Manta Montage T First Build

[Randy V]

Eric,

I'm afraid you've reached the limit of my knowledge on the issues as far as this site is concerned.
You might want to get a photobucket account and upload your pictures there, then post the IMG links here from your Photobucket album.
Photobucket is free to a point.

 

[Eric Hardy]

Ok, Im back on track. I thought I resized my photos prior to uploading them but failed to do so. After resizing them they uploaded just fine. Here is the 383. I need to snatch up a bellhousing, then I can complete the motor/trans swap. In order for my axles to remain in the same place I will need to move my motor 5.75" forward. I would rather move it 4.5" forward but I am concerned about the effect on my axles. I would also need to relocate some minor chassis structure.

 

[Eric Hardy]

Here is the original axle assembly. I figured I would inspect the needle bearings and replace if necessary but I would like to reuse the original axles. I just need to mate them to the zf which is larger. Any ideas?

 

[Randy V]

Nice job on the pictures! :thumbsup:

Can't tell from the pictures much, but I believe that the ZF may be a good bit wider which would necessitate cutting the axles down. That could be done by most competent fabricators or a driveshaft shop. You may want to opt for a CV joint setup to maybe allow a little more tolerance to shaft angles should you choose to only move the engine forward a little vs. a lot...

 

[Terry Oxandale]

What is the purpose of the trailing arm link in the last photo of the rear suspension?

 

[Eric Hardy]

Actually, the zf is only around 1-2" wider but my current axles have adjustable splines that compensate for suspension travel. One concern at the moment is the effect of moving the original location of the axle shaft back 2" on the transaxle side.

 

[BruceA]

What is the purpose of the trailing arm link in the last photo of the rear suspension?

I noticed that too Terry. I would have removed the diagonal brace on the lower wishbone if the trailing arm is being used for suspension location. I guess if the joints are soft enough it wont matter too much but from an engineering view it dont look right!

Last year saw a Trike with a Watts linkage AND Panhard rod locating the rear axle. And of course it all broke one day for the guy at high speed - wife is in a wheelchair and hes permanently on crutches.

 

[Eric Hardy]

Both your guesses would be better than mine, It is mounted directly on the hub assembly so i suppose its possible that the previous vehicle it was removed from required it. I am failing to see how the diagonal brace on the lower wishbone would change functionality of the design. I am completely open to build suggestions. If it is better to remove the arm now is the time to do so.

 

[Terry Oxandale]

It doesn't appear (a very cautious term here) to be providing any purpose other than to position the rear axle longitudinally. Based on the latest two photos, is appears the link is positioned vertically somewhere between the upper and lower arms, so simply removing the trailing arm link is a better option (IMHO), but I'm not in your garage, and I'm only going by photos that may be misleading. If I interpret the photos correctly (and would agree with Bruce), I would think any vertical suspension movement would cause one or both arm's inner joints, to bind (move forward and rearward at the outboard ends, but this could be mitigated somewhat by a very stiff suspension. But "normal" movement, and what also appears to be fairly short links, I can't see it not deflecting the bushings, and perhaps worse, fatigue the plates (or weld transition metal around the plates) holding them.

 

[Eric Hardy]

Well, fatigue and stress dont sound good. It is very easy to remove the rods. When I start to reassemble the car I will have a better look as to the functionality. Any ideas on axle assemblies? I will get some measurements of the zf vs porsche and post photos.

 

[Eric Hardy]

So I am in the process of deciding how to soft mount my transaxle to my chassis. Any ideas? I got the motor in place and I'm waiting on my bell housing from KEP.

 

[Eric Hardy]

Trial by Fire I suppose. My BH came in from KEP so I went ahead and mounted it this evening. Its obvious now that my transaxle would be better suited in the pantera orientation. At this point My options are to either send out the transaxle to RBT or lower the driveline in the chassis. I think I am going to fab the chassis to fit because IMO the drive line is too high to begin with. The fuel tank is my biggest concern but it could be moved forward a bit. I would love some input so check out the pics and let me know what you think.

 

[Randy V]

Hi Eric,

It seems to me that if you were to use the Pantera orientation that you may need to raise the driveline higher still in the chassis. Correct me if I am wrong here, but with the Pantera, the axle centerline was below the crankshaft centerline.

With the orientation the way you have it now, I think you may want to look into restructuring the rear of the chassis where the axles pass through to the uprights. As it is in the picture now, the axle will hit the lateral bar that is to pass below the axle. You'll want to have at least the ability to have 4" of travel from bump to rebound and then use some sort of retention to the uprights to keep them from over extending. Bmp stops can be used on the coil overs to handle compression length.

 

[Randy V]

Ah, never mind on the info regarding the chassis mods to handle axle pass-thru.. I just looked at a couple of other pics.. Will study for a bit..

 

[Eric Hardy]

Thanks Randy I appreciate it. From My limited knowledge I am gathering that I will need to lower the drive line 3.5-4 inches min. in order to get my axle centerline back on the same plane that the previous Porsche axle was on. In the long run I feel this is the best option as my air cleaner and valve covers are just barely clearing the chassis and body as it is.

One other question, I still have not decided how I was going to soft mount the transaxle. I would like to use prothane bushings but I have not found a design that seemed preferable.

 

[Mick Ridley]

Hi Eric,



Here is an intresting thread on mounting Transaxles

http://www.gt40s.com/forum/rcr-forum-rcr40-slc-p4-mkiv/38575-transaxle-mounting.html

 

[Bill Musarra]

Eric,
Couldn't make out the front of the engine and its placement. You may want to consider replacing the water pump and going electric. My 40 had the pump extending under my arm after I moved it forward. Tubing can be adapted to the block and exit on one side or the other, or just lines that join together. It will also allow you to have a flat firewall behind the seats. I used a Moroso pump and though its numbers are not that high, I have not had any issues with cooling from it. In fact if I start it up when I first crank up, the temp has a hard time getting above the 160 mark. I don't run an internal thermostat either. Heating up is a slow process this way. Over the winter I installed a thermostat trigger and warning lite to let me know it turned the pump on. It also will let the temp build up with no flow. I wanted to do this in case I forgot to turn the switch on.

Bill

 

[Eric Hardy]

Bill,

It is a very snug fit but unless I go remote, the electric pumps I have seen are actually longer than the pully set up. My firewill will need to have a slight cavity in it to accommodate it but only 2" or so. It will sit between my Kirkeys easily. My bigger issue in that area is finding mounting brackets that will mount my compressor and alternator on the side of the block below the heads. Not too low mind you. May need to fabricate something.

I have talked to dennis over at pantera performance and I am thinking I will need to flip the transaxle. However before I make this decision, my driveline will be very tight and I would prefer it to sit lower in the car. However in order to lower the driveline I will need to relocate my a-arm mounts. From an engineering perspective can anyone foresee a problem if I undermount the brackets as opposed to the current top mount position? Currently the BH will hit these brackets if I drop it lower than 2"

 

[Eric Hardy]

Thanks for the link Mick, I will need to re-read it in order to fully comprehend the opposing positions each builder was taking but I do believe I have found a solution thanks to your link along with some info from prothane.

Thanks for all the input thus far guys.

 

[Terry Oxandale]

Yeah, it looks like some pretty extreme shaft angles if left in the current configuration. The frame bracing relocation looks easy, but you'll just need to look at the arm geometry if you lower the lower arm pivot points. With the framing being fully exposed, you've got a great opportunity to make some improvements or changes fairly easy.