MPGs run, Aspire SE

[TominMO]

Once I get the cam dialed in, whatever setting that is, I will try 4 degrees advanced just to see what happens.

[jason_]

retarding the cam pushes the torque curve HIGHER in the RPM band, it sounds like you want to make more torque LOWER in the RPM band, i'd start with 2* advance.

Yup. Stock whatever one tooth advanced in 95 aspire Higher rpm it fell on its face at high way speeds. in OD my 5sp was gutless over 75. Foot to the floor, intake growling, echoing off concrete dividers , guzzling gas.

But I could slide gears every 5mph from a stop and it'll keep marching forward with ease into OD. Walks up small Hills and makes gain even at 40mph.

I might buy an adjustable just so I could get between a tooth more appropriately, I miss the torque. I'm taking a loss factory lineup with this head shaved so much.

Noticeable torque addition idle to mid when I was a tooth advanced.

Since I don't over 75 anymore , I might jump a tooth again and keep an eye on milage. At the time when i was advanced I was pumping almost 4 gallons out the tail pipe on a 100mile trip. So I toothed back, but, now I'm back to 50/55 driving.

I might fiddle with it again someday.

Anyways, confirming a statement, and giving you food for thought.

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[TominMO]

retarding the cam pushes the torque curve HIGHER in the RPM band, it sounds like you want to make more torque LOWER in the RPM band, i'd start with 2* advance.

I'm not concerned here with torque; it's all about finding a setting where the motor won't run excessively lean, and throw a code 17. The only time that has happened in the past was when I accidentally installed Matt's MPG cam one tooth (7.8 degrees) retarded. So I am experimenting with different cam timings, and started here, at approx. 1/2 tooth retarded.

[FestYboy]

retarding the cam pushes the torque curve HIGHER in the RPM band, it sounds like you want to make more torque LOWER in the RPM band, i'd start with 2* advance.

[TominMO]

Time for an update (finally!).

Got my Dickmeyer header on, his fuel pressure regulator (FPR), and a pretty blue Fidanza adjustable cam gear made for Miatas (~$100). I'd love to post a pic of all this, but now Imageshack is acting goofy too, like Photoshop was. Anyway, It was quite a process getting the header on. Not because of any fitment problems, it fit perfectly; but the section of the bypass tube that bolts to the water pump is a larger cast one than the pipe that is on the Festy. I know that for rmoltis, Matt received his bypass tube, cut off a short section then welded it back up, to clear the #1 header tube. Not wanting to bother with all that, I went to a JY and got a Festy bypass tube, which worked fine--except for one thing. The larger pipe on the Festy bypass, which connects down to the Aspire bottom rad hose, was now too long and angled inconveniently to mate up to that hose. In fact it was much too close as well. So I cut off about 1.5" of the Festy lower rad pipe. This let me use the Aspire lower hose, which I had to shorten as well, and then angle it toward the Festy pipe. When I filled the rad and started the motor for the first time, I let it get up to temp and checked for leaks. None found.

I played around with fuel pressure, and found that I could change the at-idle pressure readout on my Innovate AFR (air/fuel ratio) meter by adjusting the FPR. I set it to 38. The cam gear was set to 0 advance/retard. Ignition timing was at 10 BTDC.

I went for a short drive and found that it bogged down at those settings. Also it barely ran at idle, about 500 RPM or so. I loosened the disty bolts and adjusted it so that it idled at ~800; I didn't bother with a timing light or setting base timing. It's probably about 13 degrees base, which I will check later.

Went for another run, and it responded much better; no bogging. But the AFR meter was showing it running too lean still. Which I expected, since I have run this configuration before. Went home and set the cam timing at 4 degrees retarded. Tmw morning I will go for a run and see what happens with the AFR.

Edits:
1. I am using Premium gas to give max protection against detonation, with all these configuration changes.
2. I suspect that given that these EFI systems are batch-fire, not direct injection, the fuel pressure might not show any significant difference in AFR, other than at idle. I am hoping that I will have gains with cam timing.
3. Concerning HP, I can't comment on the change Matt's header is making, since I am running leaner than stock. Once I get this all dialed in (if ever!), I will have the car dynoed. I would like to see stock HP or somewhat better, with a significant fuel mileage increase.

[TominMO]

OK, back from Madness VII! Had a great time meeting known and unknown folks, faces to names; the highlight was Mark (Zanzer) teaching me something about doing head work. So now at least I have the basic knowledge to disassemble/reassemble a head, and have some idea about checking valve guide wear.

Did miss Greg and the whole FL crew not being there--but hey, next year....

So back to work. Tmw I am going to the JY to snag a red hatch w/wiper & washer and nice defroster lines, if it's still there. Then back to work on MPG stuff. Think I'll get the header on first, because I dont want to have to go back and do everything over, if installing it changes all my results. Then I will install the cam gear and FPR. Should be able to do it all in a day, except for the welding. I'll just test-fit the exhaust, clamp stuff together, remove it all and take it to him for welding. So I will hopefully have it ready for more testing by mid-week.

[jason_]

$1.50 @ the car was does wonders too. Cheapest place to rent a 3000psi nozzle..... Even has soap/degreaser options!

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[TominMO]

There is a spec for stem to guide play but with that many miles I'd say it's probably time for guides, especially on the exhaust side since they wear faster due to heat.

As far as removing the carbon, Dawn Power Dissolver is your friend. Spray it on, wait 20-30 minutes and the DPD will peel it off like paint stripper.

Good info, thanks!

[Zanzer]

There is a spec for stem to guide play but with that many miles I'd say it's probably time for guides, especially on the exhaust side since they wear faster due to heat.

As far as removing the carbon, Dawn Power Dissolver is your friend. Spray it on, wait 20-30 minutes and the DPD will peel it off like paint stripper.

[TominMO]

Thanks jason_.

Well OK, some good news. All cylinders pump up to between 179 - 190 ft/lbs, well within spec. So it looks like no permanent damage was done to the head or valves. Still don't want to drive 900 miles in this car with this cam until I get it sorted out, so coming in the Festy. For the Aspire cam, think I'll start with 4 degrees cam retard not 2, because there are serious issues with 0 degrees; and I figure -2 degrees is too close for comfort.

Still bringing my other head tho, for a valve clinic.

[jason_]

Dremel 398

best one I've used, will never buy a different model, and accepts all attachments. Cheaper ones won't accept some attachments. Replaceable brushes. 1000rpm increments to 5000-35000. Electric load sensing, pours more amps to do its best to hold your set rpm when hogging material. Not a cheap slide speed switch garbage. Prescision for whatever you chuck in the arbor.

225-01 flex shaft.

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[jason_]

Take a new valve and check sloppiness. Sbi sells them for $1.89. Just buy new if your concerned.

Seals, replace while in there, you'll get a set I think with a top end kit. Heat and age makes them brittle. At the same time, I personally like a few drops of oil past the guide every few thousand opens and closes...


And your best friend will be a Dremel (good digital push button one) and snake adapter. Gobs and oodles of attachments to clean and polish those chambers. Exacto knife carefully, then clean with Dremel. There's an awesome round poofy abrasive ball/wheel/whatever. . Looks like a black man's afro. Well, brown too, colors designate abrasive level. Works wonders.

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[TominMO]

Two questions:
1. Head has ~160K miles. If replacing valve seals, should I replace guides too? How long do seals and guides typically last in Festys/Aspires?
2. What is a good tool to remove caked-on oil from the combustion chamber? I'm thinking a soft metal wire brush (aluminum or copper) that is a drill attachment.

[jason_]

You might be able to save valves. Depends how much meat you grind off before they clean up. Once they get a sharp edge, they're done.

These valves are so small and cheap, buy new ones. Kenowa hooked me up @ $7 each. More meat=eats up combustion chamber cc....

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[jason_]

FYI, Compressed air will enable on car valve seal replacement.

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