vari-lift.ch

The 407 cui prototype engine (not available)

History and stages of development

The prototype engine was the original development platform for the Vari-Lift rocker arm system. This engine was used for the very first tests with the prototype rocker arm, served as a test object for the first test series of the Vari-Lift rocker arms, and was installed in a 1970 GTO Judge convertible provided by a friend for a limited time and for test purposes.
After the inventor restored his own vehicle in 2010, this engine was operated in various stages of development in this vehicle on the road until fall 2016 without the road traffic authorities catching on to the invention.

The basic short block

The engine block was based on a 1973 Pontiac engine with a displacement of 400 cui. Although the displacement corresponds exactly to that of the matching numbers engine, it differs in terms of the bore of 4.15“ and the factory stroke of 3.75”.

The center main bearing caps were bolted in place with four bolts and were specially manufactured by the inventor himself. They were made from Boehler E200 steel (1.5752).

A special Crower billet crankshaft (with tangentially drilled oil holes for high-speed applications) and Crower titanium connecting rods (6.625" center-to-center) were installed. The short block was designed for applications up to 7500 rpm.

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The numbers matching Engine block used for the Vari-Lift engine

Pontiac 350 cui Block

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Original numbers matching block with 350 cui displacement

WU code (engine with manual transmission)

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Serial number and block code (WU = engine combinated with manual transmission)

Corresponding the VIN

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VIN number corresponding to the car

Code for production date

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Production date: Feb. 19th 1971 night production

B = February

19 = 19th day

1 = first digit of 1971

Built-in components

Notched valve relief

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Clearances for large valves (this is a remnant of the 1969 350 HO block, which was equipped with cylinder heads 48, which had 2.11 intake valves and 1.77 exhaust valves).

Bore: 3.905 inch

Torque plate before bore and honing process

Bore: 3.905 inch

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Bore: 4.905 inch

The block was bored and honed using a torque plate.

ESP H-Beam rods

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Connecting rods:

ESB H-Beam

center to center 6.8"

full floating pin

Ross Pistons

Weight check

Piston with rod and rings

Ross Pistons

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Pistons: Ross flat taped with

full floating pins

Piston rings: Mahle

*Compression ratio: 9.8

(*= in combination with 88ccm combustion chamber and 0.027 head gasket)

Built-in components

Eagle Crank

Block modification

300rmseal

Eagle Crank

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Crankshaft: Eagle with 4.25" stroke

Crank seal: Thin indian viton

King bearings

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Bearings: King SI series (K-788)

Cylinder head # 94

3 angle grind

Cylinder head # 94

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Cylinder Head: Casting # 94

Springs: Comp Cam Beehive

Valves: OEM replacement (new)

Valve Guides: custom made

Valve Seats: 3 angle cut

Cometic head gasket

Cometic manifold gasket

Cometic head gasket

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Head gasket: Cometic multi layer steel gasket 0.027" thick

Intake manifold gasket: Cometic .060" HTS

Built-in components

Rev kit custom made

Lifter gallery with rev. kit

Rev kit custom made

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Camshaft: Comp Cam solid roller camshaft 51-751-11

duration int. / exh. 288° / 288°

*Valve Lift int. / exh. 0.550 / 0.550

(* = with rocker ratio 1.5)

Lobe separation 110°

Note: sample picture only

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cca-859-16_w

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The rev kit ensures that the roller lifters' rollers are pressed onto the cams even when the valve is closed (during the valve clearance phase).... Read Explanation below.

Solid roller lifter

CCA 859-16

Timing chain

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Timing chain: Comp Cam # 174

Explanation

The rev kit ensures that the roller lifters are pressed onto the cams even when the valve is closed (during the valve clearance phase) and roll over the cam base circle. Without the rev kit, the lifter rollers would come to a brief standstill, particularly when idling and at low speeds during the closed valve phase. This means that when the next valve lift is initiated, the lifters' rollers are set in motion from a standstill and briefly grind on the cam's start-up ramps. It is comparable to a aircraft touching down on the ground with its landing gear extended. The tires are set in motion from a standstill to full rotation in a fraction of a second. The resulting smoke trails are caused by friction. It is easy to see that both the tires and the asphalt suffer enormously during this short phase.
The same thing would happen to the cams, and always at exactly the same place, namely on the cam start-up ramps. At 800 rpm, for example, this would happen 400 times per minute. It would only be a matter of time before the cams wore in.