Hot Rod Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Howdy, brothers. Long time reader; first post.

Just finished installing a Fluidampr (6.25") on an early SBC 350 that I had just put gear drive in.

While I'm not an experienced mechanic, I've done this same thing three times in the past, on similar engines, but using off-brand (CAT?) viscous dampers, and not the Fluidampr brand. I had no problems with those installs.

I took off a double-roller timing chain (GM part) and stock balancer. The gear drive crank gear is noticeably thinner than the crank sprocket for the chain.

When I installed the Fluidampr, using their specs of 70 ft-lbs, It sure seems like I have a lot of exposed (damper) shaft...Is this because the Fluidampr is so much smaller? I installed it correctly; anti-seize was used, and it goes on (with some resistance) smoothly, all the way until it doesn't want to go anymore--which, for me, was when I hit 70 ft-lbs. This, I assume, is where the end of the damper hits the crank gear. Is that right? Does the damper butt up against the crank gear on the timing set?

When I installed the lower pulley, it's considerably off when compared to the water pump pulley. Is this because of the thinner crank gear from the gear drive set? It's off by about a half a v-belt width: More than I've ever had when using aftermarket dampers/gear drives.

Am I worrying about nothing? Is this common?

I have shims for the crank pulley...Is it OK to adjust it that much forward off the damper? I really don't know how else to correct the misalignment (I'm not a machinist).

I apologize for wasting everyone's time if this has already been exhaustively covered. I searched my butt off, couldn't find anything on this site (or elsewhere on the 'net).

Am I ok to shim, or have I screwed up somewhere?
 

·
WFO
Joined
·
5,030 Posts
Howdy, brothers. Long time reader; first post.

Just finished installing a Fluidampr (6.25") on an early SBC 350 that I had just put gear drive in.

While I'm not an experienced mechanic, I've done this same thing three times in the past, on similar engines, but using off-brand (CAT?) viscous dampers, and not the Fluidampr brand. I had no problems with those installs.

I took off a double-roller timing chain (GM part) and stock balancer. The gear drive crank gear is noticeably thinner than the crank sprocket for the chain.

When I installed the Fluidampr, using their specs of 70 ft-lbs, It sure seems like I have a lot of exposed (damper) shaft...Is this because the Fluidampr is so much smaller? I installed it correctly; anti-seize was used, and it goes on (with some resistance) smoothly, all the way until it doesn't want to go anymore--which, for me, was when I hit 70 ft-lbs. This, I assume, is where the end of the damper hits the crank gear. Is that right? Does the damper butt up against the crank gear on the timing set?

When I installed the lower pulley, it's considerably off when compared to the water pump pulley. Is this because of the thinner crank gear from the gear drive set? It's off by about a half a v-belt width: More than I've ever had when using aftermarket dampers/gear drives.

Am I worrying about nothing? Is this common?

I have shims for the crank pulley...Is it OK to adjust it that much forward off the damper? I really don't know how else to correct the misalignment (I'm not a machinist).

I apologize for wasting everyone's time if this has already been exhaustively covered. I searched my butt off, couldn't find anything on this site (or elsewhere on the 'net).

Am I ok to shim, or have I screwed up somewhere?
The damper snout contacts the crankshaft timing gear. If the correct gear is being used w/the correct damper, the pulleys will align as long as the damper is fully installed. There should be no need for any shims.

I'm getting that the damper is too far towards the rear of the engine, causing the pulley to need shimmed at the crank. If this is the case, are you sure the timing set is for the engine yo0u have or is it for a factory roller engine or something like that?
 

·
Registered
Joined
·
4,392 Posts
Are you sure the water pump and pulleys work with the crank pulley you are using?

I have measured at least 4 different short water pump heights when using aftermarket pumps
 

·
More machine than man
Joined
·
851 Posts
You used a damper install tool right? You didn't just set the damper on the crank snout and tighten the damper bolt down to 70 ft/lbs, right?

Check out how much this guy labors to get the damper on using the correct tool:
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #6 · (Edited)
These are my part numbers from Jegs:

LONG WATER PUMP PULLEY 720-4977
SINGLE UPPER SBC PULLAEY 720-4974
BALANCER SBC 6.25 INCH 388-620103
WATER PUMP SBC LNG 350-8821

Gear drive set doesn't seem to have a manufacturer's name (bought it on ebay)...part number is DGD-350

Seems like if the gear drive was the wrong one, it wouldn't fit?
Oh: After looking at the dual-roller crank gear, it is the same width as the gear drive crank gear...
I'm really at a loss here.

I definitely used a good tool to install the damper: No hammers came near. It took some strength to get it on, but it went on smoothly, all the way until it flat-out stopped. Looks to be a good inch of open space between the end of the crank and the outside edge of the damper. After the damper stopped--and it stopped flat out--I removed the tool, installed the crank bolt, and torqued to 70 ft-lbs.

Did I order some wrong parts?
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
Anybody have a measurement of a two-row crank pulley, long water pump, for a small block chevy? laying pulley "belt" side down on a flat surface, with ruler inserted through snout hole?
 

·
Registered
Joined
·
15,633 Posts
Howdy, brothers. Long time reader; first post.

Just finished installing a Fluidampr (6.25") on an early SBC 350 that I had just put gear drive in.

While I'm not an experienced mechanic, I've done this same thing three times in the past, on similar engines, but using off-brand (CAT?) viscous dampers, and not the Fluidampr brand. I had no problems with those installs.

I took off a double-roller timing chain (GM part) and stock balancer. The gear drive crank gear is noticeably thinner than the crank sprocket for the chain.

When I installed the Fluidampr, using their specs of 70 ft-lbs, It sure seems like I have a lot of exposed (damper) shaft...Is this because the Fluidampr is so much smaller? I installed it correctly; anti-seize was used, and it goes on (with some resistance) smoothly, all the way until it doesn't want to go anymore--which, for me, was when I hit 70 ft-lbs. This, I assume, is where the end of the damper hits the crank gear. Is that right? Does the damper butt up against the crank gear on the timing set?

When I installed the lower pulley, it's considerably off when compared to the water pump pulley. Is this because of the thinner crank gear from the gear drive set? It's off by about a half a v-belt width: More than I've ever had when using aftermarket dampers/gear drives.

Am I worrying about nothing? Is this common?

I have shims for the crank pulley...Is it OK to adjust it that much forward off the damper? I really don't know how else to correct the misalignment (I'm not a machinist).

I apologize for wasting everyone's time if this has already been exhaustively covered. I searched my butt off, couldn't find anything on this site (or elsewhere on the 'net).

Am I ok to shim, or have I screwed up somewhere?
Fully installed the damper hub should set tightly against the timing gear. The gear will press against the crank shoulder intended to seat it. The gears should align. If not, shims can be used to both align the gears and seat the damper hub.

Bogie
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #9 ·
Okay...still having the same issue.

I tried a single-row pulley (LWP) on the crank, to see if that would make a difference, and it's off by the same amount. I'm sure I have the right pulleys.

I pulled the Fluidampr back off and laid it next to the stock balancer. Height from crank-gear face to pulley face is the same on both.

What I DID notice was that the keyway in the Fluidampr looks slightly shorter than the stock balancer, but measurement with a caliper from bottom of keyway to opposite side of crank hole shows equal between the two.

This particular crank has two keys in it. It just so happens that the amount of key sticking out from under the crank gear looks like the missing space (my pulley is too far forward by about 1/4").

Could this be the cause of my issue? Does it seem weird that the crank gear would go on without any problem, but then keep my balancer from installing completely?

...and why are two keys used, vice one? Is there a harmonic reason for this? Is this normal?
 

·
WFO
Joined
·
5,030 Posts
Okay...still having the same issue.

I tried a single-row pulley (LWP) on the crank, to see if that would make a difference, and it's off by the same amount. I'm sure I have the right pulleys.

I pulled the Fluidampr back off and laid it next to the stock balancer. Height from crank-gear face to pulley face is the same on both.

What I DID notice was that the keyway in the Fluidampr looks slightly shorter than the stock balancer, but measurement with a caliper from bottom of keyway to opposite side of crank hole shows equal between the two.

This particular crank has two keys in it. It just so happens that the amount of key sticking out from under the crank gear looks like the missing space (my pulley is too far forward by about 1/4").

Could this be the cause of my issue? Does it seem weird that the crank gear would go on without any problem, but then keep my balancer from installing completely?

...and why are two keys used, vice one? Is there a harmonic reason for this? Is this normal?
Some cranks used for blowers will use dual keys in the outermost position (clocked at 12 o'clock and 6 o'clock, for example) to better secure the damper or bottom blower belt hub.

But if you are talking about having two keyways and keys -BOTH in line w/each other, this is how the bottom timing gear and the damper are indexed onto the crank so they are in phase w/each other.

There should be no key extending out past the crank timing gear that could stop the damper from going on all the way until it contacts the bottom timing gear.

Check to be absolutely sure the key that's extending from the bottom timing gear isn't stopping the damper from fully seating. This may be easier to see w/the oil pan off. There should be enough of a chamfer on the ID of the damper to allow for the key that extends from the crank gear to not keep the damper from seating.

The image below shows the crank gear on correctly and the two keys installed correctly. Ignore the arrows- the image is from another thread at Team Chevelle.com.

 

·
Registered
Joined
·
1,684 Posts
Are you sure crank gear key that is extending 1/4" past the crank gear doesn't have a burr at the front of the key. Take a fine file and smooth the edges and the top of the key. Look and feel for burrs in the damper key way too.
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top