Topic: Marlin Crawler Formula Toyota Buildup

[Skinny_Pedal]

i must say that the front axle is beautiful

[Marketing [OP]]

For our transmission we have chosen to use one of our L52-HD units.  On this rig we will be moving the engine back a few inches for radiator and winch clearance up on the front crossmember. On Formula Toys its common to go as far back as 8" with the motor and trans. A big advantage to using the L series transmissions is that it's shorter than the later G,W, & R series tyrannies. This will help keep the rear t/case shifter in a comfortable position. On the down side the L series transmission was the weakest tranny used on Toyota 4wd trucks but we have some tricks to show you to bring the L up to snuff.

The G series transmission replaced the early L series starting in 1984. The G came in 2 versions, the G52 and it's big brother the G54. The G54 features larger main shaft bearings and an updated, stronger gearset. To build one of our L52-HD transmissions, Marlin takes these later style G54 transmissions and fully rebuilds them. Each and every part is taken apart, cleaned inspected and/or replaced.



Before the G54 gear set can go in the housing, several milling steps to needed to make the needed room for the larger bearings.


Next the housings are wire wheeled clean, checked and painted.


Several units are built at the same time for efficiency


The L series tyrannies also have another weak spot, the shift forks. These forks are located into he top cover. The forks normally have a life of about 100K miles. After that the induction hardened forks wear out, leaving noticeable ridges on the fork. Once the fork is worn, the shift lever is no longer able to get the shift hub fully into place. With the shift hub not going fully into position the transmission is likely to pop out of gear.


The wear on the shift fork is due to the direct contact between two hardened surfaces. The solution is cut down the forks and replace the steel with brass. Brass covered forks last far longer than the factory steel because you now have a soft material that will conform to the shape of the shift hub with out gaulding common with two hardened surfaces. Cutting and milling the brass takes over an hour to do on a pair of forks but the resulting forks that last 2-5 times longer than factory units.


To make the shifting a little more solid, larger detent ball springs are used. Here you can see the stock spring on the left and the heaver new spring on the right.



The entire top cover is also completely rebuilt. Each rod is removed and inspected. Rods and bushings are replaced as needed. The brass filled forks and heavy duty detent springs are installed. Stainless steel safety wire is used to prevent parts from vibrating loose.


The completed L52-HD transmission is now ready for action.

[toyhatsu]

Great thread Chris I really enjoy seeing the pictures of the crew working in the shop.  Excellent pictures and write ups.

Thanks

[Marketing [OP]]

Rear Leaf Springs Mounts

The Formula Toyota rules require rear leaf springs. The rules state that the spring can be inboard mounted to as narrow as the stock front springs. Front springs are mounted at 29" center to center. That's exactly where we are going to mount our springs.

My first plan for rear hangers was to use a section 2" X 4" tubing across the frame. After talking with our fab guy Andy, he had a much better idea. He suggested using our frenched hanger and coming off it's flat sides with gussets back to the frame. That was a much better plan of action.

So I grabbed a pair of hangers off the shelf...


Using a section of scrap tubing, I tacked the hangers to the tubing at exactly 29" center to center.


Next measured 6.5" up and forward of the factory bolts and marked the frame. Then I placed the tubing on the frame and centered the hangers front to back and left to right. Next I tacked the tubing to the frame and rechecked the position of the hangers.




Next I cut 4 sections of 1.5" tubing. Each end was cut to 45 degrees. These were welded front and rear of each hanger.


After putting on all four braces I removed the section of tubing that was acting as a jig.


Short sections of tubing are placed in-between the frame and the hangers for additional support.


The inside of the frame rails on Toyota frames are thinner than the outside. The braces shown here are only intended to provide forward and back support. After the cage is installed a vertical tube will connect from the top of the hanger to the cage. 

[rockhound]

What is the benifit of running inboard? More leverage on the springs?

[BigMike]

Yes, exactly. In addition to the extra leverage, the springs do not travel as far either, so you can get much more articulation with the same amount of spring compression. The only down side is that the added leverage will induce more body roll on the roads, but this is a buggy so we're not to worried about that

[98runner chevota]

This is a sweet built up. Love all of the ideas and thinking going into the grey areas of the rules.
When are you supposed to get the chassis.

Mark

[Makohon]

do you have any pics of how you put the rear hangers on?shackle hangers?? i would like to see!! by the way it looks awsome!!!

[Marketing [OP]]

do you have any pics of how you put the rear hangers on?shackle hangers?? i would like to see!! by the way it looks awsome!!!

We just installed the rear shackle hangers today. I'll post pics after dinner.

[Marketing [OP]]

This is a sweet built up. Love all of the ideas and thinking going into the grey areas of the rules.
When are you supposed to get the chassis.

Mark

The chassis may be later this week, we are just about ready for it. Seats should be here in a few days.

Lots more tech and photos to come!

[Marketing [OP]]

Using a drill, I opened up the stock size holes in the hangers so they will fit the larger 18mm bolts.



Today Andy created a rear crossmember out of some scrap 3 X 2.5" steel tubing. The ends were cut at 30 degrees and plates were used to cap the ends.

[Marketing [OP]]

Using the specs from hendrixmotorsports, we cut the rear frame down to a length of 150". The rear crossmember is 2.5" thick, making the overall frame length 152.5".

http://www.hendrixmotorsports.com/


The rear crossmember was installed onto the back of the freshly cut frame.


You can see two sets of springs here, the stock set, our prototype 4" rear test springs.




Next the rear spring hangers were cut off and the narrow axle and springs were rolled out to the graveyard.



Using a C clamp, Andy tacked a set of rear shackle hangers under the rear crossmember






A set of 2" over stock shackles are temporally fitted in place.

[Makohon]

lookin pretty sweet!!  

[Marketing [OP]]

Big Mike, Marlin's son, will be building the motor for this build up. The original 1985 motor is well past it's prime with lots of miles on it. This old motor had been sitting in the back yard for who know how many years.



Mike placed the tired mill up on an engine stand and in about 2 hours reduced the motor to a pile of parts. He carefully sorted each nut bolt and part into boxes and muffin tins as it came apart. This will make later reassembly much faster.


I knew we had many of the parts we needed to build this truck right in the shop at the start of the project but I was totally shocked when Marlin pulled out from under his bench a fully machined 1985 engine block and matching .020 over pistons. I've been working at the shop for a year and had never seen this block before.




We also keep engine kits in stock so Big Mike is now ready to put the block back together.


Marlin will be porting the head giving it a valve job before it's put back on.

[FatAzzRunner]

Chris,

Question, Everything I have ever read on Yota frames is, If your gonna weld somthing like a link mount or a spring hanger or somesort, that you should plate the inside of the frame in the area that you are mounting to as the metal is weak and will rip.

I dont know where the pic is but there is one on P4x4 that shows where some guy mounted a link on the inner frame and it ripped a big ass hole in the frame. 

Is that what the longer angled pieces are for is to distribute the stresses over a larger area??

 

[LCOwner]

Chris,

Question, Everything I have ever read on Yota frames is, If your gonna weld somthing like a link mount or a spring hanger or somesort, that you should plate the inside of the frame in the area that you are mounting to as the metal is weak and will rip.

I dont know where the pic is but there is one on P4x4 that shows where some guy mounted a link on the inner frame and it ripped a big ass hole in the frame. 

Is that what the longer angled pieces are for is to distribute the stresses over a larger area??

 

They're going to tie the spring mount into the tube chassis when they get it.

[Marketing [OP]]

As stated in the post above, the current tubes are only hold the hangers front to rear, verticle loads will be carried by tubing that is tied into the upper chassis (not yet installed). I can't finish this part until the chassis is in place.

[mudguts]

Big Mike, Marlin's son, will be building the motor for this build up.

Maybe BigMike should start a Formula Toy Engine Build Thread 

[Marketing [OP]]

Today we received our PRP front seats.

We will be using a pair of their "Premier High Back" seats. I ordered these yesterday and received them today. I love fast shipping! I sat my butt down in them and for $189 this is a great seat deal!



We also ordered a pair of their seat sliders so we can adjust them forward or back for different drivers.


Later we will show how these are installed.

[WHITE_TRASH]

Ummm Chris, front springs are 29.5" center to center.  I really hope that 29" measurement was a typo........

EDIT:
Hmmm I measured a spare empty front housing and I got right on 29.5" pin hole to pinhole.

[Marketing [OP]]

I measure exactly 29", center of spring to center of spring.

[Marketing [OP]]

Today, rocky assembled the rear Chromoly steel axles using new bearings and seals.


The Detroit/4.10 gear Turbo third member was installed into the clearanced housing and the axles were installed. The rear housing is painted except where the perches are to be welded on.


A set of 3 hole perches are used to mount the springs to the axle. With the narrowed springs, the perches need to be mounted closer together. This causes a slight problem as the tube size gets larger when you get closer to the third member. A little bit of grinding was required to open up one side of the perch. In the photo below you can see a slight rise in the axle housing under the spring.


With the axle now in place the rear flip kit is installed. The perches are not welded on at this time. The pinion is position is estimated to be correct, but we will wait until the tcase is installed before welding the perches into place.

[Hyena]

From center of spring to center of spring it is 29".  From outside of center pin to outside of center pin is 29.5". 

[rockhound]

The build up is really starting to take shape.  It looks good Chris.
I agree, a Mikey engine build up thread would be awesome.

[TOYJOETA]

Chris this thread is awsome I love how indepth you are going with this and how many pics you have.  Keep up the good work.
P.S. When is Mike going to start the engine thread?

[Marketing [OP]]

Today I drove out to the Hendrix Motor Sports shop out in Santa Margarita to pickup chassis number 028. Mike has been busy cranking out chassis's at 1-2 per week. Parts for numbers 030 and 031 were starting to come together.


Marlin the dog was the first to greet me as I arrived at the shop.


My chassis was ready to go and hanging from the sealing of the shop. Using the roof mounted winches, Mike was able to rotate and flip the chassis for easy loading into the back of our pickup.


Here is the base used for building each Hendrix chassis.








On my way back to Fresno, I stopped by Eric Linkers shop.


I took a very close look at Lisa's Formula Toyota, the prototype for the class and current series winner.


Camo's shop has more computing power than many offices!


Lisa's newest toy!


Fork lift, the ultimate shop tool.


Arriving back in Fresno.


Using two tubes across the frame, the chassis was dropped in place. On Saturday, I removed the stock tcase crossmember, horseshoe crossmember, and rear tubular crossmember from the frame. Andy created a plate and gusset for mounting the steering box.

[Willy Mammoth]

Chris, this is looking pretty good. Keep up the good work.

[GJC]

Lookin sweet 

[Hyena]

Just curious, why are you mounting the steering box on the inside of the frame?

[Marketing [OP]]

Andy wanted to use a Saginaw steering box for this project. These are very common on FJ40 spring over conversion. This box and it's matching high volume / high pressure pump results in a steering system that has more force than an IFS box. We may be able to run without adding a hydro assist system. Using a longer pitman arm can increase the travel of the steering.