opti sparks

[Johnyd2]

Alright after searching for some cheap spare parts because i have to much time on my hands i am really confused about the opti. I know the difference between between the vented and unvented. But there is a huge price gap between a few items.

Here is a cap and rotor from MSD :
http://store.summitracing.com/partde...5&autoview=sku
from summit

http://cgi.ebay.com/ebaymotors/MSD-G...QQcmdZViewItem
from ebay

here is the "optispark ditributor"
http://store.summitracing.com/partde...5&autoview=sku
from summit

http://cgi.ebay.com/ebaymotors/MSD-9...QQcmdZViewItem
from ebay

The pictures are the same?????
can anyone explain what the difference of the two parts is, cause with the difference in price there is something up.

also is this everything i would need for changing out the opti?
http://cgi.ebay.com/ebaymotors/ws/eB...8213278&rd=1,1

any related info would be appreciated.

[Joe 1320]

The version that you purchase must be the correct one for your car. 93-95 use the unvented opti which is more expensive, the 96-97 use the vented opti. The MSD cap and rotor works well, but that leaves several items in the base of the distributer to fail at some other point, requiring you to disassemble the whole thing again. The best solution is to replace the entire unti with an AC Delco complete plug and play distributer. This way the bearings and electronics are also replaced for many more trouble free miles.

[Rob B (shoebox)]

The version that you purchase must be the correct one for your car. 93-95 use the unvented opti which is more expensive, the 96-97 use the vented opti. The MSD cap and rotor works well, but that leaves several items in the base of the distributer to fail at some other point, requiring you to disassemble the whole thing again. The best solution is to replace the entire unti with an AC Delco complete plug and play distributer. This way the bearings and electronics are also replaced for many more trouble free miles.

I think you mean 93-94 are unvented and 95-97 are vented (in f-body cars).

[Joe 1320]

I think you mean 93-94 are unvented and 95-97 are vented (in f-body cars).

Yep, senility at it's finest. That's what happens! I stand corrected. 95 is indeed vented.

[Johnyd2]

im still not following. why is one 150 dollars and the other is like 500 dollars??

can someone review both ads and give me a brief explaination.
You guys are always helpful, and this is something im really not following.

[LoudLT1]

$150 for cap and rotor only.
$500 for complete unit.
ebay has complete units ac delco for $250 or so..
on a 95 you should really replace the complete unit
eddie

[Joe 1320]

im still not following. why is one 150 dollars and the other is like 500 dollars??

can someone review both ads and give me a brief explaination.
You guys are always helpful, and this is something im really not following.

That's a good question. For reasons beyond normal common sense, the vented optis are much less expensive. Sometimes ya just gotta go with the saying "It is what it is".

[Dave Vince]

What ever you do don't buy a so called rebuilt one from any parts store. They fail to change the worst part in the unit the optical sensor.

[Injuneer]

Shoebox has links to cheap GM parts sources:

http://shbox.com/1/4th_gen_tech2.html#Dal_and_Jason


The Opti consists of two major parts.....

The base, that bolts to the front of your engine. This included the rear housing, the bearing, bearing retainer, optical module and optical wheel. The optical module provides a high accuracy cam position signal to the PCM. This signal is used to set the injector timing and the ignition timing. Your car will not run without these signals (at least the low resolution pulse pattern).

The front section is the cap and rotor. These are identical in function to any conventional distributor, they are just an unusual "pancake" shape.

While the cap and rotor fails in the majority of the cases, the optical sensor and the bearing can also fail and shut your engine down, or cause irregularities in the firing of the cylinders.

The factory GM part is the only one with a large history on it. The MSD is new and expensive. Initial installs have produced a few problems, that MSD is investigating. Its hard to justify $450-500 for a unit that may have as many or more problems than the factory unit. Units from Accel and Summit have also experienced problems, at least as frequent as the factory units. But the number of Accel, Summit and MSD units in service is too small to provide a meaningful sample size.

My choice would be an OEM GM factory unit, from one of the sources that Shoebox lists.