stirling

I have a 540 Bulldog in my boat ,that was on the dyno last year ,the actual horsepower is 540 ! measured on the crankshaft .
Torque was 643 LBS max ,don,t know at what rpm ... I love the engine, its running very strong

rmbuilder

The Merc Bulldog is an exceptional platform for upgrades. Many of these were contracted to the military, hence the overkill on the hard parts. Below are the specs on the engine.
The engines output was 500 HP when validated using the SAE 1349 correction factor. The correction factor most often used in the aftermarket is J609 which corrects ~ 5% higher than the SAE rating, or ~ 525 HP.

541.9 CID
GM MK 4 tall deck (cast# 14044807)
Block clearance to accommodate 4.375” stroke
Siamese Bore, reinforced decks with blind head bolt holes.
Deck 10.2”
2 pc rear seal
Bore 4.44”
Stroke 4.375”
(With a factory recommended bore range 4.250’- 4.560” there is plenty of room for upgrades)
SCR 8.6:1
4340 Lunati crank
Piston is Wiseco (Merc part #)
Connecting rod is Manley +.400" / 6.535"
Dart Single Plane Intake Manifold

Hydraulic Flat Tappet
Crane Camshaft Specification Card
Part Number: 13H000036
Grind Number: H-240/329-2-10 T1.2


The cam rates on a 110*LSA, 5* advance
Lift .329” Lobe .559” Valve
Lift .340” Lobe .578” Valve

Specs:

@.0042"
................Opens..........Closes............. C/L...........Duration
Intake.....43.0 BTDC.....77.0 ABDC......105*..........300 °
Exhaust...88.0 BBDC.....42.0 ATDC......115*..........310 °
85* overlap

@.050"
................Opens...........Closes...........C/L.........Duration
Intake.....15.0 BTDC.....45.0 ABDC.....105*.........240 °
Exhaust...60.0 BBDC.....10.0 ATDC.....115*.........250 °

Camshaft Is Ground with .0012" Lobe Taper

• The issues that plagued Mercury valve springs were isolated to the (99896-16) HP500 spring. Back in the late 90’s, early 2000’s, there was a batch problem with specific spring wire (used in the 99896 spring) that suffered from improper heat treat. Because there are only three companies in Kobe that supply 95% of all spring wires worldwide, this wire made its way into the system of multiple suppliers, one of which was the supplier of valve springs for Mercruiser. By the time the issue was identified the defective springs had made their way into some production engines and subsequently failed. It brought significant notoriety to Mercury, and many thought this was solely a company issue, due to the fact it appeared to be isolated to the HP500. It was, however, a material supply chain issue, not that of Mercury.

• The Bulldog spring part #99893-16 is designed for flat tappet applications and did not experience any such duarability issues.

The block is an early issue GM tall deck and would have a Bowtie emblem cast onto the side with a casting number of # 14044807. The china wall, which is easily seen externally, is significantly taller than that of a short deck block. It would be easily identified if examined.

The boat is 20 minutes from me; let me know if I can be of assistance.


Bob

Smarty

I keep seeing ads for older motors saying that it is a Mecury Bulldog, my memory may serve me wrong but the ONLY bulldog was the 540 cu.in/575 hp package from Mercury, anything is an impostor. That is way I remember it. I may be wrong, but that is what my memory keeps telling me.

BUP

iTrader: (9)

I just look at the dealer spec books it is listed in 3 of them 470 hp @ the propshaft.

Also I can pull out the retail brochures from Mercruiser to verify what they reported HP levels. I have the dealer manuals called brand knowledge and dealer product handbook right in my hands as we speak.1997 & 98 & 99 straight from OEM Mercury marine / Mercury racing. All of them say 470 hp @ PS for HP 500 BULLDOG as well that is 6 listings from OEM merc own word in writing.

I miss spoke as these manuals are listing Crane Hydraulic lifters and Crane high performance hydraulic cam.

No mentioned of roller except Crane roller rockers. I guess I was mixed up with the HP 500 as I use to see so many of them back in the day. Looks like I was totally wrong about the cam and lifters being roller.

Also I can pull all the tech and service bulletins of this motor to see what else is listed

BUP

iTrader: (9)

Closest thing I could get to pull up from the internet that list specs for the HP 500 Bulldog. Bruce Bullock is listing OEM Merc specs. The link below click on it and scroll down.

www.brucebullockmarine.com/mercury/500.html

as I said, I find it hard to believe that or as to why merc listed this bulldog motor at 470 HP @ PS but they did in everything even to the dealers.

Sydwayz

iTrader: (1)

Regardless of what the actual Horsepower output(s) were; they were named the "HP500 Bulldog".
They were the 540 cubic inches, and listed as 500 crankshaft/470 propshaft; exact same listings/advertisementas the HP500 (carb) and HP500EFI.

The HP500 Bulldog was an ideal platform for aftermarket superchargers.
I can't remember if they were allowed in Factory 1 and Factory 2 racing.

BUP

iTrader: (9)

I always liked this motor but have not seen one in 6 or 7 years ago. Anyways I pulled out some of my notes on the motor. All 1998 model year 500 Bulldog engines started internally balancing. Merc changed out 3 parts from the past year(s). The 3 parts where the Flywheel new part # 230-9425-1, damper new part # 49783-1 and crankshaft new part # 2408-849470.

It was important not to mix match old from new parts as 1997 and back were totally externally balanced. All dealers had to look for the engine serial # to determine the serial # break when internal balanced engine came into play. Many boat owners got these parts mixed up in their rebuild process along with some engine builders as noted.

Another way to find out if your HP 500 Bulldog was internal balanced or external was all internal balanced engine components will be identified by the letters " INT " after the crankshaft serial #. Also this is found on the front starboard side of the engine block at the cylinder head deck surface. "INT". Merc came out with a Service Bulletin on this as well to all dealers way back in early 1997. It basically said the same thing.

rmbuilder

Smarty,

Your memory is correct, there was a 575 HP iteration of the same mechanical platform as the 500 HP Bulldog. All the mechanical parameters were common to both including the 8.6:1 mechanical compression ratio. The difference was:

____________500 Bull__________575 Bull

Cam________Hyd Flat__________Solid Flat

Crank_____Lunati/BRC_________LA Kryptonite

Carb________800/4150_________1050/Dominator

Rods________Manley___________Carrillo

Pistons______Wiseco____________TRW

Intake_______Dart Single Plane_____Weiand Team G

Exhaust______Gil/Merc__________Stellings

Cam;
292º/300º @ .020”

256º/264º @ .050”

.618”/.638” Lift Valve (.592”/.612”)net after lash

108º LSA

Bob