backfiring through the intake...
Thread Starter
Registered User
Joined: Feb 2004
Posts: 357
From: Eldridge, IA
Re: backfiring through the intake...
Originally Posted by Pasky
Opti fell off the slot, I gaurantee it. Went through this two months ago.
http://shbox.com/ci/opti_mounting.jpg
Your dowel pin fell into '4'. That little cavity between the place where its supposed to be. The opti will fit snug and seem like it is on correct. Mine also backfired through the intake during my first cam swap. I gaurantee this is the problem.
http://shbox.com/ci/opti_mounting.jpg
Your dowel pin fell into '4'. That little cavity between the place where its supposed to be. The opti will fit snug and seem like it is on correct. Mine also backfired through the intake during my first cam swap. I gaurantee this is the problem.
Huh?!?! Not sure I understand this.
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Joined: Jan 2003
Posts: 1,362
Re: backfiring through the intake...
The opti goes on one way:
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
Thread Starter
Registered User
Joined: Feb 2004
Posts: 357
From: Eldridge, IA
Re: backfiring through the intake...
Originally Posted by Pasky
The opti goes on one way:
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
Registered User
Joined: Jan 2002
Posts: 1,469
From: J-ville,NC
Re: backfiring through the intake...
Originally Posted by Pasky
The opti goes on one way:
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
http://shbox.com/1/opti_back.jpg
Where the arrow is pointing is where your dowel pin needs to go into it (not in the small rectangle its pointing at, but the slot connected to it). It goes into the slot with the small rectangle on top of it. What happened is I know its a pain in the *** to see where its going into when your installing it, is....You put the opti on and the dowel pin on the cam fell into one of this big circles. The opti will seem like it is on correctly because it will seat against the block just fine. I bet your car sounds like it wants to start, fires off about 2-3 cylinders and back fires right? You need to re-install the opti and correct it. I had the EXACT same problem.
Registered User
Joined: Nov 2001
Posts: 3,515
From: Kansas
Re: backfiring through the intake...
I buddy of mine installed his opti wrong like you described and it wouldnt start. We set the valves a couple times and swapped injectors and looked at every little thing till we decided to just see if the opti was on wrong and sure enough.. it was. Only difference was it wasnt backfiring thru the intake but you could hear it hit once in a while. I guess you may have the dowl in the other slot.
Thread Starter
Registered User
Joined: Feb 2004
Posts: 357
From: Eldridge, IA
Re: backfiring through the intake...
yeah, when we installed the opti I didnt even realize that the dowel pin had a certain spot to time it correctly. I have another question though: The dowel pin was much longer than the original cam, so we ground some off. Is it possible that we ground it too short?
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Joined: Jan 2003
Posts: 1,362
Re: backfiring through the intake...
Taken from shbox.com:
GM specs indicate that the dowel should be .620" long (protrusion from the front face of the cam) for the vented optispark. Some people have said it is supposed to be .685". Mine was actually .650" and still was in no danger of bottoming out in the optispark drive (I'm thinking .685" might be the max it could be).
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Joined: Jan 2003
Posts: 1,362
Re: backfiring through the intake...
No idea, I doubt you went too far because your opti is being driven and is firing off sparks. If you were too short it would not go into any of the "cavities" on the opti and the opti would not spin. Your fine.
Thread Starter
Registered User
Joined: Feb 2004
Posts: 357
From: Eldridge, IA
Re: backfiring through the intake...
Originally Posted by NightTrain66
hopefully we have found the answer.
Lloyd Elliott
972-617-56710
Eportworks.com
Lloyd Elliott
972-617-56710
Eportworks.com
Thread Starter
Registered User
Joined: Feb 2004
Posts: 357
From: Eldridge, IA
Re: backfiring through the intake...
Originally Posted by wicked_95z
That can be pretty tricky trying to get it in the correct slot. Good luck
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Joined: Apr 2001
Posts: 2,195
From: Springfield, IL
Re: backfiring through the intake...
the pin is pressed in
they are a mother****er too get out (from my experience)
sometimes a pair of thin needle nose pliers to grab the back of the opti that sits over hte dowel pin is the easiest way too move it around to get it too seat corrsclty on the dowel pin
just start by lining up the rectangle in relation to the dowel pin before you put it on
physically hold the opti like you are putting it on and go "ok the cam dowel is at 9 o'clock...so i will rotate the opti rectangle too 9 o'clock also before i try to slide it on" (those sre just example reference points, it doesnt have too be at 9 0'clock)
they are a mother****er too get out (from my experience)
sometimes a pair of thin needle nose pliers to grab the back of the opti that sits over hte dowel pin is the easiest way too move it around to get it too seat corrsclty on the dowel pin
just start by lining up the rectangle in relation to the dowel pin before you put it on
physically hold the opti like you are putting it on and go "ok the cam dowel is at 9 o'clock...so i will rotate the opti rectangle too 9 o'clock also before i try to slide it on" (those sre just example reference points, it doesnt have too be at 9 0'clock)