502 Cam
 

I have a 95 502MPI in my 95 baja 272. It has about 350 hours on it. It Still runs very strong. I am looking for some opinions about replacing the cam. I am wondering if I can take the top end off and put a cam in without changing the cam bearings? Should I get new lifters? Also I would have some head work done and get the ECU remapped at the same time. I already have IMCO power flow exhaust, adjustable Fuel pressure regulator and high flow spark arrestor. Im looking for about 300 more RPM's with my current 25pitch Bravo1 prop. I love the midrange I have right now, but I am only getting about 4750-4800 rpm's at WOT. I know I could go back to a 24 pitch B1 but would really like to get the extra top speed and keep the midrange. All opinions appreciated.

You don't have to replace the bearings to put in a new cam. I've changed several and never done new bearings. Always use new lifters with a new cam.

after reading "Roller lifter shortage" I may wait a while to do the upgrade!!

After reading the roller lifter shortage post, you may HAVE to wait a while:(

Another question is would a mild cam, head work and ECU remapping get me the 300-400 RPM's?

You need to be VERY careful with your cam selection, if not, you will be very unhappy with your results. What you should use depends on how far you want to take it.....it can get exspensive very quick with that setup as you run into corks almost immediatly. So first you need to decide how much you want to spend....and yes you can just do a cam change and your seat timing will be less than you think, but you will bump your power across the entire rpm band. Just don't expect 500 easy horsepower...that takes some work and cash. EFI is great, but in your setup you can start losing its advantages rather quick. I've tried several cams over the years, just getting ready to try my 4th one, and I think it will be a winner. IMO if it wont run right with the stock programming,it's not ever going to run right...make sure it's running good first, then you can tweak your timing and raise your rev limit if you wish. If you want, you can call me at home 816-822-0945 . If being an expert is based on dollars spent and wasted, then I'm the smartest guy on this board. Take care ,Berg

502 cam
 

If you are looking for more power in your 502 my advice is to find someone with a proven track record and lots of experience and take their advice. Find a builder that's built and dynoed lot's of 502's. Anything less is probably a large waste of time and money. There are lots of builders around with experience that can tell you what you'll get before you turn a bolt. Don't gamble, invest with known companies.

Just adding a cam usually has a marginal effect on any overall performance increase. It's a combination of components that give best and longest lasting results.

There are plenty of people posting on this site with good experience. Hopefully you will find the combination you are looking for.

Good luck.

I've put slightly hotter than stock cams in mild marine small blocks and saw an easy 200 rpm. I could only assume the gains would be slightly better in a BBC. I would go for it. If your exhaust doesn't counteract reversion, choose a cam accordingly.

Listen to Liquid Lounge!!! Once you get that motor out of whack you will hate yourself and your boat.

Liquid Lounge-- What cams have you tried and what are you trying now that you think will work?

To me the problem is not so much trying to get a cam or heads that will give you more power, but rather trying to get the e.c.u. re-mapped to work with the changes. If the motor doesn't work well as a combination, then there is no sense in playing around with it. Mercruiser spends alot of time picking out a good realiable combination and then mapping the e.c.u. correctly. Due to no fault of their own, there are more than a few guys here on this board who have wipped out good motors on badly re-mapped e.c.u.'s And then guess who gets stuck with the bill for the new motor?

Just a thought ... how about a stock 500HP EFI cam?

I replaced the cam, lifters, pushrods, rocker arms, larger valves, springs, retainers, guides, locks and seals, heads slightly milled, ECU re-mapped to cam specs by ASM, stainless marine exhaust, flame arrestor, fuel pressure regulator. This was all done to a 454 mag efi in a baja 24 outlaw. I never had it dynoed and would say I picked up at least 300 RPMs. As far as MPH, I would say I only picked up 3-4 mph. I was hoping for around 100 hp increase. My speedometer reads 73-74 at WOT. Also while I had the engine apart, I replaced the main and rod bearings, honed the block and replaced the rings. The motor runs great now. I do think I need to play around with the fuel pressure though - the transom gets dark. Just my experience - kind of expensive for 3 mph.

Call Nickerson Performance in Bristol, Pa. I'm using a grind from him for my Stage II ProCharger. The motor makes great power with the supercharger disconnected too. He has done a crap load of R&D and should be able too help you with no problem. Ask for Brad and tell him that Scott with the H2X in Pa. told you to call. Chances are that an ECM reprogram should be in the works with the cam. I believe a 300rpm gain is reasonable. Hate to say this but consider someone other than ASM for the computer upgrade. I had some bad luck with that place and don't seem to be the only one. Good luck!

Do you have a # for nickerson?

The # is 215-781-1370. The last time I called this # it gave me a message for another # so get the pen and paper out to get the right connection. Let me know how you make out. Scott

Thanks for the #.. i talked to them today. Very helpful and informative. Any new parts I get will be coming from them. They sound like great ppl to deal with. sj

sj, Glad to hear it! Dean and Brad have some great ideas on what really works. I will probably never buy another cam from anyone else. I'm switching from efi to carb for my blown setup and can't wait to see the results using their parts. Take care! Scott

Hi Scott... They have some pretty wild ideas on carb work to. The want 500 for a stage 5 setup to my 800. They promise better running and a 25 hp increase. Pretty pricey but interesting. sj

sj, They aint cheep on carb work but he is probably one of the best in the business. The last time I was in there he must have had about 50 Dominator carbs lined up against the wall ready for delivery. Dean makes some amazing power with carbs. Like I said, keep me posted on your cam selection stuff. Talk to you later...

There is nobody better to work with than Dean, his carb's are wonderful. My 454 acted just like an efi when starting & never a black transom. The only adjustment to the carb I had to make was raise the idle speed 100 rpm.
After you install your parts, call him, send him your "just run plugs" and he will read them for you and advise if anything needs to be done &/or what plugs to use. Three day turn-around on my carb too!!

They sound great.. thanks guys. Im looking forward to next spring already.