Bridgeport torque settings

martynwilley · 21-10-2009, 08:43 PM

hi,

iv just finished re-assembling my 2.4 bridgeport to use as spare powerhead and have been looking everywhere on the net for torque settings. cant seem to find any anywhere.

it is mainly the big end bolts i want torque settings for, do any other bolts have to be torque set? (head bolts, reed block etc. etc.) and is there anywhere online or workshop manuals i can buy?

also the carbs i have are from a 2.5, do these need to be re-jetted for the 2.4 bridgeport or can i just bolt them on an c how they go?

many thanks

scooby_hugh · 21-10-2009, 11:41 PM

The heads should probably be torqued if your not used to that engine and i would have thought 2.5 carbs will be abit small and may run abit lean, do plug chops at increasing rpms and read the plugs

scooby_hugh · 21-10-2009, 11:43 PM

Just thought... Bridgeports are efi aaand i dont think 2.5 carbs fit on 2.4 blocks but i may be wrong

Hydrostream · 22-10-2009, 02:33 AM

As far as I know there's no difference between BP's and other merc V6.

Heads, 40 ft/lbs
Rods, 30ft/lbs
Exhaust chest, 180in/lbs
Crankcase small, 200in/lbs
Crankcase large, 34ft/lbs

2.5 carbs will fit, as for jetting what engine did they come off?

larby · 22-10-2009, 07:49 AM

Quote:

Originally Posted by scooby_hugh

Just thought... Bridgeports are efi

Wow!! The carb one in my garage must be a super rare concept one then!!

Techteam · 22-10-2009, 08:57 AM

Carb 2.4 Bridgeport is actually a MOD VP, have you modded the pistons to cool the bridge ?? And you have just finished and now you are looking for torque settings ? Have you replaced the rod bolts ?

martynwilley · 22-10-2009, 08:01 PM

no i havent, all the rod bolts are the old ones. i have made a special socket that fits thru the gaps behind the reeds so i can torque up the big ends. it has been re-assembled but bolts have been left just nipped ready for torquing as i couldnt find the specs.

i now have a workshop manual and all the torque specs so im gonna get it all torqued up and all electrics back on this weekend

i got this motor in bits for vertually nothing and not spent much on new parts so just keepin my fingers crossed it runs ok. would be a bonus if it did so i would have a spare powerhead

martynwilley · 22-10-2009, 08:07 PM

and how do i mod the pistons to cool the bridge? iv never heard of this before? i can quite easily strip it back down, just slapped it all together so i could get a compression reading really.

martynwilley · 22-10-2009, 08:10 PM

it was never efi, i have the origional carbs from it, just they look like the been rolled round in a field of mud! so i thought the 2.5 ones i had spare would be the same? if not i can clean and service the 2.4 carbs.

so does this mean my bridgeport is actually a mod vp??

martynwilley · 22-10-2009, 10:21 PM

ok, so 1 last question guys-

the workshop manual has all the torque settings i need but has 'notes' on some of them for 74degree blocks

is the mod vp (bridgeport) a 74degree block?

thanks everyone

Techteam · 23-10-2009, 10:12 AM

60 degree, Pull the motor back down and build it properly with new rod bolts and red loctite on the bolts.

baj666 · 23-10-2009, 11:37 AM

Quote:

Originally Posted by Techteam

60 degree, Pull the motor back down and build it properly with new rod bolts and red loctite on the bolts.

understanding the loctite thing but why change the bolts if there not stretch bolts...looking at my mercury workshop man it does'nt mention new bolts on the rods

martynwilley · 23-10-2009, 06:35 PM

Quote:

Originally Posted by baj666

understanding the loctite thing but why change the bolts if there not stretch bolts...looking at my mercury workshop man it does'nt mention new bolts on the rods

yeah i read thru the manual and couldnt see it anywhere either?

what sort of power can i expect out this motor? it already has carbon reeds, lightweight ally flywheel and im gonna shave the heads to up compression a little.
will this engine be a lot faster than my '98 200 XR2 on my ring 18? as i was really wanting to stay 2litre as hopefully races over here will be handicapped by cc.

larby · 23-10-2009, 06:39 PM

Both motors would put you in the same class, power will depend ALOT on how well you get those carbs set up and synchronized! Done properly they're 230-240 on reasonable compression, as I said the other day.

James

Techteam · 23-10-2009, 10:15 PM

If it's got the right heads I wouldn't skim them much more for pump fuel, they already were skimmed 2.0l heads. You can take or leave the advice your choice but think if that motor is around 19 years old and the pistons are hard to get as are the rods.

Hydrostream · 23-10-2009, 11:56 PM

Quote:

Originally Posted by martynwilley

and how do i mod the pistons to cool the bridge? iv never heard of this before? i can quite easily strip it back down, just slapped it all together so i could get a compression reading really.

Grind a flat section below the rings on the side of the piston the width of the bridge. Drill two 3mm holes in the side of the piston in line with the bridge.
Reduces wear & allows induction charge to cool bridge.

Techteam, was the modVP motor not a standard style (oval) exhaust port motor but with a larger port and hi-comp heads? I know the BP was raced in modVP but the class existed before the BP was released.

Alan

larby · 24-10-2009, 12:26 AM

Quote:

Originally Posted by Techteam

If it's got the right heads I wouldn't skim them much more for pump fuel, they already were skimmed 2.0l heads.

Skimming the heads was my suggestion, as he was apparently only seeing 115psi compression which seems a touch low to me, I would've expected 130-140psi?
What should the compression be as standard? If it should be higher then maybe there's something more serious/important causing the low readings?

James

Burty · 24-10-2009, 02:07 AM

yeah, like not doing the compression test correctly. WOT etc

steve h · 24-10-2009, 06:54 AM

Quote:

Originally Posted by martynwilley

yeah i read thru the manual and couldnt see it anywhere either?

what sort of power can i expect out this motor? it already has carbon reeds, lightweight ally flywheel and im gonna shave the heads to up compression a little.
will this engine be a lot faster than my '98 200 XR2 on my ring 18? as i was really wanting to stay 2litre as hopefully races over here will be handicapped by cc.

there were 2 bridge carb motors,both same except mod vp came with 2 litre heads with 80thou cut of to give 175psi run on av gas,second was 225hp same block but with stock heads around 125 psi,pistons should already have flat on side some had 2 holes some did,nt,dont mater they all blow up

Techteam · 24-10-2009, 11:25 AM

Quote:

Originally Posted by steve h

dont mater they all blow up

Succinct and to the point as always Steve, UK and US MOD VP was slightly different due to the time. Northern VP racing was probably the coolest meanest mod racing in the UK some of those boats really flew. Boats got lighter and lighter but the speeds peaked. Enter MOD VP the last of the 2.4 Nikasil bridgeport motors replaced the earlier 2.4 oval/fingerports which had been the thing to have very late 80's and speeds jumped by 35mph. Enter the chequebook and some of the new breed of MOD VP drivers had money to burn so a lot of 2.4 were cut with a VERY limited life. S2000 killed off MOD VP in the UK a shame as it was a good class.