90Hrs, I would stay with the new factory pieces if you haven't had any failures. The extra money you spend for Mercurys quality control is worth it. My engines had been de-tuned with flat tappet cams. I decided to go back with roller cam after breaking a timing belt. In hindsight after several lifter failures and finger pointing this is wrong and that is wrong. I found that excessive spring pressure will kill any needle bearing roller lifter it just a matter of time(any size or brand). The Isky lifter eliminates that problem. The highest quality valve spring you can buy is more than likely already installed on the 1075. When you remove your springs test them to see if the tension is going away. This is were a PSI spring shines it very hard to say if they will last longer but they hold their tension much longer.

Eddie good to talk to you today as always thanks for the information. See next time at the shop.
R.B.

Good talking with you. Glad to help. Talk to you soon. Stop by when you are in the neighborhood.
Eddie

Have many converted their 1075's from Solid to Hydraulic roller lifters?

What are the top end re-fresh intervals on the 1075 when converted to hydraulic?

Thanks,

Kurt

jesel sportsman solid body lifters are great too. the bodies are DLC coated now, picture does not reflect that...
http://jesel.com/index.php?categoryid=32

I have heard that some are changing them to Hydraulic so they don't have to do the valve adjustment.
Not sure on the re-fresh if it has a Hyd cam, looks like the valve springs will be the issue then.

I would think after you re-propped or changed the drive ratio to regain the lose of rpm the weaker valve train would wear out faster. By not being able to do routine valve lash checks a potential disaster is more likely happen. The mechanical roller cam has to be in the 1075 for it be capable of 1075 performance. I'm just unable to see the benefit in weakening the valve train for any reason. With a shaft style rocker arm system the only time you will see a change in valve lash is when the valve train starts losing stability. What every the reason its time to change the weakened parts not redesign the engine. At 90hrs if valve train not showing any signs of wear the lash will be correct. I believe Mercury calls for top overhaul at 75hr more than likely this before the spring start to losing tension and causes lifter bounce. I'm sure in many cases the parts may last longer, but you'll have to be check the lash every time you run the engine at this point if you want find a problem before it breaks.

75hr would give me more than two season.. Man Id rather change the parts in the off season so I don't miss sittin at Gliberts lookin at overstuffed bikinis and havin a cold one!!!

I'd like to hear the experiences of those who have converted to hyd roller or the new upgraded on their maintenance. Can you make em live 150+hrs?

If it was me, I wouldn't swap any part #'s in the Mercury 1075 valve train. It is very likely that either Mercury or a Mercury vendor has SpinTron tested this set up. This means the valve train is tuned so that the lifter perfectly tracks the cam and causes the least stress on all the components. Changing to a different valve spring rate or installed height. retainer, lifter weight or push rod could you a different results could = less life or increased chance of a major failure.
The valve train usually doesn't fail at idle.....

why would anyone want to deal with mechanical cam maintenance at this low power level? A hydraulic cam is way easier on parts & 75hrs is a joke for top end overhaul at 1075hp. just mho