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So I believe I have traced my (long ago original post) fuel economy and power issues to the timing, specifially the camshaft sprocket. I fear the timing mark and bolt holes are offset from what they should be. I cannot find any information about the specific camshaft timing for this motor. My valves were just beginning to open right at tdc. Last I checked they should be opening just before tdc. So I ignored the timing mark on the cam sprocket (after verifying the crank sprocket mark was at piston 1 tdc) and adjusted the opening point to guessing 5 degrees before tdc (which happens to be 1 tooth ahead on the C.S. than what the marks indicate). Both valves are then equally open at tdc.
Before this adjustment the motor would pull up to 4000rpm then really slack off, strongest at 3200 rpm, barely able to increase speed above 5000rpm in 1st. At 5200rpm there was popping in the exhuast. Average 20.5MPG. WOT 1-2 upshift jerks the car but isn't a tranny problem. RPM changes seemed slow. Dies just after starting cold unless given a little throttle. Feels like 70% of what the power should be.
After this adjustment the motor would pull up to 5000rpm, you can feel it pick up at 3500rpm and peek at 4500rpm. At 5300rpm the popping begins and is more severe than before. Average 20.5mpg. WOT 1-2 upshift significantly improved, as well as shifting in general escpecially the 2-1 detent. RPM changes seem quick and concise. Does not die when started cold. Feels like 85% of what the power should be.
Advanced the timing 1 more tooth, valve begins to open about 10 degrees before tdc. Engine sounds really deep and throaty and loud (Advancing the timing any further results in a no-start situation).
This adjustment the engine pulls okay up to 4800 rpm, but too much of the detonation above 5000 to safely run WOT. No gas mileage numbers until tomorrow on this setting. Shifting is improved over original, but not as good as 5deg advance. RPM changes about the same as 5 degrees. Starts quick and strong.
So, does anybody have an original nylon timing gear from the '86-'87 they are willing to part with? I want to see if they are different than the chinese p.o.s. one I have. I had thought the spark timing was controlled by the crank sensor, but apparently the cam sensor has more to do with it as well. I have ruled out any possibility of electronic controls being at fault. I am using the 4t60 trans, which is set up to shift at 5600rpm, which shouldn't be a problem with the valvetrain I have, but I can't run past 5k without the detonation. The engine redlines at 5300 normally. I am using Accel coils with copper ngk plugs and heli-core bosch wires, so no ignition problems. My biggest dissappointment is still the gas mileage. I just replaced the entire suspension (struts, ball joints, tie rods, wheel bearings, sway bars, rack and pinion to newer '94 FE2 system, except springs) and michelin hydro-edge tires so I doubt it's a rolling resistance problem.
I have an '87 engine on the side, but non-original timing components though it still averaged 25mpg freeway with some electronics issues. It spun a bearing and I've pretty much stripped it for parts. I had pretty much the same issues with that motor, just slightly better gas mileage.
A separate issue, my left/right brake balance is off. New rotors, shoes, pads, reconditioned drums, calipers, rear pistons and hardware, rebuilt master cylinder. The drivers side front doesn't grab well. Hard braking makes me have to counter-steer and the passenger side will lock up if I'm not careful. I've replaced sections of brake line, and replaced the rubber hoses at the struts. I feel a pulse accompanied by a bumpy/grind at low speed medium braking. Feels like it's on the front driver side... But it seems like occationally the balance is what it should be and doesn't have any pull at all, but too random. And the rear auto-adjusters have never worked. I want to put on some rear discs, but can't find anything thats bolt-on. I don't use or care about the parking brake anymore, and I don't have a cnc to make my own brackets. My front passenger rim keeps getting covered in brake dust and the pads wear heavy on that side.
But here's my biggest problem....winter is almost here and I don't like working in the cold.
So, any original nylon timing sets out there that aren't completely destroyed?
Rear disc brakes? Anyone?
Other thoughts?
_________________ Boost addict
The Fleet:
'93 SSEi - Twincharged + manual Build thread
'97 Camaro - Top swap
'05 STS - V8, AWD, her DD
'92 Trofeo - Fair weather DD
'99 Montana - top swap 3800
'04 Sierra 2500HD - LLY Duramax
Current project:
Something cool, trust me.
Upcoming projects:
'92 Bonneville SSE
'87 LeSabre T-type
'67 LeSabre
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'84 Sierra Classic - Twin turbo 3800
'97 LeSabre - Top swap
RIP:
'86 LeSabre - pictures
'93 SE - L67
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