Exceldyne Belt Stretch Question

October 18, 2020, 03:03 PM

I am looking for someone who has experience with an Exceldyne Big Block Chevy Timing belt, specifically with regard to how much they stretch. This is a 582, cam is a .805 / 287* .795 / 298* springs @ 360# on the seat so it's not a big camshaft and not an excessive amount of spring pressure. I also don't spin it up that hard, (7600).

I am getting ready to install the belt drive later this week and wondered how much they stretch.

Thanks

Bob

October 18, 2020, 04:19 PM

Curly1

I have not noticed any stretch on mine (Tall deck SBC 454) but I still replaced when I freshened it.

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October 18, 2020, 04:32 PM

Big Steve

Mine never stretched at all. I would put a new one on at the beginning of each season just because its cheap maintenance not because it was necessary.

October 19, 2020, 10:00 PM

rusty

most all belts will give up 1 degree under load,no experience with that one

October 20, 2020, 06:34 AM

Bad News

quote:
Originally posted by RPROGAS:
I am looking for someone who has experience with an Exceldyne Big Block Chevy Timing belt, specifically with regard to how much they stretch. This is a 582, cam is a .805 / 287* .795 / 298* springs @ 360# on the seat so it's not a big camshaft and not an excessive amount of spring pressure. I also don't spin it up that hard, (7600).

Why so much spring? 360 is a ton of overkill for that.
300 seat, tops 750-800 open.
Any of the Manley, PSI,Pac would work just fine.

I have ran all 3 previously with a 288/308 .475 lobe with 1.8 .820 with lash and deflection.
Probably 1 to 1.5 degrees of movement with that spring.

I am getting ready to install the belt drive later this week and wondered how much they stretch.

Thanks

Bob

October 20, 2020, 07:44 AM

NC3x58

With a PAC 1248 spring I was told to degree the cam 2* advanced from what the cam card says to account for any belt/chain stretch.. I would say installing the cam 1-2* advanced from the cam card will be fine...

October 20, 2020, 07:51 AM

1320racer

same as with a chain

October 20, 2020, 06:40 PM

RPROGAS

I bought the CFE BMF385 heads complete with a set of T&D Pro type 1.75 shaft rockers, Manley SS valves, PAC springs (360#), titanium retainers fully ported and assembled by Tony Bischoff (BRE) for $1500, yep, that ain't no mis-print, $1500 including the freight from Ohio to my house.

I thought that it was a pretty good deal.

Bob