Hi, hate to start a new thread but I really need someone to either set me straight or tell me it's all going to be fine

I was in the middle of writing up an engine build update for my build log when I realised I never measured my PTW clearance. For context, we are talking about a 6 bolt block, stock everything. Machine shop said the bores are all within +0.05mm (0.002 inch) of factory and the pistons going in them are Manley Platinum Series with standard everything - pins, bore, stroke, CR. I have aboslutely 0 shops around me to build an engine to the spec that this forum is used to and I'm always happy to learn so I am doing it myself. I am being careful to measure and keep note of everything. Well at least I thought I was. I just remembered that I never actually measured the pistons or the bores. I was so busy with the 1 gram of difference the pistons came with, I went straight to balancing and then to assembling. Which is absolutely irresponsible of me, since I spent about 3 hours filing the ring gaps - one would think I would have remembered the pistons they will live in. The short block is complete now and everything else that can be measured is within spec.

What do I do now? Do I take it apart again? Do I trust the machine shop AND Manley that the clearance is there?

What is stopping you from yanking the pistons to measure? Why can’t you verify the bores as is? It sounds like you want a reason to avoid an evenings worth of work.

You know what, you're probably right. Honestly, I think I'm just afraid of what I'm going to do if it turns out to be wrong. I somehow feel like I wanted to build this engine so bad that I kind of rushed it. Which isn't like me at all. I'm going to do it right. Thanks.

One more thing, and now I'm really embarrased I put the pistons in before addressing this, what do you make of these imperfections in cylinder 2?

I'm talking about the brown horizontal marks - they passed the fingernal test, but they did feel like they weren't level with the rest of the bore.

What’s the history of that block? Who honed it, and with what hone?

Block was originaly in a galant, then it was swapped into an eclipse, got a 14b turbo and ran for at least a couple years. When I got it, it had a blown head gasket and bad compression. After we dropped some oil into the cylinders, it held pressure, so we figured it was the rings. This is the first time it's ever been apart. I had it inspected and honed by a machine shop in november, they said the cylinders were all within 0.05 mm of factory. Don't know what hone was used, didn't know to ask. I think they either ignored these marks or they appeared sometime in december while the block was sitting.

Those marks look like corrosion. Either from sitting with water in the cylinders or cracks in the cylinder wall. I highly doubt a stock bore block cracked with a 14b, it’s probably going to need to go .010”-.020”over to clean up.

Did they mention anything about taper or out of round?

donniekak said:

Those marks look like corrosion. Either from sitting with water in the cylinders or cracks in the cylinder wall. I highly doubt a stock bore block cracked with a 14b, it’s probably going to need to go .010”-.020”over to clean up.

Did they mention anything about taper or out of round?

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They didn't, but I don't really think they are a very good shop for performance... more like the only shop around.

So basically I'm going to be out 700€ when the pistons don't fit anymore huh?

I would never buy stock bore pistons for a block I haven’t first honed and measured myself, or by a shop I trust.

It may be surface rust that will clean up with another .001” or so taken out. Those pistons will work ok out to about .0055” clearance for a street car.

It needs to be honed with a pressure head, not a spring arm, or bottle brush hone.

I waited until I had the block back from the shop before pullling the trigger on the pistons. I had the numbers and I asked them if it's good for stock pistons.

Had I known half of what I know now, I would have double checked everything but I was just way to eager to build it.

Thanks for the input, I will try to fix this.

I figured I would just continue this thread so I'm not starting new ones again - I had the block inspected thoroughly and (other than those marks in the pictures) we are in spec for the manley pistons. The shop said only one of the vertical marks could techincaly be a concern, but it's not cause enough to machine again as we would be out of spec by then. Since it is close to the bottom of the stroke, they advised me to run it. I would prefer cleaner bores but I simply don't have the facilities to source a block that is 100% confirmed to be healthier than this one so I guess that's the short block sorted for now. I will update my profile with the compression numbers and final analysis when I'm done.

Onto the new problem - the cylinder head. I was 99% sure it was good to go as it only ran for about 500km since the head gasket job, where it was resurfaced, had the valves and seats machined and the seals replaced. I tested it anyways - came to find that every single valve was leaking. None of them are bent, so I am assuming the shop got the angles wrong or cut them off-center somehow as the contact patches weren't even all the way around each of the valves. When this was being done I didn't know jack sh*t about engines so I didn't even know to check it. I guess no one else did either.

To try and fix it now, I lapped the valves 3 times - twice with a piece of hose and a drill from the top and once with suction cups from the bottom but they still let light through when installed. My dad then showed me some 'old school' method of using really agressive paste and putting A LOT of pressure on each valve when lapping.

I pleaded that this was way to agressive to be considered "lapping" but it did stop light from coming through the valves when they were done.

I don't know what this means for the geometry and specs of the valves though, because the factory manual states the seat widths should be no more than 0.05 inches, where mine are well over 0.078... I don't know if that number is refering to just the actual contact patch or the entire seat. If it is for the entire seat, we are way out of spec.



Some valves also ended up sinking about 0.5mm further into their ports than factory spec. Some even sit higher than others. My mechanic and my dad both tell me that since the lifters are hydraulic the valves will seat just fine, but I'm having a hard time coping with this since everything seems to be off a bit.

Not to mention - when I blow air into them some still let out very tiny bubbles (light does not shine through though). Dad says I just didn't lap those well enough but I literally have burns on my index finger from keeping so much pressure on them while spinning them with a drill.

I don't know about the numbers but I'm pretty sure they should *at least* all protrude into the combustion chamber the same amount. What's you guys' take? I already feel like I copped out a bit with the block, I don't want to worry about the head as well.

Lifter style doesn't matter on seating. Seating is purely a geometry thing.
I had an issue like this with the head I currently use being done by a shop who didn't know they had a bent pilot when they were cutting the seats. Only when I put all the valves in and did a leak test did I see the problem clearly. They sourced a new pilot after they checked their hardware when I told them of the problem and they redid the seats. After a lapping, they were to my satisfaction.

I was never a fan of the drill method myself but I guess it could work. I prefer the old style tool; it allows you to control the speed better and frequently pull the valve up/tapping to bring 'fresh' lapping compound into the seat faces.

I agree on the seating, I only mention lifter style because the lenght I added to the stems has to go somewhere and my concern was that the cams would put enough pressure on them to open the valves by 0.5 mm even when they were supposed to be closed. I feel like hydraulic lifters can only do so much for adjusting clearance, I don't know if they can correct for 0.5 mm of extra valve stem lenght.

I honestly dislike all of the "lapping" methods I mentioned - in every single article I read about lapping, there was talk of little pressure and only a couple minutes of work on each valve. I used a lot of pressure and did multiple passes so I don't doubt I heavily affected the already messed up geometry.

How do you feel about the extra 0.5 mm of installed spring lenght? Do you think it warrants new valves and seats or is it something a machine shop could salvage? I imagine removing even more material would only push things further out of spec...

I don't know exactly what you mean by "length I added to the stems" but I assume you mean by how much of the seat was potentially ground off. I don't even know if that's possible with paste, but I suppose it depends on which was used.

Unless your valves are almost socketed into the head itself and you've succeeded in grinding right through the seat, the lash adjusters should adjust down enough (that is, stop upward adjustment sooner) to offset a fraction of a mm. They'll pump up until a point where the resistance to pump up any higher (caused by the cams pressing down on the rocker which presses on the valve tip which is kept up by the valve spring pressure) exceeds that of the oil pressure trying to pump. It's unlikely your adjusters will try to apply more pressure against the rocker than your spring installed pressure. Just make sure they're well bled before install. At the outset, you could measure valve installed height to see what kind of variances you're dealing with and compare against OE specs. If it's far off, you'll need new seats and hope not new valves. If it's just a bit, eh, hard to say whether you want to just send it.

But I'm not certain of the likelihood of grinding the valve very deep into the seat. There will come a point where all high spots will be gone and you'll have full contact and then it will take even longer to remove material in any significant form. Depending on whether the seat is perfectly perpendicular to the guide, you could very well end up with oblong seats if it's not. This would eventually go away to some degree if you went at it for a long time, and then you'd end up an almost true seating, BUT, you'd definitely see it was off angle and you'd like end up with a valve edge that's thicker on one side than the other. Not good.

You don't need to apply much pressure when lapping valves, it's not going to do much more than increase heat. Let the compound do it's work into a fine paste and depending on how much was ground, add more or tap the valve against the seat which brings up the paste, as I mentioned earlier.

Is the seat face rough? Those concentric circles look like deep scratches.

curt-s said:

I don't know exactly what you mean by "length I added to the stems" but I assume you mean by how much of the seat was potentially ground off. I don't even know if that's possible with paste, but I suppose it depends on which was used.

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Yeah, that's exactly what I'm talking about. I'm afraid it is possible, because the paste I used on this final pass was VERY rough and very old. I also used enough pressure to literally burn my fingertips, just by spinning the valve.

curt-s said:

Unless your valves are almost socketed into the head itself and you've succeeded in grinding right through the seat, the lash adjusters should adjust down enough (that is, stop upward adjustment sooner) to offset a fraction of a mm.

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No valve is "socketed" into the head per se, but some are almost flush with the roof of the combustion chambers where others still protrude about a half mm. This is another concern - even if they are fine in every other aspect, they are not even - some valves sit flush, some don't. I don't know if that's common or something I produced with this horrible lapping job.

curt-s said:

At the outset, you could measure valve installed height to see what kind of variances you're dealing with and compare against OE specs. If it's far off, you'll need new seats and hope not new valves. If it's just a bit, eh, hard to say whether you want to just send it.

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I did measure the heights, that's where I'm getting the 0.5 mm value. Valve installed heigh should be 39.87 mm (basically 4 cm) as per the Haynes service manual, but mine range from 4.02 to 4.05 cm

curt-s said:

Is the seat face rough? Those concentric circles look like deep scratches.

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Yeah, they are pretty rough. I switched back to the fine paste I was using before the old, agressive one to try and correct this but It did seemingly nothing. I will take the head to a shop on monday to see what they think and if I get the go ahead, I will hit them with the fine paste again to hopefully get the scratches out. I don't have much hope though, I fear new seats and valves might be the move.

If your lapping so much your worried about material removal your doing it wrong and are gonna cause problems later. Lapping should really only need used to check how the valves are sealing. One valve sunk into the head .5mm more than others is an issue.

Dihtung Glava said:

My dad then showed me some 'old school' method of using really agressive paste and putting A LOT of pressure on each valve when lapping.

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Sorry but this is a terrible mistake... You don't want to put pressure to do valve lapping. Technically what you did is not lapping. It is grinding.

Dihtung Glava said:

I don't know if that's common or something I produced with this horrible lapping job.

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It seems that you took off all material for margin from the valves and seats. You may possibly need to replace them, otherwise the valves may be floating due to low seat pressure, or may damage/burn valves. You should ask a machine shop to inspect.

If you would do it yourself again, do it by hands by tapping the valve, not only spinning. And pay attention to the tapping sound and tapping feeling. You would hear and feel it different when the valve starts seating well.

I just got off the phone with a new machine shop with no good news.

I provided the same shop that did my block with the head, brand new seats, valves and guides for them to hopefuly fix my recessed valve seat issue. I also gave them all the head specs I have out of the Haynes manual. They called me back today saying that the old guides are fine and the new valves are too. They don't have the tools to cut new seats and install them but they did try cutting the old seats a bit and said they cut really well, so they wanted to see if they could be salvaged.

A couple days later, the result looks good, but the measurements are pretty bad. They were able to get the seat widths down to spec (0.9 - 1.3 mm) but that took a lot of material so the valves seat pretty far into their ports now.
Some installed valve springs heights measure even longer than 41mm now (spec is 39.9mm).

They contacted another machine shop that specialises in head work about possibly cutting and installing the new seats, but that shop said they stopped doing "race-car" level work and now focus mainly on regular traffic cars. The veteran there said he would love it as a project for himself but he just doesn't have the time to give it his best effort, which I can respect.

So now my options are either:

- Going to a third machine shop, out of the country, that still does "race-car" level work that would probably get pretty expensive or

- Having the current machine shop finish all of the seats and be left with spring heights that are out of spec - but more importantly - recessed valves giving wrong compression numbers, and just running that.

What do you guys think? Have you ever had something like this happen? Is there another fix? Thanks.