A space story

[azgolfrat]

Ha! Some would argue their is a lot of space between my ears when it comes to modding my Marauder...but this story isn't about that space. And it's not about Mars or Venus. No, its about the space, or more correctly, the spacing required to convert my Marauder, which contains a V7 Vortech Supercharger (SC), from 6 rib to 8 rib.


The V7 delivers max boost around 7500 engine rpm. With 6 rib, at least on my car, getting above about 3500 rpm starts the belt slipping pretty badly on the SC pulley. Lots of black dust everywhere around the water pump, etc.


Anyways, I started working on the 6 to 8 rib swap in the spring of '23. Not done yet. I've had the car running on 8 rib for 100's of miles; however, when I went to remote tune with Marty, the car broke. Twice.


The 1st tune, an improperly spaced/attached water pump pulley came off at about 4000 rpm. It's a long story.
The 2nd tune, there was either a boost leak or severe belt slippage or both. I suspect belt slippage. We ended the tune session early that day because of little to no boost. When I popped the hood afterwards, the belt was partially shredded. I cleaned that up and carefully drove the 20 miles home with 3/4's a belt.


A closer look revealed that alternator pulley had moved down the alternator shaft toward the front of the car about 5 threads. The threads on the alternator shaft were fine, but the pulley threads were mangled. This pulley was a clutched pulley. It's important to note that the alternator pulley and the SC pulley are very close to each other during operation.


After looking at things for a bit I found that the alternator pulley and the SC pulley were badly aligned. My bad


This brings us to proper spacing - something I had to make sure was a close to perfect moving forward.


The new balancer (Innovators West 7.25 d, 10 od) has a "different" offset than the oem 6 rib. That is, in order to get the inside/engine side rib to sit in the correct position relative to distance from the engine cover the pulley will stop against the crankshaft snout such that 3.5mm of new space, relative to the oem balancer is created. This new space is then take up by the inside rib. This amount of spacing is the key to all other pulleys, sorta.


Subsequent 8 rib pulleys need to line up with the godfather of pulleys, the 8 rib balancer. The new 8 rib ps pulley and 8 rib AC compressor pulley are installed and align with no spacing - they are designed similar to the balancer wrt offset.


The pulleys that are bolted to the engine cover must be spaced to match up to the balancer. This is true for the non ribbed pulleys as well, as a without spacing the non ribbed "8 rib" idler will bump up against the engine cover. The spacing is, again, I believe, 3.5mm away from the engine cover


The OEM tensioner, with a 8 rib non ribbed pulley must be spaced away from the engine cover for the same reason. Summit sells a very nice kit that accomplishes this spacing.


The SC bracket bolts to the engine cover. This bracket is larger, I think, than the bracket from smaller superchargers. The internal supports on the backside of the bracket bump against the new 8 rib pulleys unless the bracket is spaced away from the engine cover. I spaced my bracket a necessary 7 mm. I had a local machine shop make the spacers for me. This spacing moves anything that is attached to the bracket 7 mm away from the engine cover. This means that the ribbed SC pulley and the additional relocated idler (part of the SC kit from ADTR) are now 3.5mm out of alignment in one direction and 7mm out of alignment in the other. The net is that these two pulleys need to be moved in towards the engine cover 3.5 mm. Nice number.


That gets us to the alternator. I've thrown away the messed up clutched alternator pulley and replaced it with a non clutched 8 rib pulley. This work I have not done, however, I believe this pulley needs to be spaced 3.5 mm out to match up with the balancer (and everything else).


With the water pump and its pulley removed, I can use a pulley laser alignment tool to check alignment to the balancer for all pulleys. Some of this is done with the the SC bracket off and some is done with the SC bracket on (while aligning the SC pulley and the relocated idler.


So, in the next couple months I'll put it all back together and try tuning again, with Marty. Marty has been exceptionally patient btw - He and Jeff are good guys.


As I am not 100% certain about all of this.

[jflave]

Don't go by me but you said " With the water pump and it's pulley removed I can use a laser alignment tool to check the alignment to the balancer for all pulleys." Would an electric water pump help ? NO Pulley.

[azgolfrat]

Good question. I dont really know.

Of course, after all alignments are done I put the pump and its pulley ( and more coolant) back in place.

If I had an electric, no pulley, water pump, the belt routing would have to change a lot, and that would be a very significant change.


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