Pistons on Ford 302 / Mercruiser 188

[IslandExplorer]

While changing oil pan gasket on this 1974 Mercruiser 188 I am wondering if anyone can tell me a little by looking at the pistons and the side of the block. Seeing blue paint on block instead of just black which seems like maybe a different 302 engine was swapped in here maybe. (guessing Mercruiser was all black in 74)
Anyhow, curious as to if people think this is:
1. Original 1974 Mercruiser 188 engine
2. Stock pistons?
3. How do the pistons look?
4. Anything else you're noticing of note?

*motor sat dormant for 15 to more like 20yrs, have only run total about 15 minutes collectively test starting with fresh oil. Original oil looked water free and very dark amber but good. Fresh oil that was in during test runs when drained looked water free and pretty clean draining out. Very minimal sludge found in bottom of pan, no chips.

 

[IslandExplorer]

 

[Scott06]

I would think this was a recent rebuild prior to being put away given how carbon less it looks especially on the pistons.

Not sure if ford painted them blue then delivered them to merc or if you have a 302 from any vintage in the last 50 years...

 

[alldodge]

Could have come from a Ford truck/auto or Crusader years ago

 

[IslandExplorer]

I would think this was a recent rebuild prior to being put away given how carbon less it looks especially on the pistons.

Not sure if ford painted them blue then delivered them to merc or if you have a 302 from any vintage in the last 50 years...

Thanks for the quick reply, I was thinking they looked abnormally clean too.. I didn't clean them for pics or anything. If it is a recent rebuild that then fell out of use shortly after- that'd be great! This engine literally turned over nice and easy by hand when I first climbed into it and excavated about 3 feet of leaves, weeds, and styro to reach the crank so seems like someone must've winterized it really well. I still just don't know how it sat uncovered with all the moisture and all and not look wrecked internally. The dog house was in rough shape to say the least.

 

[Bondo]

Ayuh,.... Once ya get it runnin;,..... a compression test will give an idea of it's overall health,....

 

[Scott Danforth]

most likely a reman or a prior OMC motor

from the pics, the boat is trashed. the moss growing on the deck means the deck was done as a deckover at least once and that has failed.

 

[IslandExplorer]

Ayuh,.... Once ya get it runnin;,..... a compression test will give an idea of it's overall health,....

I wasn't able to do a compression test previously but once I put it back together I'll probably give it a try.

 

[IslandExplorer]

most likely a reman or a prior OMC motor

from the pics, the boat is trashed. the moss growing on the deck means the deck was done as a deckover at least once and that has failed.

OMC ran the blue on the block? Good to know. I think it's safe to say someone swapped this motor out at some point probably then. As for the deck- the boat has already been restored with all new floors and transom and whatnot, these pictures were to show the condition it was in when I found the boat and was getting ready to pull the motor a few months ago.

 

[Bondo]

OMC, 'n Crusader ran a pale blue,.....
That blue in yer picture looks darker, like Ford blue,....

 

[Scott06]

If you can get a scope camera put it in the spark plug holes You may find an over bore size and piston part number in the piston face. recently I was looking at buying a Pontiac V8 for my GTO, it was previously rebuilt, had seller take pics of the piston tops, and it revealed a part number for a speed pro piston that was .060 over…. So I passed as block would likely need sleeving for a future rebuild…

 

[IslandExplorer]

OMC, 'n Crusader ran a pale blue,.....
That blue in yer picture looks darker, like Ford blue,....

You're right, it does look pretty dark. I'm thinking it's pretty likely someone blew the engine previously and just swapped in a (possibly rebuilt) replacement motor.

 

[IslandExplorer]

If you can get a scope camera put it in the spark plug holes You may find an over bore size and piston part number in the piston face. recently I was looking at buying a Pontiac V8 for my GTO, it was previously rebuilt, had seller take pics of the piston tops, and it revealed a part number for a speed pro piston that was .060 over…. So I passed as block would likely need sleeving for a future rebuild…

That's a great idea! And good to know they stamp the pistons like that sometimes. I'll see if I can find the cheapo bore scope I bought a while back and take a look. Would love to know if this thing was bored out or not.
What year GTO btw? Love those cars, especially the signature grille, nothing like a tiger!

 

[kenny nunez]

By looking at the distributor cap I was able to figure the firing order.
If my count is correct your engine has a standard 302 15426378 firing order.
188s 13726548. So the engine is a 170hp. Since you got the boat cheap just use it as is once you get it cleaned up.

 

[Scott06]

That's a great idea! And good to know they stamp the pistons like that sometimes. I'll see if I can find the cheapo bore scope I bought a while back and take a look. Would love to know if this thing was bored out or not.
What year GTO btw? Love those cars, especially the signature grille, nothing like a tiger!

65 GTO Bought it years ago..1990. Had a 65 LeMans which I never should have sold, all I wanted after that was a GTO…

 

[IslandExplorer]

By looking at the distributor cap I was able to figure the firing order.
If my count is correct your engine has a standard 302 15426378 firing order.
188s 13726548. So the engine is a 170hp. Since you got the boat cheap just use it as is once you get it cleaned up.

Good eye! I found the firing order to be the same, clockwise rotation motor, counterclockwise rotor rotation, and 1,5,4,2,6,3,7,8 when I was doing the new distributor. So is 170hp what a stock 1970's 2 barrel marine holley 302 would probably have?

 

[IslandExplorer]

65 GTO Bought it years ago..1990. Had a 65 LeMans which I never should have sold, all I wanted after that was a GTO…

That is a gorgeous car! AND it's a convertible... I'm jealous. That color looks awesome on it, reminds me of the one from Bandits! I've wanted one ever since I saw that movie. And is that a 6 pack you got on there!? Thanks for sharing some pictures. Rust quickly kills all the cool cars around here so they're rare to see.

 

[Scott06]

That is a gorgeous car! AND it's a convertible... I'm jealous. That color looks awesome on it, reminds me of the one from Bandits! I've wanted one ever since I saw that movie. And is that a 6 pack you got on there!? Thanks for sharing some pictures. Rust quickly kills all the cool cars around here so they're rare to see.

Never saw the movie. That is the original color Burgundy, just the cross ref number PPG gave me when I painted it back in 1992 is a touch more red, actually like it better.

Rust wasn't too bad on this but accident damage was and the engine trans and diff had been blown up at various times. I found out after I had bought it that it was originally tripower and 4 spd. I just got the tripower back on it in 2021

 

[IslandExplorer]

Never saw the movie. That is the original color Burgundy, just the cross ref number PPG gave me when I painted it back in 1992 is a touch more red, actually like it better.

Rust wasn't too bad on this but accident damage was and the engine trans and diff had been blown up at various times. I found out after I had bought it that it was originally tripower and 4 spd. I just got the tripower back on it in 2021

That's awesome that you converted it back! The tripower setup looks so cool on there.. Heard the old 2 barrels had better mixing than the 4's at the time and that's why they ran it like that but don't really know for sure.

Now I know this is a boating forum- but did you stick with the old 4 on the floor or throw a 5 speed with OD in there?? What's your axle ratio? Sometimes the axle ratio makes the 5 speed totally unnecessary.

I was going to run a T18 in my V8 Samurai project but it was going to rev out too high on the highway so decided to go with a ZFS547 for the super low 1st and nice .7ish or so OD gear for long road trips. 302+2WD ZF5+divorced Dana/Spicer18/+ FJ62 axles w/4.11's but that thing is still no-where near done...

 

[Scott06]

That's awesome that you converted it back! The tripower setup looks so cool on there.. Heard the old 2 barrels had better mixing than the 4's at the time and that's why they ran it like that but don't really know for sure.

Now I know this is a boating forum- but did you stick with the old 4 on the floor or throw a 5 speed with OD in there?? What's your axle ratio? Sometimes the axle ratio makes the 5 speed totally unnecessary.

I was going to run a T18 in my V8 Samurai project but it was going to rev out too high on the highway so decided to go with a ZFS547 for the super low 1st and nice .7ish or so OD gear for long road trips. 302+2WD ZF5+divorced Dana/Spicer18/+ FJ62 axles w/4.11's but that thing is still no-where near done...

I don't think prior to the Q-jet coming out they had a 4 bbl big enough in an OEM format.

The AFB that was on the early 4 bbl engines is 500 cfm. I don't think the 3x2 had better mixing than the 4's. I think in the end there is a reason that Pontiac went to a higher rise intake and the q jet. The factory 67 and up intake is hard to beat.

A lot of guys have really good results with tripower and other guys have good results with a 4 bbl so I dont think one is better than the other. the tripower essentially functions like a 4 bbl as the end carbs only kick in at about 75% open throttle. End carbs dont have choke, idle, or power circuits so they are essentially the secondary's on a 4 bbl.

Where a tripower on a 64-66 GTO does excel is looks, resale value and noise when WOT. Nothing sounds quite the same as a poncho and tripower.

Unfortunately the Pontiac rods didn't like it much past 5200 so most of them didnt make it through the 70's. I bought mine in Jan 1990 and it had been off the road since 78 or 79... and by then engine was gone, trans gone, diff was previously exploded. Either the guy I bought it off of or the guy he bought it from had two 65 gtos. the front end was off a different (color) 65 GTO and the engine was cast 6 months after my car was built, so its hard to piece them back together.

I kept a wide ratio 4 spd Muncie in it. I bought it from a classified add back in the day and rebuilt it. Actually works very well.

PO had put 4.33's in my car. I got a 8.2" BOP rear out of a 66 cutlass ($45 at u pull it yard back in the day...) with 3.08 gears and a posi and swapped them in. Very nice on the highway but a little tame when you are on it. I think eventually I will go to a 3.36 or 3.55, would match my cam better

In the end I wanted to limit my mods to day 2 type stuff. I never really wanted a resto mod, and it has taken so long to actually get this streetable I am just happy I can drive it. Definitely appreciate it more than I would have when I was younger.