The length of the runners has *MUCH* more impact on that phenomenon.
Yes, flexibility drastically increases with runner length. But since Eric showed us a picture of pieces of metal already starting to look like a short-runner log manifold, it looked like that aspect of the design was already "frozen", so I didn't mention it.
The desire for flexibility is what led me towards the sledgehammer approach whereby I installed bellows between the ports of my stock 2.8 log manifolds.
[This message has been edited by pmbrunelle (edited 10-28-2019).]
Originally posted by pmbrunelle: Another possible advantage of the metal connecting strip occurred to me.
As the log manifold heats up (I'm really talking about the tapered slit tube), it will grow lengthwise. The cylinder head on the other hand, having a much smaller temperature rise, will maintain a relatively constant length.
The length mismatch that will occur between the parts may be resolved by consequences such as shearing the bolts, or sliding on the gaskets.
If your log manifold has a connecting strip that remains relatively cool, it will force the distance between the ports to remain more constant. However, there will be more stress within the manifold itself.
sliding on the gaskets is ok to some degree, shearing bolts is not, one of the details I had not yet discussed here, was that I intended to have to bolt holes at the center port round, and the bolt holes at the outer port slightly slotted lengthwise to alleviate some of the expansion stress.
My biggest concern, is that with the short runner length and long log, is that crack may form at the junction between the flange and the runner.
quote
Originally posted by Will:
The length of the runners has *MUCH* more impact on that phenomenon.
Agreed, because the stress is no longer applied in whole to the flange, it is now applied across both the runners, and the flange.
quote
Originally posted by pmbrunelle: Yes, flexibility drastically increases with runner length. But since Eric showed us a picture of pieces of metal already starting to look like a short-runner log manifold, it looked like that aspect of the design was already "frozen", so I didn't mention it.
The desire for flexibility is what led me towards the sledgehammer approach whereby I installed bellows between the ports of my stock 2.8 log manifolds.
I have yet to calculate the difference in expansion between the two parts, but I think a bellows between the ports may be way overkill. it's also a huge efficiency killer, those bellows are a huge amount of surface area, having more than one pre-turbo is a band-aid for bad engineering IMO.
I have enough material to lengthen the runners, but I want to keep them as tight to the head as I can, it will make maintenance easier, and improve overall efficiency.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
according to this, over about 12"(approximate length of the log) of pipe, and a temperature difference of around 1300F from installed state to what is probably well over max operating temperature yields an expansion of about 0.2" similar math for the head, assuming 142F rise (due to coolant) results in an expansion of 0.022", a difference in expansion of .178"
using the difference in temperature for the head, and the expansion of the stainless gives us an expansion of.019 for the flange, a difference of .003 between the head and flange, if I were a betting man, I would say that the flange is probably slightly hotter than the head, due to the lower thermal conductivity of stainless compared to aluminum, and the lack of cooling medium.
knowing this, across the entire head, I have a difference of about .18" between the log and the flange. that I need to make up. but the force on the runners will be applied bidirectionally, with about .126" of expansion between the ports further apart, and about .054 between the ports close together.
All of this is assuming steady state temperature, I imagine transient dT's would be lower.
.156" pipe .0195" head .0167" flange .098" wide .042" narrow
on the front bank, most of the expansion can be taken up by the bend from the first port. as it should be relatively free to expand towards front passenger side of the engine compartment, on the rear bank, that expansion has to be taken between the ports, as both ports will discharge at almost right angles to the pipe. short of building a 3-1 header style manifold, I don't think there's much I can do there, slotting the boltholes at the ends of the flange would allow the pipe to move the flange to a small degree, but it will also be forced counter to that by it's lesser expansion, and would have to also fight the force applied by the tension of the bolts also resisting flange movement. the angular displacement between the flange and the pipe based on these measurements is approximately 4.1-5.2 degrees.
Edit to add, I may re-do the math later with a higher flange temperature to see how those changes affect, this math currently assumes flange temperature is very close to head temperature, looking at the actual thermal conductivity of stainless and cast aluminum, I think it's safe to say the flange would be significantly hotter, which would cause an increase in shear load on the bolts, as well as reduced displacement between the flange and log.
[This message has been edited by ericjon262 (edited 10-29-2019).]
Do note that the way you're calculating thermal growth of the log assumes that the manifold is free to grow "as the part wants".
The log probably won't grow as much as predicted by the delta_temp*expansion_coefficient*initial_length formula, because the runners (which are attached to the massive stiff head) will force the log to remain shorter than it would otherwise be if left unrestrained.
Actually, the stress in the metal arises because the log is being "compressed shorter".
If you wanted to evaluate the risk of the metal cracking, the end-goal of this math/calculations could to estimate the stress in the metal at different key points in the manifold.
Here's an idea I have for an rough stress test that requires minimal tools/equipment:
1. After fabrication, cut away the connecting strip from the flange. 2. Place the completed manifold vertically in a hydraulic press. 3. Squish the two ends ports towards each other by .150", or whatever number you feel is representative of the length mismatch in service. 4. Check if the manifold has been plastically deformed. Before/after measurements may be helpful.
If you've plastically deformed your manifold, well at least you did it on the bench, rather than on the car which may entail dropping the cradle and all that...
Do note that the way you're calculating thermal growth of the log assumes that the manifold is free to grow "as the part wants".
The log probably won't grow as much as predicted by the delta_temp*expansion_coefficient*initial_length formula, because the runners (which are attached to the massive stiff head) will force the log to remain shorter than it would otherwise be if left unrestrained.
Actually, the stress in the metal arises because the log is being "compressed shorter".
If you wanted to evaluate the risk of the metal cracking, the end-goal of this math/calculations could to estimate the stress in the metal at different key points in the manifold.
which is why I also calculated the expansion of the head, in the operating temperatures the components will see, the thermal expansion of the aluminum head is actually higher than that of the stainless flange.
quote
Originally posted by pmbrunelle: Here's an idea I have for an rough stress test that requires minimal tools/equipment:
1. After fabrication, cut away the connecting strip from the flange. 2. Place the completed manifold vertically in a hydraulic press. 3. Squish the two ends ports towards each other by .150", or whatever number you feel is representative of the length mismatch in service. 4. Check if the manifold has been plastically deformed. Before/after measurements may be helpful.
If you've plastically deformed your manifold, well at least you did it on the bench, rather than on the car which may entail dropping the cradle and all that...
this test would be in no way representative of actual operating conditions, the results of said test wouldn't really tell me much.
I did realize a mistake in my math I split the length for the pipe, but not the flange, resulting in larger than actual divergence. I also re-did the math for for a higher flange temperature
divergence hot 2.049 degrees wide 0.92 degrees narrow
I feel like hot stainless should be able to handle that much without problem, I also plan on having the manifolds coated which help thermally as well.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
first ever attempts at welding stainless steel. I can tell already I need lots of practice. I think my travel speed is too slow, and I probably should have spent more time prepping the surfaces, I'm planning on picking up some stainless wire wheels tomorrow, and I'll use them to brush the weld areas, and then I'll wipe them, as well as the filler, with acetone prior to welding. I'm also going to use solarflux on the back of the weld to prevent pickling the backsides.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
yes, but very poorly executed. I think my current was a bit high, and my travel speed a bit low. I've done a couple more runs, and they look a little better, but I still need more practice.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
old on the left, new on the right. still a bit hot, but way better!
One log and runner are assembled, unfortunately, I can't really make any more progress until I get the new flanges made. tomorrow, when I get off work I plan to triple check all of my measurements and find someone to cut them ASAP. my fabrication plan is to tack weld the 45's to the flange, and then set the log on top and trim both until I have a proper fit, then weld everything up.
I've spent the past few days hammering out the flange for the new turbo manifold, I'm pretty sure I've got it spot on, now. I've had it 3d printed twice, and I think I'm already approaching the point of diminishing returns.
The final step before the laser will be a thin sheet metal "flange", as my friend's 3D printer wasn't exactly accurate for the hole sizes. once it's "proved", I'll have them cut in at lead 3/8" 304 SS and get hot on finishing them up.
Not much going on ATM, I drew up this adapter to adapt the 09 impala gas pedal to the Fiero, I'll have it 3D printed to test fit, and then make adjustments from there. once it's "done" I'll have it cut out of metal.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
A word of warning in regards to your oil return location in the side of the pan, it looks like it's pretty close to the location of the oil pickup in the bottom of the pan. When I had the water return line for my liquid/air intercooler placed in close proximity to the small bilge pump pickup area located in the water tank, the water dropping into the tank near it created bubbles that caused cavitation which was easy to to tell by the way the pump sounded, so you may need to add a small baffle near the outlet to direct the return oil away from pickup if it's close. My pan return points were always 90 deg and about mid pan, that nice efficient angle you have will produce a higher velocity in the return flow.
You also don't want the return point below the oil level. I made that mistake on my first turbo Fiero and the oil backed all the way up to the turbo because of the reduced flow rate going into the pan from being below the oil level, as the rpm picked up.
[This message has been edited by Joseph Upson (edited 11-24-2019).]
A word of warning in regards to your oil return location in the side of the pan, it looks like it's pretty close to the location of the oil pickup in the bottom of the pan. When I had the water return line for my liquid/air intercooler placed in close proximity to the small bilge pump pickup area located in the water tank, the water dropping into the tank near it created bubbles that caused cavitation which was easy to to tell by the way the pump sounded, so you may need to add a small baffle near the outlet to direct the return oil away from pickup if it's close. My pan return points were always 90 deg and about mid pan, that nice efficient angle you have will produce a higher velocity in the return flow.
You also don't want the return point below the oil level. I made that mistake on my first turbo Fiero and the oil backed all the way up to the turbo because of the reduced flow rate going into the pan from being below the oil level, as the rpm picked up.
That's a good point that I hadn't given alot of thought to. at this point, it's all put together already, so I'll log oil pressure and see how it looks and see if there are oscillations or other symptoms of cavitation.that being said, I'm not sure it's that much of a concern, all of the oil gets aerated leaving the main, cam, and rod bearings, and then just dumps into the oil on it's own. I'd really love to dry sump the engine, but that takes a bit more work than I want to do ATM.
My oil drain is higher than the standard pan fill.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I did a bit more practice running beads last night, I think I'm starting to get the hang of it, I think one of my biggest problems with producing nice beads earlier, was that the torch was too far from the material, resulting in the torch melting the filler, not the puddle, I tightened the gap, and was more careful about filler addition, and the result was the top bead in this picture:
I did several like it, and think that I'm getting to the point where I can observe the problems or poor technique better, and make corrections on the fly. I think all this stainless practice will make a huge difference in all of my weld quality, not just stainless. it seems some of the other materials are more forgiving they're appearance doesn't change as much with poor technique, whereas stainless changes alot!
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
For my future turbo manifolds, I'm going to tack weld them up and then heat the assembly up in the oven to about 375 F and then complete the welds. I have stainles sch 40 weld els also for the first time and I like the looks of it.
As for the oil return, it's the splashing on the surface upon entry that creates large bubbles below the surface instead of aeration that caused the problem I had. In your case however, it looks like your return point might be a little below the oil level so you may only need to be concerned about the possibility of oil backing up in the drain. As the rpm climbs the return oil flow is going to pick up a good bit. Just watch it closely.
For my future turbo manifolds, I'm going to tack weld them up and then heat the assembly up in the oven to about 375 F and then complete the welds. I have stainles sch 40 weld els also for the first time and I like the looks of it.
As for the oil return, it's the splashing on the surface upon entry that creates large bubbles below the surface instead of aeration that caused the problem I had. In your case however, it looks like your return point might be a little below the oil level so you may only need to be concerned about the possibility of oil backing up in the drain. As the rpm climbs the return oil flow is going to pick up a good bit. Just watch it closely.
My weld el's are SCH 10, I didn't see a real benefit to going as thick as 40.
The high approach angle make it look like so, but in reality, the drain enters the pan just below the windage tray, I think this space is almost ideal, I am unsure of the oil volume exiting the turbo, and how much concern it should be, but I'd bet that it doesn't discharge with enough velocity to impinge the surface of the oil in the pan with enough force to be of concern. that being said, I do intend to log oil pressure with the MS3, and see exactly what's happening, if I need to further improve oil control, I have a few ideas that I'll explore,
[This message has been edited by ericjon262 (edited 11-26-2019).]
Thanks, it's been a ton of work, with lots more to go.
I did a little junkyard digging today and scored a couple of small wins.
a new UIM and a/c compressor.
and a few more 3500 injectors, I'm going to decap them and send them to Derr Injector services for cleaning and flow testing, I have 16 of them, so I'll have them flowed and I'll take the best 6 matching and use them.
I also did a little work on the "coolant tree". Normally there's a pipe that goes over the valve cover to the back side of the engine to act as a return path from the heater core. I decided that I am going to plumb my heater return into the passenger side coolant tube running under the car, and eliminate one of the pipes under the car. it is necessary to keep the tree in place though, because it receives the recirculation line to prevent dead heading the water pump.
I started by removing the pipe
then welded it up and painted it.
The welds are a little nasty, I think there was still some antifreeze residue in there that kept trying to gas off.
I cut the neck out of the new intake, and have begun fitting up the new one, it's a bit bigger, and will better accommodate my 76mm LS4 throttle.
I still need to finish it up, but it's coming along nicely.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Probably heating with a torch, or a bake in your kitchen oven would have allowed any contamination to outgas.
not sure it would have gotten hot enough, at this point, I'm not too concerned, the welds are ugly, but they'll hold, and its in a spot that will never be seen. if I redo it, I'll take a few added precautions to ensure the parts are triple clean beforehand, but I don't think I'll end up doing it.
I read on here somewhere there was a pulley and belt tensioner catalog with pictures, anyone know where to find it?
this is my current alternator and tensioner bracket. it uses an LT1 F-body tensioner, and an Astro van alternator. it also requires an idler at the top bolt hole the holds the bracket to the head. I made it a few years ago, it's a bit bulky, and holds the alternator pretty far from the block, it works, but I'm not too happy with the execution, the welds are **** ...
I'd prefer the alternator hug the block, but then I have to find a new tensioner. the one pictured appeared to be the ticket, until I started lining the belt up and realized it would need an additional idler to work, and there isn't really room.
I found a fairly compact tensioner, that pulls the opposite direction. it has a ribbed pulley that I swapped for a smooth pulley, I'm going to make a mount to hold it in between the a/c compressor and the block, the mount will bolt in using the A/C compressor bolts, which acutally works out well, the A/C compressor requires a spacer between itself and the block, as the original application for the engine had an anti rotation mount sandwiched there, so now the space will be used for something.
mounting the tensioner there will also eliminate an idler pulley as well, which did require the mount boss on the timing cover to be ground off.
I'm done for tonight, but I hope to have this mostly done tomorrow as long as it's above freezing...
I tacked it together about 10 times, before finally settling on this:
the belt will be routed as such, maintaining the tensioner on the slack side of the belt. with the tensioner fully retracted, the belt still has clearance, between the tensioner and waterpump.
I used the stock engine lift bracket as a guide, and cut the foundation for the alternator mount to match the shape, except extended lower so that the alternator will have something to mount to.
My goal is to tuck the alternator as close to the block as possible, the back is going to get kinda close to the exhaust, so I'm going to make a thin heat shield to protect it as best as possible.
what I have left, I need to add gussets to the tensioner bracket, I dont' see any flex as is right now, but I don't want to revisit it later because I got lazy. and obviously, I need to mount the alternator still, and the last thing, find a belt, I hope that goes easier than last time... lol.
belt tensioner bracket is gusseted, I need to clean it up and paint it, but otherwise it's done.
a quick go with the plasma cutter and some tack welds got me a kinda functional bracket.
it needed significant bracing, as well as something for the bolts to tighten into, so I heated up some 2" flat stock, and bent it to approximately match the contour of the alternator case. I also notched it so it would nest into the offset parts of the bracket.
Then I put a small spacer between the alternator and the new back brace, and welded it to the bracket. I should have cleaned the material better before welding, but I think it should hold fine.
I then put the whole assembly back on the engine and verified the belt alignment, as well as gave it a trial fit to see how everything will look. in this picture, the belt is bypassing the crank pulley to give it enough length to go around the alternator, water pump, and tensioner. I'm considering adding an idler pulley at the mounting bolt for the alternator, to increase the belt wrap around the alternator pulley. at this point, all that is left for the alternator bracket is the above mentioned idler, the mounting ears on the back of the brace, the gussets for the brace, and cleanup/paint.
quick tip, if you need to add an idler and don't have a boss for one, a 15mm hex head, like found on most M10x1.5 bolts, fits nice and snug inside the bearing of a pulley, is the the best way? no, will it work? yes.
Here is the proposed idler arrangement. it would be attached by a threaded rod going all the way through to the back of the alternator, a boss to hold the pulley on top of the bracket, and then a nut to tighten the whole assembly.
a bit of trading with belts and pulleys ended with this:
I think I have a winner. I liked the belt routing better with the the idler on the bracket, as it netted quite a bit more wrap on the alternator. the problem was the belt got really close to itself, and belt stretching would only make the problem worse, so I went with the timing cover idler.
Have you looked at the relationship of the alternator and the axle?
I have, and it is a factor that I am fairly confident I won't have to worry about, the alternator is in more or less the stock fiero location, and above the oil pan rail, the output of the transaxle is below the oil pan rail. the only way to know for sure is to mock it up on the cradle and cycle the suspension through it's range of motion. worst case scenario, I still have my old bracket, I can still use it, and it definitely clears.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
lots of progress on the new front plate, it took two takes, the first, take, I made it too tall, and without enough material to notch it for the axle to pass through. take two, I made the entire mount much taller with a large sweeping notch to clear the axle. I also made a plate that bolts to the oil pan to help stiffen the mount
here was the first go.
and here is the second I intentionally made it way wider than it needs to be so I can trim it back to fit the cradle.
and here is the brace that bolts to the oil pan, again, with lots of extra material so it can be trimmed back.
I also spent about an hour swapping all 24 lifter springs in my stock replacement springs for springs out of a set of LS7 springs, is the work worth it? not sure, the LS7's rev way higher than a stock 3500, and many of the SBC guys rave about the LS7 lifters in their gen 1 SBC's, so hopefully they're worth something. I have the lifters soaking in oil right now, tomorrow morning I am going to drop them in, and get the lower intake, and valve covers on for good.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Is it going to be a giant engine mount, wide enough so that a separate dogbone is not needed?
yes, that's the plan. each end will use leaf spring bushings to provide cushioning.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
a little bit of today's progress, I decided to take a break from the mounts.
all of the lifters are installs, and the retainers, and the pushrods and rockers.
The heater pipe taps off of the intake manifold near the thermostat, and goes up and over the valve covers like so:
I didn't really care for this layout, it obstructs access to the valve cover, and is kinda ugly, so I decided I could do better. I got started by cutting it up, and then I welded it back together in a manner I like better.
The pipe will run straight under the head, and pop out just below the alternator bracket, under the belt. this will end up much more compact than what I had before, and look much cleaner, I would have it finished tonight, if I hadn't run out of material...
instead of getting some sleep so I can be rested in the morning, I decided to do some more work.
This gives a general idea of the routing described earlier, unfortunately, this piece is aluminum, and the rest is steel, or else I'd be a step closer to being done.
this picture shows what is one of what will be 2 mounting tabs, one here on the head, and one on the side of the block near the alternator. it also gives a visual representation of how much clearance exists to the coolant temperature sensor, which should be more than adequate to allow for future replacement.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I now have a functional intake manifold again, the old one was badly warped from the welders, I suspect that they welded it without any pre heat in typical lazy pensacola "professional" attitude. I pre heated the manifold with my casting furnace torch, and was able to weld it without problem. without the pre heat, I'm not sure my welder would have had enough heat to do it. the welds look like crap, I'm going to blame that on the casting having impurities, but it's really because I suck.
I can mount the throttle either way, if hood clearance is an issue, I'll mount it upside down to gain about 1.5" of clearance. which has the added benefit of locating the electrical connector closer to where the wiring will be routed.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I didn't have much time to work today, so I worked on a smaller project, I tacked these stainless bungs to the stock 3500 rail, the intention is to build a parallel flow setup to provide even fuel pressure to all 6 injectors. if I can remember, I'm going to mail off my decapped LX9 injectors fuel injectors for flow testing. FYI, stock 3500 fuel rails have a very small orifice to feed one fuel rail through, for a stock application, it isn't a problem, it may be a problem for applications making double the power. The two bungs closest to the throttle body in the pictures will be the supplies, the near bungs will be the return lines. I'll fully weld the bungs once I have a proper purge rig to ensure the weld doesn't sugar on the backside.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
