MHG as I think I've heard they don't require such a smooth surface as the HKS ones (50ra as oppose to 20-30ra).

 

[vCo2v]

Going to grab a straight edge to do the block but yeah I'm in that dilemma of going oem or cometic

 

[Stepchild21]

If you're not gonna get the block decked don't go with a metal headgasket. Just asking for issues.

 

[3p141592654]

With diamond paste and a large lapping plate a skilled worker can get to the specs needed, everyone else will fail. Sandpaper and a sanding block will not work. The proper solution (for the block) is a CBN cutter on a surface mill. If the block has deep grooves around the cylinder as most do, you will never remove enough material to get the surface needed without a mill

 

[Backlash2032]

Is a CBN cutter really required? At school we've been taught those were basically for hardened steels. And at work we've gotten some pretty damn good finishes with just carbide. Biggest cutter I've ever used is a 2 inch face mill though.

 

[SideWinderGX]

As far as cleaning material off of the block, the only thing you can do is use a gasket scraper and be careful to not gouge into the block itself. Use WD-40 or something like that so the chips don't jump all over the place and spend as much time as you need to. Don't use a wire wheel or anything like that.

 

[3p141592654]

Is a CBN cutter really required? At school we've been taught those were basically for hardened steels. And at work we've gotten some pretty damn good finishes with just carbide. Biggest cutter I've ever used is a 2 inch face mill though.

Factory service manuals are calling for 8-12 microinches RA or better (e.g. Ford 4.6L V8). That's pretty much a mirror finish (glass is about 3 RA). For an aluminum head or block a PCD tool is preferred over CBN, which is better for an iron block. Getting those RA numbers (plus waviness and overall flatness specs too) is tough without PCD or CBN cutters, dry milling, and a newer mill with tight-tolerance bearings. That said, I've heard of people measuring 5 RA on aluminum with carbide cutters, but they won't keep that spec as consistently over time as a PCD cutter will.

What RA are you measuring?

 

[755hp]

As far as cleaning material off of the block, the only thing you can do is use a gasket scraper and be careful to not gouge into the block itself. Use WD-40 or something like that so the chips don't jump all over the place and spend as much time as you need to. Don't use a wire wheel or anything like that.

Thanks man, I appreciate it. I wish either you or this other guy (who are more experienced in this area) could take a trip over to my place and inspect the block's surface to see if its ready/decent for a new head gasket seal. Honestly, I feel I can't judge accurately seeing as I've never done this before and therefore have nothing to compare to. Can I spray a bit of carb/brake cleaner on the block surface to loosen/clean some crud off??

By the way, (if I can get myself together here) maybe soon we can head over to Esta 1/4 mile and test our new found powers out. Lol, you're newly built (and now tuned) 7M and my (FINALLY) Bpu'd 7M.

 

[755hp]

Alright, here's a comparison of some sort of 7M block surface's that have been prepped; not machined/resurfaced (including mine):


FIRST black89t's first 7M head gasket prepped block (as posted by him earlier in this thread):




SECOND www.mk3supra.org GUIDE: Changing a head gasket thread (by the way, this guy block sanded w/ carb/brake cleaner slightly on the block surface) - http://www.mk3supra.org/topic/43-guide-changing-a-head-gasket/?hl=guide#entry8304




THIRD Mine: Yea, well....see what I mean. Lol

 

[black89t]

so that pic of my block the hg is sitting on the deck still. heres a pic of what it looked liked before cleaned it i don't have a pic of it cleaned. i can't really see yours that well in the pic. take closer pic with good lighting if you want us to give you an idea oh how clean or not clean it is.

and don't go sanding it though a gasket scraper and razor blade will clean it fine. the main thing you have to worry about is pitting not really gasket material thats burned into the block. the composite hg will seal to that fine. get it scrapped clean so its nice and smooth and show us what it looks like after. it doesn't have to be shinny metal. just can't have old gasket material built up making the surface uneven but scrapping should take care of that. what it wont seal to is deep pitting. like i pulled a junk motor appart and it had been driven so long on a bhg the coolant jacket to cylinder section had a grove eaten out of it.....

 

[755hp]

so that pic of my block the hg is sitting on the deck still. heres a pic of what it looked liked before cleaned it i don't have a pic of it cleaned. i can't really see yours that well in the pic. take closer pic with good lighting if you want us to give you an idea oh how clean or not clean it is.

and don't go sanding it though a gasket scraper and razor blade will clean it fine. the main thing you have to worry about is pitting not really gasket material thats burned into the block. the composite hg will seal to that fine. get it scrapped clean so its nice and smooth and show us what it looks like after. it doesn't have to be shinny metal. just can't have old gasket material built up making the surface uneven but scrapping should take care of that. what it wont seal to is deep pitting. like i pulled a junk motor appart and it had been driven so long on a bhg the coolant jacket to cylinder section had a grove eaten out of it.....

Yea, after I posted your photo, I kinda realized it still had a gasket sitting on top of it. Lol

Last thing I need to have is pitting in the block. I'll take another photo of it tonight (close ups). Thing is, my head gasket was clearly on its last leg and had I thrown on the 57trim turbo, I would have blew it out completely. However, I was checking my coolant in the radiator and it was always full; I never lost any coolant, never really over heated. I'm assuming no coolant leaked into the engine internals; also, when changing my oil, I was checked the condition and it was just dark, never milky/brown.

I literally caught this BHG just in time before it got worse. Kinda like how the other guy posting here earlier was saying (catch BHG before it gets worse).

Also, as I was typing this post up, the machine shop called and said my engine head is done (resurfaced and washed a little)!! However, they weren't able to get the cam gear backing plate screw out that I stripped when doing my cam seals June 2014 (yea, I over torqued one cause I'm an idiot); they told me it cost $50 to get that out....I'm broke right now so, it stays. Lol

 

[SideWinderGX]

If you're using a Toyota OEM gasket you can spray it with copper gasket spray and that will absolutely take up any imperfections in the block.

Cleaning the block with it still in the car is going to take a while, but you'll be happy you did it. Keep posting pictures if you're unsure.

ESTA opens this weekend, we can make it out there sometime during the summer haha.

 

[755hp]

Alright guys, here it is; I got my 7M head back from the machine shop today. They decked it taking off 0.0012 (cost of $80) and cleaned the head up a little (cost of $25).









Gotta get on an online compression ratio calculator now and see where I'm at (CR based on stock HG). Lol

As for the rest of the night, I'm going to jump into the valve seal job; got the idea to get/use these tools from Poor Man Mods (changing 1jz valve seals on YouTube).



However, after that....yea, well....I'm going to have to heli-coil my exhaust manifold threads in the block. Technically, only one stud/thread stripped out when I took off the nuts at the machine shop. However, should I just do all of them now or only that one stripped thread; I'm thinking....start fresh w/ all of them??

 

[SideWinderGX]

1 thou isn't enough to change CR at all.

You should definitely do all the studs now that you have the head off, much easier now than later when another strips.

 

[755hp]

Heli coiled my exhaust side studs today. Went in with a drill bit, then a tapped/re-threaded and then inserted the new heli coil/thread; installed the studs with the "anti-seize" stuff.

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Here are some close-shot photos of my block's surface. I took a gasket scrapper to it multiple times on different days; I also used a razor blade (scrapping only; not angled toward the block - angle away and dragged) and wiped it down with carb clean. I'm calling it "done/prepped"; its the best I can do with those two tools. I was about to block sand it but Sidewinder talked (and texted) me out of it. At this point, I'm just going to spray both sides of my OEM HG with copper gasket spray to help seal up any imperfections in the block....DONE.

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[755hp]

As you can see from the previous post photos, the pistons looked damn bad so, I took a brass wire wheel (installed on a corded drill) and cleaned up the piston surface; I also used carb clean to loosen/break up the carb build up. Carb clean I found, works fairly decent; not a perfect finish but much better than before.

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For the final task of the day (which took me 4hrs till 3am), I cleaned out my bolt holes thoroughly. I used carb clean, compressed air can, my lungs for additional compressed air (cans finished) and the bottom tap from DM. All holes were done; I even screwed in an ARP stud in 3 holes (test/check) and it went in all the way with very minimal/no resistance at all.

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TOMORROW (or today, whatever), STARTS THE REASSEMBLY!!

 

[din904]

I would not put that head on that block you need to slow done and get that block cleaned or this will turn into another I hate 7m going 2j thread this why so many people have problems with their 7m. you can see old gasket material still on the block do yourself a favor take your time it's a lot of work to do just to have your head gasket blow shortly after reassembly. Scrape with a blade towards the block you can use a blade holder and keep as flat as possible just enough angle to clean that shit off also use brake clean to clean the surface of the head and block before you reassemble. Slow down and get it done rite or you'll be kicking yourself later good luck!

 

[755hp]

I would not put that head on that block you need to slow done and get that block cleaned or this will turn into another I hate 7m going 2j thread this why so many people have problems with their 7m. you can see old gasket material still on the block do yourself a favor take your time it's a lot of work to do just to have your head gasket blow shortly after reassembly. Scrape with a blade towards the block you can use a blade holder and keep as flat as possible just enough angle to clean that shit off also use brake clean to clean the surface of the head and block before you reassemble. Slow down and get it done rite or you'll be kicking yourself later good luck!

I'm telling you guys, I went at this thing multiple times. Its hard to tell from the photos (which I went at it again after taking them); I feel all I'm scrapping at this point is iron....not gasket material. Thing is, I don't want to scrap into the block causing low/high spots. If it blows....hehe, sigh....if it blows, I'm just going to rebuild the whole friggin' engine (decked block/head)....I mean, I don't know. Look....its not going to blow, sigh, let's not think like that; I'll be fine (hopefully).

But one thing I'm won't do is abandon the 7M Engine. There too many threads/stories about that over the years....and honestly its just comical. JZ engines are the easy way of life....compared to 7Ms. Lol

Thanks for the tips man.