Engine and Transmission Tech

Jim, everyone

Yes, got the flywheel on Monday but really didn't have time to do anything with it until today. I'll add more detail later but according to LSC, it weighs 17.5 lbs. I'll check that figure later but I'm very happy with it.

Thank you, Scott. Been dying for an update. Now, get that starter bolted on! :)

It's been a while since I've gone into any detail about this project. I'm really having fun with it and learning a lot.

First, I should say the LSC Performance is great to work with. They are very responsive to questions/concerns. It took a little bit to get the flywheel here but Tom warned me when I talked to him in March that summer is a busy time for them and it would take some time to get it done. I found them to be really honest and straight forward to deal with. Highly recommended.

We spoke at length about the flywheel design and decided to exactly duplicate the dimensions of the S-10 flywheel for my application. Now that the flywheel is mated to the motor I think that was a good decision. It lines up well with the starter gear. The face of the flywheel is about 0.1" closer to the bellhousing mounting surface than my V6 flywheel (I'm planning to use the current bellhousing behind the LS4) so I will need an adjustable throw-out bearing going forward. Based upon my starter mount design, it looks like the flywheel could be about 0.1" thicker but not too much more than that otherwise the starter mount would have to be rearward of the bellhousing mounting surface and the bellhousing would have to be modified to accommodate the change.

I did run into an issue when mounting the flywheel. As you can see in the picture below, there is a ridge on the flywheel hub on the crankshaft. Not sure why GM would do this but I had no idea it was there until I started troubleshooting why the flywheel wouldn't go back to the flange. Totally my fault for not looking closer given that this motor was only mated to an automatic. In hindsight, it would have been a good idea to send along a stock LS4 flexplate to LSC. I measured a difference in diameter of 0.0035" between the step and the smaller diameter of the hub. I carefully honed the center hole of the flywheel and it fits snugly now.



I did measure the run-out on the hub and got about 0.0035". While I was at it I checked the axial run-out and got 0.003" there. This was without the flywheel bolts being torqued to spec so it will be done again. I'm pretty confident it will be within specs



The starter mount is coming along nicely. I'm waiting on some longer M6 X 1.00 bolts for the starter to starter block to starter mount surface in order to complete the mount. I started fabricating the starter support bracket as well. I'll put together the details on the mount design when it is complete in a separate post but I am using the starter block as a part of the starter mount. You can see how it's been modified in the picture below.



The main reason for using it is it is designed to support outer bearing for the starter gear and any of the shims that were included with the starter. It's easy to work with too. Not being equipped to fabricate something like this is probably another good reason for using what is there. :) The next picture shows the starter gear in it's final position.



The paperclip is 0.0285" thick and the specification calls for between 0.020"- 0.035" clearance between the top land of the flywheel gear and the bottom land of the starter pinion gear.

That's all for now. Next steps are completing and testing the starter mount. It should only take a few hours to finish it but I'm not sure I'll be able to do much in the next week or two unfortunately. Lots of family and work things going on right now. I'm planning on pulling the V6 from my B for the last time in mid-October and starting the LS4 conversion at that time.

Scott

Looking good, Scott!

All eyes are on this conversion.......

Did some quick testing today. I haven't fabricated the front starter support bracket yet but the starter seems to be pretty rigid as is.

Oh yeah, looking good, Scott!

Well Done! Scott!

Thanks.

The mount is just about complete. I need to trim the angle iron a bit and complete a few minor details. Fabricating the starter support will be next. I got the muffler clamp for the support but didn't like the way it was fitting/looking so I'm going to go with Jim Blackwood's approach of bolting it to the front of the starter. I think the support is a necessity for this application.

Here are some additional pictures of the mount in it's current state:







You can see how well the starter fits up against the block, looks like it was custom made for this application. It's very compact as well. The only modification to the block that is needed is grinding down the fixturing boss. The starter itself is also unmodified...if you don't count the aluminum block. I think the starter can be removed/replaced fairly easily in the event of a failure...I'll confirm that at some point.

Oh, I did weigh the flywheel on my digital bathroom scale and got 17.4 lbs. FYI.

Scott, You are doing a great job. I am impressed.

Dale

Thanks Dale, it means a lot coming from a person with your talents.
Scott

Excellent.

Jim

Except for painting it, I completed the starter mount finally. I made some final adjustments and built the front support. I actually partially built 3 different designs for the support and abandoned what I ended up using before going back to it. I'm pleased with how ridged the starter is now. Here's a picture of the support.



Here's a picture of the completed mount.



I got a shot of the fixturing boss and how it interacts with the starter body. I took a bit more off of the section that is touching the starter after this picture was taken. Modifying the fixturing boss like this will allow fairly easy removal of the starter once installed in the car.



I'll post more information about the construction of the starter mount once I get it apart for painting.

Thought I would write up the starter mount design/construction and close out this phase of the project. It's really pretty simple. Here's a photo of the whole thing. At the top is the starter with the modified mounting block. The bottom row is the angle iron support then the steel plate and finally the front support.



The steel plate is 1/4" thick and uses the lower right side (facing the rear of the motor) LS4 rear cover bolts which are 8mm X 1.25 to secure it to the block on the left side of the mount (facing the rear of the motor). The angle iron support top bolt is 12mm and is used to secure right side of the mount to the block as well as the bottom right hand side of the bellhousing. Another 12mm bolt on the bottom of the angle iron support is used to secure the steel plate and starter mounting block to the angle iron support. Hope this isn't too confusing.

You'll notice on the steel plate that there are three smaller holes surrounding the large starter pinion hole. Those match up to the starter mounting block bolts which are 6mm X 1.0. I drilled the existing mounting block bolt holes straight through and got longer bolts so I could bolt the starter/mounting block and steel plate together. You can see the bolts sticking out of the starter block. The bolt holes in the steel plate are bigger than the bolts and this is how the final adjustment to the starter pinion gear to flywheel gear gap is accomplished. I used nuts to secure the steel plate to the starter and then welded them to the steel plate once the adjustment was complete.

For the front support I used some 1/2" square tubing and welded it to some reinforced strap I had laying around. As I mentioned in an earlier post, I started down three different paths with this component before settling on this one. As I look at it now I think I need to tweak it a little to give it a bit more strength. Figures...it's painted now. It did add a lot of rigidity to the whole mount and as I mentioned a couple of times in this thread I think it is necessary.

I wanted to talk a little about the 142 vs. 148 tooth flywheels. The next picture shows how the modified mounting block mates up to the block.



With a 148 tooth flywheel there is plenty of wiggle room to get the starter and flywheel adjustment to spec. A 142 tooth flywheel will require an additional 1/4" to enable the same adjustments. As you can see from the photo there isn't enough meat on the mounting block for another 1/4" so if you were to use the same starter it would mean that you would have to modify the block. I don't have a picture of this but it would be problematic going into the block because the LS4 rear cover ends right at the block in this area and a 1/4" there would be into the rear cover gasket. You could try going up into the bellhousing mount "tab" but I'm not sure you could get close enough to the flywheel ring gear with this approach. Bottomline, I don't think the starter used here will work with a 142 tooth flywheel. The only other option would be to find an even smaller starter.

I'm sure I'm leaving out a million details so feel free to ask questions if you have any and I'll try my best to answer them.

Tomorrow morning I'm going to start pulling my V6 and begin the LS4 conversion. I'm thinking about starting a journal to document it. Should I continue to use this thread instead? I'm interested to hear what you think.

Scott

Scott this is great stuff. I think you should continue to use this thread then the thing does not get disjointed.
Keep up the good work and give us lots of pictures.
It would be great if you could document all the steps for converting these engines. Of particular importance is the engine harness and ecu being that these engines have this DOD system.

Cheers
Byron

Scott, Looks Good! Maybe you could tie in your front mount with the threaded hole above the starter. As far as the fixtureing boss, I would completely remove it. It was used by the factory to hold the block for machineing.

Thanks Byron. I'll go into more detail about this later but I won't be messing with the DOD. My understanding is it is difficult to get it to work properly in a conversion anyway. Also, I'm using an 0411 PCM which has no support for DOD. I'm not doing this to improve my mileage. :)

Jim,

Thanks for the suggestions. The fixturing boss has pretty much been removed at this point. That threaded hole on the block is where one of my knock sensors will be living. I'm actually pleased with how the front support turned out even though it might not sound like it. I was in a rush to get it done. It's going to do the job I need it to do.

Scott

Yeah Scott, Those DOD lifters make me nervous with the plastic part and little spring above the lifter to gain about 2 MPG. I read somewhere you can replace with LS7 lifters and boxes and use stock pushrods. Plug the DOD oil passages in the valley. Use LS2 valley tray. They recommend the 42lb newer style shielded relief valve and drilling drain holes in the lower center of the lifter boxes to help oil drain back. If your LS4 was before they added steam balance lines you ought to add them also. I personally think going to a older style PCV system would be worthwhile also. Those tiny little stock lines plug up and cause problems. The main issue of the LS4 you solved with the starter. The others are minor. You're a trailblazer Scott! Now, the rest of you guys go out and get your cheap LS4's before the price starts going up.



Edited 2 time(s). Last edit at 10/11/2013 03:20PM by mgb260.

I'm waiting for them to start showing up in the pick-n-pull!

Jim

While we are patiently waiting for another update from Scott... Here's an interesting, info filled LS page:

[www.fbparts.com]