Honey I blew up the chrysler... 1970 55hp

[Woka]

Hello all, hope you can shed some light on my misfortune.
After fixing my carb and ignition and then replacing my shift rod seal on my leg I have now next to no compression and a blown head gasket.
The string of events that led to this were the head gasket blowing out at the top of the bottom cylinder which then pressurised the cooling system so that water would not flow past the thermostat then the engine severely overheated and I assume has melted the piston rings. I now have a compression of 40psi on the top and 70psi on the bottom. Far from ideal!
So....I had the pleasure of informing my lovely female boating companion to pick up a paddle the other evening.
I guess I am now up for a new head gasket and piston rings, obviously I already have the gasket off but how much work is involved in changing the piston rings and is there a guide on how to do it?
Thankfully the cylinders are only lightly scored and so cross hatching them for the new rings should be enough.

I need a parts catalog so I can figure out the part numbers, does anyone have one? Also what other parts will I need in the process of pulling the head apart to change the rings and then put it back together?

If anyone can provide instructions or suggest a video or book that will help that would be appreciated as although I know about engines, I don't know how to pull one to pieces and successfully put it back together again.

How much will a set of rings and a gasket cost, from a brief look online it's $40 for a gasket and $50 per set of rings. Is that about right?

Is there any possible way of avoiding replacing the rings or with compression that low and the scoring is it a done deal?

Thanks for your help,
Warwick.

Here is an external pic, I'll post some of the insides tomorrow. View attachment 206452

 

[jerryjerry05]

Re: Honey I blew up the chrysler... 1970 55hp

First if it's bad enough to score a piston??
Then the cylinders need to check by a machine shop.
Just honing might not be enough.
If the piston rings riding on a defect it's only gonna get worse.
Your cost.The rings can be found as low as 35$ and up.
Pistons can be found for as low as $60 and up.
Gotta shop around.
Wiseco sells a good piston.
There are other manufacturers too. Cheaper too.

 

[Frank Acampora]

Re: Honey I blew up the chrysler... 1970 55hp

Before going crazy, buy another head gasket, install it and see where the compression gets to. Try a little Seafoam treatment in case the rings are stuck and see if that helps. --Unless you enjoy doing a complete rebuild.

 

[Woka]

Re: Honey I blew up the chrysler... 1970 55hp

Thanks for the quick advice,
Here are pictures of the head gasket and cylinders.
The place where the gasket blew has also caused some damage to the outer part of the cylinder wall, the sleeve is fine though. Any idea on how to repair?
I will get a head gasket and re assemble before I rip the thing to pieces and see what that does.
How bad is the scoring?

Cheers!

 

[tater76]

Re: Honey I blew up the chrysler... 1970 55hp

#1 looks pretty rough. However, it could just be aluminum ruboff from the piston. If the scratches are deep enough to catch a a fingernail, then it should be bored over. The 55 is super simple, and takes little time and skill to disassemble and repair. It costs me about $75 to have my machine work done here. Then you need an oversize piston and rings. I bet you would be looking at $300 for the whole thing.

If you are going to have it bored, you may as well do both holes while you are apart. If your cheap like me, then find a used piston, buy new rings for both cylinders, gasket kit, carefully remove the aluminum rub-off on the walls, hone both cylinders, put it back together. I have a 73 55 that has over 200hrs with the above semi rebuild in it.

 

[Frank Acampora]

Re: Honey I blew up the chrysler... 1970 55hp

The only sure repair is to replace the block. As it stands now, any head gasket you put on will blow out because there is not enough support with that massive chip missing. If you know a GOOD welder he might be able to fill in the gap but is is really stopgap and likely to happen again. Sorry for the bad news.

 

[Woka]

Re: Honey I blew up the chrysler... 1970 55hp

Well I have decided to go full DIY and try fixing it myself, I will of course take photos and let you all know how it goes.
Plan is,
1. Use high temp epoxy (jb weld) to fix the Chip in the outer cylinder
2. Resurface head ( sandpaper and glass)
3. Reassemble and cross fingers that compression improves.

Any recommendations from anyone with experience in this stuff, I.e. tips and hints on getting a good seal on gasket.
Should I use gasket goo??

ALSO CAN ANYONE CONFRIM THE PART NUMBER FOR THE 1970 55hp model 554BA HEAD GASKET, IS IT THE SAME AS THE 74?
I have a sierra p/n of 18- 3856 which looks exactly like the one that's in there but looks can be deceiving!

Thanks for the advice.

 

[Frank Acampora]

Re: Honey I blew up the chrysler... 1970 55hp

If you just epoxy it, the constant heating and cooling will blow out the patch. Instead, square the corners of the gap and fabricate an aluminum piece to fit into the gap and BETYWEEN the gap and external block wall. Now, epoxy the aluminum plug into place and after it is set, surface everything smooth. See if that helps.

And yes, I believe the head gaskets are the same.

 

[Woka]

Re: Honey I blew up the chrysler... 1970 55hp

Thanks frank, sounds like a more permanent fix. Would it matter what sort of alloy? I have access to aircraft grade aluminium but none that would be used in a high temp environment.

 

[Frank Acampora]

Re: Honey I blew up the chrysler... 1970 55hp

I suspect that almost anything will do. I have done just this on a 3 cylinder block and used some sheet semi-hard that I had laying around. As yet have not had time to test the engine so I can not say for sure that this will be a permanent repair

 

[Woka]

Re: Honey I blew up the chrysler... 1970 55hp

Ok so finally got a new head gasket. A little info and picks for anyone reading:

1. Machine head.... borrow the wife's stovetop and tape some sandpaper to it ( a emery paper kit with several grades would have been ideal, I used 600 wet and dry which did the job.


several sheets of sandpaper and a lot of dust and sweat


Still a little way to go here.

While your waiting for your new gasket to arrive, get the misses to polish the boat


Once you have a good finish clean well.
I had to jb weld a chip in the water jacket so wrapped a straight piece of metal, a thick ruler works well, with sandpaper and get the block smooth.
I used a wire wheel on a bench grinder to clean the threads of all the bolts up and then coated with anti seize.
Placed new gasket on and tighten bolts as per correct sequence ( middle out wards basically and to 22.5 ft/lbs as per the manual.

I cleaned all the surfaces with oil to remove the dust before assembling, not sure if this is the best thing to do but it worked well.

So I drop it in the lake and start her up, initially the gasket leaked a little water but this soon stopped once it heated up, I assume this is normal.

I then drove around for a whole to run some sea foam motor treatment I had added to the fuel to help if the rings and stuck from overheating.

All was fine until it then died randomly.... I left it for a minute then started up again, no problems. Got back to the dock and it died at idle.

I haven't checked compression since changing the gasket but will tomorrow. It seemed to run quite hot, plenty of water going through it but the head was quite hot to the touch, how hot should it run?

Any ideas on why it died? I am going to tune the carb a little tomorrow and set the idle a little higher and see what happens.

Cheers for your previous and future advice.

 

[jerryjerry05]

Re: Honey I blew up the chrysler... 1970 55hp

If it's too hot to touch then it's overheating.
You should be able to touch anywhere on the block except right next to the plug.
The JB Weld isin't gonna work.
Take it to a shop that welds alum.
If the guy's any good he might be able to fill that spot?
Otherwise, start looking for a block.

 

[Woka]

Re: Honey I blew up the chrysler... 1970 55hp

Yep, it's still overheating then.
Plenty of water going through it. What would be the cause of it getting to hot if its got a good amount of water flowing through it??

 

[jerryjerry05]

Re: Honey I blew up the chrysler... 1970 55hp

Overheating,can be the impeller is bad, the housing is bad or the tube to the motor isin't connected or it's plugged.
The thermostat blocked,bad,missing.
The exhaust is blocked with sand or corrosion?
Not sure if the 70/55 had a pressure by/pass.It could be blocked?
Remove the lower and hook a hose direct to the tube.

 

[Frank Acampora]

Re: Honey I blew up the chrysler... 1970 55hp

Too hot to touch is a subjective measurement and may not indicate overheating: They use water at 135 degrees F to scald and de-hair hogs. Water at 135 degrees F will take off your skin if left in contact. At 135. an engine block is uncomfortable to touch and you would not want to leave your finger or hand in contact with it. I chose 135 degrees because this is what some low temp thermostats in outboard engines are.

While the engine is hot and running, scoop up some water and toss it on the top of the block. If it sizzles, boils, and flashes off, then the engine is overheating. If it simply evaporates relatively slowly, the engine is not overheating.