gutless bluetop *solved*

[rollaholic]

more AE85 woes.

the bluetop conversion engine is massively gutless before 4500rpm, and has remained that way despite my attempts to even it out a bit. it performs quite well above that rpm, about as well as i'd expect.

for a while i wondered if my 4AGZE ownership had spoiled me in terms of low - mid torque, but i really expect more from a 4AGE. this engine struggles to climb hills unless its past the magic 4500 number - for example, coming out of a sharpish corner at 30-40kms in second gear and starting up a middling steep hill, the engine really struggles - it reminds me alot of how my 2E was driving while the timing was too retarded. speaking of which, said 2E would whip this car off the mark (if it hadnt been rear ended that is).

the thing that really stumps me is the way the engine performs once it comes on song - it reminds me of a 4AGZE, people who have driven a car with this engine will know what i mean - you can 'feel' when the charger comes on, the whole attitude of the engine changes and great big gobs of power are suddenly avaliable... but below 4500 it struggles to pull, feels like its constantly bogged down or something - anything but the lightest throttle pedal results in lots of intake noise and a very sputtery sound from the engine. it revs freely once warm sitting still. theres also a rather large pause right as the revs hit 4500, and sometimes it refuses to rev past 4500 if im hard up it up a hill or something. is a bit of a c**t to start in the mornings, coughs along at 500rpm then stalls 4 or 5 times before its willing to idle a bit more normally. doesnt run well till its warm.

things i have done so far -

checked cam timing (was good)
checked and set ignition timing to 15 degrees advance (car just about impossible to drive with anything less)
replaced plugs and checked leads
checked compression - 130-150 on all four

check engine light is on, codes indicate o2 sensor missing - i had planned to replace it, but was told it wasnt nessecary for the engine to run well.

still need to check dizzy cap and rotor, ran out of time tonight.

the car is also guzzling gas, $40 of 95 has garnered me about 140kms.

anyone got some thoughts on other things i could be looking at?

[Rick]

Is TVIS working?

[rollaholic]

no idea. how can i check it?

[matt dunn]

From the symptoms you describe I'd almost guarantee it's the TVIS not working. My brothers AE82 was like that once, they are real crap under the 4500mark.

Dont just take it to an average w/shop to fix it as if they dont understand how the TVIS works they will just spend hours sussing it out.

First check and make sure it's there and connected.

There should be a blue solenoid under the inlet manifold,
make sure it is plugged in electrically.
There should be a black round vacuum tank, make sure it has vacuum lines attached and ther are no other vacuum line floating around under there.

do that and report back for more info,
or find someone willing and able to suss it out.

[rollaholic]

im an apprentice mechanic and i've been doing all the work myself - im pretty keen to pull the inlet manifold off this weekend and have a good look for myself... it doesnt look too complicated from some of the pictures i've seen.

when rick mentioned the TVIS i smacked myself in the head and did some searches.

two heads better than one etc

[l1ttle_d3vil]

yep, when I done my conversion I had the EXACT same issue. once i'd wired the TVIS up it went fine.
one easy way to tell when its hooked up + running is the difference in the intake noise, you can hear it sucking air through alot more above 4500rpm.

[matt dunn]

im an apprentice mechanic and i've been doing all the work myself - im pretty keen to pull the inlet manifold off this weekend and have a good look for myself... it doesnt look too complicated from some of the pictures i've seen.

when rick mentioned the TVIS i smacked myself in the head and did some searches.

two heads better than one etc

No need to pull the inlet manifold off.

Easiest thing to do is put it up on stands and look from underneath.

No point pulling the manifold off as it's all externqal bolt on's to the manifold.

[Stealer Of Souls]

Are we suggesting TVIS stuck open or closed?

If we're suggesting stuck open... I am surprised. My original bluetop with TVIS removed completely drove fine below 4500, and drove a crap load better above 4500.
Even my current bigport head/smallport bottom end drives fine below 4500 and really starts to take off above that.
Anyway. At no point did it "struggle" significantly.

[pc]

few things off the top of my head
- 10degrees and the engine should run fine. Make sure you connect the diagnostic connector before setting timing though.
- TVIS may not be working
- ECU maybe incorrect for engine. There are different ECUs for the 16 valve, they all seem to work, but with varying results.

[slighty_sykotic]

few things off the top of my head
- 10degrees and the engine should run fine. Make sure you connect the diagnostic connector before setting timing though.
- TVIS may not be working
- ECU maybe incorrect for engine. There are different ECUs for the 16 valve, they all seem to work, but with varying results.

Something is wrong with the timing... It shouldnt be on 15degrees


Like PC said, 10 should be prefect, and yet you say it doesnt run hardly on that?

I'd check ecu as pc said aswell.

Double checked cam timing? Right cam gears? Really doesnt JUST sound like tvis is stuck, as it shouldnt be THAT bad if the butterflies are stuck open, and they can't be stuck closed as it would be the other way around (great low end, crap top end).

--Sykotic

[big_boy]

im gessing these cam gears have the 3 holes to chose from like most if so there posably on the rong one

i know of a couple of race car`s that are in a class were all parts on the motor must be stock so they retard the intake cam (i think) on the belt & slightly advance the exuast & then set the spark at about 18` & they have a short but good power band from about 5-7.5k but about an extra 20% power than stock in there

[rollaholic]

i had the diagnostics pins bridged when i checked the timing, it was 15 degrees plus when i got the car, i wound it back to 10 or so and the car was even worse to drive. it idles fine at 10 degrees advance, however it has zero power.

my first suspicion was that the cam timing was out, however all the marks lined up in the appropriate fashion. im unsure if the cam gears are correct, its possible they are secondhand replacements as they have 'IN' and 'EX' as appropriate written on the face.

just had an interesting experience on a steep driveway, car refused to drive up it... kept bogging with less than 4500 revs on,, and you can imagine the results reversing up a steep, wet driveway by holding 4500 rpm on the tach.

[big_boy]

i know its a pain but can you take off your top cam cover & post up a pic of the gears while on the marks

[rollaholic]

this car is missing the top cam cover, "racer style". i'll take some pics tomorrow, though i did see some bluetop cam sprockets on trademe with the timing marks on the internal finger part of the sprocket, whereas mine have the marks on the toothed part. not sure if thats relevant to identifying them or not, but i can assure you they do line up.

[pc]

definitly sounds like something is wrong with the cam timing, a couple of teeth out or something like that. You will probably need to check the sprockets on another bluetop to be sure you have the right ones. The timing marks are really obvious, so you probably haven't got that wrong.
The indentation on the sprocket is on the tooth part, and is used to set the timing.
I can't remember if it's possible to get exhaust and inlet round the wrong way, IIRC there is only one way to put the sprockets on...

[slighty_sykotic]

definitly sounds like something is wrong with the cam timing, a couple of teeth out or something like that. You will probably need to check the sprockets on another bluetop to be sure you have the right ones. The timing marks are really obvious, so you probably haven't got that wrong.
The indentation on the sprocket is on the tooth part, and is used to set the timing.
I can't remember if it's possible to get exhaust and inlet round the wrong way, IIRC there is only one way to put the sprockets on...

Yeah its possible. Been there :p Its easy to see though, so I only bolted them on, and went shit, and turned it around.

I would check it isnt out on the bottom sprocket aswell.. That can have interesting effects.

--Sykotic

[rollaholic]

yeah i've checked the crank sprocket too - all three match up as they should. how can i tell if it has the wrong cam gears on it? i might take the rocker covers off on the weekend and check the lobe positioning... are people saying that different engines have different sized cam gears? that'd be a pain in the ass.

[rollaholic]

for those interested, the problem was indeed cam timing - the crank sprocket had flogged out around the keyway, allowing the sprocket to slide back and forth on the crank shaft by 1/3 - 1/2 of a tooth or so. obviously this was translating into a much bigger problem by the time it had transferred to the cam timing.

additionally, one of the vaccum lines from the TVIS vaccum reservoir was not connected, i believe this one was self inflicted while i was taking out the heater pipes just below it to have them repaired. the cam timing was the main problem, but no doubt this was contributing to general lack of low rev torque.

at the risk of sounding like backyard bob i tidied up the damaged keyway and crankshaft end with some sellys knead it, and replaced the crank sprocket with another one i had handy. reset timing at 10 degrees and car is now driving like a dream... it begs to go sideways and i cant stop grinning.

thanks for all the advice folks.

[RedMist]

for those interested, the problem was indeed cam timing - the crank sprocket had flogged out around the keyway, allowing the sprocket to slide back and forth on the crank shaft by 1/3 - 1/2 of a tooth or so. obviously this was translating into a much bigger problem by the time it had transferred to the cam timing.

additionally, one of the vaccum lines from the TVIS vaccum reservoir was not connected, i believe this one was self inflicted while i was taking out the heater pipes just below it to have them repaired. the cam timing was the main problem, but no doubt this was contributing to general lack of low rev torque.

at the risk of sounding like backyard bob i tidied up the damaged keyway and crankshaft end with some sellys knead it, and replaced the crank sprocket with another one i had handy. reset timing at 10 degrees and car is now driving like a dream... it begs to go sideways and i cant stop grinning.

thanks for all the advice folks.

I'd watch the crank pulley if I were you. I've seen two race engines with destroyed crank pulley, crank and flywheel through the keyway sheering. Not pretty and very expensive. Seems to be reasonably common on the 4age.

[l1ttle_d3vil]

Seems to be reasonably common on the 4age.

I've had it happen twice to my 4age within 12 months. The engine sounds like its got a real bad rattle when it comes loose.

I'm sure theres supposed to be a washer type thing in there though which I was missing. Figured that out after I'd put it all back together though and instead put a big washer in between the crank pulley and bolt and tightened it up heaps. Seems to work fine now too.

I would look at replacing the keyway AND crank pulley sometime in the near future though, as it will probably turn to crap again shortly.