ENGINE WORK June, 2007
June 4 - lots of questions continue to swirl around some of the STi engine specs and components as we STi customers get closer to flying and start to realize in more depth some of the details. The whole PSRU issue, mentioned last month, continues to really tick off the STi customers, as Jan Eggenfellner now says the Gen 2 PSRU units we got with the engine are "marginal in every respect" and today he said "Gen 2 boxes are no longer recommended on the STI engines." Eggenfellner VP Gary Newsted continues to maintain, however, that the Gen 3 upgrade is optional and that Eggenfellner won't pay for our Gen 3 upgrades to turn the STi engines into something we can use. Jan also told one of the customers "Your warranty expired after two years. The "at cost" Gen 3 will be available for a short time. The cost will then be $4995." So, besides Gary's excuses that Gen 3 is an optional choice for us to make, another excuse to avoid supplying us with a non-defective PSRU is that our warranty has expired. Lovely.
Another STi customer has been researching the cooling issues. Apparently, the cooling system, which was OK on the original 160 HP engines, was put onto the 200+ HP STi engines with no changes. The switch was then made to the NPG+ coolant (which is actually less efficient at cooling) to make the cooling system less likely to boil over as the engine runs hot, rather than addressing the underlying problem of marginal cooling capacity. At least one STi customer has abandoned the supplied radiators and cowl and is going with a redesigned radiator and a James "smiley" cowl, which should be much more efficient at cooling. The one flying STi customer says he can't do a full power climb for more than 60 seconds without overheating the engine.
Another STi customer has just realized that we may be overdriving the supercharger, too, especially with higher engine RPM from using the Gen 3 PSRU . We are looking into that now. More info as it develops.
As I once commented on the Eggenfellner list (and was threatened by Jan with expulsion for doing so), the block and cylinder heads are about the only thing we haven't had to swap out on this "complete FWF package".
June 5 - yet another STi customer has expressed his frustration thusly:
Our firewall forward package that cost a lot of money because we didn’t want to develop our own has required many “updates” and aircraft modifications prior to first flight.
1. Change the valve timing sprockets.
2. Block oil lines in the head.
3. Because of poor documentation I think we had it apart 3 times. Once just to make sure it was torqued properly after the disaster with Steve’s engine.
4. Change the pulley that drives the supercharger.
5. Cut away more of the timing belt cover. The engine was mounted so close to the motor mount that the plastic cover was bent inward toward the belt and was rubbing. Since this was discovered while doing steps 1 and 2. I guess it’s a good thing we had to do steps 1 & 2.
6. Take it apart again to put the retainer rings on the new pulley.
7. Give up on the engine light. What good if it is on all the time.
8. Feel fortunate that our engine was shipped with gen 2 and new flywheel.
9. Take the exhaust manifold off to have it cut and welded to fit the airplane we are building.
10. Remove the oil cooler, purchase new one, and mount it aft. The original will not fit inside the cowl.
11. Create an ungodly bump on the cowl to make room for the supercharger that had to be mounted outside the motor mount because the supercharger mount was made to fit the only belt available. (Somehow I have always doubted the available belt story.)
12. Lately we have found that the psru Is marginal for the STI engine, but may be alright if we check the alignment of the engine with the front mounting plate. At this point I don’t trust that the factory properly aligned the engine.
13. We are given the opportunity to purchase a new psru that is heavier and slightly longer than the old one. Do we modify the cowl or leave the gap?
14. We are told that the new psru is available “at cost”, $3,000. I am just a country boy and don’t know a lot about the cost of manufacturing but just when I was thinking maybe the factory needs to look for better sources for machining and parts, one customer offered to help with sourcing. He received a smart-ass answer about “Chinese bearings”. I am thinking there may be a big pad in that $3,000 for cost of development. Like close to 50%.
15. Now we find that changing the psru may cause an unsafe situation with the super charger and we might need to change one of the pulleys and the belt. If we change the pulley we will have to redo the cowl bump as we did not leave enough clearance for a larger pulley. We are especially fond of the supercharger bump.
and that's just a partial list. Just what we need - more weight up front (Gen3 PSRU is even heavier than Gen2) on an engine that's already so heavy Eggenfellner had finally bit the bullet (while continuing to dodge the questions on what is the total weight), and said everyone should mount their batteries in the rear, to keep the plane in balance. See here for more details of this that I've thought of. And these are just the big things. We've all worked for two years on this, and we're getting fed up with the never-ending list of components that are defective, inadequate, or poorly thought out. I could go on for pages with details, but it isn't worth the trouble.
June 6 - it now appears that, not only will the engine be significantly overdriving the supercharger if we use the Gen 3 PSRU, we are even overdriving it with the supplied Gen 2 PSRU. Eggenfellner is completely avoiding any responsibility for any of this, with a plethora of the most specious excuses. According to current info, max sustained rpm for the supercharger is 14,000 rpm. John Moody provided us with this data:
The drive pulley is 11" diameter and the supercharger pulley is 3.5" diameter.
Hence the drive ratio is 11/3.5=3.14
Hence max supercharger speed with Gen 2 is 2700 x 1.82 x 3.14 = 15,444 rpm
Max supercharger speed with Gen 3 would be 2700 x 2.02 x 3.14= 17,125 rpm.
This is all getting very depressing. Now, Jan is giving us a line of crap like saying we can limit boost to 4 psi (one-quarter of what he has said all along). All the STi users are furious at Eggenfellner's positions and statements on this.
June 17 - there has been lots of talk on the "private" (no Eggenfellner) STi list about how to deal with the various problems. One person came up with lots of good info on swapping out the SC pulley for a larger one, so we are not overdriving the SC. The big question on this is how to pull the existing SC pulley. None of the STi owners expects to get any useful info in this from Eggenfellner. I looked over what it might take to get the SC pulley off. I might be able to get puller fingers behind the pulley. Also, noted a 4-pronged fastener in center of pulley, probably what holds it on - I don't know of any too that will fit it, though. Also, if we have to do a new SC pulley, in addition to all the hassles directly associated with that, we will also have to redo the belt, the arm on the SC mount frame, the SC duct, and the SC adjuster rod. The idea of having to redo all this completed supercharger-related stuff is quite depressing. I also noted that the belt is currently in the center of a 2.5" wide pulley. If we use the more narrow one proposed by the other STi user, will it be too close to the SC or will it mount so its center is where the pulley center currently is? Also noted that belt is Gates PowerGrip GT-2 15128MGT20. I wonder what might be the next shorter increment in this belt. 0.5 hr
This odd (and fairly mangled-looking) fastener (pic taken with flashlight and mirror) is in the center of the supercharger pulley. Assuming it is a fastener, I don't know what tool would fit it. I asked about it on the Eggenfellner STi list, but I don't expect much of an answer from Jan. It was later suggested to me by John Moody that these 4 bumps are splines on the output shaft of the supercharger, which is probably correct.
June 18 - Jan Eggenfellner continues to back further & further from any support for the group of STi owners, as we struggle to get these engines working correctly on our own. One of the STi owners wrote an email last week, practically groveling to Jan, asking Jan to provide info on how to deal with the marginal cooling issues, and asking about getting and using the larger radiators that we hear Eggenfellner is now providing for the H6 engines. All we got back was another of Jan's terse little replies, ignoring the questions about the radiators and saying we should make a 6" cowl flap. Ziggy is already flying with a 4" cowl flap, and we doubt another 2" in the opening is going to make a big difference. Obviously, if we have issues with quite marginal cooling capacity, and we're making at least as much HP as the H6, then it would be logical that we should be using the new H6 radiators. But then Jan would have to admit that the STi radiators are inadequate and then we'd rightfully expect that the correct radiators should be part of the whole package that was so poorly thought out.. At least one more STi owner is getting close to flying, so it will be most helpful to see what he encounters. I sent a couple emails to Eggenfellner asking several questions about the cost and availability of the new H6 radiators and about how to remove the SC pulley. Expectations of anything useful/helpful from Eggenfellner are very low.
June 19 - I didn't expect Jan to reply at all to my several questions about the the H6 radiators and the SC pulley. I did get back this minimalist little quip: It is of our interest to see the STI engines fly. I recommend the existing coolers, 6" travel on the cowl flap and existing supercharger setup. Jan seems to be making an effort to give as little information as possible in his terse little replies. He's downright gregarious on his Eggenfellner Yahoo list, but he's trying to sell more engines there, so he presents quite a different face there than he does on our STi list. I replied and asked about the situation with him also recommending the Gen 3 PSRU and the fact that the Gen 3 PSRU will overspeed the supercharger (the Gen 2 is already overspeeding it by 5%). That question continues to be ignored by Eggenfellner. Another STi owner, the one flying, also responded to Jan and said the existing radiators are inadequate and what we really need is bigger radiators. As he said, what Jan is really suggesting is that we limit our power to 50%. Now, there's a clever, Eggenfellner solution! We're all awaiting the next gushing fountain of information from Jan on that.
Mike Casey is addressing some of the Eggenfellner cooling and drag issues HERE.
June 20 - Jan Eggenfellner's attitude continues to worsen. He attacked another STi customer on the STi list for suggesting that Jan is not being helpful or cooperative regarding these engine problems. It's becoming quite clear now that the cooling is completely inadequate, although Jan continues to deny it. Jan's solution for the PSRU/SC overspeeding problems is to limit engine rpm. Another STi user has done cooling calculations for the STi based on the cooling planning spreadsheet in the EAA web site, and reports back that the STi cooling capacity is approximately 50% of what it should be.
June 21 - the longest day! John Moody provided me with this info on the available supercharger belts:
The pulley c-c distance of the current setup 1512 belt/ 108 teeth drive pulley/ 36 teeth sc pulley is 18.07 in
With the proposed 40 teeth pulley, the c-c distance is 17.79 in (0.28 in shorter)
The next shorter belt size is 1440-8mgt, about 3 in shorter than the 1512 belt. Pulley c-c distance would be 16.34 in ( 1.73" shorter)
The next longer belt is 1584-8mgt, about 3 in longer. Pulley c-c distance would be 19.23 in (1.16" further)
So, even with a new pulley, it appears that the best belt would be the current one.
In the evening, I did another test run of the engine: 0.5 hr
Right after start; amps = 25a, drops down to about 20, then 15 as battery charges.
Due to how my electrics is wired, I am not getting amps reading unless Avionics Master is on. I will be rewiring to fix this. So, these amps are with engine charging battery and running 2 EFIS (BMA & GRT) as well as EIS
Pop alt F breaker – amps drops to 0, idle speed increases 75-100, EIS low amps warning comes on – as it should be
Reset alt F breaker – amps goes back to 15, idle drops to 1300 indicated (really 650 – “tach p/r” issues), MAP is 7.5, fuel press is 27-28, volts = 13.8 (DVM says 14.0)
Switch aux battery on - Idle drops about 75rpm, amps rises to 22, then begins slowly falling as aux battery begins to charge up
At the end of a 20-30 minute run, amps=17 (2 batteries, 2 EFIS, EIS online), MAP =7.3, idle=710 (with EIS "tach p/r" now set to 4), GBT=90 (no prop), water & oil temp = 200, fuel press=27. All good.
June 25 - got responses from my inquiries to Gary Newsted about cooling issues (inquiring about H6/E6 radiators) and PSRU alignment issues. Gary suggested trying what I have, which at least is the easiest and cheapest solution. I'll continue to monitor what others closer to flying discover. On the PSRU alignment tool, Gary explained that it isn't aligning the PSRU; it's aligning the engine mount frame and flywheel. So, if I'm not one of those who had to swap Gen 1 for Gen2 and replace hte flywheel, then I should not need any alignment, and in fact the factory alignment, done with the engine on its back, pointing up, will be more accurate than anything I can do with the engine mounted to the firewall. Gary's answers are far more complete and useful than Jan's. I will just work with Gary from now on.
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