Roger Perkins

Went to the barn today to hopefully finish my winter project,installing a 250 blower on a Gen. 5 502. Bought a used blower,looked ok,but what do I know. Finished all new plumbing etc. , but when engine was started I had no boost psi, actually running a vac. of up to18 psi. at wot. Tried hooking a separate vac. guage to confirm dash guage reading,the same. Unhooked blower belt , no differance. My thought is seals on blower are shot.looking for second opinion,anyone??

bford1

Were you running the engine out of the water? It won't make boost without a load on the engine. Mine will run up to 50mph with 0 boost. You need to test it with a load on the engone first. If the blower was in good condition it may jus be something simple.

Roger Perkins

Yes running on garden hose. Checking for any leaks, setting timing,etc.. Didn't Know about needing a load,May have to splash her tomorrow to check Thanks for the info.,maybe I can put the blower rebuild off till next season,it's always something

bford1

I'll bet that once you get it on the water and hit wot you'll see that boost gauge rise. You do have a gauge I assume.

BTW not all blowers will need a load to create boost. The need for a bypass valve depends on the amount of boost. But, most blowers will have some sort of bypass valve so that when the engine is in vacuum (part throttle) the boost is routed out of the intake tract. Now, if you were testing your engine and you are showing 0 vacuum (wot) and it's still not making boost you have a problem. I'll be interested to see what happens.


Brent

mcollinstn

Can't measure blower boost unless throttle is wide open. If the throttle plates are closed, there's no air for the blower to compress..

Pure Energy

Ummmmm, WOT on the hose???

Prowler

most important question,what size pulley are you running??

Roger Perkins

The weather is not looking too good for Sun..I'm running a 3" pulley and the wot was only for a short burst. Air intake was the first thing that we checked along with the throttle plates,everything seemed to be alright as far as we could tell .Just heared weather update ,basically they don't know what it will do Anymore suggestions i'm all ears, may just have to get wet tomorrow

Reed Jensen

If the output volumn of the blower is the same size or smaller than the displacement volumn of the engine ... the blower will NEVER make boost... unless you drive it faster than crankshaft speed... Good Luck...

Dave F

I thought the same thing. with a side of