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Homebuilt GC8 for Time Attack

63K views 269 replies 24 participants last post by  bue car 
#1 · (Edited)
Hi!
Always wanted to start a build thread but never had enough time or interesting things to write about. Now looking back I thought that I have something to share, some ideas for this season in local racing series, and it will be good to start a journal just for my own record and as a motivation to move forward.

Short background story.

It all started in 2013, by that time I already owned Impreza STi type-R for couple of years and found myself a bit confused with it. Here I need to mention that I live in Cyprus. It's rather small island in Mediterranean Sea :) Cars are RHD here and before country joined EU lots of JDM cars were imported. So, sometimes you can spot quite rare japaneese cars here. When I saw my Type-R I was amazed because in Europe you rarely could see 2-door Impreza. At that point I wasn't even aware of existence of these models, I thought that type-R sticker is just a bad joke of some honda fan. Also, I wasn't big subaru fan at that time. Imprezas were just much cheaper than similar vintage EVOs.
So, after owning this car for some time I was confused. It was old (1997), poor market value, not very reliable but eating money really fast. Insurance was expensive, fuel costs were crazy... Then I ran into head gasket problem while trying to sort out mess with vac routing. I had engine rebuilt only to get a dropped valve 6 month later (the next week after I got car mapped after prolonged break-in period). So, I just put in used engine from salvage yard and thought "what to do next?"
I wanted to mod the car but I kept questioning myself, why do I need to do that? Well, at that point I ran onto local time attack series and it was perfect. Owning this car become full of sense in one moment and participation in "Street" class with strict regulations promised to save me from expensive mods. Basically I had to keep engine stock and no lightweight parts were allowed, so I could only get suspension. I was happy with this because I wasn't excited in modifying good and quite a rare car extensively. I even bought DZ03G tyres in size that fits without any modifications like arches rolling.
On local track where all time attack events are held I got lap times around 1:18 after I changed some shitty lowering springs for stock sti ones and I managed to get nto 1:15.xx on the first event I took part with coilovers and group N bush kit installed. It was mid-season 2013 and I even managed to win that event in my class although I knew that there's one EVO 6 lapping the track in low 1:14.xx, he just wasn't taking part in that event.

Then my Dunlops arrived. That was the day when I realized that tires are probably the most important single thing that will define your lap time. This time fast EVO came to the event and did low 1:14.xx lap again. I managed get to 1:13.xx. (he had same tires btw ;)) It was a shock, for me in the first place. The next event was on the next day and some guys came to check the car asking if turbo was stock and so on, because such time for street class car was rather surprising :)

Long story short, this car took me to second place overall in 2013, and win in 2014 in AWD (Unmodified) Street class. The car won every race it participated in. In 2014 I managed to set fastest unmodified street awd class time ever and if I recall it right - second fastest time among all street cars time loosing more than 0.5 sec to GDB from senior "Street Modied" class (engine mods allowed + removing aircon and stuff) and winning just 0.03 sec from Corvette ZR-1 in third place.

This is how it looks like




And this is one of the most fun videos - free ptactice session before final 2014 event, in wet

2014 Time Attack 5 Practice:


At the end of 2014 season I decided that keeping a track dedicated car in good looking condition capable for driving around city is hard, expensive and not worth it. I promised myself to stop tearing good rare car in competition.

So, this journal will be about this one:


I don't plan anything extraordinary, it's not going to be record breaking project, rather story full of pain and suffering about fixing old cars :)
hope you like it.
 

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#84 ·
I believe he's asking 350 EUR for that...
Probably better stick with stock cast ones and concentrate on doing something instead of buying crap parts )))
Thanks everyone!

Build is moving slowly, I managed to finish all suspension preparation stuff and now just need to bolt some parts to the car. Some bits are already on, just need to torque everything to specs.

Had a lot of issues with car being swaped previously... Incorrect bolts and screwed threads everywhere. Like all 4 bolt threads for gearbox mount where ruined. Had to helicoil it from under the car with gearbox on single jack and no mounts installed.
It appeared that my fuel tank wasn't strapped properly. One strap was too short and was bolted to subframe instead of body on one end. Other strap wasn't torqued down on both ends...
Well. Now neweley painted rear subframe is in and locked with whiteline lock bolts, diff is in, fuel tank strapped with two correct length straps, new gearbox group N mount is bolted to cleaned and painted gearbox crossmember and installed. New driveshaft bolts arrived (ordered visually identical kit for 240Z) because it was really mismatch of different shitty bolts.

Tried to pressure test brakes and looks like nothing leaks, although seems like i still need to bleed them a bit more.
BTW, after speaking with my friend who recently bought caged EVO for rally-sprints and hill climbs, I ordered a booster delete kit. I don't know yet if I will install it now because after I finish the car I don't know if I will be able to pass inspection to have car road legal with it. But I really want to try it at some point.
It's really not helping that it's again freaking hot here. In farenheit it's three digit temps for several weeks already... Thinking about the idea to get the engine inside the house for valve shims. ))) Wife will not be happy though...
anyway, ordered some small missing bits like TPS sensor and new clutch pilot bearing (btw, if anyone knows if it can be installed without removing flywheel - please let me know).
Basically I need to adjust the valves, seal engine, and start dropping everything inside. This will be the plan for next few weeks... Unfortunately, it's moving really slow...
 
#86 ·
Moving slowly with the build. Front arms install took much more effort than I expected. Due to ALK rear bushing front bushing were misaligned and getting bolts in it was a really painful experience. I wonder if some offset bushing should have been used in this case but since I had whiteline ALK and Whiteline front bushing I thought that they got that covered. Just checked their site and they don’t have any special front bushing options to install with ALK, so it should be fine.

Also got my hands on fender roller and decided to test fit my new tyres.
New 235s on the left, old 215s the right.

Before fender rolling:

After:

Right side after rolling:

Looks like tyres will fit inside the arches just fine

I don’t know if I’m going to get wider rims.. 7.5 seems to be narrow for 235s, but not as bad as I thought it will be.

Still need to torque some stuff to specs under the car but transmission and suspension is now intact, so I decided to move with engine.

Got cams out and cleaned surfaces for new valve cover gaskets.
All buckets and shims re-arranged for correct clearance specs out and prepared to be installed.

It was Saturday night. Had to work in the evening because during the day it’s to windy and engine will be full of dust. And heat… Weather was so hot that next day I decided to move to air conditioned area, which turned out to be this:

That’s how you can tell that one’s wife left him home alone for a couple of weeks :)))
I wasn’t using kitchen anyway…
Ok, I’m joking, it’s blocking the fridge. It’s in the living room now :)
Today I took cams and cam caps to my mechanic for his advice on strange spots I found on journals.

Whatever this is, it doesn’t seem to affect dimensions or surface of journal so we decided that it will be ok.
So, soon (hopefully today) I’ll put this thing together with new seals and gaskets and from there it would be assembly and wiring.
Have some time to work on the car now, so I hope more updates will follow ;)
 
#87 · (Edited)
looks like plasticgauge

Id stay away from air to water intercoolers. Your water will warm up fast. I run a FMIC, and have a GM IAT in my intake manifold. My cruising intake temps air usually just a few degrees over ambient, if i sit and idle i can climb a few more degress but it drops right back down. on a 30° day i might see 40° temps after sitting, cruising I'm 33-34 and at wot it will only climb 1 or 2 degrees during the pull. I actually start pulling timing out of my advance map for temps over 40°

If more people kept the IAT's in the intake, there would be better data on this. But i think for hassle and performance, you cant beat a fmic

log for example, its in farenheit though 3rd to 4th gear pull, hot as balls out
 
#88 ·
Got myself GM IAT as well, should arrive soon. Will be running mafless on ESL ECU :)
I mkow than frontmounts are quite effective, especially for road racing stuff. I just want to try WTA intercooler setup for some reason, we'll see how it goes. Although i will probably start it on stock topmount timewise. But! I'm going to log/test it to see the difference.
 
#89 ·
I was putting everything together when I found out that I missing rubber grommets for valve covers and cam seals. I got them ordered but probably I lost them somewhere at home. Because I kinda remember they where somewhere here. I turned all the stuff in the house upside down trying to find them, but nothing...

Now need to order and wait, but that's not the worst thing happened.
I kind of put right head together because I had four new grommets and re-used two old ones until new parts will arrive and decided to install the cams in left one so I will only have to put the cover when I get the parts.
Guess what? When I was trying to torque down the final cam for final check of the clearances, one of the bolts on front cap snapped...
I was following manual and using torque wrench. Now I have to drill it out somehow. I can't take engine anywhere because it's fully assembled and it's in my hall. And I don't trust myself with handheld drill in this case either... Need some options to consider. Any ideas?

Pics of RH side before final assembly, found some signs of old repairs/welding on oil galleries.

 
#90 ·
Got it out! really happy about it.
Here it is on it's way out:

All the tools used:


I used piece of 6 mm o.d. aluminium tube that fits nice in the hole as a guide to make sure i'm centered with the center punch. Added some masking tape over the tube to fine-tune the clearance. Also I got simple square-drilling tool from local hardware shop. Again, used bigger piece of tube fitted inside 6mm hole on the tool for added accuracy. Magnet with remains of the bolt attached where used to remove shavings from the hole while drilling.
used automatic center punch, then 1 mm drill bit to start nice hole in the center of the bolt, then 2.5 mm and 3 mm drill bits and finally, after I got nice hole 4-5 mm deep, I used left-hand threaded extractor that got it out pretty easily :)
It all took about 20 min to complete.
New bolts are ordered, will probably change all of them on this head.

By the way, on these older style heads all cam cap bolts are the same. Manual says to torque them all to 20 Nm, but on some cams when I torque caps nearest to the pulleys it becomes substantially harder to turn the cam..
It still turns fine, but others are like free spinning until cam lobes start hitting the valves.
My torque wrench starts at 20 Nm, so it's hard to say completely accurate, but before I torque these caps to 20 Nm from let's say half of that, cams take much less effort to spin. Maybe I should leave these cap torqued to 10 Nm? I really don't like the difference in resistance to spin when they torqued down to specs...
Another thing is these front caps according to the manual require application of sealant. I wonder if adding sealant will make them spin better when torqued down, because for now I had no sealant applied because it was assembly to measure valve clearances.
 
#91 · (Edited)
double check your torque specs, usually the bolts at the cam seal caps are smaller and require half the torque of the other 4 bolts per cam. And i remember my 96 heads, pretty much the same as yours having ALL smaller bolts so most cam specs online are going to be wrong

I hate torqueing those, these days i just hand snug them with a 3/8 rachet. I feel better when i can "feel" the threads on those tiny bolts. You almost need a 1/4 torque wrench for them
 
#94 ·
Me too ) That's why I got three GM IAT sensors :)
But unfortunately it's long road to go based on my progress so far.. I wonder how many new generations of Impreza are going to be released before I finish this one ))))

Here comes the part when I wanted to add pic of the page in the manual that stated 20Nm torque for that bolts, but I can't find it. the only one I could find on this computer says 10Nm :wtf: And it's proper manual for 96 with HLA heads.


Now I'm thinking what to do... the problem that I already had one cover installed and I don't want to open it now. Yesterday I re-torqued front cap on the cam that was moving slightly harder on that head because these front cap bolts are outside the cover and torqued down last in sequence. So I unscrewed them half-turn back and basically torqued them by hand until I'm comfortable that they are not loose and both cams now spin free without virtually any resistance until cams lobes come to the buckets.
Probably will leave them like this and torque other side to 10Nm..
 
#95 ·
Well, I knew it was strange when I found 10 Nm instead of 20 in the manual I thought I was using for assembly... So I decided to get my hands on my "field" win X tablet I use when I work on cars to check that specific manual which is pinned on the taskbar. I was very confused when i realised it'sexactly the same file that I used to get this scheme above with 10 Nm torque specs.
Looking a bit more through the file I found this:


The manual looks like a solid one, not a compilation, but 10 Nm and 20 Nm specs are given in the same manual, in "Component parts" and "Service procedure" sections respectively.
 
#97 ·
New bolts for cam caps finally arrived and the labeling on the head of the bolt is different.
old ones used to have "9" while new ones have "C". Also old ones used to be gold color and new ones are silver/chrome looking.
Well, at least dimensions are the same, they are OEM (p/n 808106180) and I have plenty of them now...
 
#100 ·
Well, the progress on the build is embarrassingly slow. Still hardly can find any time to work on it and even engine standing in the middle of the living room is not helping.
Last couple of weeks I managed to spend about 20-30 min every other day to do something on the car and despite this being ridiculously insufficient to do something major, I managed to get couple of things sorted out.
First, all cams and covers are installed. I installed RH cam seals using 32 mm socket, but LH ones appeared to be tricky because my socket is not deep enough to get over the cam - on this side it’s a bit longer. For one of LH seals I used second seal as additional extension, but to place the last one to it’s final position I need to find something new. Basically this keeps me from putting all the timing bits on.
New water pump is installed, all front covers are cleaned from heavy PS fluid leak, managed to put together one good set of rubber seals for the covers from two engines.
Finally got my turbo from my other engine laying at friend’s garage.
It’s VF28 and it was looking not as good as I expected.
All cartridge was covered in oil, but I hope it’s just from bad drain pipe gasket, because it was worse at the bottom.


The worst surprise was aluminium particles I found in hot section

That’s what your turbo gets when your valve snaps…

Rust from coolant line on the left, head and piston remains - on the right.
Well I hope that damage is not that bad, I couldn’t get the housings out yet, both sides are stuck… But it spins fine, no shaft play, all blades look fine to me and grease on the inlet and outlet of the cold section makes me hope that seals may be fine as well, there just was some blowby issues on the old engine...


Anyway, gave it a gentle blast with brake cleaner to wash away the oil, and now it looks like this.

Still need to get the housings off, inspect the blades on hot side, clean cold side from oil residue
And put it back together…
I should have every gasket/o-rings to redo all the plumbing on the cartridge, but after failing to get any of the banjo bolts out I wonder maybe it’s better to leave it as is and just replace the gasket on the drain pipe…
Another stopper is coolant drain pipe

20 years of doing it’s job took a toll on it. Need to check the condition of this pipe on my other engine but when I took the turbo out I had to cut the coolant drain hose because I couldn’t remove any side of the hose from it’s pipe.. So, I’m not very optimistic…
Looks like not a big deal but from initial search I found these new for 50 bucks + shipping.. And 2-3 weeks delivery, because you know… Island life :)
 
#101 · (Edited)
Managed to remove the compressor housing. There was some red sealant between the plate and the housing. I wonder if I should use sealant at assembly as well?
Despite all my efforts turbo housing was stuck and I really began to worry that even if I get it moving I'll damage the blades. Luckily I remembered that I have cheap android/pc borescope kit somewhere. Finally I got a good use for it.

Despite some marks on blades I believe this turbo will have some track time :)
 
#105 ·
Terry, I watched your video on VF43 rebuild couple of times while trying to figure out what to do with mine, thanks! )))

Looks like it was original sealant then. Will Threebond 1215 work there?
I'ts basically everything I have on hand now - got it because it was recommended in the manual for valve cover gaskets job. Contact surface is quite big there, if sealant will be too strong it would be really hard to take this thing apart next time. Well... if anybody will ever need to do that )))
 
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