Merc 420 to 525sc in a Formula 242.
 

I have an 86 242. I have a 420hp Mark IV engine. I just purchased a 525sc blower setup. I am planning on leaving the low hour short block as is. I am having the heads looked over and inconel exhaust valves installed. There is just a few grey areas.

Does anyone know if the DUI distributor will clear a 177 blower?

I suspect my motor has stock 454 mag oil system. Combo oil and PS cooler with the oil filter on the exhaust. I have a new 10778 Melling oil pump going in. I would like to either get a stock HP500 oil system or a nice aftermarket setup. Any thoughts on the required oil system for my HP level?

I have also heard of swapping to a 134561 cam versus the 132561 I have now. i am not really looking to spend the extra to go roller right now. Any flat cams with good results?

Thanks in advance.

Here are some pics of the current setup and the blower/carb/arrestor setup I bought.

http://i880.photobucket.com/albums/a...65182309_o.jpg
http://i880.photobucket.com/albums/a...82904155_o.jpg
http://i880.photobucket.com/albums/a...79347345_n.jpg

A little off topic but your engine compartment was my inspiration to clean mine up. I'll post pics when done.
Where did you locate your bilge blower hoses? Good luck on your project boat looks great.

They are now by the trim pump. They were not in for the pic.

I don't think the HEI style distributor will clear, but it might.

I would run the 134561 camshaft, 236/246 114LSA .553/571 , and prop it for around 5300-5400rpm.

That combo, will put you in the 575hp/600ft lb range. Wayne272 did the exact same setup to his 454 mags in his 31 Bullet, and dyno'd them. If you plan on running a water thermostat, you're oil cooler may not be sufficient. If you do not plan on running water thermostats, it might be ok. If you are not going to run a water thermostat, I highly recomend an oil thermostat.

Watch your ignition curve, and your jetting. Once that is dialed in, you should have a very reliable combo. I would run a AR134 plug, 5673-8 NGK, or MR41T delco.

So basically the thermostat slows down the water flow to the engine, therefore the water going through the oil cooler is also slower, allowing less heat to be removed from the oil. If I go to a crossover setup, more water will pass through the cooler, allowing cooler oil, but i would then need an oil thermostat to bring the oil up to temp? Am I understanding this right?

Yes and no. Main thing people forget, is an engines water temperature, has a direct relationship to the oil temperature. Some vehicles, dont have external oil coolers, the oil temp is maintained from the temperature of the engine. So, the colder water temp engine, will also serve as an oil cooler so to speak. Having a water stat that warms the engine to 150 degrees, also helps warm the oil, and vice versa.

The best advice i have, would be to invest in an oil thermostat, replace the stock merc crappy lines, and replace with good flowing an fittings, and a good sized oil cooler. I would do that, before replacing the oil pumps. The stock pump is fine for what youre doing imo. Mercs fittings were restrictive . You want that oil to flow quickly to the cooler, filter, and back to the engine in an efficient manner. I would do -10AN oil lines, with full flow ends. The stock HP500 style thermostatic filter head mount works great as well.

I get what you are saying. Engines remove heat by both coolant and oil. So if I run cooler water temp, the parts will run cooler, then there will be less heat for the oil system to remove. I am currently running a 160 stat. The boat consistently runs 155*.

It would seem to me that a cooler block would also aid in preventing detonation with 8.75 compression and boost.

The oil lines coming off the block are very large, like garden hose size. The ones to the filter would be the ones that look small, along with the fittings at the filter. I already have the new pump. It seems many people like the 10778 pump. I would feel better using it.

I had a trouble free summer (48hours) last year. I really just want this thing to be turn key all summer.

Its mainly some of the inverted flare fittings merc used that are restrictive.

Sounds like a fun upgrade. I think youll like the way it runs

Joe, do you think my risers are long enough for that bigger cam? I was also just looking at CPs website. They have a 120* thermostat. Would that be cool enough?

Ive seen that cam work for 700 hours in 454/370s with stock center rise iron manifolds, with no reversion, that were rebuilt by competition marine center many years ago.

Those risers will be fine, but you have to watch out when you idle for extended periods of time. You must clear it out ,,,, meaning put it in neutral and rev it up every five minutes or less. this keeps water from walking up the the tail pipes. I would jet that thing on the FAT side. And as for timing ,,,, well I would go no more the 28* , But MT can help you with what his buddy ran for timing. But remember each motor is different in that aspect due to alot of variables. Oh and it sure looks nice in the boat, motor and bilge

Summit racing lists the same springs for both the 132561 and 134561 cams. Does that mean I could re-use my springs?

Yes. Just make sure they are set up correctly. As far as timing goes, i can tell you this. Back when i had 177 blowers on my 454s, they had dart aluminum heads, in the area of 8.75 :1 compression. The way the previous owner set them up, was with an 18 degree advance bushing in the distributor, with 34 or 35 deg total timing, no water stats. They ran great that way. Never hurt them.

I have spent some time on the dyno with various timing curves on supercharged stuff with mike tkach. What we learned, was the engines liked timing at high rpm, and didnt like it at low rpm. Basically, different than what most NA engines like for timing down low, at least at full throttle.

We first ran this particular engine with timing locked at 34 deg. That setup has worked for us in past. Then we played with programmable curve. We removed nearly 10 degrees of timing in the 3000-5000 range. What we found, was actually an increase in torque numbers, as well as a reduction in exhaust temperature. Once we started bringing the timing back in, in the upper rpm range, the engine loved it. Going from 34 to 35 deg at 6500, netted about a 20hp gain, as well as cooler egts.

Too much timing down low, esp with a roots or whipple, capable of full boost at any rpm, can get you in trouble. Engines are more likely to detonate at peak torque, than wot.

Would it be wise to run the engine on the hose and make a chart of the timing in 500rpm increments? Then I could get my DUI recurved at Davis if need be.

Put the boat in the water if your going to do that, or at least back it into a boat ramp. Problem with leaving it on the trailer in the ramp is the angle the boat is at for the carb. The water hose is ok to idle but will NOT supply enough water for High RPM.

The octane of the fuel has alot to do with it as well as far as timing. Higher octane, slower burn, more timing needed, as you need to initiate the combustion process, earlier, due to the slower burning fuel. And of course, the higher octane, is more resistant to knock. It can withstand more cylinder pressure before detonation happens. Theres really a ton of factors that come into play, but its all about lighting the spark at the right time, and again depends on many variables. The dyno is where this comes in handy tuning this area, and thats actually what dyno's are meant for. Not bragging rights, or to compare others build combinations.

I'm sure back in the days before knock control, map sensors, and modern engine management, these engines had to be setup, that if in fact, the customer ran lesser grade of fuel, the engine wouldn't self destruct, so they played it safe on timing. Usually giving up a good amount of power/effieciency, to prevent immediate failure. Today, most modern engines, will adjust timing, based on things like IAT temps, map vs throttle position, coolant temp, knock sensors, and so on.

I'm not familiar with DUI setups, and how they are curved, or can be curved. Generally, you'll find you want a good amount of timing at idle, at least around 18*, with a fairly "stiff"' curve up until max timing/rpm. This is an engine combo, you really don't want to "bring it all in at 3000" type of setup. Here is a 525 timing graph. It doesnt bring max timing in until 4000. I would even consider delaying that another 500 rpm on your combo.

26 childish back and forth posts out of 40 posts have been removed. No value to the thread and just a rehash of the same bickering.

Its terrible that somebody posts looking for advice and then has to sift through all the BS to get to any technical opinions.

STOP or be prepared to be stopped by the Mods


Oooops. This was supposed to go in the other thread.

I think you posted on the wrong thread.

Don't mean to derail the thread but does the OP have offshore engine mounts? If not might want to look into that while engines are being swapped.

I run 91 octane, ethanol free fuel. No ifs, ands, or buts. The DUI people will re-curve the distributor to whatever curve I want for a small fee. I really want to make sure this thing runs properly.

I have aluminum brackets through bolted to the stringers with large backing plates. The rubber mount then bolts to that. My rubber mounts are crappy. I was going to replace them with these billet pieces. That way they would be ridged but remain adjustable.
http://i880.photobucket.com/albums/a.../620-52380.jpg

NO he deleted those threads.

That is a nice piece there. And for your application will be great. The only thing I would do is go to McMaster Carr and order Nylock nuts to replace those nuts so they wont loosen up. Just a little insurance.

Good Call. Or a dab of loctite.

Yup you were right it was another thread..My bad ... lets continue :lolhit:

On a few builds with mounts like that, I did try red loctite, but some did come loose. Then I switched to the nylock nuts and they never had a problem. Merc has those thin metal bend tabs but they are a pain in the a$$. And they are more money then the nylock nuts

run two nuts on the bottom side if you have enough room.

I was putting my shopping list together at Summitracing. I discovered that inconel is brand specific to Manley. Upon further research, my 420 may already have them. That assumes the builder that rebuilt it put inconels back in it. When I pull the heads off, how can I tell if they are Inconel already? And what valves should I put in if they are not Inconel?

Ooooopps. Yes, I meant to put it in the other thread.

No thread was deleted. Just some posts of no value

Inconel has been around since the 40s, with many different grades, there is even a company out there tat can 3d print with it.

I chose Ferrea Super Alloy P/N F2120P, if you are a vet the Ferrea company will give you a 40% discount.

Are Ferrea Super Alloy > or = to manley Inconel?

Read their webpage, these are the best exhaust valves they make, better than Inconel, from one of the best valve co, IMHO.

Newest potential issue: pulley alignment. I have a CP performance crankshaft pulley

This one.
http://i880.photobucket.com/albums/a...r/13850_4_.jpg
http://i880.photobucket.com/albums/a...r/13850_1_.jpg

I see that mine is much different than the one that comes on most 454 mags and 525sc. Will the 525sc lower blower pulley mate up? And if not, are all lower 3v pulleys interchangeable?

Ok progress began today. I yanked the motor out today. There is no way that my oil cooler is big enough for even 420hp. The oil cooler portion is only 3 inches long. I think my lines are large enough except right by the filter. Tear down will begin tomorrow.

Here are some photos of my oil system.

http://i880.photobucket.com/albums/a...r/IMG_2249.jpg
http://i880.photobucket.com/albums/a...r/IMG_2251.jpg
http://i880.photobucket.com/albums/a...r/IMG_2252.jpg
http://i880.photobucket.com/albums/a...r/IMG_2250.jpg

back to original question, yes the DUI dist will clear, here's pic of one of my old setups, suggest locking the advance and running 32-34 timing

http://i227.photobucket.com/albums/d...r/100_3409.jpg

A little update: The motor is down to the shortblock. The shortblock appears to be in good shape and will be used as-is. The head are another story. Cylinders 1,3,5,7 all had sunk in valves with 3,5 being sunk in at least 1/8th inch. The heads are at the machine shop right now being gone through. I have new oil cooler on the way. I also hope to be installing a hp500 thermostatic oil filter boss. Thats about it for now.

Update: I pulled the shortblock apart. I had a bad feeling. Upon tear down i found the following.:

#4 rod bearing was pretty beat on the upper half. The others were not horrible. The corresponding piston looks like all the others.

#1 main bearing had a big groove in the lower.

http://i880.photobucket.com/albums/a...36209810_n.jpg
http://i880.photobucket.com/albums/a...58237239_n.jpg
http://i880.photobucket.com/albums/a...18736978_n.jpg
http://i880.photobucket.com/albums/a...46411369_n.jpg

Like was mentioned on your FB posting... that sucks! Sorry for the unfortunate news. Good thing you pulled it all apart. Fixing is easy. How bad is the crank?

What caused the valves to sink? Were they tulipped?

Valves did not appear to be tulipped. I dont know for sure what caused it. My machinist suspects they went slightly lean.