Have a chance to pick=up a pair of 900sc s at a good price.
Zero hours since rebuilt. however,they only had 28 hours since the first rebuilt..Top end both times
How many hours is normal between overhauls and how many lbs of boost are they suppose to be running, I noticed these had 49 tooth pullys on the top.dont know if this what they come with or not. Owner says this amout of hours is normal thats why Merc gives suck a limited back=up on this engine, If all this is true, I think that I will have to pass..
I would appreciate any information that I can get on this subject.
Thanks,

eliminator219

I am sure someone will chime in, i think they run 7lbs boost and they inspect the top end every 50 hours[pull the heads and tear down]and replace anything thats loose are worn, bottom ends are every 80 to 100 hours, could be a little off but not much,
Eliminator had a pair of 900sc's not long ago, are these the same motors?
Mark

7 to 8 lbs is normal they should in the real world go several hundred hrs bottom end and 100 or so top if valve stay adjusted
and you take care of them !!
Their nothing super exotic ,don't know why they would wear out any sooner ,withsome proper care ,,
If you don't take them please p.m. me the info as I may be a buyer

Solid roller motors need periodic lash adjustments. If this is neglected a few rockers could get loose and be damaging to parts. Bobby D is right bottom end should go several hundred hours and valve springs and lifters should be replaced every 100 or so. I do not see a need to pull the heads if the valve lash is maintained. Believe it or not soft lobe solid roller cams are very gentle on parts as long as the lash is adjusted so the valve closes on the slow lash ramp. If lash is loose it could allow the valve to shut at the steep part of the cam lobe.

Les, if you put those in your Daytona, just maybe , you could beat me this summer.

I have a pair of 900sc. You need to check the lash every 25 - 30 hours and replace the springs at 65 hours - dont mess with this!

At 130 hours I would recomend a complete valve job - new valves, springs, lifters, etc..... (I just did it).

The lower is good for maybe 300 hours if you treat it nice.

They run 9lbs of boost.

They have been very relieable so far.

Thanks for all the replys and advise,think that I will have to give a little thought to this subject.. and as for you Payton, Cant blame me for trying can you? Sometimes its not too much fun going SLOW!! summer is almost here,see you soon..

eliminator219

Maybe you should trade your new drives in on #6s.

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Looks like any spring you buy would do better than this and valves ???
The poor old 500efi has inconel valves they last ,Its hard to understand their thoughts on building the 900 that way

I always thought the 900sc turns about 6200rpm's and the 500efi is good for 5300? that might be part of it, plus i heard they cut down the flow of oil to the top end[restrictors] and it makes the springs run hotter? has anyone else heard anything on this?