Originally posted by Jncomutt: That filter WILL choke it out.
I need to keep it there to avoid scaring forum members with the raw uninhibitted power. It's like a NASCAR restrictor plate. I'll be working on a replacement very soon. With all of the other stuff going on I didn't give the filter a second thought. Glad you all pointed it out before I vacuumed it into the compressor.
Great build but I only question one area- 11.3:1 compression and 8.5 psi boost? IMO if thats your combo, KR's are going to be very hard to control. I know that some will site modern technology, piston and combustion chamber design as safeguards against detonation but I'm still from the old school when it comes to buiding a boosted engine. Still use 8.5:1- 9:1 compression with boost. How do you expect to keep detonation under control?
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by Dennis LaGrua: Great build but I only question one area- 11.3:1 compression and 8.5 psi boost? IMO if thats your combo, KR's are going to be very hard to control. I know that some will site modern technology, piston and combustion chamber design as safeguards against detonation but I'm still from the old school when it comes to buiding a boosted engine. Still use 8.5:1- 9:1 compression with boost. How do you expect to keep detonation under control?
First there are many old school practices holding back new school technology in addition to the boost and compression issue. Old school would say you've lost your mind if you think you are going to get away with 9.8:1 compression on 87 octane fuel, but it does with some boost to boot. As a matter of fact had I had the time to fully tune the first engine it showed it was capable of 7 psi on 87 octane alone with that compression and stock turbo grand prix timing instead of the midgrade fuel I used and that was mixed with 87. There was no detonation under boost with a lousy tune if it was even that good and 212 degree intake temps.
The combustion technology in this engine and the non direct injected 3.6L with 10.2:1 compression and an 87 octane rating is that good. I've done my homework as well as read up on a number of 11+:1 compression boost motors on pump gas.
I have 4 octane points to climb up to if needed, I have oil squirters that have a documented 100 or more degree reduction in piston temp effect, I'll be running engine oil and coolant temps at a maximum of 180 degrees, I'll have pre and post turbo water/meth injection. That's more than enough to make 8 psi a minimum goal.
What's important to note are the benefits to my approach. High compression with boost equals blazing offline performance relative to stock, higher efficiency overall that should translate into more power over the full rpm range and better mpg. Don't forget its 4.2 litres now. I'm a 0-60 driver, the build is right where I need it.
I'll post the results as I progress. If by chance it proves problematic, thicker headgaskets will get me over the hump.
I am very interested in reading about your results. I would be concerned with head gaskets as I would with blowing a piston. A couple of guys I know blew pistons in a 3800SC and that was just by upping the boost a bit w a 3.2" pulley. You may be able to suceed in running high compression and high boost but then again you might not. I believe that it is an uphill challenge to do what you wish to accomplish. Please prove me wrong.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by Dennis LaGrua: I am very interested in reading about your results. I would be concerned with head gaskets as I would with blowing a piston. A couple of guys I know blew pistons in a 3800SC and that was just by upping the boost a bit w a 3.2" pulley. You may be able to suceed in running high compression and high boost but then again you might not. I believe that it is an uphill challenge to do what you wish to accomplish. Please prove me wrong.
I understand your concern but that's an area of advantage the stock 3900 has over the stock 3800, O.E. multilayer steel head gaskets. You'd have to read up on the advantages MLS head gaskets have over composite, as well as copper. I've also read where LS1 owners experience showed they had more dependability out of the OE multilayer steel gaskets than the aftermarket MLS gaskets they used from Cometic.
The stock motor with the cam advanced and single turbo was a considerable improvement over the twin turbo setup on 7 psi with the cam advanced. 7 on this motor with the cam at the right angle should be very impressive for me. 10 psi is the maximum goal and I suspect that might be a little scary. Right now I'm trying to correct the turbo drain having had some oil back up in the turbo. Hopefully tomorrow will return a good testdrive. Jumping to 60 lb/hr fuel injectors has taken the tune status way down.
[This message has been edited by Joseph Upson (edited 11-14-2010).]
I just ordered a WBO2 module to help things along, as it stands I'm shooting in the dark it seems at this point the tune is so far off with the larger injectors.
I decided to run TGP code until the new wideband arrives since thats the closest thing I have to a driveable tune. It's running decent despite the desperate need for WBO2 help in establishing the proper base pulse constant. The Vacuum canister with its built in check valve tied into the top port on the wastegate worked as planned holding the wastegate open to help avoid boost. The main spark table has been reduced by about 7 degrees over the entire 0-100 Kpa and rpm range so once the wideband is in place I can correctly set my base pulse constant and start tuning and adding the timing back.
Coolant temps are hoovering around 183 deg but that's with the fan running a good bit. Tomorrow I'll consider putting the HD aluminum unit in and seeing if the current temp minimum limit is the result of the modified 190 thermostat which has a couple of holes drilled in the face and a clipped spring or the radiator. I'm also going to look for a 160 deg stat.
Oil temps are running around 220 deg so I'll be installing the oil cooler up front to get down into the 170-180 range I want. I had an episode with the oil return due to a drain location and fitting change that caused oil to back up in the turbo. It cleared up after swapping the fitting to increase the incline to the pan fitting but by then I had ordered a motorcycle oil scavenge pump that I'll "T" into the drain line for assisted return just in case. It cost $60 and is rated at 1.8 L per minute.
well good luck on you boosting adventures. 11.1 and 8 pounds of boost... you can make more power with lower comp ratio and moar boost.. just sayin my Cobalt ss/sc has a 9.5.1 and we had to tune a lot to get the KR out and thats running a 2.85 = 16.8 LBS of boost and max timing is 17 that is with a Intake air 2 temp of 135-145 and top of 3 starting from second at 90 deg just keep an eye on it, you might crack a sleeve since you have pistons.
Originally posted by mrbeef: well good luck on you boosting adventures. 11.1 and 8 pounds of boost... you can make more power with lower comp ratio and moar boost.. just sayin my Cobalt ss/sc has a 9.5.1 and we had to tune a lot to get the KR out and thats running a 2.85 = 16.8 LBS of boost and max timing is 17 that is with a Intake air 2 temp of 135-145 and top of 3 starting from second at 90 deg just keep an eye on it, you might crack a sleeve since you have pistons.
That's not what this build is about. It's about making the most power and fuel efficiency for the boost I intend to run. Therefore I'll get more power and better mpg by raising the compression. Practically everyone builds for just more power. I achieved that by stroking the motor and raising compression alone. 400 hp on 8 lbs of boost is much more impressive to me than 400 hp on 12 lbs and lower compression.
If you lower the compression first you decrease performance over the entire rpm range and only gain in the boosted range. If you increase compression you gain over the entire rpm range plus that much more in the boosted area. If I accomplish 7-8 psi over the stock spark table only needing to run higher grade fuel I've succeeded at what I set out to do. The car is much faster than it has ever been right now if one launch from a light yesterday is any indication so at this point the planned boost level is just right.
Higher compression and higher boost will yield more horsepower but it greatly increases the possibility of detonation (KR's). I believe that it must be said that whether or not an engine will detonate depends on the combination of compression ratio, boost pressures, piston design, cylinder head design, gas (octane) quality, intake air temperature and cam timing. I choose the traditional 8.5:1 C/R boosted route for the 3800SC but have been involved with past boosted engine projects that used.up to 9:1 C/R. Having done this I would say that high compression/high boost is a area best left for those that know what they are doing.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Originally posted by Dennis LaGrua: Higher compression and higher boost will yield more horsepower but it greatly increases the possibility of detonation (KR's). I believe that it must be said that whether or not an engine will detonate depends on the combination of compression ratio, boost pressures, piston design, cylinder head design, gas (octane) quality, intake air temperature and cam timing. I choose the traditional 8.5:1 C/R boosted route for the 3800SC but have been involved with past boosted engine projects that used.up to 9:1 C/R. Having done this I would say that high compression/high boost is a area best left for those that know what they are doing.
Originally posted by Dennis LaGrua: Having done this I would say that high compression/high boost is a area best left for those that know what they are doing.
As a high performance and racing engine builder, I agree. Fortunately, you appear to be one of those people. Keep up the good work.
I usually keep the total quench down around 0.040" with the usual zero deck height. How thick are your head gaskets; 0.064" as mentioned earlier? Your deck height was 0.040" just by itself, right? Making a total of 0.100"? From my experience, quench quickly loses its effectiveness as the clearance climbs past 0.060". That's the main thing that sticks in my mind when reading about your build vs your intended goal.
Any idea of how effective GM's "mist quench" is with the higher numbers? How sensitive is it to variations; in other words, is the chamber tolerant of the quench dimensions? Is the extra quench height possibly to reduce emissions?
If I remember correctly, a boost in compression ratio has about double the efficiency increase at part throttle that most charts show at full throttle.
[This message has been edited by mender (edited 11-16-2010).]
A few more comments; I'm assuming your rod bearing clearance at 0.0015". I'd recommend next time staying closer to 0.0020" - 0.0022". You can mix a set of standards and 0.001" unders to get the right clearance.
I realize your piston options are limited but having the valve pockets in the wrong locations cuts your compression slightly and can disturb the flame front slightly as well.
And dropping the compression ratio by using thicker head gaskets usually turns out to be a bad decision, as increasing the quench more often increases the octane sensitivity despite the drop in compression.
Also, what year/make/model is your engine?
[This message has been edited by mender (edited 11-16-2010).]
A few more comments; I'm assuming your rod bearing clearance at 0.0015". I'd recommend next time staying closer to 0.0020" - 0.0022". You can mix a set of standards and 0.001" unders to get the right clearance.
I realize your piston options are limited but having the valve pockets in the wrong locations cuts your compression slightly and can disturb the flame front slightly as well.
And dropping the compression ratio by using thicker head gaskets usually turns out to be a bad decision, as increasing the quench more often increased the octane sensitivity despite the drop in compression.
Also, what year/make/model is your engine?
I've looked into all of that and GM has broken pretty much every rule you are referencing regarding the subjects you've touched on with this engine. 3900 V6, they're all the same from 06 up except for the rare DOD version and a few get the single stage upper plenum.
Minimum recommended rod bearing clearance per GM spec: .0007-.0024", I didn't want to start on the high end it was close to with oil being bled off at the cam phaser and oil squirters so I used a std & .001 under bearing. Idle oil pressure still hoovers around 37 psi and doesn't go much higher than about 45 psi by design as my motor is not the only one that reads in that range. Oil temps and pressure are affected by bearing clearance. Temps currently run about 220 and I'm sure some of that heat is from the turbo and being sprayed on the bottom of the pistons. Exhaust temps about 650-750 so far.
Top piston ring gap: .006 which is what I measured for the stock ring before checking the spec. I gapped the LS1 rings to LS1 specs. Quench area: .09 + and GM still refers to it as "mist quench" in their literature. I'm sure you are aware that's far from the recommended range for quench area. There is no extra quench here, there is ~.0006" less or should I say subtracted from stock as the gaskets are stock along with the head and deck surface.
Whether or not the valve reliefs in the middle are an issue I don't know. The heads were designed after the LS1 heads and considering they are depressions I would hope they don't cause any more concern with flame front here than they do in the LS1 with the same bore, but who knows.
The compression was not dropped it was raised and should be right at 11.5:1 maybe slightly higher. Mahle also manufactures the stock pistons for this engine so except for the valve reliefs they are very similar in design.
So far the engine runs well and the majority of the few knock counts I've recorded have occured at off throttle decel where a high vacuum area has a little too much advance under that condition or decel needs adjustment the same was the case with the stock motor I never got around to doing a full tune on using TGP code. Code59 for example which I'll be switching back to, reads spark values from the 600 rpm row when you let off the throttle, anyone not aware of that when trying to tune out a detonation blip at say 5500 rpm and 32 Kpa of vacuum after letting off the throttle would be chasing their tail because reducing spark at that point would not address the problem.
Right now I'm waiting on a wideband controller to replace the broken unit so I can start tuning the engine. The wastegate spring has been removed to help stay out of boost until the natural aspiration tuning is completed. The car is still fast and feels as fast now without boost as it did with the stock motor and 7 psi. It runs well so far so I'm happy. Appreciate the constructive input.
[This message has been edited by Joseph Upson (edited 11-16-2010).]
The tight bearing clearance will restrict the oil flow right at the bearing, leading to the rise in oil temp at the bearing itself. That's what the charts in the article you cited mean, not that the overall oil temp will rise, just locally. The load capacity drops as well when below the 0.0020" mark as well. This is why I stay right around the afore mentioned bearing clearances. You did measure the clearance and not just assume, right?
The "stock" bearing clearances of 0.0007 to 0.0024" are not meant to be a recommended range but an out in case production tolerance vary. The Clevitte bearing books that I and most crank grinders use list same those clearances for quite a range of engines dating back quite a ways, and the numbers are ignored for the most part. Actual numbers are based on the crank grinders' and engine builders' experience and are the 0.0020"-0.0022" range for the vast majority of engines.
Regarding the piston valve reliefs. my comment was that with the correct location and depths you would have gained slightly more compression than you presently have and have a smoother flame front as well. I also have to use the pistons available when the customer can't or won't afford a custom piston and was just commenting on the small but present disadvantages of doing so. No biggie.
On the ring gap, again for performance no one in their right mind uses rings right out of the package without checking them! I file-fit the rings on every engine and only recently have seen good enough dimensional control to use some sets as is out of the box .
Listen guys, this is a build to my liking that you and accepted specifications may or may not agree with. Although I appreciate the input, my thread is being cluttered with small and increasingly undesirable chat. So please if not for me, at least for the sake of experimentation, refrain. I've already been through this kind of sidebar distraction with Will resulting in my deleting most of my responses to eliminate substanial unnecessary thread length consumed with needless debate and explanation after the fact. Keep up the good work and allow me to develop my own.
My rings were file fit. Not even going to dignify the question of whether or not I measured bearing clearance with an answer.
[This message has been edited by Joseph Upson (edited 11-16-2010).]
Thank you for documenting this build. I have a 87gt w/ a DoD 3.9 for a dd(swap in progress), and (if time/money works out) would like to do a similar build less the turbo for a weekend driver. Matt
Listen guys, this is a build to my liking that you and accepted specifications may or may not agree with. Although I appreciate the input, my thread is being cluttered with small and increasingly undesirable chat. So please if not for me, at least for the sake of experimentation, refrain. I've already been through this kind of sidebar distraction with Will resulting in my deleting most of my responses to eliminate substantial unnecessary thread length consumed with needless debate and explanation after the fact. Keep up the good work and allow me to develop my own.
I'm enjoying your build. Back in the early '80s I built a small V8 for turbocharging and I had people (OK, everyone) telling me 7.5:1 to 8.25:1. Of course this was pre-computer and I went with 8.00:1. But here's the deal: lower static compression will probably allow more max HP, but it makes for a dog to drive every day. A car is under boost for a small percentage of time. Other than that I was driving a gutless wonder.
If I have a complaint with this forum, it's the constant ADD of its members. If I say I've decided to paint my car red and I'm asking for input on metallic vs. non, maybe I'll get ten responses. Five will say not to paint it red for various reasons, four will suggest a different color altogether and one will ask how to use PIP.
Great build so far. Keep it up.
PS, I think I see a speed ban coming. Did my part, anyway.
Without reading thru the whole thread, I can tell you that you can not use a high compression motor with turbo boost. Ideally, 8.5 - 9 to 1 is what works best without exploding. My Ferrari kit had a turbo on 3.1 motor with 8.5-1. It put out just shy of 300 hp and ran great for the 100,000 miles I put on it. If the rod and piston can take the compression, the side will be blown out of the cylinder or at the very least, you will seriously blow head gaskets. If the short block survives, you will blow the heads off when the bolts snap. In simple terms....the weakest link will not take it.
Without reading thru the whole thread, I can tell you that you can not use a high compression motor with turbo boost. Ideally, 8.5 - 9 to 1 is what works best without exploding. My Ferrari kit had a turbo on 3.1 motor with 8.5-1. It put out just shy of 300 hp and ran great for the 100,000 miles I put on it. If the rod and piston can take the compression, the side will be blown out of the cylinder or at the very least, you will seriously blow head gaskets. If the short block survives, you will blow the heads off when the bolts snap. In simple terms....the weakest link will not take it.
Taking a break for a moment after receiving the disappointing news that the WBO2 controller will not show up before Friday. I'd like to give the ebayer a neutral for not shipping Mon. since he had all weekend to prepare for it. My fault for damaging the first one and having to buy a second.
The engine still runs fair although I need the WBO2 to sort out the idle AFR and work on tuning out the occasional off throttle stall. I have been getting some knock retard but thankfully it seems to be an off throttle issue somewhere in the middle of the spark table instead of at wideopen throttle although I don't take it there much.
I installed the heavy duty aluminum radiator and so far haven't been impressed at all but that maybe due to having removed the thermostat combined with the unusual flow pattern for this engine. (It's also another issue for discussion as aluminum is lighter but brass rads transfer heat/cool better as it appears in this case where brass appears to be doing the same work with 1/3 less capacity).
In the 3900 the stat has a dual function, when it opens it closes off the coolant flow directly from the upper coolant crossover that connects to the front of the heads and receives the return coolant intended for the radiator for a total of three inlets including the heater core return to the pump. When the thermostat is closed water circulates through engine in two closed circuits, the heater core and itself sucking in hot water from the upper outlet and circulating it back through the engine.
My old radiator is a brass 2 row and with the thermostat in place and modified with several holes drilled through its base to allow water to by pass it my coolant temps are running pretty much neck and neck with the fan running continuously, ~185 deg although at times the aluminum 3 row has produced slightly lower temps as in mybe 175 but with no stat and the fan running continuously I'd expect much better. I may close off the return feed directly from the engine so that only cooler water from the rad and heater core circulates to see if it makes a difference since the hot water coming from the heads displaces cooler in coming water.
You also have to be careful burping this engine, despite the high level filler neck. For about 2 min the water did not circulate period. With the engine running and the return hose at the radiator disconnected and seeing the radiator full of water as well as the rear filler the levels did not budge, not even with a little revving. Finally bubbles started moving and water began to circulate but without a thermostat I find that unusual.
It's up in the air now, depending on what progress is made before Saturday I may leave it yet again depending on the tuning progress. I'm also sanding on the body in hopes of at least getting primer put on it so that it looks decent to take some of the pressure off the new wheels to make it look good.
My exhaust temps are still in the very safe zone 600-700 despite the compression ratio and oil temps are reasonable about what you'd expect with a turbo, 210-220 though I'd like to get it down to 180ish.
If I decide not to take it I'll at least try to do an MPG test and video if I get it tuned enough to demonstrate performance safely.
To better illustrate what I was explaining about the coolant flow design possibly preventing maximum cooling by the new radiator, the two curved hoses on the right are connected to the inlet bowl behind the water pump, inlet from upper coolant crossover and return from heater core. The fitting for the inlet radiator hose would be in close proximity to them but it was removed. At the crossover pipe above are four holes, filler neck (broken plastic base), outlet to heater core (visible from top), outlet to radiator and outlet back to the water pump below it, that's the feed I intend to close off so that 185 degree water leaves the heads and goes straight to the radiator instead of back to the water pump.
[This message has been edited by Joseph Upson (edited 11-17-2010).]
Joseph, I know one of your goals with this project is exeptional fuel economy. I thought I read somewhere that code 59 doesn't have provisions for lean cruise mode. Will this hinder your actual fuel economy?
Originally posted by LZeppelin513: Joseph, I know one of your goals with this project is exeptional fuel economy. I thought I read somewhere that code 59 doesn't have provisions for lean cruise mode. Will this hinder your actual fuel economy?
I thought I saw a constant for it a few days ago but I was doing something else and didn't stop and investigate. Now I can't seem to find it in the XDF file. I don't think it will be a problem since there is also a 3 bar AFR table to activate and in it you can force leaner values in the curise area.
You mentioned installing water/meth injection before the turbo. I am not 100% certain on this but to me that sounds like a bad idea. Water droplets hitting the compressor in your turbo will have the same effect as sandblasting it. Also, Im sure you know this but relying on water/meth injection can be dangerous, as I spun a bearing in the past due to the water/meth system not working when I expected it to be.
Although it is not standard practice, running a turbo motor on 11:1 compression makes for a fun motor. The high compression will give you more starting torque and spool the turbo faster. The key is conservative tuning, as with any motor build. I was running 14 psi on a mitsubishi 3000gt motor with 11.1:1 compression and water meth injection. It made a lot of power for many miles until the water/meth failure killed it. After cleaning the gold dust (mulched bearing) out of my entire motor, i rebuilt it back to stock and sold the car.
Listen guys, this is a build to my liking that you and accepted specifications may or may not agree with. Although I appreciate the input, my thread is being cluttered with small and increasingly undesirable chat. So please if not for me, at least for the sake of experimentation, refrain. I've already been through this kind of sidebar distraction with Will resulting in my deleting most of my responses to eliminate substanial unnecessary thread length consumed with needless debate and explanation after the fact. Keep up the good work and allow me to develop my own.
My rings were file fit. Not even going to dignify the question of whether or not I measured bearing clearance with an answer.
LOL... Dude, chill out. People suggest these things because they don't want you blowing up your new engine, scrapping crankshafts or having significant problems.
If you keep chastising people for offering feedback, eventually no one with anything interesting to say will post and all you'll get are atta-boys. If that's what youre ego wants, then so be it, but that doesn't make for a worthwhile thread. Discussion and disagreement are what make the existence of forums worthwhile.
Originally posted by Will: LOL... Dude, chill out. People suggest these things because they don't want you blowing up your new engine, scrapping crankshafts or having significant problems.
If you keep chastising people for offering feedback, eventually no one with anything interesting to say will post and all you'll get are atta-boys. If that's what youre ego wants, then so be it, but that doesn't make for a worthwhile thread. Discussion and disagreement are what make the existence of forums worthwhile.
How's it going Will. My first impulse was to disregard but then I thought "What the heck, I'll humor him anyway". I wasn't looking for advice when I started this thread. A certain amount of risk was assumed and understood on my part before starting the project. I've been building and turbocharging engines since the days when Paxston Superchargers was adding additional fuel with the use of extra injectors rather than ECM tuning.
The comments I find annoying are the ones that would suggest I'm building my first engine, along with others that would not have been made in the first place had the thread been read from the beginning. Then there is the space consumed with useless dialogue (like this) for anyone actually trying to learn something, or see the results so that they know from fact whether or not an idea is viable for this engine in particular.
I don't recall a single comment in this thread so far that has illuminated anything in regards to what I'm doing. All that means is that I've done my homework reading countless pages on everything I've set out to accomplish here. The build is simply testing theory so there's no need for regurgitating risks I'm more than well aware of. If i'm not successful I'm okay with that. On the other hand the engine runs pretty well and can only get better with tuning so I have already succeeded.
Here is an example of what can be done to address the variable camshaft without PCM control. You can lock it into position by installing a screw and jam nut on both sides of the vain, or on one side to allow room for retarding the cam to the proper install angle which will be easy to adjust in with the screw. The full advance position is referred to as park and the cam is locked there until oil pressure reaches the proper psi and unlocks it. That is to prevent the cam from oscillating when the engine is being started. To degree the cam I advise a small degree wheel not much larger than the balancer, I used 8-32 screws which you may have to cut to length as 3/4" or less is about what is needed and I also suggest the next size down in screw diameter. Be careful not to get too close to the hub or you may get interference with the jam nut before it can be tightened.
If you decide to lock it without any movement, the return spring the assembled module has will not be necessary. If you decide to allow room for retarding it you have to install at least one guide dowel or screw driver etc before removing all three bolts from the back side of the sprocket or else the hub will spin and unload the spring and that would make for a pretty interesting plan to reload it without the proper tool.
As a high performance and racing engine builder, I agree. Fortunately, you appear to be one of those people. Keep up the good work.
I usually keep the total quench down around 0.040" with the usual zero deck height. How thick are your head gaskets; 0.064" as mentioned earlier? Your deck height was 0.040" just by itself, right? Making a total of 0.100"? From my experience, quench quickly loses its effectiveness as the clearance climbs past 0.060". That's the main thing that sticks in my mind when reading about your build vs your intended goal.
Any idea of how effective GM's "mist quench" is with the higher numbers? How sensitive is it to variations; in other words, is the chamber tolerant of the quench dimensions? Is the extra quench height possibly to reduce emissions?
If I remember correctly, a boost in compression ratio has about double the efficiency increase at part throttle that most charts show at full throttle.
Having thought about something you pointed out and reviewing and understanding what you meant this time, pardon my misunderstanding. You made a comment about the tighter bearing clearance resulting in lower load capacity which I did get from the article link I posted. What I forgot to address in response to that is by moving to the small block chevy rod I also adapted the wider bearing, not sure what the offsetting penalty is but hopefully it's in my favor. What's particularly aggravating is that I made it a point to keep all the extra parts together yet I can not find the extra chevy bearing to compare the width difference.
If you know what the part number is chances are pretty good that I can measure it for you, I have a pretty good selection of SBC bearing sets on my shelf at the shop.
