Everything we learned after tearing apart our Subaru WRX engine
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- Опубликовано: 1 окт 2024
- Last week Davin was able to disassemble our 300,000 mile 2002 Subaru EJ205 engine. Did he do it the right way? Maybe not. Did it come apart? Yes it did. However, after going through all the work and talking to some local Subaru guys we learned a few things that we thought would be useful to pass along.
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this is actually my favorite type of redline rebuild video. all the fine details and interesting things about a specific engine.
I enjoy this series because i appreciate the fact that you can rebuild old school V8s and you're not afraid to work on a turbo charged Japanese engine and not criticize it
Call up IAG in Maryland, ask for Adam (used to work for the same company I came up in) and bend his ear on this project. I guarantee he'd help you guys out.
1. Look for cracks on that piston. Especially the ring lands. The chances of them not being there are slim to none. I'd highly recommend an upgraded hypereutectic forged piston for the turbo application. Rods are fine at stock level power, but easy to upgrade now if a bigger turbo and more fueling is expected. The ring lands fail often. Good call on the new rings of course.
2. Oil pump - yes, get the JDM larger OEM pump (12mm), IAG modifies their offerings but the factory 12mm is fine. They don't like us over here, so we get the cheap and fail prone parts.
3. No, that oil pan is garbage. It's a part of the problem, same as the oil pump pick-up. Yes, you can get a cheap used STi pan and then get an aftermarket stainless steel properly welded (not brass brazed) pick-up that won't fail.
4. DO NOT DELETE THAT OIL FILTER HEAT EXCHANGER. It is being cooled with coolant, and in turn for street use actually heats up the oil to operating temperature more quickly in the cold months as well. It provides a more balanced temperature range for the oil under hard use.
5. ORDER AN AIR OIL SEPERATOR. IAG, Crawford, whatever. Just got one on that car after all this work. Factory PCV system blows and contributes to oiling issues.
Make a video on porting and polishing the turbo if you plan to keep it. Delete the up cat (another prone to fail), but obviously keep the down cat. Plenty of info out there on it but it makes the car much more responsive and far cheaper for the media budget than a new turbocharger. Although, at this mileage I'd seriously consider tossing a new balanced CHRA in it.
Seriously love this series. I know you don't. I know a lot of others don't. But thank you for doing this.
I would add that 4032 is a good material for forged pistons that aren't seeing crazy power, less thermal expansion than 2618 that leads to tighter clearances, less noise, and less wear. Another reason that reusing the pistons is bad is because the clearances to the cylinders will probably be too large after boring.
Also, when boring, it is best to not only use a torque plate, but also to bolt the case halves together to make sure the cylinders are strained as they will be when they're assembled. The cylinders can change up to .001" when those forces are not present.
Getting the valve clearances right is tricky- usually they'll tighten up around .001" when the heads are bolted to the block, so at least check them again after the heads are installed.
And don't use too much sealant on the larger cam caps, there's pressure relief/drain channels that, if clogged, will cause the cam seals to pop out and leak.
And finally reference the Subaru factory assembly manual, it is wonderfully detailed. Doing a motor like this without one would be doomed to fail.
Have you heard of the channel Gears and Gasoline? One of them has a WRX that just got a full IAG engine. If you like this channel you'll probably like G&G also.
@@ol_smokey9370 Thanks for the heads-up, I'll check them out
As someone who has built and tuned a couple Subarus, I have to agree with everything you've said here. One time I was working on a 2010 Forester XT with a fresh engine combination, no oil cooler. Oil temps on the interstate were up to 240-250F. Slapped an EJ257 waterpump and oil cooler on there, and BAM oil temps around 205F cruising down the interstate. I cringe every time some one says "I'm going to delete the oil heater". My only other recommendation would be the Killerb windage tray and a full Aisin (for the love of god, not Gates!) timing kit.
@@jeremiahjorenby2275 yes, windage tray with the pick up is required especially when buying IAG. Stock won't work.
Ive owned many classic V8 muscle cars....also owned a 2004 Subaru WRX STI....300hp 4 cylinder rocketship that handled like it was on rails!...it was AWESOME!
As someone who pointed to some youtube videos to watch previously, let me say that the ONLY reason I even mentioned them is that I know this engine has a few quirks to assembly that can make your life suck or make it easy, and had no clue if you knew any Subaru people to ask when you ran into weird Subaru problems! What you did for disassembly was perfectly fine. You got the block apart and nothing broke, and that is what counts. As the saying goes, no harm, no foul.
Yeah, I know that Subaru's have horizontally opposed cylinders, but it's cool seeing something that is not the normal fare. I also enjoy the fact that this engine does have some life left in it and that you are using some of the original parts. I do have my preferences in my hobby which is motorcycle restoration namely that I love the inline 4 cylinder bikes (air cooled), but if asked to work on a two cylinder V engine (whether domestic or foreign) I would also appreciate the challenge.
I have an old 61 Bonneville with a parallel twin I've been working on. Worst part is all the Whitworth hardware, and the fact that I know nearly nothing about old British bikes.
We do a lot of Subaru heads at my shop. I have discovered that when you do the valve job, if you will trim .005- .006 off of the tip and keep the valves in order. Your adjustments will be extremely close.
This kind of videos, this kind of gentlemen gives me motivation to make an old car reusable, like a stock car who gets out of the dealership and to be an everyday driving car.
Take care, Grettings from Swiss
Don’t fall for trolls friends.
this is more fun to watch than you give it credit for. I would sit through more. Easily.
Change the oil pickup! The factory ones and brazed and are a known failure point
One of the MANY known failure points. 😅
@@TML34
Right?
I agree Subaru probably had crappy QC on a few the oil pickups but it seems like kind of a marketing myth. Just because somethings brazed doesnt mean its crap. If brazing is done correctly, the joint will be stronger than the base material. (The pipe will tear before the braze joint fails). 90% of metal pipes on all cars are brazed. (I daily drive a WRX with 180k miles and used to be a production engineer at a supplier that made pipes for Honda and Toyota)
@@4pimp4 True!
I worked in a machine shop 5 years, we al=ways brazed every oil tube on street and ALL the race car engine we build NOT One failed ever!!!
Some ppl say this that the Other etc about brazing. They have NO idea what they are saying. ALL welding is known for superior strength then the other parts that are joined by weld brazing.
Ive welded for 50+ Year and seen that if the #1 Trait of the welding industry!
Great stuff Davin! 👏 FYI, Aisin makes the best aftermarket timing/water pump kits … oil pickup tube really should be replaced or upgraded and the o-ring on it is a critical part that’s easily confused with other o-rings in the assembly. 👍✌️ cheers!
Aisin is also an OEM parts supplier for Toyota and Honda
@@s0nnyburnett Exactly! 👌
I love the fine details of a build! The sandblasting and prep work has always fascinated me. When me and my dad did our 289, I asked if I could come by the machine shop to learn this whole process. Best couple of days I ever had and a wealth of knowledge I gained about our motor and motor builds
I believe that engine case turned dark gray because the aluminum reacted with one of the products you use in your jet washer. This same thing happened to my dirt bike engine cases when I cleaned them in an ultrasonic cleaner. Only difference is it is a problem for me because I don’t like it. I think it looks fine on your engine case and would probably look quite nice an an engine bay. I don’t think that dark gray will look very good against the bright green frame of my KLX300R though, unfortunately. Might have to get them vapor blasted.
This was my thought as well. Chemical reacting to AL. A concern would be if it could cause any material issues.. likely only on the surface but perhaps impose brittle or soft condition. I guess a surface hardness test would give some idea. As always, quality content.
6:50 They're actually not. They're easily confused for torque-to-yield though because the short-hand identifying of that fastener type is the degree spec e.g. "turn the bolt 90 degrees" at some point in the process. In Subaru's case though, that degree value is for "crimping" the head gaskets. Subaru technicians will reuse your existing head bolts, and they've been doing so for 30 years without issue.
I'm just happy to see something new done! The more variety the better! It's good to see someone who has little to no prior experience with a certain type of engine or certain brand just throw themselves at it, it always results in seeing things you wouldn't see otherwise.
I love that you changed things up a bit with such a different type of engine. It's not all about the old school blocks.
That being said...if you guys get the chance to do a Ford 427 or something like that, I wouldn't hate it 😁
Those cast piston tend to crack ringlands (if you get pre ignition knock) and the rods are cast. If a bigger turbo in the future slap some forge pistons and rods. The MLS stock gaskets is great.
Ringlands more of an issue for the EJ25 and specifically the hypereutectic pistons in the STI. Knock will definitely be a killer, but the rods are the weak link here for sure.
does that copper gasket spray also work well with MLS gaskets (as in two-three decent coats)?
@@haydenc2742 As a general rule, you really shouldn't be using copper gasket spray. Especially on any MLS or composite gasket which already has a rubberized coating or soft seal areas. I would basically only use it on an engine with crappy block or head surfaces that I wanted to seal up well or on a gasket I was reusing in a pinch.
great video, amazing job. The Grey is a perfect outcome. Please consider uprating the head a little, and going up one size on the turbo. Thx for the update. I have never seen the grey come out that well. Waiting for the clear coat
The dark color of the aluminum casting is due to the chemicals used in the parts washer. Certain rust inhibiters used for ferrous metals will react with aluminum. You see that with bare aluminum pots and pans in your home dishwasher as well.
I can concur. The same happened to me when I used Zep purple degreaser on some aluminum parts. They also turned a similar dark color and I learned my lesson, 😂
I loved my Subaru Outback. It was my very first brand new vehicle. It was fun to drive (stick) and had decent power for such a big vehicle, and there was certainly little that it wasn't capable of dealing with, weatherwise. I comfortably drove through a blizzard at 70 mph in it once. I took very good care of it too, sticking to the recommendations on the factory schedule, and of course, oil changes at 3K, per my insistence. Even that wasn't enough to keep it from the dreaded oil-burner issue that was so common for a bunch of years in the early 2000's. It eventually clogged two cats and after the second one, I parted ways with it. A shame, as it only had 120K on the odometer and was in great condition in every other way. Almost wish that I'd kept it so that I could have rebuilt the EJ25 and given it a shot of power with a Manley stroker kit and a bit more cam. Would have been a blast.
I would definitely replace the oil pick up tube since they are known to fail, killer b and iag make great ones, change the oil pan as well. And get upgraded pistons, as others have mentioned, stock pistons are known to Crack ringlands.
EJ20s dont crack ringlands, thats really never been an issue. It was an EJ255/EJ257 thing, and even then not *that* common.
Those pistons are not hypereutectic so do not suffer from ring land issues, and the oil pickup wasn't an issue back then either
3:04 Seriously with the head gaskets?!? This is an DOHC EJ204 WRX (or STI) engine, they don’t have that issue. It’s the NA SOHC Impreza/Legacy/Forester engines that have head gasket issues. I bet you think all Porsche’s have IMS bearing issues?
Dear Hagerty, Christmas is coming soon, and I would love to get a vapor hone. Maybe y'all could upgrade yours, and donate the old one to a good cause (me!) :) :) :)
Love the redline rebuilds!
Subarus are kinda my thing but, i was actully enjoying the fact that they're not yours. Great vids, really enjoyable.
Given the variance in clamping on the heads, I have always gone with the ARP studs and either OEM or FelPro latest MLS gaskets. Bulletproof and necessary for the boosted Subarus
I'm enjoying this series so much.
🧐
I appreciate the consideration of the comments from the last vid. Was it painful to watch? Yes. But was it enjoyable content, also Yes. Keep up the quality!
I am glad to see you take the Subaru engine apart. I own a 2019 Subaru Impreza. Now I know what to look at in the engine. I put over 100,600 miles on the engine in the year 2022 so far. I'm having carbon build up problems. Your tore down the engine with no knowledge on the order it was suppose to be tore down. Well, I'm with Stupid just like you. Learn as you go. No complaints from me. I'm just going to watch and lean.
After your cleaning and sand blasting it makes the engine block look like a plastic.
I wouldn't mind if the videos were longer. They are really enjoyable. =)
Damn - if I had "vapour hone" or sandblasted cabinet, that is what I would do all day everyday, it is so enjoyable to watch as well! So don't skip tat part in the video... yes sure you can speed-it up, but I am absolutely enjoy watching it, could one even finish small bottle of corona and pack of 25g of chips lol!
A tip for the reassemly, measure the clearence from chim to camshaft for all. It could still be to much or to little after assembly
Like to see a Corvair Flat Six eventually! Is there a oiling system fix for the engine? Reminds me of the Oldsmobile 455 where oil gets up into the heads and slowly migrates or doesn't migrate back into the pan at all!
The block half you are showing us (at 1:00) almost looks like it has JB Weld or actually been welded behind that one bolt hole. Strange. Probably just shadows, eh.
Love your videos Davin!! Btw, I’d be willing to bet that you get called “David” more than I do-😎
Hey guys show how you rebuild a 4g63t engine from Mitsubishi Evo and tell your opinion
Subaru engines are very misunderstood. Props for looking at one even if it's not your first choice. Most people who work on Subaru end up loving the brand.
Love this series so far. Can't wait for the next episode.
Great work Davin! I always like seeing expert mechanics teardown a Subaru motor for the first time to get their opinion on the block itself. Older Subaru's always looked great to me but man do they lack that reliability.
I'm flabergasted by this rebuild ! I thought the Subaru engines were only upgraded VW flat fours - which I'm quite familiar with.
How little did I know ! And reading comments down here from guys in the know, man, this technology is from another universe than the old 'merican V8s, big or small !
Well, Darren, I guess you're in for a lot of reading infos.
Thanks Davin and Hagerty for making Mondays one of the best days of the week.
The savvy Subaru owner like most PT Cruiser owners know to look under the rear seat where there's a factory hidden 6 pack of head gaskets 😂
id love to see davin build a vw or audi engine just to see the complexity of it and to see his reaction to it 😂
He's done a VW engine previously. The old air cooled one. Look it up.
Thank you for the cool video, but can you just sandblast a block? Sandblasting takes away small portions of material, isn't that a problem for such precisely produced products like an engine block?
Oil pump: Shim for higher pressure instead of going to STI for more volume. The volume won't help unless you replace the bearings with under sized (more clearance so you need the volume)
With the block split would you have to mill the 2 half’s and then line bore?
The stock oil cooler is very effective, both at warming up the oil on cold climate and also on cooling the oil during severe driving. It’s a lot better with it. Also the head bolts on these EJ engines are not torque to yield, but it’s better to replace them since it can be overtorqued and yielded on a previous reassembly.
Very few specific version of the 2.5 na boxer engine had head gasket problems stop spreading bs. You don't even have that engine. 2000-07 ej251 and ej253 naturally aspirated. Only ones with issues. The fix for the problem is using the head gaskets you just threw the ones from a turbo engine.
I have a wrx and the check motor light came on.
I’ve really been enjoying this series. The domestic builds are great, but it’s been interesting to see you step outside of your comfort zone. Keep up the fantastic work!
Great introduction. RUclips has removed some people`s willingness to find out for themselves. Good point Davin
9:50 That the Fuji Heavy Industries logo, Subaru's parent company and you'll see it all over the car.
I am a mechanic myself and I watch your videos all the time
you always give me energy to carry on 🙏🙏🙏 I am really appreciate it 🌸🌸🌸🌸🌸
The gray color is because the cleaner you are using is a base/alkali formula. Good that you like it because it's a sumbitch to remove.
Please rebuild the Subaru WRX to mint condition. Hagerty should find it
I will make fun of my buddy at work BETTER with this video. Thank you.
I placed an order with your sponsor yesterday morning so we'll see how they deliver. They were the only place I could find wheel bearing and hub assemblies NOT made in China. I'm crossing my fingers the part matches the pictures and is truly a Japanese wheel hub and bearing assembly.
300K miles, nice... make sure to use Subaru's recommended oil brand/weight/viscosity. if you deviate even slightly you are running the risk of throwing a bearing. don't ask
Stretch bolts only stretch out side of the thread they are screwed into. They stretch at the weakest point which is where the thread on the bolt exits the block. As they stretch the bolt goes past the yield point. It cannot recover from this so the thread deformation remains. When you screw the bolt back into the block, the distorted thread locks into the block and gives you low clamp torque, so the head gaskets will fail. If you really go at it then the bolt will fail as you screw it in and getting them out is a long project. Stretch bolts are used once and once only.
In regards to your monologue when the video began. I still would have you assembled an engine of mine any day of the week over some of the guys I have locally.
I've had 2 subaru foresters and they were both garbage. Would never buy another subaru. I never beat on them either.. just drove them normally and they still were unreliable.
Hey Thanks Davin, with your help digging that 15 foot long 1 foot deep ditch through base material to help me run electricity to my shop. By the way great work on that Subaru engine, as that I think is similar to the old 1967's VW beetle engine's.
Nice! I'm liking the grey color it came out to be after the sandblasting and washing. Nice work. 👍
8:22 you don't put a shim under the cap. The shim IS the cap. if you need to make an adjustment, get your micrometer out, measure the current shim then go hunting at the head shop or order some new ones.
Just make sure the Turbo Encabulator is properly aligned. You don’t want any hydrodynamic flux matrix relay conduit wobble.
What's the thinking behind re-using the head bolts? I would think that, since they are torque-to-yield, you would get new ones everytime, no question.
Yeah I'm not sure either, when I did my jeep it said they could be used twice. Once from the factory and then 1 more time after. I ordered new ones.
When I rebuilt the engine on my '02 outback, I did some research on this. Lots of opinions out there as you might imagine. However, there is a line of thinking that it OK to reuse them on NA engines and necessary to replace on turbo engines.
They aren't TTY. But there is is stretch in them at the torque specs. The _Factory Service Manual_ lists 2 different tightening procedures, one for brand new botls (stretch, loosen, and then torque) or for reused bolts (just torque).
better off just spending the money for ARP head studs. Its a good upgrade and one of those things that I would recommend doing while you are in there on these engines
Having done a lot of this work it was "good enough" ! loved it
keep an eye on the piston orientation as well as the rod orientation. A lot of Suby pistons have a slightly offset piston pin. Looking good! Are you really going to put that motor back into that metal termite infested hulk? Seriously need something fun to put it back into. Factory5 818, wink wink
Im pretty sure most every engine has piston pin offset. except way back in the idk 40's early 50's and back they were dead centered like old tractors and such. . Makes for less rattle and less friction.
"It's my understanding that one of the issues with subarus is oiling" *cut to Davin absolutely bouncing the engine off the rev limiter* hahahaha
In regard to the rod bearings, I believe that you're right in that head pump-up is to blame, aircooled vws also do this, seems like it's a boxer thing. However there are other factors, the rod bearings are smaller and critically, narrower than say a V8 or even I4 which means they see higher pressure on that film strength. So good oil supply is critical. I also think windage is a factor, less so on this EJ20, more so on the EJ25. And to that end IAG makes a nice windage tray kit. At very high power levels the case bolts can stretch and cause oil to bypass the mains and lose pressure to the rods despite having good pressure at the pump. Also, when you hone the block, use a torque plate to simulate the presence of the head, these blocks are pretty wobbly and distort when the head is attached. Either that, or just dingle ball it.
That gray color is actually awesome! Hopefully you can keep it like that with just a clear coat over it.
I actually love this Subaru build!!!
This brings me back to my days of running a Subaru shop. I lived doing ej25 closed deck short blocks on EJ20 heads to make a high horsepower bugeye wrx.
That's awesome! I have had a bugeye for 13 years and it's still my daily. eventually I would like to turn up the horsepower. Are the ej20 heads pretty good for high horse power? They have 133,000 miles on them. I'm trying to save a little $.
I love evriting whot you work and great job 👍💪
It's always good to learn something new. I like watching this although I have a different Subaru engine, an FA20 and not an EJ. But as both come with their own different pros and cons it doesn't harm to watch something about Subaru boxers in general. Mine was taken apart by my Toyota workshop as part of the valvespring recall and luckily has not grenanded since - about 3500km since the recall was done. When it comes to head gaskets I hope neither my FA20 nor my 7M-GTE will surprise me with that, althouh the latter usually is notorious for doing so :-D
Prefer to watch this type of video instead of yee har shouty stuff.
Good Angle😉
This is a fun and educational series! Kudos for treading different territory, maybe next try some kind of foray in to electric motor stuff since that will be a part of the very near future…. Whether we like it or not …. :) Cheers from Tennessee
Потрясно делаешь, золотые руки, спс за контент
Он не говорит по Русски)
Can watch timelapse block cleaning all day.
Great video can't wait for the full time lapse
This was awesome. This video series format is incredible. Keep these up.
It's cool that you're rebuilding this to keep the car original, but you would've been better off finding an EJ207 that needs a refresh instead.
I love mécanique ⚙️
Boring? This is the stuff I'm here for!
Hey Davin, I love the fact you are doing this Subaru especially because it might be a bit out of your “comfort zone” we only learn when we seek new things out, I am excited to learn this engine with you. Like always, you do a great job explaining things and being real when you make a mistake, again, that is how we learn.
Love the show and how eclectic in its variety it is.
That looks like a hassle , but you're doing much better than I ever would . My patience would have went south after seeing the bearings. Good on you.
Love a cleaning pr0n video!
My 2014 Subaru STI had an oil pump failure at 31,000 miles. Subaru replaced the short block and the turbo under warranty.
Throughout this greatly edited content, my main though was, isn’t it monumentally sad that in 50 years time all this wonderful engine knowledge that’s taken years of experience to accumulate is completely void in the EV world that is being forced upon us 😥
Don't ever reuse head-bolts.
So nice to watch you take your time with this!
That “swoosh Star Trek” symbol is actually the Fuji Heavy Industries logo. Subarus parent company.
Hmmmmm 🍿
The valve buckets and shims are identical to the parts used on many motorcycles though most of the newer models use the shim under the bucket system.
Well, there is always RTFM. In my world, a retired ASE Master Tech who wrenched from the '60s to into the '90s (longer as a hobbyist), you can't remember everything or know everything. And you can't necessarily pick the jobs you are given. You have to do a professional job on a paying customer's car and do it in a timely manner. That's what the manual is for. It bolsters your basic wrenching knowledge and skills. What's wrong with cracking the books before a project like this? Sets a good example.
Have you priced a set of FMs from Subaru or any other manufacturer? It's ludicrous what they charge. Chiltons and Hayes are both a joke and a travesty. Sometimes you get lucky and find shop manuals from ... "alternative sources", but generally only for vehicles that are 5-10 years old or older.
@@JCWren Doesn't matter. It's the old right way, wrong way, Army way thing. It doesn't matter so much if you are wrenching on your own stuff. You eff it up, it's on you in every respect. Lot's different when it someone else's car and you are a paid pro. But I feel the pain you mention and am a die-hard advocate for Right-To-Repair. I'm a retired tech with a newish SUV and played hob (and paid big) getting a manual for it. As complex as some cars are now, your chances of effing something up playing it by ear are greater, so you have the choice of getting the manual up front and paying the vig, or replacing stuff you eff'ed up... maybe paying more.
@@SootHead My hot button is bolt torques. 90% of the time, that's what I'm looking for in shop manuals or online. I'm OCD about a few things, and using "ugga duggas" or "goodentight" is complete BS in a lot of situations, especially heads or safety critical items. Completely agree about RTR.
right, on something like a Subaru its best to do some research before digging into it these cars and engines are pretty unique. These are popular performance cars and there is a ton of information out there on the internet for free both youtube video's and on subaru forums so there is really no good excuse for trying to reinvent the wheel and figure it out on your own when its already been done and figured out by a million other people.
Subaru EJ series run-down. EJ25 (non turbo) DOHC usually (typical) internally leaking head gaskets, the EJ25 (non turbo) SOHC externally leaks coolant and can do this for years without issues (messy, keep an eye on your fluid levels). Other EJ engines generally dont have head gasket issues (unless you overheat them). To fix an EJ25 SOHC permanently - replace the factory head gaskets with the Subaru genuine TURBO head gaskets (same fit).
Other misc tips - oil pump screws back out after 100k-200k kms - remove pump with timing belt job, replace o-ring (use GENUINE part) and red locktite the screws in, use anaerobic sealant to reseal it for no leaks. EJ25 head gaskets can be done without a resurface (CHECK FOR WARP SPECS) and you can reuse the head bolts (skip the stretch stage). Crank bolt - easy removal - the EJ blocks have ports in the sides near the torque convert / clutch you can insert a long screw driver into to jam it so you can undo the crank bolt easily. EJ25 SOHC also has 2 different timing belts - be careful when replacing.
oem subaru head bolts will strech at like 270hp
There is literally zero reason to use the stock bolts if you are going to do any turbo or power upgrades down the line. Just put studs in there.
Oiling issues are due to non-baffled oil pan and people hammering on these through the twisties with bare minimum oil level. Killer B oil pan and pickup solves this issue. Head gasket problems with EJ251D (naturally aspirated single cam 2.5L), not turbo EJ 205/255 207/257 series problems. Use ARP head studs. Found broken head bolts on both my EJ 205 rebuilds that had never been apart prior to me. My experience has been to get the shim over bucket close, then trim the valve stem to get them spot on after measuring gap with the head fully torqued- hence why the head studs are the way to go over torque to yield bolts.