Mercruiser ECM replacement?

[Ferrarakias]

The casting number has more digits. Should have commented at the time, but the arrow in Chris pic is pointing to the wrong location. Look below the distributor on the port side. The number will be at least 6 digits

To all,
Best wishes for the new year!

Alldodge,
I think I found the number this time...

024388 or 0243880

Is it correct?
Kostas

 

[Lou C]

Don’t think so where did you find this #?

 

[alldodge]

If there is a "1" which starts off the number then its
10243880...350...95-00...2 or 4...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

It would be a roller cam with vortec heads

 

[Lou C]

A better pic of the intake with the wiring harness not covering the bolts would also help..

 

[Ferrarakias]

If there is a "1" which starts off the number then its
10243880...350...95-00...2 or 4...Vortec truck, Gen.I crate motors and "ZZ4", roller cam, one piece rear seal

It would be a roller cam with vortec heads

There was something before the first "0" that looked like "1" but thought it was a casting residue.

 

[Ferrarakias]

A better pic of the intake with the wiring harness not covering the bolts would also help..

Took some pictures...

 

[alldodge]

Looks like 4 bots on each side of intake, and if so that's a vortec

 

[Tail_Gunner]

There was something before the first "0" that looked like "1" but thought it was a casting residue.

A engine of this magnitude? Little drama going on there, look at the comprehension ratio and cam profile. Not a TBI candidate.

https://www.corvetteforum.com/forums/c1-and-c2-corvettes/2211790-crate-motor-casting-number-10243880-a.html

Well maybe, that Chevelle forum can be very accurate.

what HP and Year is this Motor?

www.chevelles.com

 

[Lou C]

It’s a pre Vortec for sure like I thought. First the Vortec bolts go straight down not at a angle and second I see one of the extra bolts near where the choke stove would have been if it had the Quadrajet.
You can see the tin cover that covers the choke stove opening with a bolt in it and below that is one of the extra bolts the pre Vortec had. Vortec has no exhaust crossover at all therefore no choke stove. So Vortec engines with carbs had to use electric chokes.
With the pre Vortec the 4 front & rear bolts all go in at an angle and the center 4 may appear to be at a more shallow angle or almost straight up & down. On my V6 those were tough to get a torque wrench on!
Still could have a roller cam though because the roller cam came in 87/88 and Vortec heads in 1996.
alu version of pre-vortec:

Edelbrock Marine SBC - V8 Performer Intake Manifold W/BRASS (1987-95) OUT OF STOCK ETA 11/26/2021

Edelbrock Performer RPM Marine intake manifolds are designed specifically for demanding marine applications. They feature low-rise, dual-plane design with patented runner tuning and an 180 degree firing order that you won't find with the competition. The

www.michiganmotorz.com

cast iron Vortec intake, notice the 8 machined bosses for the mounting bolts, straight up & down....

5.7L - 4 bbl. Vortec CAST IRON Intake Manifold (1996-Current)

GM Vortec 5.7L - 4 barrel CAST IRON Intake Manifold

www.michiganmotorz.com

 

[Tail_Gunner]

It’s a pre Vortec for sure like I thought. First the Vortec bolts go straight down not at a angle and second I see one of the extra bolts near where the choke stove would have been if it had the Quadrajet.
You can see the tin cover that covers the choke stove opening with a bolt in it and below that is one of the extra bolts the pre Vortec had. Vortec has no exhaust crossover at all therefore no choke stove. So Vortec engines with carbs had to use electric chokes.
With the pre Vortec the 4 front & rear bolts all go in at an angle and the center 4 may appear to be at a more shallow angle or almost straight up & down. On my V6 those were tough to get a torque wrench on!
Still could have a roller cam though because the roller cam came in 87/88 and Vortec heads in 1996.
alu version of pre-vortec:

Edelbrock Marine SBC - V8 Performer Intake Manifold W/BRASS (1987-95) OUT OF STOCK ETA 11/26/2021

Edelbrock Performer RPM Marine intake manifolds are designed specifically for demanding marine applications. They feature low-rise, dual-plane design with patented runner tuning and an 180 degree firing order that you won't find with the competition. The

www.michiganmotorz.com

cast iron Vortec intake, notice the 8 machined bosses for the mounting bolts, straight up & down....

5.7L - 4 bbl. Vortec CAST IRON Intake Manifold (1996-Current)

GM Vortec 5.7L - 4 barrel CAST IRON Intake Manifold

www.michiganmotorz.com

Are you sure Lou? Blow the below pic up, notice the first intake bolt. The intake bore is filled flat. There are two pics, look closely. That would be a vortec intake

 

[Lou C]

The one on the right is for sure a Vortec as you said; what makes me think the OP’s is a pre Vortec is the tin cover for the choke stove. Nothing like that on a Vortec. We ate like forensic detectives trying to figure this out lol!

 

[Tail_Gunner]

The one on the right is for sure a Vortec as you said; what makes me think the OP’s is a pre Vortec is the tin cover for the choke stove. Nothing like that on a Vortec. We ate like forensic detectives trying to figure this out lol!

Number 2 intake runner, notice the bolt and the bore...the bore hole is milled flat.

With that being said, I am quite sure going to a carbed engine is going to be far less costly. This newer engine is more that probably set up for a newer ecm.

Actually around that time frame merc dropped Mefi and went to there own system....

Maybe achris might chime in here..or Alldodge....

 

[Lou C]

I’m still seeing it at an angle like my old pre Vortec…
I think that given the difficulty in finding the correct ECM a carb engine would be easier. The OP might have to find a shop that caters to American classic & muscle cars to get a marine carb set up right. Seeing as how it’s a Merc an Edelbrock 1409 would be easiest due to the ability to find the right brackets etc because Merc used the very similar Weber 4bbl.

 

[Lou C]

To the OP simply lift the wiring harnesses and count the # of bolts holding down the intake on both sides. I think you will find 6 on each side. This answers the question of Vortec vs Pre Vortec but the issue of flat tappet vs roller cam can only be answered by the block casting #, or removing the intake and looking lol!
For the question of tuning Vortec vs Pre Vortec matters but I’m not sure that flat tappet vs roller cam does.

 

[achris]

Being as the location is Europe, there is also the possibility that someone has 'built up' an engine out of spares.

Everything I'm seeing is saying 1997 2bbl intake non-votrec, so I'll deal with it as such.

Flat cam, -807650T2
Roller cam, -861078T1

Both of these are no longer available from Merc (no surprise), but a few places can repair, or sell new.

Chris....

 

[Lou C]

That tin cover over the choke stove area and the few bolts I could see are angled not straight up & down says to me it’s pre Vortec for sure.

 

[Ferrarakias]

Being as the location is Europe, there is also the possibility that someone has 'built up' an engine out of spares.

Everything I'm seeing is saying 1997 2bbl intake non-votrec, so I'll deal with it as such.

Flat cam, -807650T2
Roller cam, -861078T1

Both of these are no longer available from Merc (no surprise), but a few places can repair, or sell new.

Chris....

Chris,
Thank you for your answer.
So what would you do if you were in my shoes?
Had the ecm shipped to mefiburn for inspection? Does he has to know whether it's a flat or roller cam for programming it?
Something else?
Kind regards,
Kostas

 

[achris]

Chris,
Thank you for your answer.
So what would you do if you were in my shoes?

I'd be verifying everything else before an ECM fail conclusion.

Had the ecm shipped to mefiburn for inspection?

Check with MEFIBurn and see if they offer that service.

Does he has to know whether it's a flat or roller cam for programming it?

I would include as much information as possible. I would pull the distributor and use a borescope and have a look at the lifters, see if they have a flat base or a roller.

Something else?

I think, at this stage I would be opting for someone with more electronics knowledge than a mechanic. Someone who understand the granular detail of fuel injection. Most traditional mechanics only have a limited knowledge of the finer details of EFI. Personaly, I would be examining all the sensors inputs and ECM outputs with a multi-channel oscilliscope. It's unusual for an ECM to fail in the way your describe, so I'd be ruling out everything else first.

Kind regards,
Kostas

 

[nola mike]

@achris will never go for it, but you will solve your problem with a few hundred $ carb and maybe an intake. I would sooner do that than try to fix an obsolete proprietary system that isn't that great even when working correctly. You have limited resources where you are ...

 

[achris]

@achris will never go for it, but you will solve your problem with a few hundred $ carb and maybe an intake. I would sooner do that than try to fix an obsolete proprietary system that isn't that great even when working correctly. You have limited resources where you are ...

The distributor is also driven by the ECM, remove the ECM when you fit the carb, and you're going to need to replace the entire distributor system too. Add another 'few hundred dollars' there and it's starting to get cheaper to just fix what's wrong....