Anonymous
01-22-2003, 10:24 PM
Rob D
normal member in standard member. 1. Why do most Shamrocks have Ford engines in them?
Just wondering why most shamrocks either have a ford engine or a diesel. I imagine it's probably because they came with them but are they easy to convert to a gm block? I was looking into repowering a 26 and feel more comfortable with a 350 rather than a ford. Is there much modification to fit the Gm(Crusader or Mercruiser)in the engine bay. Also, what brand of inboards are the best? Are there any significant differences between the SeaMaxx and the crusader? Any info is greatly appreciated.
Date: 11:59 p.m. on 04-13-2001
Leprechaun
premium member in standard member. 2. Re:Why do most Shamrocks have Ford engines in them?
Rob - The reason you see most older Shamrocks with a Ford marine base engine is that the original Shamrock Marine had vendor contracts with PCM and later Indmar - both big proponents and suppliers of Ford engines. Plus, if you examine the Ford vrs Chevy debate from a MARINE perspective you will find that the Ford will just naturally supply more torque at a lower rpm than the Chevy will. This is due to the restrictive nature of the tiny ports in the Ford heads, vrs the big humpin' ports that Chevy nearly always used. What worked AGAINST Ford at the dragstrip, works FOR Ford in boats. Go figure.
Here's a post a wrote some time ago on another board addressing this question. Go to answering post #2:
5/28/1999 9:26:00 PM Eprechaun (12.79.12.201) from NEW YORK says Mercruiser - Crusader - PCM
Charles - forgot to address the engine manufacturer question. Be glad you have a Mercruiser over the Crusader. Have you ever seen the snakes-nest of hosing on the Crusader FW cooling system? Much simpler (and less expensive to maintain) on the Merc. Still not as good as the PCM, which IMHO is the best marinizer of gas engines and keeps the hosing down to a minimum. Also, I understand PCM just bought Crusader, so maybe there will be some standardization of components/hose types tween the 2. Hope it goes the PCM way. Anyway, your Chevy shd rev higher than my 351 Ford as the difference in intake port size in the Chevy is amazing. Seems Chevy went for high-rpm HP with large well-contoured ports while Ford went the otherway, using very small peanut-ports to maximize low-rpm torque by increasing velocity in the ports and thus volumetric efficiency - at least to about 3000 rpm. Just as well because my secondaries open at 3000 and there goes my economy. So IMO the Ford is a tad better low-rpm marine engine while the Chevy will develop more total power which may not carry a high-rpm fuel penalty in your case cause you probably have Fuel-injection which optimizes the 14:1 mixture ratio across the entire power-band. Whew, that was tough. Anyway, the raw material to make those pipes runs about $85 for the pipe and who knows what for someone with the proper knowledge to put the baffles in via brazing. My buddy does it for a dinner out for him and his wife, don't really know what he charges for the job but I would think $300 - 350 sounds about right. Of course if you dont mind the noise you have now, then just cut the 8' legnth of pipe in 2 and install. Thats what I did cause my swim platform throws the sound down and away from the cockpit. Make sure you specify "M"-gauge as the usual copper pipe used in homes is much lighter gauge and I'm not sure how it will last. Also, give some thought to trying my lubrication methods as the engines seem to last much longer with the thicker oil. Catch 'em up! LEPRECHAUN
Date: 10:51 a.m. on 04-14-2001
little toot
3. Re:Why do most Shamrocks have Ford engines in them?
rob
i have a 20 pilot house which i just repowered with a 5.7 mercruiser (350) i had a 302. the instalation of the 5.7 was not bad until i tried to put the engine box over the 5.7. it was about 4" to short. icut the top off the box abd built it up 4 ". came out real nice and most people can not even tell it was fabricated except for a true shammie man. The other problem i realized after the fact was that the placement of the oil filter was such that you could not get at it. So out came the engine and on went the remote oil filter. i have not done any mantainance on it but eveything looks like it can be reached. the 302 was a bitch to work on but everything was accessable. I was sold on the fact that the 5.7 came as a complete package with tranny, guages,wiring harness and everything else. the 302 is a dinosaur which is only available in a long block. I believe you can still get the 351 complete but in my search the price was considerable higher. One other negative was that i had to eliminate my fish box in order to route the exhaust. i still have the box and eventualy hope to get it back in with some modifications. Im not sure if i had to do it all over what route i would take, but hopefully i willnot be in that position again for a long time? So now that i confused you even more think over some of the obstacles you will face if you do change over to gm.Oh yeah the 5.7 puts out 260 h.p. the old 302 185 h.p. needless to say i don't need to take her past 2800 rpm to get out to the fish. And when i do it gets a little scary.
Date: 10:48 p.m. on 04-14-2001
normal member in standard member. 1. Why do most Shamrocks have Ford engines in them?
Just wondering why most shamrocks either have a ford engine or a diesel. I imagine it's probably because they came with them but are they easy to convert to a gm block? I was looking into repowering a 26 and feel more comfortable with a 350 rather than a ford. Is there much modification to fit the Gm(Crusader or Mercruiser)in the engine bay. Also, what brand of inboards are the best? Are there any significant differences between the SeaMaxx and the crusader? Any info is greatly appreciated.
Date: 11:59 p.m. on 04-13-2001
Leprechaun
premium member in standard member. 2. Re:Why do most Shamrocks have Ford engines in them?
Rob - The reason you see most older Shamrocks with a Ford marine base engine is that the original Shamrock Marine had vendor contracts with PCM and later Indmar - both big proponents and suppliers of Ford engines. Plus, if you examine the Ford vrs Chevy debate from a MARINE perspective you will find that the Ford will just naturally supply more torque at a lower rpm than the Chevy will. This is due to the restrictive nature of the tiny ports in the Ford heads, vrs the big humpin' ports that Chevy nearly always used. What worked AGAINST Ford at the dragstrip, works FOR Ford in boats. Go figure.
Here's a post a wrote some time ago on another board addressing this question. Go to answering post #2:
5/28/1999 9:26:00 PM Eprechaun (12.79.12.201) from NEW YORK says Mercruiser - Crusader - PCM
Charles - forgot to address the engine manufacturer question. Be glad you have a Mercruiser over the Crusader. Have you ever seen the snakes-nest of hosing on the Crusader FW cooling system? Much simpler (and less expensive to maintain) on the Merc. Still not as good as the PCM, which IMHO is the best marinizer of gas engines and keeps the hosing down to a minimum. Also, I understand PCM just bought Crusader, so maybe there will be some standardization of components/hose types tween the 2. Hope it goes the PCM way. Anyway, your Chevy shd rev higher than my 351 Ford as the difference in intake port size in the Chevy is amazing. Seems Chevy went for high-rpm HP with large well-contoured ports while Ford went the otherway, using very small peanut-ports to maximize low-rpm torque by increasing velocity in the ports and thus volumetric efficiency - at least to about 3000 rpm. Just as well because my secondaries open at 3000 and there goes my economy. So IMO the Ford is a tad better low-rpm marine engine while the Chevy will develop more total power which may not carry a high-rpm fuel penalty in your case cause you probably have Fuel-injection which optimizes the 14:1 mixture ratio across the entire power-band. Whew, that was tough. Anyway, the raw material to make those pipes runs about $85 for the pipe and who knows what for someone with the proper knowledge to put the baffles in via brazing. My buddy does it for a dinner out for him and his wife, don't really know what he charges for the job but I would think $300 - 350 sounds about right. Of course if you dont mind the noise you have now, then just cut the 8' legnth of pipe in 2 and install. Thats what I did cause my swim platform throws the sound down and away from the cockpit. Make sure you specify "M"-gauge as the usual copper pipe used in homes is much lighter gauge and I'm not sure how it will last. Also, give some thought to trying my lubrication methods as the engines seem to last much longer with the thicker oil. Catch 'em up! LEPRECHAUN
Date: 10:51 a.m. on 04-14-2001
little toot
3. Re:Why do most Shamrocks have Ford engines in them?
rob
i have a 20 pilot house which i just repowered with a 5.7 mercruiser (350) i had a 302. the instalation of the 5.7 was not bad until i tried to put the engine box over the 5.7. it was about 4" to short. icut the top off the box abd built it up 4 ". came out real nice and most people can not even tell it was fabricated except for a true shammie man. The other problem i realized after the fact was that the placement of the oil filter was such that you could not get at it. So out came the engine and on went the remote oil filter. i have not done any mantainance on it but eveything looks like it can be reached. the 302 was a bitch to work on but everything was accessable. I was sold on the fact that the 5.7 came as a complete package with tranny, guages,wiring harness and everything else. the 302 is a dinosaur which is only available in a long block. I believe you can still get the 351 complete but in my search the price was considerable higher. One other negative was that i had to eliminate my fish box in order to route the exhaust. i still have the box and eventualy hope to get it back in with some modifications. Im not sure if i had to do it all over what route i would take, but hopefully i willnot be in that position again for a long time? So now that i confused you even more think over some of the obstacles you will face if you do change over to gm.Oh yeah the 5.7 puts out 260 h.p. the old 302 185 h.p. needless to say i don't need to take her past 2800 rpm to get out to the fish. And when i do it gets a little scary.
Date: 10:48 p.m. on 04-14-2001