Building a 3.0L Turbo motor.
01-13-2015, 07:52 PM
#76
Burning Brakes
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This is sort of a hot topic for me and I'm looking for experience. Tom, your blog didn't mention o-ringing the block, but other sources recommend that technique for blown engine designs and I've got it on my list of things to do with my block, along with nikasil bores.
It's good to know these HGs may accept a copper ring integrated into the gasket, which leaves me wondering if the machining is superior to a ringed gasket? Sounds as if you (Duke) may have an opinion based on experience with both solutions?
It's good to know these HGs may accept a copper ring integrated into the gasket, which leaves me wondering if the machining is superior to a ringed gasket? Sounds as if you (Duke) may have an opinion based on experience with both solutions?
Last edited by Pfc. Parts; 01-13-2015 at 07:53 PM. Reason: spelling. I wrote the message in my shop with a plastic cover on my keboard.
01-14-2015, 04:16 PM
#77
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This is sort of a hot topic for me and I'm looking for experience. Tom, your blog didn't mention o-ringing the block, but other sources recommend that technique for blown engine designs and I've got it on my list of things to do with my block, along with nikasil bores.
It's good to know these HGs may accept a copper ring integrated into the gasket, which leaves me wondering if the machining is superior to a ringed gasket? Sounds as if you (Duke) may have an opinion based on experience with both solutions?
It's good to know these HGs may accept a copper ring integrated into the gasket, which leaves me wondering if the machining is superior to a ringed gasket? Sounds as if you (Duke) may have an opinion based on experience with both solutions?
I neglected to respond to your questions about the 928 throttle body. Beware it's not a direct fit. You need to trim part of the casting off the top to prevent dinging the hood; the bolt pattern is different than the stock 951 manifold; you need fab up a linkage that works; and only one specific TB works. Will see if I posted a thread about it. I suspect there are simpler options out there these days.
01-14-2015, 04:31 PM
#78
Rennlist Member
Thanks Raj (and Tom). I hadn't paid enough attention to these cars. Always thought it was essentially the 3L block with the 2.7L head and this gave enough tq/hp for the purpose. Interesting that they reduced the port size? Absolutely must have been governed by a power to weight ratio class restriction and didn't want to embarrass the rear engine king of the day either I guess.
01-14-2015, 04:59 PM
#79
Burning Brakes
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Yes, my block is o-ringed for use with the widefire gasket. The "wide" part of the widefire is to the block, and the ring bites into the fire-ring. It's a good seal, though I can't say from experience whether it holds better of worse than an MLS or other fancy new head gaskets. It's not as sensitive to surface RA as some of the other gaskets, so maybe a little easier to use.
I neglected to respond to your questions about the 928 throttle body. Beware it's not a direct fit. You need to trim part of the casting off the top to prevent dinging the hood; the bolt pattern is different than the stock 951 manifold; you need fab up a linkage that works; and only one specific TB works. Will see if I posted a thread about it. I suspect there are simpler options out there these days.
I neglected to respond to your questions about the 928 throttle body. Beware it's not a direct fit. You need to trim part of the casting off the top to prevent dinging the hood; the bolt pattern is different than the stock 951 manifold; you need fab up a linkage that works; and only one specific TB works. Will see if I posted a thread about it. I suspect there are simpler options out there these days.
On the 928 throttle, my ears perked up because I thought it might have allowed you to use a 928 MAF (which I also have one of)? if you have clearance problems with the throttle though I guess that might not be possible?
01-14-2015, 05:52 PM
#80
Race Car
This sealing ring gaskets sounds like a great idea but aluminum has a very high (compared to other metals) thermal expansion rate.
At a 4" bore (roughly 100mm) and a range of operating temperature of 70F-300F the cylinder would expand .02 inch (.5mm).
104mm bore would obviously be greater since expansion would be proportional to size/length, etc..
Unless the upper cylinder, which is surrounded evenly with coolant, matches the combustion side (cylinder head) in temperature, there would be a discrepancy in expansion....and with this type gasket, described as "embedded", this could be a problem.
T
At a 4" bore (roughly 100mm) and a range of operating temperature of 70F-300F the cylinder would expand .02 inch (.5mm).
104mm bore would obviously be greater since expansion would be proportional to size/length, etc..
Unless the upper cylinder, which is surrounded evenly with coolant, matches the combustion side (cylinder head) in temperature, there would be a discrepancy in expansion....and with this type gasket, described as "embedded", this could be a problem.
T
01-14-2015, 06:03 PM
#81
Burning Brakes
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Certainly though, this would be an equal problem with all gaskets? Unless the head is also water cooled, it will always tend to run hotter than the block? There may be factors that mitigate this, such as a smaller exposed surface area in the head, but all things being equal, any gasket will tend to isolate the head from thermal migration to some degree (no pun intended). How would an MLS or other gasket design differ significantly from any other gasket in this respect?
01-14-2015, 10:59 PM
#82
Race Car
The blocks that later had siamesed cylinders adressed the movement (paraphrasing but an ex-factory engineer/tech once described them as "dancing cylinders" or something similar) of the cylinders in relation to the cylinder head but we are talking about thermal expansion that would be common to both engines.
Also, this type of gasket being discussed would "marry" the two parts in relation to each other, a characteristic not shared by other gaskets unless you count the mechanical o'ringing.....there is probably enough imprecision in this method, especially given that the ring is a much more dense material, meaning that the aluminum groove would expand much more than the ring creating it's own clearance between the ring and the groove as the engine heats.
This would all be moot if it's to be beleived that there is neglible differential between the combustion chamber area and the upper cylinder, but that's doubtful.
The head is water cooled but still, that's the assumtion I'm making.
Isolation would make the problem even worse. Any heat differential that could be equalized by mating the two parts by say, an all copper gasket that would transfer as opposed to isolate would seem beneficial...., at least at keeping expansion synchronized....assuming the cylinder head reaches a higher temperature.
We are talking about a gasket that is dependant on an embedded mechanical seal with zero movement between the two parts.
I don't think the sharp ring portion of the gasket could be made of a material like aluminum, which would keep all parts at the same expansion rate.
It would have to be a material dense enough to impress the seal into aluminum.
I think the term Inox is synonymous with stainless steel....?
I just caught this thread in passing and found it interesting and the theory seemed strange....maybe it's totally fine...
T
Also, this type of gasket being discussed would "marry" the two parts in relation to each other, a characteristic not shared by other gaskets unless you count the mechanical o'ringing.....there is probably enough imprecision in this method, especially given that the ring is a much more dense material, meaning that the aluminum groove would expand much more than the ring creating it's own clearance between the ring and the groove as the engine heats.
This would all be moot if it's to be beleived that there is neglible differential between the combustion chamber area and the upper cylinder, but that's doubtful.
There may be factors that mitigate this, such as a smaller exposed surface area in the head, but all things being equal, any gasket will tend to isolate the head from thermal migration to some degree (no pun intended). How would an MLS or other gasket design differ significantly from any other gasket in this respect?
We are talking about a gasket that is dependant on an embedded mechanical seal with zero movement between the two parts.
I don't think the sharp ring portion of the gasket could be made of a material like aluminum, which would keep all parts at the same expansion rate.
It would have to be a material dense enough to impress the seal into aluminum.
I think the term Inox is synonymous with stainless steel....?
I just caught this thread in passing and found it interesting and the theory seemed strange....maybe it's totally fine...
T
01-15-2015, 04:38 AM
#83
Nordschleife Master
The blocks that later had siamesed cylinders adressed the movement (paraphrasing but an ex-factory engineer/tech once described them as "dancing cylinders" or something similar) of the cylinders in relation to the cylinder head but we are talking about thermal expansion that would be common to both engines.
Also, this type of gasket being discussed would "marry" the two parts in relation to each other, a characteristic not shared by other gaskets unless you count the mechanical o'ringing.....there is probably enough imprecision in this method, especially given that the ring is a much more dense material, meaning that the aluminum groove would expand much more than the ring creating it's own clearance between the ring and the groove as the engine heats.
This would all be moot if it's to be beleived that there is neglible differential between the combustion chamber area and the upper cylinder, but that's doubtful.
The head is water cooled but still, that's the assumtion I'm making.
Isolation would make the problem even worse. Any heat differential that could be equalized by mating the two parts by say, an all copper gasket that would transfer as opposed to isolate would seem beneficial...., at least at keeping expansion synchronized....assuming the cylinder head reaches a higher temperature.
We are talking about a gasket that is dependant on an embedded mechanical seal with zero movement between the two parts.
I don't think the sharp ring portion of the gasket could be made of a material like aluminum, which would keep all parts at the same expansion rate.
It would have to be a material dense enough to impress the seal into aluminum.
I think the term Inox is synonymous with stainless steel....?
I just caught this thread in passing and found it interesting and the theory seemed strange....maybe it's totally fine...
T
Also, this type of gasket being discussed would "marry" the two parts in relation to each other, a characteristic not shared by other gaskets unless you count the mechanical o'ringing.....there is probably enough imprecision in this method, especially given that the ring is a much more dense material, meaning that the aluminum groove would expand much more than the ring creating it's own clearance between the ring and the groove as the engine heats.
This would all be moot if it's to be beleived that there is neglible differential between the combustion chamber area and the upper cylinder, but that's doubtful.
The head is water cooled but still, that's the assumtion I'm making.
Isolation would make the problem even worse. Any heat differential that could be equalized by mating the two parts by say, an all copper gasket that would transfer as opposed to isolate would seem beneficial...., at least at keeping expansion synchronized....assuming the cylinder head reaches a higher temperature.
We are talking about a gasket that is dependant on an embedded mechanical seal with zero movement between the two parts.
I don't think the sharp ring portion of the gasket could be made of a material like aluminum, which would keep all parts at the same expansion rate.
It would have to be a material dense enough to impress the seal into aluminum.
I think the term Inox is synonymous with stainless steel....?
I just caught this thread in passing and found it interesting and the theory seemed strange....maybe it's totally fine...
T
The cooper ring gaskets (it's a stupid name that is too easily confused with copper gaskets) are not new and they are used in most of the high hp turbo engines in professional racing (mostly rally and rally cross with small displacement high boost situations). So they are proven and commonly viewed as the "solution" to be able to run 2-3 bar of boost on the smaller engines without sealing issues.
Really excited to try these gaskets out!!
01-15-2015, 08:00 AM
#84
Race Car
Hey Duke...., been a while.
Don't come around these parts much anymore...., mostly hang around the racing forums and I stay pretty scarce even there these days.
Just a couple of points then I'll bow out of this one and defer to your "boostology"...., I'm mainly doing the N/A stuff. The only turbo car I have has been shelved for 5 years. You have made a lot of progress with your car in that time, looks great...!
In theory, the stock type gasket would allow for minute longitudinal movement.
In layman's terms, the difference would be like having two pieces of wood with 100 lbs (clamping force) rested on top. The two pieces of wood would generally remain in position but still move in relation to each other given enough force was applied.
If you replicate the example again but nail, screw, bond, whatever, the pieces together, there is no allowable movement...., and in the event that force overcame that bond again and again, it would be compromised and never as strong as it were when first applied.,
Understood. I meant to use copper in the preceding post, no confusion with the name. Many engines use solid copper head gaskets. Perkins diesel (read high compression) as an example.
In small 1/4 mile drag race Asian import engines, they also weld the cylinder head to the block in really high boost engines as a "solution". The engines aren't long-lived enough to worry about ever servicing them.
Likewise, "professional" race teams would tend to disassemble and inspect an engine way more frequently than a person here who built a high performance street car.
Again, I defer to your experience here though. I'm sure these will work out fine for you.
Thanks for taking the time to reply,
T
Don't come around these parts much anymore...., mostly hang around the racing forums and I stay pretty scarce even there these days.
Just a couple of points then I'll bow out of this one and defer to your "boostology"...., I'm mainly doing the N/A stuff. The only turbo car I have has been shelved for 5 years. You have made a lot of progress with your car in that time, looks great...!
I understand the concern in theory but it is not an issue in reality. If the longitudinal heat expansion of the head would be significantly greater than the sealing ring it should destroy every type of cylinder sealing ring. Including the embedded sealing rings of the factory type gasket. And cause a number of other issues.
In layman's terms, the difference would be like having two pieces of wood with 100 lbs (clamping force) rested on top. The two pieces of wood would generally remain in position but still move in relation to each other given enough force was applied.
If you replicate the example again but nail, screw, bond, whatever, the pieces together, there is no allowable movement...., and in the event that force overcame that bond again and again, it would be compromised and never as strong as it were when first applied.,
The cooper ring gaskets (it's a stupid name that is too easily confused with copper gaskets) are not new and they are used in most of the high hp turbo engines in professional racing (mostly rally and rally cross with small displacement high boost situations). So they are proven and commonly viewed as the "solution" to be able to run 2-3 bar of boost on the smaller engines without sealing issues.
Really excited to try these gaskets out!!
Really excited to try these gaskets out!!
In small 1/4 mile drag race Asian import engines, they also weld the cylinder head to the block in really high boost engines as a "solution". The engines aren't long-lived enough to worry about ever servicing them.
Likewise, "professional" race teams would tend to disassemble and inspect an engine way more frequently than a person here who built a high performance street car.
Again, I defer to your experience here though. I'm sure these will work out fine for you.
Thanks for taking the time to reply,
T
Last edited by 951and944S; 01-15-2015 at 08:52 AM.
01-15-2015, 11:25 AM
#85
Burning Brakes
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The blocks that later had siamesed cylinders adressed the movement (paraphrasing but an ex-factory engineer/tech once described them as "dancing cylinders" or something similar) of the cylinders in relation to the cylinder head but we are talking about thermal expansion that would be common to both engines.
My question concerned the difference between a MLS (or perhaps "cooper") gasket and any other gasket with respect to heat transfer across the gasket between the block and the head, and how that might effect differential thermal stability of the parts. My intuition tells me a barrier to conduction is just that, and that any two barriers of roughly the same composition will result in the same behavior.
Also, this type of gasket being discussed would "marry" the two parts in relation to each other, a characteristic not shared by other gaskets unless you count the mechanical o'ringing.....there is probably enough imprecision in this method, especially given that the ring is a much more dense material, meaning that the aluminum groove would expand much more than the ring creating it's own clearance between the ring and the groove as the engine heats.
This goes back to my question concerning the different heat transfer characteristics of different gasket designs; do they exist in any significant way? How do we know this?I'm not sure why aluminum isn't used in o-ringing blocks or in gaskets, but I don't think "hardness" or density in general is the concern. My guess is aluminum lacks the tensile strength to maintain a pressure barrier given the necessarily small dimensions the ring must have; a value limited by cylinder wall thickness. In my experience aluminum is just about as ductile as annealed copper and much more ductile than stainless (or INOX) steel, so I don't see that being the issue?
The head is water cooled but still, that's the assumtion I'm making.
Isolation would make the problem even worse. Any heat differential that could be equalized by mating the two parts by say, an all copper gasket that would transfer as opposed to isolate would seem beneficial...., at least at keeping expansion synchronized....assuming the cylinder head reaches a higher temperature.
01-23-2015, 07:02 AM
#88
Rennlist Member
Good for you. Keep us updated.
01-23-2015, 07:32 AM
#89
Burning Brakes
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Will do Patrick.
I expect I'll start a new thread for the build as soon as I can get my camera working. Step 1 isn't going to be too exciting; new clutch and motor/transmission mounts, a complete refresh of the engine to get it in top shape, some track time to understand the car, then the real work begins.
I'm debating (with myself) about buying another 3L block for the project to keep the car on the road while I build the engine, but I already have the 928 to keep me on the street. Haven't made up my mind yet.
I expect I'll start a new thread for the build as soon as I can get my camera working. Step 1 isn't going to be too exciting; new clutch and motor/transmission mounts, a complete refresh of the engine to get it in top shape, some track time to understand the car, then the real work begins.
I'm debating (with myself) about buying another 3L block for the project to keep the car on the road while I build the engine, but I already have the 928 to keep me on the street. Haven't made up my mind yet.
Last edited by Pfc. Parts; 01-23-2015 at 09:47 AM.
