copiercat

someone else said my air cleaners were too small
heres a pic, is that possible?

articfriends

iTrader: (1)

I ran into almost the same exact scenario this year,I switched from a merlin 2 block on my 540 to a dart block,assembled motor with .0033-0035 on rods and mains (nothing too tight by any means),used the same part number melling high volume blueprinted pump with high pressure spring and found I had 100 lbs of oil pressure most of the time when running 20w/50 kendall gt-l,I used the same oil, Same part number oil pump,same brand lifters,etc,same crank and rods but crank was polished even looser and enigine has 20 lbs more oil pressure then it ever had before. I ended up running 10w30 synthetic on the dyno after we were sure rings were seated and been running 5w40 synthetic this season to get oil pressure to a normal level. Putting a softer by[pass spring in the pump(which I have never had to do) would just cause the oil to churn and heat up more in the pan. I think I could have used a pump with shorter gears in it. The thinner oil was a good fix BUT I was out running one weekend and the oil was due to be changed (it had about 14 hours on it) and I noticed if I leaned on the throttle above 4000 oil pressure would drop,cut filter open there was nothing in it,changed the oil everything was back to normal. I normally change oil once a month around 10-12 hours (it gets fuel diluted fast from the blower set-up running rich),I think with the thinner oil the oil thinned out faster from fuel dilution so I am just keeping a eye on it. The merlin block must have had more internal leakage then my dart block,I know the lifters were bleeding some oil off because of the short lifter bosses on the merlin block,the dart bosses are longer,Smitty

copiercat

i thought i would let people know what the end result was, after changing the oil pumps from high volumn /standard pressure i still had 70 lbs at idle and 100 when i cracked throttles, so i changed the pumps again to standard everything and now the pressure is at 54 lbs idle and 70 cracked still using the castrol 20/50 oil. i think were there for the problems, ..
thanks for all the responses !
scott

Wobble

Maybe you can add your experience to this thread, http://www.offshoreonly.com/forums/s...ssure+problems

That thread should be required reading for anyone that tackles DIY engine swaps or any kind of HP upgrade

priceb

Hi Scott,

I'm glad you've solved your problems and I'm also glad to read these posts. I think I might have similar problems.

I have Dart big blocks and my pressure is running about 100 at full throttle. I have oil coming out of the breathers and the caps on the rocker covers.

The guy I bought the boat from said that that is standard for Dart motors to have such high oil pressure.

Any feedback on this would be great. thanks

articfriends

iTrader: (1)

I'm getting the feeling that the oiling system is so good on a dart block that you need to use a std volume pump instead of a high volume pump which is where my high oil pressure came from but like I said,I used the same part # pump on my merlin block with my rods and mains slightly tighter and oil pressure was about right. If I had to do it over again I would use a std pump but I have no intentions of ripping it down,I will just run lighter oil until I freshen it in a few years,Smitty