Replace, rebuild, refresh blower motors?
 

I am working on my '87 Formula F311 SR1 this winter. Just bought the boat last year, and it needed some TLC. It has 454/420's in it with B&M 174 blowers with around 400 hrs. BW tranny's and TRS drives. TB IV ignition at 28 degrees. I run it offshore in New England. After much general maintaince to get her seaworthy, I ended the season with 2 major problems as I saw it:

- One engine overheats with a thermostat in - take it out and everything is fine, except no engine temp (not the thermostat I swapped it for a known good one)

- The other engine is getting some water in the oil (aka milkshake) It seems to do it more when hitting high speeds. It also leaks / drips a small amount of oil toward the rear of the engine - couldn't pinpoint it with the motor in the boat.

The intakes were fairly rotted (maybe the source of the leak?), and I have new ones in hand as well as the thermostat extenders.

The blowers are at the Blower Shop now and are about to be rebuilt (slightly noisy and didn't want to take a chance). I had Nickerson performance rebuild / update the carbs last summer. Exhaust is EMI and is 2 years old. I put Stainless Marine bypasses on last summer, as the circulator pumps were leaking. Many other new smaller parts as well (water pumps, etc).

The engines are coming out next week so we can better inspect their condition. With the exception of the problems listed above the boat runs great. What I am trying to decide is how much work is worth putting into these engines, or should just looking for crate motors and starting over? I am trying not to break the bank, but don't want to break down during our next short New England summer.

I know there is a lot of expertise on this forum, and would appreciate any insight / opinions on this project.

Fix 'em, replace 'em, or do the minimum and just run it?
Thanks!

If one engine is getting water in the oil you definitly have to fix it.

If you're lucky it is a blown headgasket.
Less lucky,cracked block/head.

The oil leak is probably the rear main bearing oil seal.

If you're happy with your engines,do a comlete rebuild.

It's possible that the water pressure is a bit high, and that it's pushing some water past the intake gasket(s), especially with some water passage corrosion.
38KV is probably correct about the oil leak but it doesn't hurt to double-check the oil pressure senders at the back of the block. You might have one down by the oil filter adaptor too.
On the temp issue, are the two engines identical as far as plumbing and thermostat housings are concerned?

Hi Crazyhorse,

That would be nice if it is just a water pressure issue. I have seen posts about that issue. Does anyone have a link to a pressure gauge suitable for testing this? I have transom mounted water pickup going through 1 1/4" hose through sea strainers then up to the pumps. I think I am going to pull the heads off of that engine and have them checked anyways, possibly install new valve springs. Where water (salt) was getting in, do I need to disassemble the lower end too?

On the temp engine problem, both engines are plumbed identically. One strange thing to note is that the raw water pump drips through the hole in the bottom. I replaced it with a used one, and then a new one too. All 3 of them dripped for some reason, even when the engine is off. The only other thing that I can think of is that I have the sea strainers tapped for fresh water flushing. When I connect the flush system on that motor to the hose, water is leaking out past the sea strainer gaskets in a good amount. It doesn't leak when running normal. Maybe it is sucking in air, and it is getting trapped at the thermostat?

The sea strainers can and will let air in if the top isn't tight or if the gasket is bad. That's a common overtemp problem on inboard cruisers. Go-fast boats typically run fast enough to force water through the sea strainer when on plane but if it's a bad enough leak at the gasket it can still pull air.
Chances are, though, that you've got another issue, possibly a head gasket that's passing combustion gasses into the water jacket.

Crazy is on track.

If it overheats with a tstat, and does the same if you swap tstats.

AND

you got milkshake.

I'd look awful hard at headgaskets.

Actually, it is 2 separate motors, 1 having the milkshake, one having the overheat.

One other thing on the milkshake - the oil level isn't really rising, just that when I pull the stick, it's there. Also can see it inside the valve covers when looking into the oil fill hole.

I am also wondering considering the age of the motors (original 1987's 454 / 420's) and that they have had the superchargers installed for about 10 years, how much $$ is really worth putting into them? They perform great, but could I get a short / long block somewhere for a reasonable cost (if so, any suggestions greatly appreciated)? Or just start tearing these down until any / all suspect and recommended maintenance parts are replaced?

I'm just not sure what is the best approach.

you running circ pumps?

I am running a corssover aon avery similar engien and had temp issue until i pulle dout the thermostat. SH etake as while to heat up now so it has to idle at the dock for a while but once it warms up its fine.

geta water psi guage maybe you have too much and thats whats causing water in the oil.

No circ pumps, crossovers. I put thermostats in the motors to see if the milkshake was just condensation, and the circ pumps leaked like crazy. So I just decided to go for crossovers, especially using the superchargers -figured the extra cooling would be better.

The funny thing is that the motor that has the milkshake runs fine with the thermostat. The other one that has no apparent problems can't run a thermostat without overheating. Both motors are set up identical. Go figure?

If you have the original engines from 1987 and the circ pumps leaked like crazy,I think there is a chance the water passages in the block/heads is choked up with rust.

I had that problem with my previous boat (also from 1987).
The engine overheated and when I teared it down,It was so corroded it went straight to the junkyard.

If that is the case, it wouldn't be a bad idea to look for new longblocks.

Tonto has a nice pair of 420 engines for sale and you can buy his for less than you can rebuild yours.
You might want to look real close at the blowers if they've got a lot of time on them. Pull the carbs off and look at the rotors to see if they've been rubbing on each other. If you can see any evidence of this you'll need to get them serviced. I just had Holley do one of mine for $550.

I know of brand new 522 C.I.D. long blocks blower ready for just under 10K each. Perfect for smaller blowers.

Dart, Callies, J&E, Comp roller valve train with the new Isky heavy duty hydraulic roller lifters, Edelbrock Marine heads. Just over 800 HP and 850 ft.lbs with 8 lbs of boost. 750 HP and over 800 ft/lbs at 6 lbs.

The blowers are at the Blower Shop getting reworked now.

I looked around, didn't see a listing for Tonto's motors here. Tonto - if you see this, PM me if interested in selling.

I called around today looking for long blocks, and most people seem to steer me towards 502's. I have heard though the 174's are too small for a 502 - need at least a 250. Also, I just had my carbs setup for the 454's, not sure if they would need at least a re-jet or more. Probably looking to stay close to what I have because the boat is quick enough for me already, and I don't want to start blowing trannies and drives (already lost one lower gear set on my first season!)

Jaybird, look in the Apache section for one of Tonto's posts and e-mail him from from there. Or you can look in "boats for sale", find the 35 Cafe Racer he has for sale and reach him that way. Or you can just throw a post up in the general discussion section and I'm sure he'll see it and reply to you.

One other thing to consider. I noticed that you have TRS drives. Do you have the stock Mercury dual cooler bellhousings? If so, and you are using 1 of the coolers to cool the engine oil, you may want to pressure check that cooler to see if it is leaking oil into the water and it "may" want to "suck" water back into the oil, creating your milky oil cond.
Just a thought.

Yes, I have the stock dual cooler system. Thanks for the suggestion - I will check it. I believe that the oil cooler on that engine is the one that cools both the oil and power steering fluid.

Is there a simple way to test a cooler (air compressor with low pressure?), or should it be sent out?

While discussing coolers, is it really neccessary to add an oil thermostat to the system? It's not part of the stock system, but I have heard it mentioned. If so, one more thing... I am thinking about adding that newer Merc water pressure relief valve to the cooling system too. I never put a pressure gauge in the system, but a lot of people here feel strongly about this issue. Just wondering if oil temp is as big of a problem.

If the same tstat works fine in one engine, but not in the other, then it is going to be a restriction somewhere in the cooling system.

If you have not tried it yet, drill airbleed holes (about 1/8 dia) into the tstat plates. You need bleed holes on crossover motors. Didn't know you were running crossovers or I'd have said something earlier.

If you're buying blocks, of COURSE go with a 502 block.

Sure 174's are small for a 502, but you already got em and they will work. Just don't expect to be able to pulley it for over 5 pounds of boost.

carb jetting will be close but will need tweaked a tiny bit. Nothing major.

I doubt that "the" cooler on that engine cools both the oil and the P.S. If it is a dual cooler bellhousing, then one of the coolers may cool the transmission and the other does the engine oil. Usually there is a separate "in-line" cooler for the P.S.

Sorry if my previous post was confusing. That engine has 2 "in-line" coolers. One does the transmission, the other does both the oil and the power steering.

Has this boat been in salt water it's entire life? If so, even with regular flushing, all castings that have water flowing through them are suspect. Also all coolers should be tested. You can test them with a garden hose and some fittings. Just plug one end and connect the hose to the other. If any water leaks anywhere replace.

The boat supposedly has been used 50/50 salt / fresh. Overall, it also supposedly hasn't had too much usage - about 400 original hours (if the hour meter can be trusted).

As far as testing castings, are you suggesting I should disassemble the entire engine, and have the block and heads tested? If everything is ok, then since it is apart, it should be rebuilt I guess (heads reworked, bearings, rings, rods, new tin, timing cover & chain, etc,etc). I'm trying to determine if that is worth the $$ (don't know how much that will cost) considering the castings are '87 and could fail later on.

I'm getting the impression that I need to totally rebuild these due to the problems I have.

Yes sort of. I'm saying that before using any casting again, they would have to be carefully inspected. Even then you run the risk of spending large amounts of money rebuilding only to have a casting finally rust through. It's a gamble. My father in law boats on Long Island Sound. His exaust manifolds lasted 5 years, cast iron, on a new boat.