1275 Rev limit

[JohnDough]

Hi guys

what rev limit would you propose I set on a 1275 engine

spec
60" oversize (balanced with conrod)
std crank, balanced
lightened flywheel about 1 kg off
288 scatter cam.
center strap (only 2 bolt)
40 DCOE weber and lcb manifold
alternator

 

[racingenglishcars]

I guess the first question is:
Does it have 1 5/8" journals or 1 3/4 journals?
If it's 1 3/4 journals, are the connecting rod big ends lightened? They are much bigger than the 1 5/8 rods.
The strap helps, but lightening the rod big ends helps just as much. Wedging the crank helps even more, but since it's stock we will just leave it at that.

 

[Hap Waldrop]

Street car right? If so, who knows, it might go to 6500 or beyond, but why would you want to on the street, most of the time on the street the only time you going to get to redline is shifting in the lower gears, so with that being said, a trip up to 6000 rpm now and then is going to kill it, but doing this all the time will for sure limit the life of the engine. In race trim, 15.0 to 1 compression lighten crank, Carrillo rods, race clearenced motor etc., etc., I shifted at 8100 rpms, but it took $10K+ race engine for enjoying that privledge /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[JohnDough]

Will be street use. The engine revs freely and i don't want to trash it, on teh journal side i actually don't know never measured them :-(

I'll stick to 6000 for now

Thanks

 

[Jim_Gruber]

My 1098 sounds like it's reached it's upper limit at 4,500. I don't think I want to push it much beyond that. And I thought they were supposed to rev better than a 1275

 

[Hedgehog]

Rev limits I've used on my various race engines over the years. 948cc was 8000 (occasionally hit 8500), 1275 was 8000, and the current 1098 is 5500 (stock rods).

Personally, I really loved the way the 948 revved!