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Ecklers AutoMotive
Username Post: Definitively, can a 4L80E be fitted in a 67 Tunnel?        (Topic#353772)
mjc1 
Senior Member
Posts: 1525
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
11-05-18 09:54 AM - Post#2750505    

Can anyone here that has done it give some insight once and for all into what has to be done? I know there is a member here that did it in a yellow 66 (cant find him??), but that was an LS conversion, which probably moves the engine for or aft to a different spot then a Mark BB.
I know all the external stuff that needs to be done along with the cross-member mod and the banjo cooler fittings, it's just the tunnel and under seat floor bracing interference that concerns me somewhat. Everything else can likely be easily overcome.

Any thoughts?
Cheers and thanks, Mark

1967 Grande Parisienne 4DR HT
My Flickr page



 
Ecklers AutoMotive
9Teen67Biscayne 
"2nd Year" Silver Supporting Member
Posts: 137
9Teen67Biscayne
Loc: OK
Reg: 07-29-16
11-06-18 07:50 AM - Post#2750597    
    In response to mjc1

Mark - I don't have specific dimensions or comparisons but... on my 67, I installed a 2004r behind the LS...no modding of the tunnel - slid right in... one of the reasons I went that way was due to the area being tight. negatives with mine were increased cost to bulletproof the trans... but I do think the 4l80e is much larger and would require some enlarging of the area. Oh...here's the link to the yellow 66 that stuck the 4l80 in.
https://www.chevytalk.org/fusionbb/showtopic.php?t...

Tim Saepe Expertus- Semper Fidelis- Fratres Aeterni

"He must be the stupidest sonofabitch alive - but he sure is fast." - F. Gump


 
mjc1 
Senior Member
Posts: 1525
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
11-06-18 12:47 PM - Post#2750619    
    In response to 9Teen67Biscayne

Thanks for the reply Tim.
And thanks for the link. Looks like Gerald hasn't been here in a while.


1967 Grande Parisienne 4DR HT
My Flickr page



 
65_Impala 
Very Senior Member
Posts: 4172

Reg: 12-29-02
11-09-18 09:00 AM - Post#2750875    
    In response to mjc1

I can't see it being too difficult. The TH400 and 4L80e cases are very similar. The 4L80e is a little bigger in diameter in around the last 1/4 of it's length and the large part of the case is maybe 2" longer before the tail piece starts. The TH400 fit, so I can't see it requiring too much massaging to get the 4L80e in there.

Here is an example picture of both side by side to see the difference.

https://www.700r4transmissionhq.com/th400-vs-4l80e...







 
mjc1 
Senior Member
Posts: 1525
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
11-11-18 05:05 PM - Post#2751083    
    In response to 65_Impala

Yes, I can see that some interference might happen on the last few inches of the main case. There are some gussets that stick out pretty good. Maybe they can be trimmed down or rounded off just a little?
There is also a bulge for the forward planetary just behind the bell housing that the the 400 doesn't have.

1967 Grande Parisienne 4DR HT
My Flickr page



 
toro455 
"4th Year" Silver Supporting Member
Posts: 546
toro455
Loc: Western NY
Reg: 06-15-02
11-12-18 03:04 AM - Post#2751115    
    In response to mjc1

Mark,
I don't know if I like this idea myself yet but one way to gain a small amount in the rear would be to lower the transmission mount position. That would primarily affect the rear because the pivot point would be the motor mount area. If the transmission cross member was lowered by something like 1/4" it seems it would be next to nothing in the front where the fan needs to go through the shroud. I've been making some of the transmission mount support brackets and I could change the bend point of the tongue to lessen the offset/step and that would in turn lower the mounting point. If I take too much out the ears which get welded to the vertical portion of the frame would need to be extended because they would get into the lower radius of the frame. At the moment I'm working with photos I previously took but you can probably follow the idea.

Obviously it would be great if it just fit but if it is so close that you think machining some bosses might help this might be another way to avoid touching the floor. You would still need to correct pinion angles. It would be easy to calculate the amount the front would tip up if we had the distance from the center of the motor mount to the front of the fan as well as the distance from the motor mount to the transmission mounting surface. I know the front face of the bell housing to the transmission mount point but I guessed at the rest of the dimensions in the example (we can easily adjust them).

The slight angle would slightly rock the motor mount but the angle would be very small. If the guesstimates are close about 0.30 degrees. The fan would come up by about 0.074”.

This also leads me to believe that if someone uses the wrong frame stands and does not realize it the answer to your question of whether it fits will change. Factor in tolerances and your question becomes difficult to answer.

Scott

Attachment: ImpalaTransmissionSupportBrackets.JPG (140.18 KB) 3 View(s)


Transmission cross-member support brackets


Attachment: TransMountHeightChangeExample.JPG (76.51 KB) 2 View(s)


Transmission cross-member height change example.




 
Shepherd 
Frequent Contributor
Posts: 1684

Loc: Lake George, NY
Reg: 11-11-15
11-12-18 05:55 AM - Post#2751117    
    In response to toro455

Nicely done



 
mjc1 
Senior Member
Posts: 1525
mjc1
Loc: Burlington Ontario Canada
Reg: 09-15-04
11-12-18 05:31 PM - Post#2751193    
    In response to toro455

That certainly is a good solution toro, would not effect the fan position too much like you calculate. The poly motor mounts probably wouldn't complain too much either.
I have adjustable upper and lower rear control arms, so getting a good angle wouldn't be an issue.
It would almost be worth it to buy a beaten 80 core, gut it to be used as a test template for tunnel fitment and the crossmember mount modifications.
Thanks for this!

1967 Grande Parisienne 4DR HT
My Flickr page



 
bry593 
Contributor
Posts: 822

Reg: 10-07-13
11-19-18 11:28 AM - Post#2751787    
    In response to mjc1

Trigonometry Toro at your service!



 
toro455 
"4th Year" Silver Supporting Member
Posts: 546
toro455
Loc: Western NY
Reg: 06-15-02
11-19-18 01:36 PM - Post#2751801    
    In response to bry593

Thanks guys. Yes I was curious about how much things would change.

I think the question is still how much extra room is needed if any. I can think of a few things which could vary from car to car. As an example I remember the topic of headers on BBC applications (may have been within the 65-66 part of the forum) where some of the variation people noticed made me wonder if everyone had the correct frame stands. Mark asked me about the transmission mount bracket in a PM and I believe he is using the proper frame stand for BB.

This thread also made me wonder if everything is factory what is the GM original design angle of the engine with respect to level. It seems like it would even vary slightly for the same engine depending on the transmission if it wasn't designed to be level (two different fore-aft mount locations PG vs TH400). I haven't dug into the reference material to see if there is a designed in angle by combination.

I'm also considering the 4L80E for my '68. My project is running behind so if Mark is closer to trying the 4L80E on his '67 it would be good information to know. If as little movement as 1/4" at the mount is enough I suspect I could change the bracket enough without altering my blank (the angle change seems very small). If the bends are altered "too much" the ears which get welded to the inside vertical part of the frame would start to get into the corner radius of the frame. I won't have access to my car to check to see about how much it could be moved until later this week.

If Mark has a frame with only one set of mounts I could send him a standard set to mock-up his set-up (The 4L80E position may interfere on a frame which already has the second set for TH400). If the trans clears with the standard height bracket great and if not he could easily tell me how much he needs to lower the mount. If it's negligible I could just alter the bends. If it's more significant I could make some altered blanks but before doing that I think the change in angle should be considered again (how much change in angle is too much).

Scott





 
bry593 
Contributor
Posts: 822

Reg: 10-07-13
11-20-18 02:08 PM - Post#2751931    
    In response to toro455

Old school GM drive angle is 3 degrees down at tailshaft. That puts an old school 4 barrel carburetor pad at level. Of course, this can vary a bit, but I think that is what the General intended.



Edited by bry593 on 11-20-18 02:09 PM. Reason for edit: No reason given.

 
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