72 Thunderbird Formula w/twin 165hp Mercs

[archbuilder]

Man that milkshake oil almost wants to make you cry when you see it! Hopefully its something simple!

 

[alldodge]

Dang that sure is a bummer. I'm thinking head gasket, if it was the intake there would be water in more cylinders.

Can you provide a quick over view of the history of the motor and what was done to it, old and new parts kind of thing?

 

[sphelps]

Crud ! sorry Mark that stinks !
Mechanically I am pretty much zero help .... Your troubled engine prolly runs better than my lawn mower at the moment .. :facepalm:

 

[Mark72233]

Thanks for the encouragement. As far as being here to help trust me you guys on here help a lot if you were near by I wouldn't put you to work anyway. Well engine is out.

Noticed part of the starter sitting in the bilge. That would have been the clunk sound as I tried to crank it yesterday not knowing I had water in the cylinder. The amazing thing is the starter still works and cranked the engine several times after this happened I am sure. I hope valves are on. The fun has just begun now time to tear it down, fingers crossed.

 

[Mark72233]

Meant I hope valves are ok

 

[Mark72233]

Head is off and serious signs of surface rust on both 3 & 4. 3 looks worse. I don't have any experience with a blown head gasket or cracked block or head. I see no obvious signs of the gasket having any issues on 3 or 4 or between them. Lots of water in the oil. Drained the oil and it had at least 1 quart probably 2. My plan is take head and block to a shop and see if they find anything. AllDodge the history on the engine is it was the engine I bought in Jacksonville and it was already .030 over and needed another .030 so it's been bored .060 over. I never had them checked, magna-flux.

Number 3


Number 4


Number 1 & 2 for comparison


Cylinder 3

 

[Mark72233]

Elbow is used but looks good. Manifold is used but looks very good. I still don't think it is either of them. Leaning towards a crack in the block. Could the crack be so small I haven't see it yet.

 

[WOEISMEIGOTTA470]

Mark, I feel for you bud! Quite the downer, but keep your head up! If it were me I would have each component pressure checked for leaks. I would actually be very suspect of the manifold and elbow personally, as there could be an internal water jacket leak that is impossible to see with the eye. Pressure check those to make sure there are no leaks in the water jackets. From the photos of the head, I don't see any evidence of a blown gasket there. I would've said before removing the head, pull the rockers and do a leak down test on the cylinders, and listen for air escaping into the cooling hoses (indicating a crack in the head or blown head gasket). You could maybe still try getting away with testing the head by bolting the head back on quick and torque back up the head bolts. For the amount of water you had though, seems to me more like a manifold issue to me, which would be the better scenario. I hope you can get things figured out and turned around soon!

 

[Mark72233]

Woe thanks for the guidance. Again I don't have any experience with blown head gaskets or a cracked head or block. Your suggestions sound good and wished I would have tried that before disassembly. I do have past experience with rusted out manifolds on both a in line 4 and 6 and every time the water always ended up first in the last or rear most cylinder, #4 or #6 respectively and when the leak was bad enough it would get into the next cylinder but in this case it is right in the middle, number 3 is worse than number 4. Anyway no signs of water getting into #1,#2, #5 or #6. Also looked at the manifold again and it is the new manifold not the used one and the elbow looks to be almost in brand new shape. The way the head is made there is a separation between the exhaust ports and it looks like water in both so I am thinking since the cylinders were bored out to .060 over I just got unlucky and there are cracks, the first one on #3 and than the second one developed on the adjoining wall in #4. I am going to try and get it to a shop today or Tuesday and find out.

 

[WOEISMEIGOTTA470]

I guess that's the chance you take with old blocks :-/. See what the shop says, if they do in fact find something, possibly they could give you a partial discount/refund I hope???
Meanwhile for peace of mind, it wouldn't hurt to check the manifold anyways. It is possible even for new manifolds to have casting defects. I checked my new manifold before installing it just to be absolutely sure. Below are pics of a tester setup I've used in the past.

My cheap homemade tester:


Testing the manifold: You'd need to fabricate a blank block-off plate, simple square plate with 2 holes, OR make a solid gasket and use elbow. Easy for me since I already have it blocked off for closed cooling use.


Best of luck Mark.

 

[Mark72233]

Thanks Woe, that looks easy enough. Fancy engine you got there and a fuel pressure gauge along with braided lines. Sweeeeet

 

[WOEISMEIGOTTA470]

Thanks Woe, that looks easy enough. Fancy engine you got there and a fuel pressure gauge along with braided lines. Sweeeeet

Thanks, I couldn't get the hard fuel line to work or fit right, so I went with flex. It's easier and looks neat lol. I added the gauge cause why not. I'm just hoping that I don't run into any major gremlins when that day comes I hit the water. Engine seemed to run great on the stand, but as you know things are quite different under load. I bought the engine already rebuilt, so I hope it was built right!
Edit: I'm running a new carter mechanical fuel pump, but I'll be interested to see how your electric pumps work out for you when you get that going.

 

[Mark72233]

Yep I haven't install the new electric Holley Red fuel pumps yet. I guess I have time now and with the starboard engine out it gives me room to install them. Trying to look on the bright side of this latest issue

 

[WOEISMEIGOTTA470]

Yep I haven't install the new electric Holley Red fuel pumps yet. I guess I have time now and with the starboard engine out it gives me room to install them. Trying to look on the bright side of this latest issue

Always gotta look at the bright side. Still very impressive how far you've made it, you transformed that old hull into a real thing of beauty. You built yourself a gem, just have to get though this last hurdle. I'm way behind, and still have a daunting amount of catching up to do if I want to see a splash myself this year. Going to make it a goal of mine to not let one day slip by without doing at least SOMETHING on the boat. That being said, I'm off to do some sanding! Catch you later!

 

[alldodge]

Been out of town, man .060 over, that's bad news, wish I would have seen that before it was done. I'm going to go out and think you might had a crack block.

Hate to ask but was the other one done the same way?

 

[Mark72233]

Hey AllDodge I was wondering where you were hiding. Yes .060 over is pushing it but still within specs but probably with in specs on a truck block not used on a boat. No the other one is standard not bored at all. Hide sight this engine alway ran hotter than the other one about 180-190. The other engine runs at 150. Tore the block all the way down and I know cracks sometimes aren't visible and without the expansion from heat and pressure from compression and water pressure but I don't see a dang thing wrong anywhere on that block so anyway tomorrow I will get to the shop and see what they find.

 

[alldodge]

Standard bore is 3.875, going to 3.935 (.060) when there are 3.895 (0.050) and that is stretching it. My first question for the machine shop is could it be honed out at .030 and how much out of round are the cylinders?

Unless the shop was dead on perfect +/- .001 the bore could shave the walls by another .005 to .010 to one side

Just looking at the heads I see no sign of head gasket failure

 

[Mark72233]

It was already .030 over from a previous owner. Shop found wear and needed to bore it and the only kits I found at the time were .030 or .060.

 

[alldodge]

Morning Mark, how's it going

 

[hogbare35]

Mark
Ive been following your project for a good while , just joined up today . Before you scrap that block make sure your exhaust manifold is not partially plugged with rust . I had that problem on 165 Mercs before , I pored muratic acid in them to break up the rust. Its kind of a messy job ,but with a little beating with a hammer the rust will come out ,then you get better water flow thru the manifold which takes out more heat .
You have done a fantastic job on that boat .If you know any one looking for a Formula 23 , I have a 1976 that would be a good project . I'm working on a 1973 26 Stamas or I would try the formula . Good luck.