My First Engine Build: PDX Flavor

[lgt503]

Today I was hoping to finish up the Long Block. Unfortunately the valve are almost all out of tolerance:mad: go figure! The valve clearances were fine before the timing belt was put on.

 

 

 

Based on the linear increase in valve clearance on both the exhaust cams it makes me think the journals got over machined. I think ill plasti gauge the Head Cam Journals to determine if they are ok. hopefully the journals are fine and I can just buy new buckets.

 

My main concern is that the valves were tipped by the machine shop. I know Sgt.gator warned against this and advised me to do the buckets myself. Maybe I should adjust the valve clearance on the tight end so if the valves compress the will be less likely to end up out of tolerance.

 

I am now going to reschedule me break in tune with Cobb. Hope they don't mind?

[birkhoff]

There's something wrong with that table -- cannot be measurements in mm, right? So this must be inches.

 

Ok then, it looks to me like your clearances decreased, a lot, not increased. Am I wrong? Pull the belt and spin the cams a few times to settle things. Measure again. Check twice and if it is still wrong, call the machinist.

 

Your previous post said the lash checked good at the bench after you got the heads back. It is really hard to see how it could change so much after the install.

 

There is an error somewhere.

[birkhoff]

I just read your post again carefully. You say you checked lash after installing heads and cams, but before the belt and it checked out. Now the belt is on and clearances have closed up 4-5 thou. This makes no sense!

 

Are you absolutely sure you are measuring against the cam base circle? The lobe must point directly away from the contact point on the bucket. If you get lazy and set the cam so that the lobes are 'mostly' pointing in the right direction, so you can measure them all at the same time, you'll not get the most accurate measurements.

 

I'm suspecting measurement error.

 

A couple of other points. Valve lash closes up over time, not opens. The valve heads work their way into the seats, especially the exhaust, and that closes up the gap. So if anything, you want to set your clearances a little loose, not tight as you suggest in the post.

 

Also, IMO there is nothing wrong with tipping valve stems; it is done all the time. There is a depth of hardening on the top of the stem to facilitate this. Of course, a careless machinist can mess up the measurements, or grind through the hardening, but it doesn't sound like you are dealing with that kind of machinist.

[Sgt.Gator]

I know it makes no sense that there could be enough tension on the timing belt to change the valve clearances. I CAN see how torquing the heads down to the block could make a change. However there are several threads about the timing belt installation changing the clearances. I'm still not sure I'm a believer in that, but I do have to note that the FSM procedure includes the timing belt being installed.

 

I think Boxkita has the right idea, get a used block setup just for torquing down the heads, install the timing belt, set the buckets. You could use a block/crank with no pistons installed so there is no chance of valve/piston interference damage.

 

I expect someday Boxkita will setup his Subaru head shop and perform that service for us.

[lgt503]

Are you absolutely sure you are measuring against the cam base circle? The lobe must point directly away from the contact point on the bucket. If you get lazy and set the cam so that the lobes are 'mostly' pointing in the right direction, so you can measure them all at the same time, you'll not get the most accurate measurements.

 

I measured the valves clearance according to the FSM where you have to rotate the cams to 4 different positions. I also measured some of them twice after a set of rotations and they measured the same.

 

A couple of other points. Valve lash closes up over time, not opens. The valve heads work their way into the seats, especially the exhaust, and that closes up the gap. So if anything, you want to set your clearances a little loose, not tight as you suggest in the post.

 

Thanks for the tip! As long as the valves tips didnt get cut past the hardened steel I shouldnt worry about the gap widening over time.

 

I know it makes no sense that there could be enough tension on the timing belt to change the valve clearances. I CAN see how torquing the heads down to the block could make a change. However there are several threads about the timing belt installation changing the clearances. I'm still not sure I'm a believer in that, but I do have to note that the FSM procedure includes the timing belt being installed.

 

Im thinking if when the journals got polished (removed the scoring marks) and 1-2 mil gets taken out then there is a lot more play in the cams. I picked up plastigage today so hopefully I will find out the clearance on the cams to head. FSM say this clearance should be .0015" to .0028". If clearance is out my options will be do nothing, get new cams or get new heads, hopefully it doesn't come to that.

[lgt503]

Today I took off the timing belt and measuring the valves without the belt. Here are the measurement without the belt.

if you compare these numbers with the previous measurements you can see the belt causes the cams to pull in by a few mil.

 

 

Next I measured the cam to head clearance with plastigauge. I measure with the RTV still on the heads and after it was scraped off. The clearance was nearly the same with and without the RTV.

All the clearances were out of tolerance. Im not sure if this is a big issue or not. I didn't get around to measuring the right cam but its probably about the same. If the journals are fine being out of tolerance I will just need new buckets. I will try to measure the cam diameter tomorrow to see if new cams would help with the journal clearance. Another possibility is have the machine shop remove a few mil from the bearing caps and then re hone the journal. I really hope I dont need new heads.:spin:

 

 

[Sgt.Gator]

If your cam journals are out of tolerance you're screwed. You need new heads now.

[lgt503]

I need to talk to the machine shop and see what they say. Is it my fault for not specifying to measure the journals or do you think the machine shop should take some responsanility and try to make things right. I already spend $800 on the heads at the shop and now it looks like I might need to buy new heads. Damnit!!!

[birkhoff]

I'm glad I never checked my clearances after installing the belt!

 

It is definitely not your fault. All clearances should have been checked by the shop during teardown and rebuild. If a part was out of spec, they would have contacted you for instructions.

 

Can't wait to hear what the machinist says. I was going to offer that with big clearances like that, the cam journal may get pulled onto the bore by the belt, dry, but once the oil wedge is in there it should centre. But then that would take a lot of oil! Kind of grasping at straws here.

 

Seriously, this is one of the more curious threads in a long time. . . Considering the hundreds, maybe thousands of head 'jobs' done by subaru shops every week, do we think the professionals are taking the time to fit the belt take measurements and then swap out a bunch of buckets on every install of newly refurbished heads? NOT!

[Shadow_419]

If your clearances are where they should be, the lash shouldn't change too much when you put everything together. Obviously every situation is going to be unique, and sometimes adjustments will need to be made after assembly.

 

Personally, my valve lash didn't change much after putting the heads and cam caps at required torque (-0.03mm). A measurable amount for sure but still well within spec.

[lgt503]

If your cam journals are out of tolerance you're screwed. You need new heads now.

 

I have read a few threads and there doesn't seem to be a definitive answer. I read this article that helps explain how machine shops can bore heads.

 

http://www.enginebuildermag.com/2006/06/line-boring-equipment-a-boring-subject/

 

I guess they mill off material from the mating surface on the bearing caps and cut the holes back to original dimensions. In theory this sounds good however I was just looking at my right head and was able to fit a .005" feeler gauge between the cam and head on the back exhaust journal, the front journal had a .004" gap.

 

Since the heads journal clearance is .005" (limit .0028"). removing material from the cap wont solve the out of tolerance heads . There is a possibility that its the cams that are causing the gaps. i recall some scoring on the cams as well as the heads. What would really suck is replacing the heads only to find out the cams are whats out of tolerance.

 

Does anybody know the nominal diameter for the cam bearing surfaces?

 

I work long days so Ive been waiting to call the machine shop til i get the next day off. I plan on taking the heads off tomorrow night and taking them to the machine shop the next day.I hope the shop will take responsability for not checking the journal tolerance. After all I brought the heads in with chewed up journals and cams and you would think a machine shop would make sure the journals could still hold tolerance.

 

 

On a seperate note taking off the head caps is a PITA. I used The Right Stuff and it really holds the caps on tight.

I really tried to spread the sealant on thin so i didnt get leakout around the oil passages. Still some leaked out occurred but it didnt block the any of the passages fully. When I reinstall these next time I will use even less RTV around the passages

[Sgt.Gator]

They should have looked at the heads and cams and given you a quick evaluation something like, "They are both scored. We're not sure if they will still be in tolerance once they are cleaned up. We'll give it a try but if they are too far gone we'll call you".

[lgt503]

I'm glad I never checked my clearances after installing the belt!

 

It is definitely not your fault. All clearances should have been checked by the shop during teardown and rebuild. If a part was out of spec, they would have contacted you for instructions.

 

Can't wait to hear what the machinist says. I was going to offer that with big clearances like that, the cam journal may get pulled onto the bore by the belt, dry, but once the oil wedge is in there it should centre. But then that would take a lot of oil! Kind of grasping at straws here.

 

Seriously, this is one of the more curious threads in a long time. . . Considering the hundreds, maybe thousands of head 'jobs' done by subaru shops every week, do we think the professionals are taking the time to fit the belt take measurements and then swap out a bunch of buckets on every install of newly refurbished heads? NOT!

 

Did your heads ever have scoring in the journals? I would imagine people are driving on heads with wider clearances than mine just fine.

 

I talked to the machine shop today and he told me that if I wanted to source new castings he would transfer everything to the new heads for me. I split as to what I should do.

 

I still need to plasti gauge the left head. I would also like to determine how much of that clearances are due to the cams and how much is due to the heads. It looks like the exhaust clearances are the worse. Maybe some new cams would tighten up the clearances.

 

One option is to buy new head and or cams. I would order head castings from Heuberger. For the exhaust cams I would try to find ones on eBay.

 

Another option is to leave the heads and see how long they last. If the heads have issues down the road it will most likely be due to valve clearance. I just need to make sure valve clearance issues won’t cause my engine to blow up?again haha. like birkhoff said, The cams should center out once the oil is being fed into the journal and the valve clearance should open up from what I measured with the timing belt on. They valve clearance did measure fine when I first got them back from the shop.

As for the oil pressure change due to an extra few mil in cam journals... Simple I’ve removed the banjo filters so there is a higher flow to the cam . But seriously I think the heads would be fine to install as they are. It won’t be that hard to remove the engine in the future plus I will have all the tools and know how if something bad happens . Once I win the lottery or marry a rich woman I can buy the heads my true love deserves.

 

Heads are expensive so Id like to spend my money elsewhere but if the 0.0028” clearance “limit” is really that critical the extra $ might be worth it. I need to sleep on this decision.

 

BTW Thanks for all the great feedback guys, I couldn't do this without you!

[lgt503]

Im made good progress yesterday. I discovered the cams were all missing material form the bearing surfaces which was causing the oil clearances to be way over tolerance as the data in post #57 highlights.

FSM had the following info on camshaft bearing journal diameters

 

I decided to buy new cams! Carr Subaru gave me the Heuberger price on the cams which is awesome and unexpected sometimes you just have to ask. I was thinking of buying just the exhaust but the cams they had are hollow, like the eBay ones I briefly had before I returned them. I didnt want to mix the solid intake cams with hollow exhaust cams so i just purchased all 4. I could have probably got a set on eBay for half the price but I didnt want to deal with used cams that potentially had missing material like mine. Also its best I got all 4 because although the exhaust cams were the worse the intakes was also missing a few mils of material.

 

When I remeasured the Left head with my new cams all the oil clearances were ~0.002" (0.051mm). Visually I can see the cams fit the heads much tighter. the new cams should also solve my issue with changing clearances once the timing belt is on.

 

Here is the newest valve data along with the buckets I need to purchase.

I've set my target clearance on the loose side as you can see.

 

I am going to call the machine shop later today and see if he has any extra buckets that I could trade.

 

Im happy I didnt need new heads and Im happy I dont need to take apart the engine and buy new head gaskets...

 

I also picked up the 1 ton engine crane from harbor freight for $100, what a steal .

 

Hope I can make some smooth progress after i acquire the right buckets.

 

I canceled me Cobb Surgeline break in tune a few days ago since i wasnt sure how long all this head stuff was going to take. I will probably reschedule sometime in the following week or 2 now that I have the heads figured out. Surgeline usually have a 3-4 week wait so that still gives me time to get everything up and running.

[Shadow_419]

Awesome to hear

[birkhoff]

Did your heads ever have scoring in the journals? I would imagine people are driving on heads with wider clearances than mine just fine.

 

I talked to the machine shop today and he told me that if I wanted to source new castings he would transfer everything to the new heads for me. I split as to what I should do.

 

My cams needed a little clean up. I know the machine shop cut the caps and honed the line to fit. I checked the running clearances with plastigauge and the lash, but I didn't redo the lash after installing the belt. That's what I mean by 'didn't check'.

 

It is always good to call the machinist when odd things like this pop up. If they are any good, they take pride in their work and appreciate the back and forth. The response you got was . . . strange. Almost like, we don't know, but if you bring in new parts we fix you up good. Huh? The place I work with would KNOW there was a problem before the job went out the door. And they wouldn't have let it get that far. I would have been consulted.

 

You may want to shop for another shop if you do this again.

[Darth SpecB]

Good news is great news when it comes to not getting new head casings! I would have upgraded cams since you needed to change anyways. Hollow cams are good too.

 

Sent from my SAMSUNG-SM-G900A using Tapatalk

[lgt503]

I thought about upgraded cams but I cant recall coming across many other people upgrading theirs. I figure stock cams is the way to go. I don't care to change the valve duration or lift. I image upgraded cams are more important on high HP builds.

 

Today I measuring all the buckets with 2 sets of micrometers, to my surprise all the buckets shrank by ~0.002''. I went to Carr Subaru to purchase 13 new buckets and I talked to a mechanic about the changing thickness in these buckets. I think he was as surprised as I, that the buckets lost 0.002", guess thats what 110k does to these buckets.

 

I installed the buckets and measured valve clearance. I will post up some final measurements once the timing belt is installed.

 

I installed the bearing caps with RTV (The Right Stuff) on the heads but to my dismay the exhaust cams on both sides do not spin as freely as Id like. I really wish I didnt RTV the caps:spin: At least Im a pro at applying thin coats on the caps so little to no rtv leaks into the oil passages .

 

I can easily turn the intake cams by hand but I need to install the exhaust belt gear to easily turn the exhaust cams. If only the FSM defined an acceptable amount of resistance. I've rotated the exhaust cams multiple time and they aren't getting any better; there not getting worse ether. I followed FSM for torque and pattern so thats not the problem. the clearances were also plastigauge and fine. I think Im going to take one side off and see if the aluminum edges of the journals are dinged at all. If I can track down any ruff spots I will hit them with some wet 1200 sandpaper. I will look for any dirty streaks of oil when I spin the cam in the journals.

 

I should take bets on the next issue that will arise haha.

[Shadow_419]

Any chance it's just a case of having a thicker coating of assembly lube on the exhaust cams?

 

I'm still kind of taken aback by the machine shop not realizing that the cam clearance was off enough for you to have to buy new ones.

[rhino6303]

That is great news about your cams being the culprit. It sucks paying more money, but it's better than new head castings...and then new cams too.

 

What are you using for assembly lube on the cams?

[lgt503]

What are you using for assembly lube on the cams?

 

Ive been using Red Line Assembly lube. Its a lot thicker than motor oil which causes more resistance. The sticking cam might be exacerbate by the oil but there is some other underlying cause for the resistance.

 

Last night I got one of the exhaust cams fixed. 3 down one to go .

 

Brian at M&B Cylinder Heads was nice. Let me give you a breakdown of what was performed on my Subaru rebuilt Cylinder Heads.

 

Valve adjustment (.013-.015 exhaust, .007-.009 intake), checked valve springs, grind valve seats, resurface deck, pull galley plugs, polish cam journals polish camshafts, grind valves, and assembly.

 

If my heads worked at this point I would have been fine, but Ive since spent another ~1k which was necessary to have proper oil clearance and valve clearance. Never thought the heads would cost more than the SB. took me 5 minutes to measure the old cams with calipers to determine they are bad, and Im slow at all this haha. the heads look fine and the head journals torqued down still measure fine relative to the cams (pics coming soon)

 

I don't like shit talking hard working businesses. When all is said and done my experience will hopefully help others make a better decision on how to deal with heads with scoring from metal contamination. Sometimes businesses don't realize the power of the internet and customers ability to share there experiences. I hope this helps someone else save money in the future.

 

One thing this car has taught me is if you want something done right you have to do it yourself and pay lots of money. you will certainly run into unexpected issues on one of these builds, so be ready too pay up. It just so happens I got a nice sized unexpected "bonus" at work so sometimes these issues just work out haha. If only i didn't need new cams and buckets, I would have gotten that nice new GS TMIC, guess ill just keep dreaming about it

 

I may come off as inexperience which is true, Ive never done anything like this before. .Plus Im doing it by myself, thats not true, I also have this wonderful group of people, and the internet. I like hearing everyone personal opinions and experiences, Its like taking to a bipolar legacy gt mechanic that has 10 ways to unscrew a bolt

[lgt503]

One more thing, We all have bad experiences at dealership myself included but I have to say from my experience CARR subaru is a real class act. They took apart my car, have been accommodating to all my needs and are very personable. Also they price matched Heuberger for my costly recent purchases. No waiting required on most parts , they had lots of buckets and the cams in stock. I settled for one size less or more on 3 of the buckets, larger in the back smaller in the front .

 

There is a quote in the Parts Counter at CARR that says

 

“A customer is the most important visitor on our premises. He is not dependent on us. We are dependent on him. He is not an interruption of our work. He is the purpose of it. He is not an outsider of our business. He is part of it. We are not doing him a favour by serving him. He is doing us a favour by giving us the opportunity to do so.”

-Gandhi

 

The Parts Guys truly live up to these words. As do the other members of the Subaru family.

 

Royal Moore Subaru can still suck my Royal D

 

Disclaimer: I have no affiliation by any dealership, I just hate them as much as the next guy... most of the time

 

Smiley make the wallet hurt less:)

[birkhoff]

I installed the bearing caps with RTV (The Right Stuff) on the heads but to my dismay the exhaust cams on both sides do not spin as freely as Id like. I really wish I didnt RTV the caps:spin: At least Im a pro at applying thin coats on the caps so little to no rtv leaks into the oil passages .

 

I can easily turn the intake cams by hand but I need to install the exhaust belt gear to easily turn the exhaust cams. If only the FSM defined an acceptable amount of resistance. I've rotated the exhaust cams multiple time and they aren't getting any better; there not getting worse ether. I followed FSM for torque and pattern so thats not the problem. the clearances were also plastigauge and fine. I think Im going to take one side off and see if the aluminum edges of the journals are dinged at all. If I can track down any ruff spots I will hit them with some wet 1200 sandpaper. I will look for any dirty streaks of oil when I spin the cam in the journals.

 

I should take bets on the next issue that will arise haha.

 

This is a pretty common problem. The front cam 'caps' are sometimes called the basket. They cover four journals at once. Notice that the front part has alignment pins, but the rear part does not. If you just torque the whole thing down it is easy to get the rear out of alignment and that binds the cam. The other four caps are also pinned, so they are not likely to be a problem. You have to get it so you can rotate the cams by hand, without putting the gears on.

 

Check this: Back off the rear cap bolts on the basket and see if that solves the problem. If so, you need to GENTLY bump the rear as you torque it back down, checking for free movement as you go. If you sealed down the basket, you may have to pull it (again!) before the cams will move, clean it up, and experiment with the alignment until you figure how it should go.

[lgt503]

Got the cams all rotating:), Birkhoff summed up the issue perfectly. I was installing the cap and basket for the thousandth time and the intake cam became hard to rotate, previously it spun easily and the opposite occured with the exhaust. This made me realize it wasn't an issue with the journal but instead with the basket/ cap aligment. So happy everything is coming together.

 

I'm going to pick up a compression tester today because I had a scare with the timing belt install. I don't think anything happened but I want to make sure all the cylinder hold some compression. I figure this would be a good way to make sure the valve are all seating and nothing broke. I'm just going to manually spin the crank pully for this. I can hear the pressure coming out from around the loose spark plugs right now so I know there is some compression but I would feel better to see the individual cylinders hold some compression.

[birkhoff]

If you can't spin the engine more or less at starter speed, I'm not sure you'll learn much with a compression test. Valves would have to be bent pretty bad to see something out of the ordinary.

 

In this situation (on the stand) a leakdown test is the first choice. You would be able to tell if the valves are leaking past the seats at TDC, indicating a problem. Maybe see if you can borrow or rent a leakdown tester.

 

If you describe what happened maybe someone here can put your mind at ease. People fret about this quite a bit, but I don't recall hearing of anyone actually damaging something while setting up timing. I'm sure it can happen, but probably less often than you might think.