Pennock's Fiero Forum
  Technical Discussion & Questions
  Quick stroker flex plate question

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
Quick stroker flex plate question by spcearle
Started on: 09-07-2013 09:23 PM
Replies: 25 (350 views)
Last post by: spcearle on 02-15-2014 06:47 PM
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-07-2013 09:23 PM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have a quick question regarding ARI 3.1 stroker motor.
I purchased a car that was said to have had one installed and was bored out making a 3.2...
I have been trying to track a vibration in the car not knowing if its engine related or suspension but all bushings are poly and all eng/ tran mounts are new... Well to get to the point .... I was under the car trying to track an oil leak and I was looking at the flex plate and it deff has weights on it... Now I thought you needed a neutrally balanced one for an 88+and correct me if I'm wrong but wouldn't that be one with 0 weights on it.....if that is the case is there anything I can do without having to pull the trans out... The vibration is deff there gradually more as the rpms go up so in my head this makes sence... It's bad enough that my tail light screws on the drivers side keep loosening and I have a crack in the drivers corner rear panel next to the screws on my gt

Any thoughts on this one guys
IP: Logged
PFF
System Bot
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-07-2013 09:36 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
If it really has a 3.1 crank then it needs a neutrally ballance flex plate
IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-08-2013 07:23 AM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
So is it possible to snap the weights off the plate without removing it.... If it isn't a 3.1 what affect would that have on the motor then
IP: Logged
Blacktree
Member
Posts: 20450
From: Central Florida
Registered: Dec 2001


Feedback score:    (11)
Leave feedback





Total ratings: 350
Rate this member

Report this Post09-08-2013 09:23 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
The flexplate will need to be removed. You can probably make your existing one work by removing the balancing weight, and having it re-balanced. But it won't be as simple as just removing the weight. It will actually need to be re-balanced. Otherwise, you'll end up with the same problem all over again.

It might actually be cheaper to just buy the correct flexplate, instead of having a machine shop re-balance your existing one.

You're probably wondering why you can't just remove the weight from your existing flexplate. There's a good reason for this. The externally balanced flexplate is not just a neutral-balance flexplate with a weight added. It's actually built to a different balance, with the weight added to fine-tune it.
IP: Logged
larry mimbs
Member
Posts: 142
From: Tennille, Georgia, U.S.A.
Registered: Jul 2011


Feedback score: (1)
Leave feedback

Rate this member

Report this Post09-08-2013 04:37 PM Click Here to See the Profile for larry mimbsClick Here to Email larry mimbsSend a Private Message to larry mimbsEdit/Delete MessageReply w/QuoteDirect Link to This Post
You can drill the spotwelds and knock the weight off. (I've done it) Then what you have is the same as if you buy a new neutral balance flywheel. I work in an engine building shop, and I do the balancing. All flywheels have too much weight variation. For that matter, so do the cranks.
IP: Logged
Blacktree
Member
Posts: 20450
From: Central Florida
Registered: Dec 2001


Feedback score:    (11)
Leave feedback





Total ratings: 350
Rate this member

Report this Post09-08-2013 05:15 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by larry mimbs: You can drill the spotwelds and knock the weight off. (I've done it) Then what you have is the same as if you buy a new neutral balance flywheel.

This may be true for a Fiero flywheel, but not the flexplates. The external-balance flexplates have 4 big holes in an asymmetrical pattern, whereas the neutral-balance ones have 3 big holes in a symmetrical pattern. If you take the balancing weight off an external-balance flexplate, the flexplate will still NOT be neutrally balanced, because of the asymmetrical hole pattern.

Edit to add photos of the two different flexplates:



[This message has been edited by Blacktree (edited 09-08-2013).]

IP: Logged
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-08-2013 07:01 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
Flex plates should be a dime a dozen, I just tossed one from a 3100, you should find piles of them at the scrp yard. Larry
IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-08-2013 07:39 PM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Finding/ buying isn't the issue... I'm planning an overdrive swap in the future but didn't want to have to pull the tranny for any reason till then.... Any way of verifying in fact if it is a 3.2 or just a 2.8
IP: Logged
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-08-2013 08:11 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
If it shakes so bad you cracked body pannels I think you have answered your own question. Are you sure the block is a 2.8? Look to see if there is a place to bolt a starter on the back side of the engine, if so then it is likely a 3.1 RWD engine and will need a newtral FW. Larry
IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-08-2013 08:51 PM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
As stated it wasn't ever said to have been a 3.1 block I was told the motor was rebuilt and bored using an ARI kit... The crack was there prior to my purchase and the engine only had a cpl hundred miles... I've put an additional 1800 on it since I bought it... Not sure if the vibration is in fact from the engine all I saw was weights on the flex plate which either tells me it's the wrong flex plate that can explain the vibration or its not a 3.2 and the vibration is somewhere else
IP: Logged
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-08-2013 09:29 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
Short of pulling the pan I don't know of any way to tell for sure what you have. I would tend to believe what the seller told you, every thing you say points that way. If you could find an inspecton camera that will fit through the oil drain plug you could look at the crank and know for sure unless someone put a windage tray in it like a 3100 has. Larry
IP: Logged
PFF
System Bot
MarkS
Member
Posts: 431
From: Flemington, NJ
Registered: Mar 2006


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-09-2013 07:20 AM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by spcearle:

As stated it wasn't ever said to have been a 3.1 block I was told the motor was rebuilt and bored using an ARI kit..


If it is an ARI kit, then it has the stroker crank and needs the neutral balance flex plate. Did you get any receipts from the previous owner?

BR's,

Mark
IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-09-2013 07:39 AM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
No receipts..... Will I be able to tell possibly by looking at the crank or anything?
IP: Logged
fierosound
Member
Posts: 14509
From: Calgary, Canada
Registered: Nov 1999


Feedback score: N/A
Leave feedback





Total ratings: 280
Rate this member

Report this Post09-09-2013 08:50 AM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Wrong flexplate/flywheel IF you have the ARI engine.
http://www.engine-parts.com/GMV6/gm2831stkr.html

"You MUST use a Neutrally balanced flywheel with this stroker engine!"

I sure sounds like someone MISSED reading that line.


------------------
My World of Wheels Winners (Click on links below)

3.4L Supercharged 87 GT and Super Duty 4 Indy #163

[This message has been edited by fierosound (edited 09-09-2013).]

IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-09-2013 10:01 AM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's either that or it's not a stroker kit in it and is just a rebuilt 2.8
IP: Logged
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-09-2013 11:19 AM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes, you can easily tell by looking at the crank. Larry
IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-09-2013 11:26 AM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
What do I need to look for... I'll drop the pan to inspect to verify
IP: Logged
Blacktree
Member
Posts: 20450
From: Central Florida
Registered: Dec 2001


Feedback score:    (11)
Leave feedback





Total ratings: 350
Rate this member

Report this Post09-09-2013 12:20 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
The stroker crank will have a crank trigger wheel in the middle of it. It's basically a big disc with some notches cut in it. The stroker crank also has casting number "981" on it. See photo below.

[This message has been edited by Blacktree (edited 09-09-2013).]

IP: Logged
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-09-2013 12:36 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
Some of the cranks may have the wheel with no notches cut in it. Larry
IP: Logged
MarkS
Member
Posts: 431
From: Flemington, NJ
Registered: Mar 2006


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-09-2013 12:55 PM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trotterlg:

Some of the cranks may have the wheel with no notches cut in it. Larry


Yep & I believe 486 is also a 3.1 crank casting #.

BR's,

Mark
IP: Logged
Blacktree
Member
Posts: 20450
From: Central Florida
Registered: Dec 2001


Feedback score:    (11)
Leave feedback





Total ratings: 350
Rate this member

Report this Post09-09-2013 08:31 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Mark, you may be thinking of 186, which is what 981 looks like upside-down.

Edit to add: there was also a casting number 268, which IIRC is interchangeable with the 981 crank.

[This message has been edited by Blacktree (edited 09-09-2013).]

IP: Logged
PFF
System Bot
trotterlg
Member
Posts: 1378
From: WA
Registered: Aug 2011


Feedback score: (2)
Leave feedback

Rate this member

Report this Post09-10-2013 01:10 AM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think you are lucky to find the problem, that is probably why they sold the car. It is really quite an easy fix, you can probably do it by just dropping the rear of the cradle down and pulling the transmission while supporting the engine with a 4X4 across the strut mounts and some chain. Larry
IP: Logged
MarkS
Member
Posts: 431
From: Flemington, NJ
Registered: Mar 2006


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-10-2013 08:19 AM Click Here to See the Profile for MarkSClick Here to Email MarkSSend a Private Message to MarkSEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Blacktree:

Mark, you may be thinking of 186, which is what 981 looks like upside-down.

Edit to add: there was also a casting number 268, which IIRC is interchangeable with the 981 crank.



The 486 was in a Marshall crankshaft kit I was thinking about getting several years back. Dunno, maybe they were reading it upside down! Could be the 486 was the early Transport TBI 3.1 crank.. In any event, I didn't buy it as I might wind up with a welded up rod journal in one of those kits.

IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post09-10-2013 09:39 AM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well either wating guess I'll just start looking for the parts for either the overdrive swap or piece together the stuff to drop a 5 spd in it.....I'm really certain that it is the wrong plate in the car which is no biggy but if the tranny has to come out to replace it it sure as hell ain't gonna go back in(. 3pd tranny with no 1st gear). I could use the extra gear / gears anyways since I do a lot of trips in this car for my military...plus I figure if I'm upto 25 mpg on this motor and missing a gear and having a balance issue that is shine can't be helping mpg any having an extra gear and hopefully smooth running motor should help on gas and performance some
IP: Logged
raysr11
Member
Posts: 1254
From: Concrete, WA
Registered: Nov 2008


Feedback score:    (12)
Leave feedback

Rate this member

Report this Post09-10-2013 02:39 PM Click Here to See the Profile for raysr11Send a Private Message to raysr11Edit/Delete MessageReply w/QuoteDirect Link to This Post
You could get one of those small cameras that go through the spark plug hole and look at the pistons. 3.1 will be dished.

[This message has been edited by raysr11 (edited 09-10-2013).]

IP: Logged
spcearle
Member
Posts: 163
From: rochester,ny,14623,us/ brooklyn ny 11209
Registered: Jan 2013


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-15-2014 06:47 PM Click Here to See the Profile for spcearleClick Here to Email spcearleSend a Private Message to spcearleEdit/Delete MessageReply w/QuoteDirect Link to This Post
well it took a long time to be able to getthis into a garage to do this but i finally got the pan dropped

first off it definately has the center piece on the crank with the notches but comparing it to the picture above in this topic it is not nearly as large diameter...in the picture it looks fairly close to the edge of the block where as mine deffinatly has alot more space their

also the car doesnt knock and oil pressure is always around 60psi but the rods do have some front to back play ...is this normal .. i mean i can slide them on the crank just a littlebit side to side....no up and down play
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock