Running 5.7 L on engine stand, wiring questions-gctid814296

[C-NUMB]

My intention is to try to run the 5.7 L GM/merc removed from my project 2556 on my DIY engine stand. Engine has a frozen block. Never done it before so need little advice....Here is the situation now. Engine is removed from boat, it is pretty much untouched but

have done a few things. No visible cracks but there was water in the bottom of oil pan. Engine moves freely when turning with a wrench(plugs off), not much visibility but can not see anything special from spark plug holes. I guess its only a theoretical possibility but

hoping it is only damaged head gasket....but guess more likely damages in lifter valley.

- removed electric fuel pump, planning to run it as gravity feed fuel supply

- removed power steering pump

- obviously removed the wiring harness connector.

- fogging oil through spark plug holes

- oil change

At this stage planing to start it without water supply as a dry engine(but oil of course), if it starts only running for let say 20 sec to check how its working. Is this a bad idea? what happens to the circulation pump?

Other option is to run it on the garden house but obviously then need to connect the alternator to have the circulation pump running( due to the belt) and also water will be leaking in the engine, is this a better idea? Do i need to do some special wiring if running

the alternator not to destroying it if the engine starts?

To get the engine running, planning to connect/wire it as following, is this OK?:

gravity feed fuel supply

Battery + to big post on starter solenoid.

Battery - ground to engine block

Coil power from battery + through on/off switch to coil +

Start wire from Battery + through start button to start terminal on starter solenoid.

Here the wiring questions: It has a thunderbolt ignition, do i need a resistor to the coil and if so, what type of part i am looking for(don't know much about resistors). Another one, do do i need a separate points wire from distributor

to coil or is existing engine wiring sufficient?

A lot of questions , sorry for that

[SomeSailor]

You need to power the ignition through the ECM (on those older motors it was called a MCM). It controls the base timing, idle, mixture and knock control. Is this a mechanical fuel pump I'm guessing? Then a gravity feed would work.

Pretty simple motors really. Start it on a tire is an easy way to manage it.

[Ruffryder]

Mike, ECM? was this a EFI engine?

Perhaps Mike was referring to a ignition module.

Cunmb, we need more info...MPI, carb,

Also try to find out which Thunderbolt system you have also.

[FBKboater]

If it was siezed with the plugs in but turned with plugs out, it sounds like hydrostatic lock up. If this is a carbed thunderbolt IV ignition, you'll want the wiring harness hooked up to the components on the engine it's alot easier than wiring up buttons and switches and trying to keep track of everything if something goes wrong, plus it gives you correct timing and takes care of any alternator current being produced if engine starts. Take the harness plug, jumper positions 5 and 6, and run a lead into position 7. Take a jump start battery and connect the cables to the + post on the starter solenoid, and - to somewhere on the block. To start the engine touch the lead running to position 7 on the harness plug to the + jumper cable connected to the starter solenoid. Once engine starts break the contact between 7 and the jumper cable. When you want to shut the engine down pull out the jumper between 5 and 6. Gravity feeding the fuel can work, but it's kind of iffy, and you'll need to prime the carb. Running with no coolant and no water pump for a few seconds won't hurt anything. If this a fuel injected system then disregard everything here, and you will need a fuel pump.

[SomeSailor]

"Ruffryder" post=814316 wrote:
Mike, ECM? was this a EFI engine?

Perhaps Mike was referring to a ignition module.

Nope. The thunderbolts actually have a little ECM. They called the ICMs or MCMs, but they actually set your base timing, handle all the timing for anti-knock and carry some data like hours, RPM history, and some other data, It's more than a simple ignition module, but less than a full up ECM we all think of for MPI motors.

[Ruffryder]

Umm...

No little ECM other than the ignition module that I know of.

Yes all the timing, timing advance, knock control is done in the module , but the knock module is only incorporated in TB V. No knock sensor for TB IV. We could be just calling it differently.

[Don77]

Hi all!

A 1990 5.7 has a TB4 system not a TB5!

So no knock sensor ! And its not FI unless someone added it after market!

Don

[builderdude]

Run it using the engines wiring harness as FBK suggested, I'd supply water to the raw water pump myself, let it draw from a 5 gallon bucket, keep the bucket full with the garden hose. As for fuel supply, it can pull from a temporary gas can.

https://youtu.be/YVEXKDhZ5jo

[SomeSailor]

My bad... missed the 1990 part. My 2355 had a TB5 and I was amazed at how smart it was. Not as simple as connecting to the coil. A 1990 may be though.

[2850Bounty]

Yes...... a lot of questions.... but you are wise for asking them!

As said..... use the engine harness to power the 12 vdc.

The alternator can remain and will supply a charge to the battery that you connect up.

The steering system Power Assist pump does pose an issue.

Operating the engine circulating pump "dry" for a short duration should pose no issues.

Perhaps remove the drive belt and eliminate operating the Alt, PA pump and the Circ pump.

Operating the engine "dry" without coolant and for a short duration, should pose no issues.

No need to circumvent the OEM fuel pump.

It sounds as though you will be storing this engine. If so, I would do your oil and filter change prior to operating the engine.

I would also suggest performing a "cylinder leak-down" test before removing cylinder heads!

FYI.... Engine Fogging is done dynamically..... not statically.

If you spray fogging oil into each spark plug port.... this is NOT Fogging!

Fogging is done with the engine running.

The fogging solution must enter both planes within the intake manifold. (miss one plane.... and you miss 4 cylinders!)

At around 1,200 RPM, cut the Ignition while the fogging solution process is being continued.

Good luck!



.

[builderdude]

"Don77" post=814362 wrote:
Hi all!

A 1990 5.7 has a TB4 system not a TB5!

So no knock sensor ! And its not FI unless someone added it after market!

Don

Yup, I'd also think it would have a mechanical fuel pump too. OP says he removed an electric fuel pump, maybe a conversion was done or a repower at some point with newer stuff. Pics would help (hint)

[Ruffryder]

"SomeSailor" post=814380 wrote:
My bad... missed the 1990 part. My 2355 had a TB5 and I was amazed at how smart it was. Not as simple as connecting to the coil. A 1990 may be though.

Mike, I missed you on Monday morning...

Guessing you guys took off early in the morning.

[C-NUMB]

Hi all, and thanks for input so far! Obviously need to add little information my bad

- boat was sold "as is" with a frozen =cracked block, leaking water. As far as i know it is not seized. Was told its a runner...

- engine is i guess kind of a mixture... A GM long block repower done 2009( old style head's) but ignition parts from a merc vintage 1990(original engine), definitely a carb engine

- there is no mechanical fuel pump, not even a place for it on the block. Will run it from an outboard engine tank with priming bulb

- i am not 100 % sure even its a marine version as there is an auto style drain plug in the oil sump...!? the bar code on the sticker is still visible, 12557558 ( not marine i guess)

- removed already the power steering pump. Alternator and circulating pump shares the same belt so assume its safe to do a short run without either

- fogging oil was used only to add little lubrication on the cylinder surfaces to ease hand cranking attempt , not much help but not much harm either?

Thanks for the idea of running it by the engine harness, sounds like a good idea, think will try that one instead. Previous owner told there was a external water leak located possible from head or intake, but no crack can be seen. Probably the block is shot beyond repair but maybe other parts can be salvaged, that's why trying to run it so i know if they work. It is said to been run only 19 hours before the winterizing did go wrong, expensive mistake for someone! Will take some pictures soon.

[builderdude]

Sbc if freeze damaged will usually crack horizontally just below where the head bolts on. Could be very hard to see it. The exhaust components could also be cracked do to the freezing. IMO You could run it briefly with no coolant then do a compression, leak down and cooling system pressure test to find out if it's worth trying to save.