View original topic: Help identify my new rail project
vwdad Thu Aug 06, 2020 3:37 pm

Please help ID my frame.
I just picked up my newest project and I'm not sure what frame I have. It does look vintage with the last ORV sticker dated 1994 in Michigan. It was used at Silver Lake Sand Dunes. It has a 2.3L Ford motor in it now. I'm also looking for some advice on the rear shocks because I'm thinking the air shocks aren't going to cut it. My plan right now is to make it a street ride.

Q-Dog Thu Aug 06, 2020 4:37 pm

Could that be the name right there on the front beam clamps?

rayjay Thu Aug 06, 2020 4:55 pm

Hi Jumper on the clamps if I am seeing it right.

I don't think the shift rod setup is usable.

Need some coil over shocks in the back. Also so some sort of camber compensator.

Going to need some brakes in the front.

Dual master cyl brake pedal assy with balance bar would be nice to dial in the brake bias.

jsturtlebuggy Thu Aug 06, 2020 6:36 pm

It is a San Fernando Buggy Center Hi-Jumper Sand Sprite III.
I never ever seen the front beam clamps cut in half and mounted with 4 bolts.
It is a early version with that type of beam clamps. Later chassis used steel half clamps bolted together to mount front beam.
The rear shock I see are a cheap air shocks. Originals used a coil-over Bilstein shock with about 5in of travel. Also were available Air shocks that where like the original FOX Air shocks for motorcycles with a large diameter piston.
You could coil over shocks for it if you want from a place like Speedway Motors, They sell shock and different rate springs for race cars that would work.

Great handling buggy in the sand. I have owned 3 different Hi-jumpers over the years, A Ascot in the 1970s and two different Sand Sprites. They are a well built chassis.

rayjay Fri Aug 07, 2020 5:00 am

I recently scored some old magazines off ebay and one had an ad from Prowlers Speed and Custom in Canyon Country CA

In an ironic twist, the guy selling the mags is in Atlanta :)

You should seriously investigate insurance and tags before spending any money. I think Georgia makes it a pita for custom built vehicles. You might have to put a cheap fiberglass 29 Ford roadster body on it and call it an antique :)

rayjay Fri Aug 07, 2020 5:09 am

Also, if you are serious about making it a pavement pounder but can't get tags or insurance there is always SCCA autocross. Atlanta Region SCCA has a good AX program. This thing with a good pavement suspension conversion would have Fast Time of Day [ FTD ] potential.

In the High Performance forum I just started a thread "Aussie Formula Vee....." that shows a state of the art swingaxle rear suspension. Personally, I would graft on an A-arm front suspension from something like a Spitfire.

dustymojave Fri Aug 07, 2020 9:21 pm

San Fernando Buggy Center, owners of the Hi Jumper brand invented the Sand Sprite chassis design. Years later, the owner of San Fernando Buggy retired and sold the rights to that design to Prowlers in Santa Clarita.

This one having the cast clamps means that it's a Hi Jumper Sand Sprite, not built by Prowlers.

Back in those days, San Fernando Buggy was at the end of my street 1/2 mile from my house. Later, when San Fernando Buggy sold off to Prowlers, I lived in Santa Clarita, not far from that shop. My avatar is my mid-1970s Hi Jumper, and so is the trailer I have for carrying my buggy and so is the fiberglass Glitterbug body I have set aside to build later. My brother's father in law had been the General Manager of San Fernando Buggy in '69-'70. When I was operating my offroad business I used to buy parts from SF Buggy. When I was a kid living up the road the business was known as San Fernando Auto Body and my neighbor across the street worked there. It seems I have some connection to the outfit.

vwdad Sat Aug 08, 2020 5:48 am

Thanks for all the info.
I figured it was a Hi-jumper but couldn't find any pics of the rear suspension with the frame looping around the rear shocks.
All though not very functional the shifter and linkage look like they were actually original to the build back in the day and I'll probably go cable shift.
I'll probably go with coil-overs in the rear similar to what would be on a hot rod any suggestion on what springs to start with on the rear shocks?

jsturtlebuggy Sat Aug 08, 2020 2:00 pm

The original shock mounts on the chassis and rear axles are in different places is why the lower rails in the back have curves.
Originally the upper shock mounts were on out side of the upper frame rails and the lower shock mounts were further out welded onto the casting the rear axle bearing is in.
I have to try and find some pictures of what it looks like.

As for spring rates, check the weight at the rear tires. I think the ones that Hi-Jumper sold with the 5in travel Bilstein shocks was something like 250-275lb spring rate. They were 2in diameter. With the Pinto engine you may need a stiffer spring.

rayjay Sat Aug 08, 2020 3:00 pm

From looking at the pics I see several issues that need addressing. In no particular order -
The rear brake hard lines need to be rigidly mounted to the axle tubes. The current arrangement will eventually fracture the hard line leading to no brakes.

You should rethink the water filler arrangement. It will be difficult to get all the air out of the cooling system because the current setup has the filler neck below the cyl head. Moroso makes inline filler necks that go in the upper radiator hose. You could also fab a water manifold that bolts to the front of the cyl head and has the radiator cap up about the level of the top of the valve cover. This would be the best as filling with coolant would be foolproof.

I would make a simple scoop to help duct air to the radiator.

vwdad Sun Sep 13, 2020 6:39 pm

Finally got around to working on this. Kinda bummed the trans had water in it so its gotta come out for a rebuild. Hopefully I'll get that out in the next couple weeks.

rayjay Sun Sep 13, 2020 7:45 pm

The trans in my 74 bug was full of water too. Fortunately I scored another a few months back.

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