BuiltZ28

Did these cars come with a non serpentine accessory belt drive at any point in time? If so can anyone tell me the stock diameter of the groove on the crank pulley that runs the power steering pump as well as the diameter of the power steering pump pulley. I have an aftermarket pump/pulley and have basically no power steering at idle.

sofakingdom

iTrader: (1)

All of them came with V-belts up until 86 or 87. Then for that year or 2 they had the wide flat ribbed belt but in the same configuration as V-belts; then in 88 they went to the serpentine system, which of course also used the wide flat ribbed style belt.

Don't recall the pulley diameters though, and I'm too lazy to do anything further. Seems like the crank pulley groove for the alt/wp belt was about 9" dia, (at least for the L69, LG4 may have been smaller, can't remember) and for the ps and ac grooves, it was smaller, like 7½". The wp itself was maybe 6"; the ps pulley would have been around 6½ - 7".

NoEmissions84TA

iTrader: (1)

I use the 4 v-belt setup (82-85?), then there was the hybrid setup that replaced just the alternator v-belt grooves with 1 serpentine belt - still v-belts for the rest. I'm switching to that because emissions will be removed as well as A/C, so I will have 1 serp belt for the ALT and 1 v-belt for the PS.
I will measure the pulleys tonight.

AlkyIROC

I've played with pulley sizes on my race car just to keep the speeds down. Not the same as a street car but my rpm range is also a lot higher.

How many things are you turning with the belt?
What is your normal engine operating rpm?

Alternator speed is usually 3 times the engine rpm but generally, they need to spin around 2400 rpm at idle. If you normally operate below 3000 rpm then the rpm will be spinning up to 9000 rpm and the alternator speed should not go over 18,000 rpm. With stock pulleys, you're really limited to operating below 6000 rpm engine speed which is where the majority of street cars operate anyway.

Power steering pumps will only operate at a maximum set pressure. As long as the pump spins at least 1500 rpm at idle, spinning it faster won't make any more pressure. It's internally regulated and any excess pressure is simply bypassed. Flow rate however will increase as the pump spins faster. A power steering fluid cooler is always a good idea. Since you state that you have no power steering at idle, I would guess that you need a smaller pulley on the power steering pump to speed it up or a larger pulley on the crankshaft.

Water pump speed depends on a few factors. Speed is too slow and coolant can't circulate fast enough through the cooling system to cool the engine. Pump speed too fast and coolant is flowing through the engine too fast to absorb heat from the engine. Both can cause overheating.

Because my race car runs an electric water pump, I run 3 different belts off a crank mandrel. One belt runs the alternator. A second belt runs a vacuum pump and the third belt runs a fuel pump.

BuiltZ28

I have a 3 groove crank pulley its older stuff I randomly pulled off a late sbc years ago. The forward most pulley drives the stock 87 alt and a water pump. The middle groove drives the PS pump only.

It is a saginaw eBay pump. For lack of better words I unscrewed the valve off the back of the oem PS pump and installed it on the new one as they were different (threads at least).

It is strictly a street car. 6spd, 4.11 gear sbc stroker.

sofakingdom

iTrader: (1)

The 86-87 system with the one wide flat ribbed belt wasn't a "serpentine" ("snake-like") system... it just used a wide flat ribbed belt of the same design that was later also used in serpentine designs.

Vader

A.K.A., Poly-V (trade name for multi-ribbed belts). And as long as we're getting the terminology, none of our cars use pulleys. They use belt sheaves.

AlkyIROC

Measure the diameter of all the pulleys including the crank pulley to calculate drive ratios.

NoEmissions84TA

iTrader: (1)

OK, OK - flat multi-ribbed poly-v reinforced rubber thingy.


Here are the "pulley" measurements from an 84 LG4 305 engine (all v-belt grooves):


WP pulley 14037740 (from outermost groove to innermost)
4 5/8", 6 1/4", 6 1/4"


Crank pulley 14029145
all 3 grooves are 7 3/4" OD


Additionally, if anyone wants to know the measurements of those common aftermarket aluminum pulleys, ALL grooves measure 6 5/8" OD for both WP and Crank.

Drew

iTrader: (58)

You kiss your mother with that mouth?

How is MULL IT and Red Neck censored, but sheaves is ok?


Thinking right off hand the V belts and serpentine belt pulleys are about the same diameter. At least that's my impression from moving them around in storage.

BuiltZ28

My ps pump pulley is 6 inches diameter and the groove on the crank pulley driving it is approx 6.5 inches.