RockLobster

iTrader: (7)

Ok i am trying to set the timing on my car. This car was a basket case when I bought it a year ago, i have had to rewire much of the engine bay and basically strip the engine down to the block and put it all back togeather while in the car. The engine is a mazda reman that seems to have been installed by a complete nimrod.

I think i have everything in order now and the car seems to run pretty well. Car produces good vacume and boost. Plenty of fuel pressure and fuel pump voltage. The timing is the only major issue left. The car is very rough running under heavy throttle and at higher RPMS.

When I use the timing light as instructed by the FSM i do not see the marks. The pully has clearly visable marks but not when the engine is running using the timing light. As part of the teardown I took the front pully off and installed a solid thermo pellet. Is it an easy at all to install the pully on the boss in the wrong orientation? As i understand it the thing is keyed by the irregluar radial locations of the 4 bolt holes on the pully. But is it possible to install it wrong still without realy trying to stretch the holes?

I am also thinking that it is possible the CAS was installed incorrectly. Is it fairly easy to restab the CAS if it was installed by someone else incorrectly?

The car actually runs ok, just dosn't purr like i belive it should. So it cant be that far off but i bet it is enough to possible damage the motor under boost WOT.

RockLobster

iTrader: (7)

Maybe this discussion needs to go the way of methods for finding TDC without using the pully marks.....

HAILERS

..............................When I use the timing light as instructed by the FSM i do not see the marks. The pully has clearly visable marks but not when the engine is running using the timing light. As part of the teardown I took the front pully...................................

So? When you used the timing light and the marks did not align, did you rotate the CAS until they did align??? Or did you rotate the CAS and then the marks still did not align?? As in turning the CAS while the engine is running and you have the timing light on at the same time.

The bolt holes are off enough for you to have noticed you were screwing up if you had the pattern off.

There is no method for finding TDC with the engine in the car. Screw that thread/post that has you pull the plugs and look for the apex seal to show itself in the trail plug.....make a mark......turn the shaft til the apex seal shows itself in the lead plug hole. THAT is nothing more than a ballpark figure. Ain't no damn good for finding true TDC. I'm talking spot on TDC.

You'd be better off buying a used first generation carb pulley and mating its marks to your second gen pulley.

RockLobster

iTrader: (7)

Meaning the marks are so far off, + or - 60° or more that when the timing light is flashing they are not in the realm of the point on the front cover.

Yet the car still runs fairly well.

HAILERS

When your using the timing light, your on the LEAD wire??? Either will do. Use the one that gives the most steady pattern of flashes.

Did you notice anything when you had the engine running and turned the CAS???? Did any smudge/mark/dent/scratch on the pulley move as you turned the CAS when at the same time you had the timing light shining on the pulley????

RockLobster

iTrader: (7)

I do need to play with it some more. I am still suspecting that the CAS was stabed wrong either way...

ill know more tommorow.

HAILERS

There's a couple of tack you could take. Remove the four small bolts that hold the pulley on the hub and see if they are wallowed out. If not, then reinstall the pulley.

Then restab the CAS. By......removing the top black cover off it. Then align the pulleys first mark with the fixed pointer. Then align the bottom of the cas gear with the fixed mark on the body of the CAS. Holding the CAS in that position, now look in the top of the CAS and note where the gears/any gear is in relation to a fixed point on the CAS.

Now with that gear and fixed point on the CAS body in mind, install the CAS in the engine. The shaft of the CAS will move as you install the CAS. So what you do now is rotate the body of the CAS until the gear in the CAS again aligns with the fixed point on the CAS none moving part. Make sense?????

If you find that when you rotate the cas body the gear and fixed point won't align due to not being able to rotate the CAS body enough, then restab the cas again but try moving it a tooth off one way or the other til you get the desired result.

HAILERS

Tell you what. Go to the thread I'm attaching at the bottom of this post. Go to the second page of that thread and you WILL see a jpg I attached. It shows the top of the CAS internals when the CAS is stabbed and the first mark on the pulley is aligned with the fixed pointer.

So go align your pulley's first mark with the fixed pointer. Take the top off the CAS so you can look at the internals. If you loosen the CAS attach bolt and turn your cas til it looks like the one in the jpg, then the timing should be almost spot on. Just look at the two top gears that are 180 out from each other. See how they almost cut the corner of the two black coil assy's??????

If you can make your cas match the jpg then when you next put a timing light on the engine you should be able to see the marks align with the fixed pointer.


The thread (second page on that thread) https://www.rx7club.com/forum/showth...ht=picture+cas

That jpg was taken with the CAS on a scanner, so don't be looking for a CAS clamp down bolt holding it in place.

RockLobster

iTrader: (7)

I think that should make it pretty straight forward.

Thanks...

I'll let ya know what i find.

RETed

There is no way the pulley can be installed incorrectly.
No, you cannot "stretch" the holes so that all 4 bolts would fit.


-Ted

RockLobster

iTrader: (7)

Well folks i found the problem. CAS was stabbed wrong by the installing mechanic of the reman (prior to my ownership). It was off at least 1 tooth.

She now puuuurrrrrssss. Rock solid 750rpm idle under all electricall loads. Good power, good vac. After nearly a year of messing with the car everything is coming togeather.


Now, the marks were probably 15-20° to the left of the needle even when the CAS was turned as far clockwise as it could go (closest to lineing up marks possible) Does this mean the car was running retarded or advanced a whole bunch....???

trochoid

iTrader: (6)

You would be suprised what morons can do. I had a guy show up at my house, with a 7 he had had for 2 weeks. The guys that replaced the waterpump did manage to get the pulley indexed wrong. Since it couldn't be tightened down properly, the pulley loosened up and wallowed out all of the bolt holes.

New pulley and he was on his way. I still haven't figured out how they managed to get it bolted up wrong.

HAILERS

It was advanced too far.

It's still advanced too far if the marks are to the left of the pulley.

Make sure the idle is below say 800 rpm. Preferably closer to 750. If over approx 1100 rpm the ECU advances the timing. You don't want that to happen.

RockLobster

iTrader: (7)

We'll hopefully not too much damage was done. And I should correct myself, the marks were 20+ deg left of the needle even when the CAS was clocked counter clockwise all the way.

HAILERS

If your looking towards the pulley, and the marks on the pulley are to the left of the fixed pin, then the timing is advanced to far. Maybe reinsert the cas again? As in try, try, try again? Are the rpms in the 700-800 range? When you check the timing?

RockLobster

iTrader: (7)

RPMs are good, timing is now perfect. I was just commenting on where it was before i restabed the CAS. I know it is correct now. Everything is good. I just hope i did not do damage to my engine.