Did either of these machine shops actually do a vacuum test on the valves?

^^^This

bryanwheat said:

Did either of these machine shops actually do a vacuum test on the valves?

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Nope. That is what needs to happen next. Some sort of pressure test so they can see the leakage. Hopefully will get sorted out this week. I'll keep this thread updated.

Just got off the phone with the shop and they are going to try and figure out the issue. Just have to find time this week to take the head off...

Well just when I thought I had it kinda figured out, the car threw me another curve ball. Was tearing everything apart in preparation to remove the head and decided to leak it down before I loosen the head bolts. This was with both manifolds off, and nothing but the valves and springs in the head. Wouldn't you know it the numbers improved pretty remarkably.

Cyl #1; 100 psi in...94 psi out, leak from intake and exh. valves, slight CC

Cyl #2; 100 psi in...84 psi out, leak from in. and exh. valves. Rings are worst on this cylinder.

Cyl #3; 100psi in...90 psi out, Mainly intake valves, slight exh, slight CC

Cyl #4; 100psi in...94 psi out, Mainly intake valves, slight exh, slight CC

The worst cylinder in the previous test was leaking about 40%, now the worst cylinder is leaking 16%. With cylinders 1 and 4 pretty acceptable especially for a cold motor. 2 & 3 still have me guessing. But how and why did it get better from the last test? Since the last test all I did was try and run the car and she didn't seem to want any parts of it. With these numbers I would think the car would certainly run half decent but that wasn't the case. Unless having the car just sit for the past week somehow helped the valves seat a bit more, idk?

I really don't know what I should do from here. I do know the last thing I want to do is put it all back together AGAIN just to have it run like complete crap again. Then tear it all the way down for what seems like the 20th time in the last month.

It shouldn't' be leaking at all from the valves if this is a freshly rebuilt head. You should only be leaking at the rings. I would still pull it and have the valves and seats done properly.

bryanwheat said:

It shouldn't' be leaking at all from the valves if this is a freshly rebuilt head. You should only be leaking at the rings. I would still pull it and have the valves and seats done properly.

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I agree and that is what I'm going to do but is there ever a "perfect" seal? Like should I be able to spray brake clean in the ports and not be able to see or hear any bubbling going on? Or will there always be a bit of air making it through?

90_GSX_DSM said:

Yea, I mean obviously I'm sure it works for some people but I personally don't know anyone who doesn't spray their metal HG.

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Some of the higher-end MLS gaskets (the Fel-Pro PermaTorque MLS for example) are made with a coating applied at the factory. Applying copper spray to these gaskets can actually hurt their sealing ability, since there is no practical way to apply it as evenly as the factory coating is applied.

90_GSX_DSM said:

I agree and that is what I'm going to do but is there ever a "perfect" seal? Like should I be able to spray brake clean in the ports and not be able to see or hear any bubbling going on? Or will there always be a bit of air making it through?

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There will always be "some" leakage, but it should be so small as to be practically unnoticeable if everything is done properly.

*****

My bet is on the valve seats not being cut perpendicular to the guides, or the valve grinds not sealing against the seats.

BTW - Have you verified the valve stem and guide dimensions?

Calan said:

There will always be "some" leakage, but it should be so small as to be practically unnoticeable if everything is done properly.

*****

My bet is on the valve seats not being cut perpendicular to the guides, or the valve grinds not sealing against the seats.

BTW - Have you verified the valve stem and guide dimensions?

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The head is going back to the original shop on Thursday morning. It is confusing to me on how the numbers improved but they are still not where they should be with a fresh head.

I haven't verified any of that. The valves are standard sized Manley's with oem guides. The valves were from my previous head. The shop was informed of all of this and I feel if there was an issue that would make one part not compatible with another that is their job to figure out.

90_GSX_DSM said:

The head is going back to the original shop on Thursday morning ... <snip> ... I feel if there was an issue that would make one part not compatible with another that is their job to figure out.

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A proper vac test as bryanwheat mentioned will easily verify the leakage, and it will either be in the valve/guide/seat geometry, or some weird crack or something in the head (not likely based on your description). Given that, they should give you back a fixed and TESTED head a couple of days after you drop it off, unless there is something inherently wrong with the head not caused by the rebuild.

FWIW, the machinist that did my head had to replace and re-cut the seats twice before he nailed down the wobbly mandrel and indexing issues, but he finally got it right. He also swore to never work on a DSM head again right after that, but I digress.


****

I may have missed it, but did you or the shop check the valve springs, seats, shims, and retainers in relation to the valve stem height? In other words, are you sure the valves were fully seating? Did someone accidentally try to install some Honda springs or something?

Did they measure the seat pressure (always a good idea, especially if you are running big cams).

A fresh valve job should seal 100%. No leakage at all past the valves.

Our engines, before being started up will only have 4% leakage when cold and that's leaking past the ring gaps.

Take your cams out and perform the same test. I would bet that your valve install height is wrong for your cams. Not your spring install height. That may very well be wrong... but the valve install height.

Each time you have a valve job performed, if you didn't install a larger valve than you had, then you recessed the valves into the head. That brings the valve stems closer to the cam. Kelfords DO NOT LIKE THIS. They need to be set up with the factory valve install height. They generate higher lift than almost everything else out there for the 4g63. There isn't room for this kind of work when you use those cams. You can correct the valve install height simply by grinding the butt ends of the valves down on a valve grinder, but if you do this, check your spring pressure at your spring installed height to make sure they're not too loose. The recommended seat pressure for Kelford 272's is 98 lbs.

I bet you pull the cams, do the leak down, and they leak 0%. It's a little less work than pulling the whole head, but if you pull the head, suddenly this will get much harder to test. The condition you're describing can be caused by the valvetrain being pre-loaded. This condition would be horrible. The machine shop that told you to "run it like that and it should settle itself out" is correct, but not the way that you'd want them to be correct. It would settle itself out once you melted your exhaust valves. The problem would then be very apparent. They'd know then what they're looking at, and you would have a problem to correct that they can then help you with.

Something's wrong with the assembled geometry of your valvetrain. If 2 machine shops handled it lauding the other shop's work as being correct, but all of the valves leak, then it's all that it can be.

I learned the valve install height issue while researching the Kelford 272's for my own build. I have not yet assembled the engine, but the head is done with 1mm OS [which I didn't want to do because now I have to upgrade my turbo and shift at a higher RPM to meet the flow rate for the new holes] minus the cam installation. I should have gone with .5mm OS because I could have accomplished the same thing.

-Jafro

Jafro said:

Take your cams out and perform the same test.
-Jafro

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From the quote below it looks like he did that.

90_GSX_DSM said:

Well just when I thought I had it kinda figured out, the car threw me another curve ball. Was tearing everything apart in preparation to remove the head and decided to leak it down before I loosen the head bolts. This was with both manifolds off, and nothing but the valves and springs in the head. Wouldn't you know it the numbers improved pretty remarkably.

Cyl #1; 100 psi in...94 psi out, leak from intake and exh. valves, slight CC

Cyl #2; 100 psi in...84 psi out, leak from in. and exh. valves. Rings are worst on this cylinder.

Cyl #3; 100psi in...90 psi out, Mainly intake valves, slight exh, slight CC

Cyl #4; 100psi in...94 psi out, Mainly intake valves, slight exh, slight CC

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91-GS said:

Was going to say that valves might be bent (from a previous timing belt mishap, or something similar) but it sounds like valves are new, so that theory is out of the question.

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On the theory that's out of the question, can you explain to me how replacing the same sized valves and cutting new valve seats brings them back up to the correct install height?

Edit: Oops, wrong guy.

edged1g: I read this whole thread and missed that one sentence. Having never seen the car, and only referencing the use of Kelford 272's, I stand by my diagnosis. I may not be spot-on for the exact cause, but in my head I feel I'm in the 97% range. 3% chance the lifters aren't bleeding down.

Have all of the lifters been purged?

That's not good man hope you figure it out, did you trust the shop, to go through it, I always talk to my shop and we stay in touch about everything in detail. I hate doing things twice.

I dropped the head off this morning. Told them that the head needed to be pressure tested to reveal the leak so they can correctly diagnose the problem. Unfortunately it's sort of a third party deal, the shop I dropped the head off at isn't the actual machine shop. They have their preferred machine shop they deal with which did my work. I asked if there would be a rush on this and he said he's going to get the head to him right away and hope to have a resolution by the end of the week so we will see. Now I wait...

Calan said:

I may have missed it, but did you or the shop check the valve springs, seats, shims, and retainers in relation to the valve stem height? In other words, are you sure the valves were fully seating? Did someone accidentally try to install some Honda springs or something?

Did they measure the seat pressure (always a good idea, especially if you are running big cams).

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I would love to think they checked all that but with the results of the head I can't be sure. I don't normally feel the need to ask all of those questions when I pick up a head because I assume it's all just been done correctly. I'm not sure the valves were fully seating, I actually believe this is the issue, valve heights. But I'm getting sick of speculating. The head is hopefully where it needs to be to have a resolution...

Oh and I definitely noticed my Kiggly beehives weren't replaced with any Honda springs

JacksonAuto said:

A fresh valve job should seal 100%. No leakage at all past the valves.

Our engines, before being started up will only have 4% leakage when cold and that's leaking past the ring gaps.

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That's what I always thought with a fresh head job. Which is why I was so shocked when they tried telling me it could be valve grinding compound or dirt. Sounded so far fetched and I feel dumb for now thinking that was plausible.

Now for whatever reason the numbers definitely got better before I yanked the head this past time but the valves were for sure not sealing 100%. I could still physically feel air making it past the valve seats in some runners, not all and not as bad as it was before, but not where it needs to be.

Jafro said:

On the theory that's out of the question, can you explain to me how replacing the same sized valves and cutting new valve seats brings them back up to the correct install height?

Edit: Oops, wrong guy.

edged1g: I read this whole thread and missed that one sentence. Having never seen the car, and only referencing the use of Kelford 272's, I stand by my diagnosis. I may not be spot-on for the exact cause, but in my head I feel I'm in the 97% range. 3% chance the lifters aren't bleeding down.

Have all of the lifters been purged?

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With the exception of the very last leak down test the numbers didn't vary at all with the cams in or out. So I don't think it would be any different now if I leaked it down with the cams in. But I do know the first thing I'm doing when I get the head back, leak down without cams, and then with cams.

The lifters are in the same spot they have always been since my last head. I definitely would have bled them all if there was a difference in the leak down with cams in or out but there wasn't so I feel no need to bleed them down.

iugrad92turbo said:

That's not good man hope you figure it out, did you trust the shop, to go through it, I always talk to my shop and we stay in touch about everything in detail. I hate doing things twice.

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Yea I've never really had any issues in the past with communication or quality of work in the past with this shop and I've been dealing with them for this car since 08'. But when it comes to this head the communication has broken down and I feel like I've been getting the run around from them when it comes to finding the problem with this head.

I'm still not going to say the name of the shop because I still have hope they are going to make this right. However this is my last ditch effort with them. I feel that I'm extremely patient and most others in my shoes would have hung them out to dry by now...

90_GSX_DSM said:

I feel that I'm extremely patient and most others in my shoes would have hung them out to dry by now...

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I'd have to agree. If you've been as calm and mature with them in person as you seem to be here, then they should be so lucky to have more customers like you. Hats off to for your patience with them.

Well didn't hear from them like I thought I would today. I'm speechless...

90_GSX_DSM said:

Well didn't hear from them like I thought I would today. I'm speechless...

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That sucks.

Well it sounds like my luck finally took a turn for the better. Although I didn't get a call when I thought I would I finally took it upon myself to call them today and they had just gotten the head from the machine shop. They ended up recutting the valve seats and relapping in the valves. Then pressure tested it up to 100psi with all the valves sealing 100% besides one intake valve that had a slight bubble.

They are not charging me anything as they certainly shouldn't be. Overall I'm just so freaking relieved the problem finally got resolved. Definitely took longer than it should have and this should have been pressure tested the first time I brought it back. I won't be 100% relieved until I fire the car and hear it purr like it did last year, but I'm fairly confident it will.

I just received my catch can from Calan and it looks amazing, this might just be my good luck charm . Going to pick up the head one of these next mornings this week and hopefully get the car fired up on Saturday. I'll update this thread this weekend with the results.

Thanks for all the responses!

Finally got around to getting the motor all back together yesterday. Went to fire it up and wasn't really getting anything. But I could smell fuel and lots of it. So I hooked up the laptop to try and see what the car was doing. My map sensor was reading 38 psi all the time, thus dumping ridiculous amounts of fuel. Disconnected the map and programmed the ecu to run a stock maf and she fired right up.

90_GSX_DSM said:

Finally got around to getting the motor all back together yesterday. Went to fire it up and wasn't really getting anything. But I could smell fuel and lots of it. So I hooked up the laptop to try and see what the car was doing. My map sensor was reading 38 psi all the time, thus dumping ridiculous amounts of fuel. Disconnected the map and programmed the ecu to run a stock maf and she fired right up.

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That's good to hear. I hope you

90_GSX_DSM said:

Finally got around to getting the motor all back together yesterday. Went to fire it up and wasn't really getting anything. But I could smell fuel and lots of it. So I hooked up the laptop to try and see what the car was doing. My map sensor was reading 38 psi all the time, thus dumping ridiculous amounts of fuel. Disconnected the map and programmed the ecu to run a stock maf and she fired right up.

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Good to hear. Don't overlook the fact that you were originally having hg sealing issues just cause copper spray helped seal it up. I would look into it before I started running the car hard. Also you never mentioned degreeing the cams. Just another thing that wouldn't be a bad idea given the circumstances.