Poor decision on a faulty engine or?

[Weanuts]

Have a chance to purchase a 4 year old Yammy 90 for $500 Have invested $200 so far to try and recover engine. The problem initially was a crack at the lower right water jacket. I had a shop repair the crack and doing so has caused an uneven deck surface. I have reassembled engine but the surface is not flat enough to retain coolant.

The engine has very low hours and was unwarrantable.

My questions are:

1/ Is there a sealant that can be applied to a head gasket to enhance the head gaskets sealing ability? Permatex contact cement, Dicor, Sicoflex, Jb weld, or????

2/ As a general rule, is any sealant applied to the new head gasket and or head bolts?

Suggestions appreciated.

 

[GA_Boater]

Re: Poor decision on a faulty engine or?

I can see exactly what you mean - NOT. Please, some pictures.

 

[glenn property of pam]

Re: Poor decision on a faulty engine or?

if you have had the head welded and its caused distortion then it will have to be machined flat before it will work. Like GA said pics so we get a idea of where the repair was carried out will help us to see whats going on

 

[Weanuts]

Re: Poor decision on a faulty engine or?

I could go out and remove power pack to take pictures of the block but it is block deck I am inquiring about not the cylinder head. My main questions are as stated is type of material aside from welding again or machining the block to recover a flater deck surface. I have, since first posting, found a product by JB Weld, called, High Heat epoxy, unlike JB Weld 2 part epoxy.

Also, I would like seal the gasket in the sandwich with ???

thanks for looking and answers

 

[GA_Boater]

Re: Poor decision on a faulty engine or?

JB is not the right thing to "sandwich" the gaskets with. You might have to remove it again. Pica of the repaired are really needed to give you good advice. You have to take it apart to fix, so grab some pics.

 

[99yam40]

Re: Poor decision on a faulty engine or?

hard to believe you had it welded but did not have block checked for straight.
It would have been easy to have it surfaced then.

You will not have any faith in a rigged fix, at least I would be afraid of it giving up at any time while you least need it to happen.

Fix it right and be done with it

 

[Weanuts]

Re: Poor decision on a faulty engine or?

I will take the answers to my question last to first. To 99yam40, the block was checked prior to welding with machinists straight edge and .0005 feeler gauge, and it was straight. My wallet may not be as thick as yours so I decided to try this method.

To GA_Boater, I do not want to bed the gasket with JB Weld, only raise the area in the picture (as poor as it is) to recover a straighter surface. My question with (???) was what kind if any material (sealer) might I apply to the complete gasket both sides to install in the bite to try and stop any further leaks.

The picture as poor as it is shows the block behind the power pack, which has had a thin coating of JB Weld applied to it . The weld itself cannot be viewed itself and I am not about to remove that coating. The surface below the head bolt hole is depressed.

The reason that the deck became depressed was due to (excessive?) heat.

If a satisfactory repair is not found I may purchase a decent block to exchange with the welded block.

I do appreciate the answers and the forum.

 

[glenn property of pam]

Re: Poor decision on a faulty engine or?

welding pulls material as it cools so the question is how far out is it now. You may be able to build up a small area if the rest of the block is straight and the area is not under a large amount of pressure. If you build up its better not to do it on the gasket but to build it up and dress it real careful with a file and sand paper until level. (im thinking of a small notch being low not 3 inchs long being low)

 

[Weanuts]

Re: Poor decision on a faulty engine or?

I can remember back in the fifties using copper clad head gaskets more than once. Today gaskets were not meant to be used more than once. The fabric or non metallic gaskets in use today were not meant to be used a second time as they adhere, and break when pulled apart. Most are covered by a shellac or such. As that part of my query as not answered, I will shut down now and let the forum know the results of my endeavor as it presents itself in the days to come.

Thanks again for the input

 

[GA_Boater]

Re: Poor decision on a faulty engine or?

To answer your part of the query - gaskets, copper or not, require a flat surface to work. They are designed to make up for minor imperfections because no machined surface is perfectly smooth.

Copper head gaskets are still used today just like the ones I used eons ago. Sure, you can anneal and re-use them. But only if the two surfaces aren't warped or depressed. From your description, that isn't the case.

Hope whatever you do works out.

 

[Weanuts]

Re: Poor decision on a faulty engine or?

Back in business. No leaks . (yet) I used a product by JB Weld called "High Heat" 2 part neadable epoxy. To cover with a reasonable thickness, I used a piece of plastic packing tape, sticky side to head surface, applied epoxy installed head allowed to set. Stoned flat and applied a gasket material "cement" called High tack by Permatex , to pickup any imperfections. Allowed to dry and no apparent leaks.

Now I know nothing is perfect but, in this case it will do until a GOOD block can be acquired. I will continue to enjoy this forum and will post again at least at end of season, or sooner should my fix not hold.

thanks to the forum and especially those that helped with their answers. Have a great season.

 

[crabby captain john]

Re: Poor decision on a faulty engine or?

Get back after 20 hrs or so under load and let us know,,,,