engine problems

[Afraser]

hi all hope one of you might be able to help

back ground

I had a 5.7 mercuriser engine ran sweet. great idle etc. long story short head gasket went, cylinder got water in,
put rod thou block (you get the picture) guy before be put normal car head gasket in and it rotted away with the
sea water etc.

got a recon merc long engine. put new starter, fuel pump, raw water pump, engine water pump, alternator, new cap rotor arm and plugs. only used exh and int manifolds dizzy (delco EST) and cab (qjet)

above 900 rpm smooth as silk when engine drops below 900 (would like it to idle 650-750) it hunts from 550 (ish) to 850 (ish) when its really hunting but maybe 650 to 850 normaly, never stalls and its bored 30 over with 10 over bearing main and con (according to the sticker on the engine)

also its suppose to be a 87 - 94 engine but what I got is a 880 block (vortec I believe) and dart 10021070s heads (I found it strange mercuiser left the porformce heads on but I though it was a bonus)

so far I have 3 times now checked for vacuum leaks a few different cans affects engine when shot into carb but no where else
bin all over inlet manifold base of carb etc

althro plug were new (ac delco r44 something) replace again with ngk br6fs (i think that's the part no. checked they are right plugs)

used the timing shunt to lock timing and checked 3 or 4 times now its at 6 and 11 when shunt removed

rebuilt carb took apart soaked over night and used a rebuild kit now runs a little smoother about 900 but same under 900

tried a qjet carb (same model) off a friends engine that happy idles 550 but engine still same as with my carb

checked and redid the valves as I found 2 where too tight

fitted a vacuum gauge (in manifold) ad it reads 25 and steady above 900 but under 900 reads 18 - 22 but maches engine so when engine drops so does reading and when engine recovers so does the vacuum.

compression test shows 170 -172 in all cylinders except 5 it shows 178


I think that's everything I have done so far. everything has bin check multi times not just once

anyhelp would be more that welcome as I not got a clue now

thanks

andrew

 

[alldodge]

Re: engine problems

Hi Andrew and :welcome: to iboats

Sorry if I'm missing it but what did you set the timing at while it was idling at 600rpm and the shunt in place?

I'm sure it's right but could you recheck your plug wires and there respective firing order location

 

[jimbo_jwc]

Re: engine problems

How about a bad bearing in the distributor .

 

[Afraser]

Re: engine problems

hi thanks for the replys

I have set the timing with the shunt and about 800 to 900 as when I try any lower the engine hunts from about 550 to 850. I tried making setting it at 4, 8 and 10 at 800 to 900 but didn't make any differce but having said that with the shunt in it seams not to hunt as bad. I just put that don't the the timing changing because the revs were

hi jimbo I not checked the distributor bearing. I will when I go back to boat but the dizzy is of the old motor and tha ran smooth

does anyone know if the newer 95-00 880 vortec block will work ok with the older 87 -94 dart heads. I didn't know that vortec and older heads were interchangeable

 

[Afraser]

Re: engine problems

hi thanks for the replys

I have set the timing with the shunt and about 800 to 900 as when I try any lower the engine hunts from about 550 to 850. I tried making setting it at 4, 8 and 10 at 800 to 900 but didn't make any differce but having said that with the shunt in it seams not to hunt as bad. I just put that don't the the timing changing because the revs were

hi jimbo I not checked the distributor bearing. I will when I go back to boat but the dizzy is of the old motor and tha ran smooth

does anyone know if the newer 95-00 880 vortec block will work ok with the older 87 -94 dart heads. I didn't know that vortec and older heads were interchangeable

 

[Scott Danforth]

Re: engine problems

you can put vortec heads on early blocks, and visa versa. The head to block interface is the same for all Gen I smallblocks from 1955 to today. (not couting valve size, ect) its the intake manifold that needs to match the heads. The newer 95-00 blocks just have roller cams vs flat tappets.

 

[Afraser]

Re: engine problems

hi scott


I read that about roller lifters in the newer blocks but mercuiser put flat lifer cam and lifters in my block. would that cause a problem

 

[harleyman1975]

Re: engine problems

Still sounds like a vaccume leak. perhaps sucking from internal part of engine below intake.

 

[harleyman1975]

Re: engine problems

does idle change if oil cap is removed?

 

[NHGuy]

Re: engine problems

Shoot carb cleaner all over any perforations in the intake. All around the edges, distributor opening, oil sender opening. If that doesn't help go to the crankcase, which would be valve covers, front timing cover, oil fill holes.
It really sounds like vacuum leaking. Mainly cause both carbs act the same.
Are you sure you sprayed any openings in the intake including the carburetor base gasket?

 

[Afraser]

Re: engine problems

hi all

no idle doesn't change if I remove oil cap. as I had valve covers off watching valves to make sure they were all opening correctly. I have sprayed all over intake carb ends with WD40 and something that's like wd40 and butane. no change unless I spray into carb. im thinking must be sucking under intake. going to remove and replace next weekend and see what happens

 

[Scott Danforth]

Re: engine problems

hi scott


I read that about roller lifters in the newer blocks but mercuiser put flat lifer cam and lifters in my block. would that cause a problem

then you have an 1986-1994 block

 

[Afraser]

Re: engine problems

-block casting no is 880 which s a vortec block 95 -00

 

[alldodge]

Re: engine problems

-block casting no is 880 which s a vortec block 95 -00

Your engine should be a 7 digit number

The block casting number on smallblock and big block Chevy V-8 motors is located on a ledge found at the rear of the block, most often on the driver's side. This ledge is below the deck of the block and the ledge forms the mating surface between the block and the transmission bellhousing. Some of the later model blocks have the casting number on the passenger side of this ledge. The number itself can have 6, 7 or 8 numeral digits. They might look like this "361959" or "3970010" or "14015445". The block casting numbers do not have any letters in them. There are sometimes individual letters found on blocks like "GM" or "CFD" for the Central Foundry Division, but they are not part of the block casting number. Also some of the later blocks have the size of the motor shown in liters. You may see a "5.0" (305) or "5.7" (350) cast on the rear ledge of a smallblock or a "7.4" on the side of a big block 454. On the side of some later blocks the last three digits of the block casting number are cast into the block, but these are difficult to see when the engine is in a vehicle.

 

[Afraser]

Re: engine problems

hi the whole number is 10243880 for the block and 10021070s for the dart heads

I found this for the block

10243880 1995-00 350 2/4 Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

 

[alldodge]

Re: engine problems

hi the whole number is 10243880 for the block and 10021070s for the dart heads

I found this for the block

10243880 1995-00 350 2/4 Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

You have done your home work, just posting the last three had me thinking different