482 Chevrolet Turbo-Marine

[earntaz]

Need some help with identification of some Big Block Chevy parts I have. Eons ago I did some swapping of Chevy parts and I wound up with a 4.250 stroker crank along with a set of 6.405 rods. The crank is forged and has a cast mark of 3521 and stamped M525. 3521 cranks were produced in the late 60s and early 70s from what I can tell. The rods have the name “Kiekhaefer” cast on the side with the number 621-3404 cast on the opposite side of the rod. The rods have been “worked” (polished, rough edges removed) with full float pin bushings and have an “A” beam shape similar to an FE 427 Ford connecting rod. The only reference I have come up with is in H.P. Books ... How to HOTROD Big-Block Chevys by Bill Fisher and Bob Waar. To quote them: “Chevy developed the 482 Chevrolet Turbo-Marine engines”. They go one to say that “Chev made 25 of these motors for Kiekhaefer and were destined for off-shore long distance racing and a few rods, cranks, and pistons were available for a short period of time”. This is a long shot, but is there any way of telling if these parts are part of that batch? The TAZ

[earntaz]

I knew this was going to be a tough nut to crack ...

[earntaz]

Over 130 have scoped this out an no comment? Must be much rarer then I thought...

[bofus]

I have 7 rods and looking for an 8th. Any ideas?

[earntaz]

Try Marine Kinetics back east ... TAZ

http://www.marinekineticsonline.com/index.html

[Lee Stewart]

The parting line on the forging is hand ground smooth the full length of the rod. Areas around the bolt seats are given a generous radius to reduce the potential for stress risers. GM had a design sheet for race preparation of the dimple rod. The Kiekhaefer rods are prepped in identical fashion.
There were 25 of these engines assembled at GM in cooperation with Kiekhaefer. At that time all production Chevy big block packages were designated “Turbo Jet” engines. These development engines were designated 482 Chevrolet “Turbo-Marine” engines even though none were ever turbocharged.

The architecture of packaging a 4.25” stroke into a Std. deck block was much more challenging in the late 60’s, early 70’s than today. There were no aftermarket 4.250” cranks or shelf stock piston pin heights raised .125” or 6.385” connecting rods available at that time. That left two choices for an engine builder. Sourcing a costly custom crank from Moldex or Hank the Crank, or welding and offset grinding a OEM crankshaft, using a Std, piston pin height, a long rod, and a raised deck block. Kiekhaefer , had semi finished rod forgings made that would accommodate the necessary 6.405” c to c length of the rod to package the assembly. The packaging of the assembly is why a tall deck block had to be utilized, in spite of its inherent design disadvantage.
What is a routine 482/489/496 build today, utilizing parts sourced from the aftermarket, was considerably more difficult in 1969.

Block deck dimension Std Deck (454)____ 9.800”
½ stroke/stroke radius_______2.00”
Rod C to C________________6.135”
Piston Compression Ht._____1.645”
Piston to Deck_____________.020”
Total_____________________9.800”


Block deck dimension Tall Deck (482)____ 10.200”
½ stroke/stroke radius_______2.125”
Rod C to C________________6.405”
Piston Compression Ht.______1.645”
Piston to Deck_____________.025”
Total_____________________10.200”

http://www.offshoreonly.com/forums/g...springs-4.html

[Lee Stewart]

[olredalert]

----I was just about to suggest going on the Off Shore Only website and ask those guys because some of them pretty much know everything about Mercruiser Racing (Kiekhaefer) stuff, but Lee beat me to the punch......Bill S

[Verne_Frantz]

I don't have specific information on the engines in question, but Chevy made quite a few marine engines for different companies. My Tonawanda production totals showing engines shipped to Kiekhaefer as of 7/17/69 are:
3951055 normal rotation: 1200
3951056 opposite rotation: 176

It also lists:
3962652 Hi-Perf normal rotation: 1

I have no idea what these engines consisted of. Maybe someone can find references by part numbers.

Verne

For added interest, here's a twin turbo version shipped to Daytona Marine.

[SuperNovaSS]

The 3521 crank was produced as a standard 454 crank with a 4 inch stroke. Are you sure it's a 4.25 stroke?


Jason