Had a similar situation on an old airplane I was working on about five years back. It wouldn't make proper static RPM on the ground and after checking compression, mag timing, carb settings and anything else we could think of, did a strobe check of the prop with an optical unit and determined that the tach read 200 RPM low and everything else was spot on. Beat your head against the wall for a while.......it feels so good when you stop.
Old6 will be off line for a few days, (computer getting upgraded), but I got a call on the land line yesterday and he seems to have solved his problems. All I can say is look out Rocky and Lee.......it sounds like he's ready to rock 'n roll.
Glad to hear he has a handle on it. Now we get to wait for all the gory details of the fix (till his 'puter is fixed).
Howdy folks, I'm back .......... Got the computer up again today, now I'm getting used to the new stuff and formats. Also have today and tomorrow sans rain here and got back to diddling on the HAMBster. Now that I have the problem area correctly identified I back-tracked to our original base settings on the timing & tuning and slipped the old needles back in the carbs. Once I got the damn thing to tach past mid-range we found we hadn't been all that far off in the first place. I'd sunk to questioning possibilities like slipping timing marks on the old damper, skipped timing chain, weakened valve springs and/or burnt seats but a series of basic tests showed all those to be in order. Turns out to've been mostly carb problems after all. I did a hard core rebuild of'em and threw in some primary modifications this time as well. The integrated float model SUs use a fuel temperature driven jet tube adjuster for smog applications, thus the old system of "choking" (enriching) the carb with the jet tube was replaced with a seperate circuit for the purpose. The new circuit has quite a collection of seals and fittings, all needing to be in good to excellent shape to function well. Ours were in less than stellar condition to say the least, rendering the carbs all but untunable at mid-range and just barely within the limit of adjustment at idle. After discussion our final decision was that we don't need no stinking chokes anyway. So rather than fuss with'em I eliminated the circuits (greatly simplifying the whole thing) and she's running very much better now. However I do get to start from scratch on the carb tuning once again. One favorable thing I noticed when I went back to the old needles though, is that due to the air/fuel imbalance in the wayward "choke" circuits I'd gone rather a bit overboard in needle correction and was seriously rich on the top instead of the lean I'd thought. It actually wants to be leaner than the old needles now. We'll keep'em for later though, as they should be about right for the amount of cam and valve we're considering some day. I'll have some numbers in a few days ......... So ...... anyone want to buy some slightly used, "spring" style, really rich SU needles? I also want to let you know that Russ is on the "mending" list for likely at least a couple months. He's had a few medical set-backs early this year and had to do some hospital time, but is out now and under family care while he heals and rehabs. He's hoping to be back in the game in time for Butch's first meet this year, and well enough to stay for Randy's as well. He says hi, and promises to refrain from annoying the starters in '09.
OK, Finally got the SUs doing what they should be doing and I have some numbers again. Clean and strong right up to 5500 with a little ****ping left around 6000. Tom thinks it may be valves up there and I think he may be right. We're not running that high anyway so we'll start the season off with what we have and possibly one more minor dist recurve. Also have some more bits & pieces on'er, I'll pop some new pictures in the album next week.
****, I read your last post and was wondering why you have a curve in the distributor. Why don't you just lock the timing and set the total timing for the best power. I think you'll find the throttle response and low-end TQ will be better. Just a suggestion. Ron
I guess "curve" isn't exactly the correct term but I'm not sure what would be. We like to have the advance back for idling, mostly to keep the heat down some but also to ease battery starting and to mellow'er out in the pits & lanes. I try to have it all in early enough to not be a problem at the line but it's enough of a balancing act that sometimes even minor carb changes can effect it. I'm working on a partial cooling system that should lessen the need for it from the heat angle and only add 7 lbs. If that works out well but I don't keep the "idle curve" under control we'll likely quit fussing with it and vote to go "locked" at some point. If so, I'll look into a manual advance lever for the purpose. Hell, I may just do that anyway ........
Don't worry.......you can make it as complicated as you want.......just don't add the "secret sauce". If they would just let us go back to push starting like the old days we could solve a lot of these problems.
Tom, it's enough of a grunt pushing'er by hand up the lanes. I don't think we could run fast enough to bump'er .....
OK gentlemen, I've added a few pictures of this year's changes and upgrades on the Barn Job to'er build album. I've also started on her races album. I only have the first '07 ANRA show & tell (last time at Palmdale) in it so far but will be adding the rest as I get time. For now you'll need to click up from the build album to "sets", then click on the races album. I'll get the links straightened out and hopefully added to the opening post in this thread, if I can figure out how to do it, since the edit thing seems to've timed out for that post. I figure I'll finally master these computers about the time everyone else drops'em and goes to direct mind linking ......
He's coming along. He'll be awhile getting past this one and hopes to make April and May, but can't say for sure just yet. I've told'im that if he doesn't I'll just have to buck up and force myself to do all the driving, no matter how much it hurts ......... His response wasn't really printable here ...........
Hell, most of his responses ain't printable anyway. Tell him Patti and I sent our get well fast wishes too. (If he can't stage fast, at least he can heal fast.)
Howdy gents, I've had a few inquiries on this, so here's Russ' address for awhile. Cards ( & MONEY ) may be sent there, he's under "house arrest" at .......... Russ Tidd 79421 Port Royal Bermuda Dunes CA 92203
Gentlemen, It's time to close out this thread and start a fresh '09 one as the edit feature'll time out again and I won't be able to keep the info updated. Here's the link to the new (continuing) thread ....... Barn Job #18, '09 build thread. See you there ..............
The Jalopy Journal
