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engine/transmission in wrong place? by fierosound
Started on: 05-22-2007 03:15 PM
Replies: 15
Last post by: fierosound on 07-01-2009 11:35 AM
fierosound
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Report this Post05-22-2007 03:15 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

You guys swapping in a 4T60 4-speed automatic may want to check this on your installation.

I noticed this on the cradle (best photo I have), and it has now been verified with engine and transmission in car. Looking at the axles in this 4T60 swap, you can see that the centerline of the axles is about 1" further back with the axles angled that way (looks the same on BOTH sides). Stock Fiero mounts are used. Do the axles normally align "straight in" with a 4T60 swap?





Fast forward - the engine/transmission and cradle are in the car (86 cradle in an 84). All stock mounts are used, the 4-cylinder engine/trans is "square" on the cradle. The cradle doesn't appear to have been modified. Measurements verify this. We have the knuckles straight up as they would be with struts installed, and everything looks the same - axles angled back to transmission.

But another measurment is way off. Measuring from the head's intake face (intake not installed) of the cylinder head to trunk wall is 1-1/4" LESS than every other Fiero with a 4-cylinder I measured. They all have 11-1/2" of clearance. I have 10-1/4".

It's a total mystery - 4 of us have looked and measured everything we can think of and the only thing that looks "wrong" is the angle of the axles and our measurements indicate the engine/trans should be 1" forward on the cradle.

The only thing left to try is to move everything onto the original 84 cradle and see how that fits (used the 86 because it was less rusted than the original). We compared measurements on both cradles and they appear to be the same. Theortically, we should wind up with the same "problem" since the cradles are supposed to be identical.

But then, what is causing this problem? It's a mind-bender!!

------------------

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[This message has been edited by fierosound (edited 06-29-2009).]

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fierosound
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Report this Post05-22-2007 03:32 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

I found this diagram of the cradle dimensions from the 86 Service Manual. I don't have the 84 manual handy (at work right now), but the dimensions should be identical.

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RCR
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Report this Post05-24-2007 07:52 AM Click Here to See the Profile for RCRClick Here to Email RCRSend a Private Message to RCRDirect Link to This Post

Measuring the centerline of the input shaft to the axel on your old trans and similarly on the new trans will tell you right away if there is an issue.

Now, I'm doing a swap using the 4T80e and my axle centerline is about 1.5" back from the stock axles. I've been told this is fine and will not affect anything.

Bob

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fierosound
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Report this Post05-24-2007 10:25 AM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

 
quote
Originally posted by RCR:

Now, I'm doing a swap using the 4T80e and my axle centerline is about 1.5" back from the stock axles. I've been told this is fine and will not affect anything.



Thanks Bob. That's what I was hoping someone could answer about the 4T60 swap, because I don't have the original trans around. I've never seen any mention of the axle centerline being further back than with the stock transmission on any of the "tranny swap" directions at all. But if that's "normal" for this transmission swap, I won't worry about it because I didn't think it would cause a problem anyway.

But what really puzzles me is why I seem to be missing 1-1/4" of clearance between the head and trunk firewall. Things are really tight in there and there isn't much clearance! I have to put the engine/trans on the original cradle and put it back in to check, because I'm sure the fit was better - but it was 8 months back when I took it out.

Could you guys with 4-cylinder Fieros measure from intake gasket to firewall and tell me what you have?

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RCR
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Report this Post05-25-2007 06:53 AM Click Here to See the Profile for RCRClick Here to Email RCRSend a Private Message to RCRDirect Link to This Post

Does the dogbone still fit? The engine itself shouldn't be any closer to the firewall. Is the motor tilted back?

Bob

[This message has been edited by RCR (edited 05-25-2007).]

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fierosound
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Report this Post10-03-2008 12:49 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

 
quote
Originally posted by RCR:

Does the dogbone still fit? The engine itself shouldn't be any closer to the firewall. Is the motor tilted back?

Bob



Just updating an old topic. No the dogbone would not fit either, the motor was tilted back.

It seems that if you use the stock Fiero transmission mounts with the 4-speed auto (4T60 in this case), the entire powertrain is tilted toward the trunk firewall. In seems most people haven't noticed this or have not had a problem with it. When looking underneath we noticed that the front of the transmission pan was higher than the back edge of the pan relative to the cradle.

We solved the problem by using a 1" Dodge mount for the front transmission mount. We just burned off the rubber from the Fiero mount and drilled/bolted in the Dodge mount. This tilts the engine/transmission forward into the proper position. The transmission pan is now completely level with the cradle, the engine is verticle and the axles are in line with the hubs now.

Not my pictures, but this is essentially what I did. Engine and rear transmission mounts are stock, but for the front transmission mount, an Anchor Industries PN 2266 (67-69 Dodge Dart 273 V8 engine mount) is used. It is about 1-inch thick and has 2 offset mounting bolts.



[This message has been edited by fierosound (edited 10-03-2008).]

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NW-Fiero
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Report this Post10-03-2008 07:30 PM Click Here to See the Profile for NW-FieroSend a Private Message to NW-FieroDirect Link to This Post

And this is why Rodney makes/sells an adjustable Dog Bone....?

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fierosound
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Report this Post10-04-2008 01:32 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

 
quote
Originally posted by NW-Fiero:

And this is why Rodney makes/sells an adjustable Dog Bone....?



I suppose that would work in some cases, but I still wouldn't have been able to get the 4-cylinder intake on because there wasn't enough clearance between the head and firewall. So in MY case that would not have been any good, and repositioning the transmission/engine back to it's correct location was a better route.

Before and after pictures.

The bracket sits on the end of the intake manifold and the 3/8" thick plywood is a mockup of this thickness.



Changing the front transmission mount brings everything back in line. The intake manifold will now fit.

[This message has been edited by fierosound (edited 10-06-2008).]

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Raydar
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Report this Post10-04-2008 01:43 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarDirect Link to This Post

 
quote
Originally posted by fierosound:
I suppose that would work in some cases, but I still wouldn't have been able to get the 4-cylinder intake on because there wasn't enough clearance between the head and firewall.


That's not a surprise.
The only 4 cylinder Fiero I've ever owned was my 88 coupe, before the swap.
The air filter canister was very close to the trunk wall. Actually, close enough to smack the trunk wall, when the dog bone bushings wore out.

Glad you figured it out. I never realized that there was a difference in how the 4T60 mounted.
(I'll have to check out the 4T60E in my 4.9 car. )

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86GT3.4DOHC
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Report this Post11-10-2008 05:53 PM Click Here to See the Profile for 86GT3.4DOHCSend a Private Message to 86GT3.4DOHCDirect Link to This Post

Hey! My mounts.

FYI, I had a hell of a time with those things always ripping apart. Actually it was my rearmost tranny mount, but I seperated the rubber from the metal twice before I just replaced it with a captured round mount. (Think dogbone).

I dont remember if the front ever broke on me, but I replaced it with a caputured mount as well. My DOHC might have sat funny or torqued funny, I dont know.


... wait a minute. That ground doesnt look familiar, and I never had my rear struts off, maybe those arent my pictures. Okay, well I did exactly the same thing as those pictures, close enough, I thought those were mine. Anyway, just relating experiences.

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fierosound
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Report this Post06-28-2009 11:06 AM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post



If you're swapping in a 4T60 4-speed automatic, you should look underneath to see if your transmission pan is sitting level horizontally.

[This message has been edited by fierosound (edited 06-29-2009).]

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Isolde
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Report this Post06-29-2009 01:43 PM Click Here to See the Profile for IsoldeSend a Private Message to IsoldeDirect Link to This Post

most years of Porsche 911s run the axles not in-line, but at an angle.

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josef644
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Report this Post06-29-2009 08:44 PM Click Here to See the Profile for josef644Click Here to Email josef644Send a Private Message to josef644Direct Link to This Post

fierosound
Good, no, Great information, and a + from me for this tid bit.
Joe Crawford

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fierosound
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Report this Post06-30-2009 06:39 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

 
quote
Originally posted by josef644:

Good, no, Great information, and a + from me for this tid bit.



Thank you...

When I found this problem of not being able to install the intake manifold, I searched A LOT and found absolutely no mention by anyone of this problem when installing a 4T60 transmission. I suppose the V6's aren't in as tight against the trunk firewall as the Duke engine, so most people just made do with a shorter/adjustable dogbone instead of fixing the real problem of engine orientation. It seems the transmission is just slightly wider than the stock TH125 so a shorter front transmission mount is needed to correct this.

[This message has been edited by fierosound (edited 06-30-2009).]

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Dennis LaGrua
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Report this Post06-30-2009 08:55 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaDirect Link to This Post

For the 4T60 trans to sit squarely in the cradle you must slot the rear trans mount holes in the cradle towards the center and reverse the Fiero trans mount so that offset is achieved. There is a write up on Fieroaddictions website.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
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fierosound
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Report this Post07-01-2009 11:35 AM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundDirect Link to This Post

 
quote
Originally posted by Dennis LaGrua:

For the 4T60 trans to sit squarely in the cradle you must slot the rear trans mount holes in the cradle towards the center and reverse the Fiero trans mount so that offset is achieved. There is a write up on Fieroaddictions website.



Been there when I started and I did all that. http://www.fieroaddiction.com/4T60a.html

Still, people should check how their transmission pan sits relative to the cradle and ground.

[This message has been edited by fierosound (edited 07-01-2009).]

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