1991 bridgeport

[boatdoctor32]

whats the pros and cons of a bridgeport that is stock with nickasil or one thats been completly sleeved?? where can i find info on performance mods. it would be nice to stay with 93 oct. it is a efi air horn model. also will be mounted on a 1991 procomp when finished and i would like to see tripple didget. all and any info would be great... thanks

[boatdoctor32]

come on guys,, i know someone has the answerse

[sho305]

Just for a ttt, if you look at the tech section here you will see many posts on mods, or search for them (the search box up there, put in "bridgeport mods"/etc). Also see the features on the main page. Should be able to find lots of info on near any Merc perf motor here if you want to browse.

Sleeves add a little weight to the motor, but then you can bore it or replace them if you have a problem (obviously :o ) Depending on the pistons/heads you have about 145-150 lbs is max compression you can run on pump gas, compression is one thing you want to get right to be safe with it for the fuel you use. Have to cc the heads and get it right unless someone here can tell you what to cut for your parts.

[rock]

Since you are asking the advantages of one over the other, I assume you are looking at purchasing one or the other. Like sho said, there is more info in the search mode than any one person could probably give you. Read. I have had both and they both work well. A steel sleeve is easier to fix if you cook a piston and allows you to do some cylinder porting without replating. You can easilly get 280-300 HP out of these motors. I had one on a 1990 Pro Comp and ran in the 115 mph range. If you have not bought a motor, what you should be looking at is a 2.5 and not a 2.4. The difference in torque would really be worth the extra money you might have to spend. Much less maintenance as far as rebuild goes and much more user friendly than a heavilly modified 2.4 motor. Sometimes it is cheaper to buy a more expensive motor. Good luck.
Rock

[chris_lacey]

One thing to consider is operating temps. On a coated bore, the bore and piston expand at similar rates, a sleeved cylinder expands at a different rate than an aluminum piston. Steel bores must be warmed up to prevent cold seizure.
On the other hand, a fully sleeved block is more rigid at high rpm.

[STV_Keith]

If you are buying a powerhead to rebuild, hold out for a 2.5. My 2.4 BP EFI ran good, but nothing like my 2.5/260. Much more midrange and bottom end punch as well as top end charge...and the 2.5 will make peak power almost 1000rpm higher up, which means a wider powerband.

More RPM means a lower pitched prop to accelerate better yet still have the capability of turning a big number on top.

[boatdoctor32]

i have already purchased this engine for a good price. it has 2 sleeves in it already and a couple more cyls that need them so i was considering doing all. as for the heads there is no markings on them but i will have them cc'd. thanks for the responces and i will do the searches.. thanks

[STV_Keith]

If it has any, I'd do them all...so they expand at the same rate.

[MARINER RACING]

the problem with BP`s usually is that a bridge cracks
i had one with 2 cracked bridges so i installed 2 sleeves
i couldnt see any performance difference,compression difference
if i had the $$$ at the time i would have had the rest of the holes sleeved
i ran that motor @8300 rpms without problems hope i helped
Jay@SST Marine 561-687-3636