Head Gasket Sealer for pitted block

aclmvh · May 21, 2009

I have a '98 Johnson 115 SPL (90 CV) and I'm changing the head gaskets out. I think I've read every post regarding using or not using sealer on head gaskets and still don't know what to do. I have a BRP factory gasket that says nothing about not-using sealer, and it's not real shiney.....only a little. However, I'm inclined to use something because one spot on the block mating surface just adjacent to the cylinder liner on one cylinder is slightly pitted- and this is where the old gasket failed. My thinking is that I should use either a gasket sealer or indian head shellac in this area to augment the new head gasket. I've attached a picture of the area in question. Please, send me your thoughts. Thanks,
mvh
Jax/FL

jonesg · May 21, 2009

Re: Head Gasket Sealer for pitted block

keep bumping your mssg back to the top until you get an expert opinion, I'd say jbweld but what do I know.

bump....

crxess · May 21, 2009

Re: Head Gasket Sealer for pitted block

^^^^^^ That was my thought also. Careful aplication of JB Weld. Sand or File before fully set. Keep away from the inner Piston sleeve.
Don't use sealers on head gaskets.

Benny1963 · May 21, 2009

Re: Head Gasket Sealer for pitted block

if the pitting is light use 3m aviation on block surface regardless of self sealing gasket ,it works just a thin coat will help have done several works every time,brp makes the same stuff comes with a brush,lots of people say that its not good with the self sealing gaskets but my boat guy that helps me is 70 years old and has been in buisness 30 years ,it works

aclmvh · May 22, 2009

Re: Head Gasket Sealer for pitted block

Thanks for the feedback guys....at this point I'm deciding between the JB Weld used in moderation, and the BRP Gasket Sealer/3M Aviation sealer (I've heard the Pro Marine Gasket sealer is pretty good also). I gather from the lack of commentary that everyone feels that these gaskets have the sealant in them already.....BRP gaskets for a '98 Johnny.

Thanks again....if I don't receive anymore suggestions I'll be giving something a try this weekend, weather permitting, and I'll let you know how it turns out....right after I reverse drill that *&%$# broken head bolt out of the #4 hole.

mvh
Jax/Fl

aclmvh · May 22, 2009

Re: Head Gasket Sealer for pitted block

Since this is the first time I've had the heads off this engine....any outboard....can someone look at the photos and give me a general opinion on the look of the sealing surface and pitting? Normal? (this is exclusively a salt water/brakish water engine).

Thanks,

mvh
Jax/Fl

crxess · May 22, 2009

Re: Head Gasket Sealer for pitted block

Normal?.......... Not exactly.

The motor probably was not maintained as well as it could have been.
Flushing after use is critical in a salt water use engine.

Having a Sacrificial anode on the lower unit is also a good idea on a saltwater motor. Prop spin creates a small electrical current which promotes erosion.

dingbat · May 22, 2009

Re: Head Gasket Sealer for pitted block

I too had some erosion on the block. Pretty normal for a motor that lives it's life in the salt. The first time my mechanic had the heads surfaced and reassembled the motor without additional gasket adhesive. The repair lasted a little over a year (75-100 hours of operation. )

This time around I figured I had nothing to loose. If it didn?t work I needed a new motor. I filled and eroded areas with JB and used aviator adhesive on the back side of the head gasket. I have roughly 75 hours on the repair so far and everything seems good?..for now.

aclmvh · May 22, 2009

Re: Head Gasket Sealer for pitted block

Good advice.....salt water is tough on these engines.....and on everything else.

I will say I have always flushed the motor with fresh water thoroughly after every use- even on vacation when the boat stays in the salt water for two weeks, I put the muffs on it flush it out with fresh water. And all the sacrificial anodes are in good shape. This engine has always been in salt water (one owner before me) and I know the engine was blown and 'factory' rebuilt- I have about 100 hours on it since I bought it (since the rebuild). Just for grins, the pictures below show what I found when I removed the heads (the holes in the head gasket are in the location of the pitting/erosion on the engine block mating surface)....and the second picture shows the 'after cleanup'. The scores in the head are from the blown engine, previous owner.

mvh
Jax/Fl

dingbat · May 22, 2009

Re: Head Gasket Sealer for pitted block

You can flush a motor till your blue in the face and it's not going to stop surface pitting in a motor run in salt for any length of time.

Saltwater is very high in disolved and partially dissolved particulate. You're basically sandblasting the inside of the motor when running saltwater through the cooling chambers.

That head looks in awfully bad shape to have been "rebuilt" only 100 hours ago. Looks like the "factory" didn't bother to plane the heads when they rebuilt it.

wilde1j · May 22, 2009

Re: Head Gasket Sealer for pitted block

I would try to find good used heads ... yours are pretty rough items. The block may need some help as well, but you didn't post the cylinder pictures.

aclmvh · May 22, 2009

Re: Head Gasket Sealer for pitted block

Thanks guys. And since you asked, here are the cylinders and pistons on the starboard bank. I think they look pretty good. Maybe I'll go head shopping....

mvh
Jax/Fl

aclmvh · May 23, 2009

Re: Head Gasket Sealer for pitted block

Still working on that broken off cylinder head bolt, trying to be patient. Man is that hard steel!! I'm using nothing but left hand bits, but I may swap out for a right hand one time to see if it will cause the bolt threads to let go. Once this is done I'll update my post with the result of my JB Weld/gasket replacement.

mvh
Jax/Fl

crxess · May 23, 2009

Re: Head Gasket Sealer for pitted block

A little heat might help get that broken bolt to let go.

D.spencer · May 23, 2009

Re: Head Gasket Sealer for pitted block

Of course the best action would be to resurface the deck.That would be time extensive and costly. If it were me, I would be tempted to use devcon for aluminum. That stuff is harder than heck.

that is actually a bit of an understatement- I wore out many carbide bits machining a part I built up with the stuff. Use a new stainless steel brush to clean the aluminum thoroughly, mask off the cylinder so it won't stick inside, follow the instructions for mixing and applying. Use a razor blade and just scrape it clean/flush( like filling a dent with body putty) before it sets. Follow post cure (use a heat gun since putting it in a oven is impractical. Buy a tempel stick - @ $10.00( a crayon that melts a specific temperatures-whatever temp you want-but follow directions with devcon) from a welding supply store or use an infrared temperature gun to maintain post cure temperature. It seems there is pitting along that seam as well as the deep pitts you are talking about. I did this type of repair on my forklift cylinder head ( it was cast iron but devcon makes a formula for that)- a very old yale that is difficult to find parts for. So far, it is still holding that was about four years ago.

Okee Jimmy · May 23, 2009

Re: Head Gasket Sealer for pitted block

hi, good quality cobalt bits will go through that bolt like warm butter, and while those heads are off you should replace the deflectors. Also, I've used aviation permatex, pro peanut butter, omc gasket sealer. and dry gaskets wilthout a failure, double oil after a rebuild, for a couple of tanks, and a retorque, and compression test afterwards is a good idea. hope this helps, Jimmy.

aclmvh · May 24, 2009

Re: Head Gasket Sealer for pitted block

Great advice from everyone. I finally got the broken bolt out with a little luck (1/2 can of WD-40, 1/2 can of Liquid Wrench and drilled the bolt out with left handed bits until I was almost to the threads....drove a screw driver into the hole I drilled in the bolt and backed the SOB out!).

Wish I had seen the post on the Devcon before.....anyway, I cleaned up the block mating surface with acetone and a nylon brush and then applied some JB Weld using a toothpick- then squeegied it with my wife's credit card. Very easy to work with and it looked good after I finished- I'll be back to it today to razor blade and file it flush and will post pictures. On close inspection it looks like Devcon or JB Weld or something was used before in the cylinder sleeve/block groove at the bottom of the bottom/starboard cylinder. Anyway, if its as heat resistant as it says the JB Weld should do the trick.

Pictures next. Thanks all.

mvh
Jax/Fl

aclmvh · May 25, 2009

Re: Head Gasket Sealer for pitted block

Okay, I shaved the JB Weld with a single edge razor blade, keeping it flush and square with the top of the cylinder sleeve. Then I followed with a few light passes with dampened 400 wet/dry. I'll apply Indian Head Gasket Shellac to the engine block and cylinder head mating surfaces outside the cylinder liner and after it sets up, I'll place the new head gasket and I'll torque it down and see how she does.

Before and after pictures are posted showing the pitting and the repairs- and a shot of the two cylinder repairs- exactly where the holes in the head gasket appeared. A coincidence? I think not.

Thanks for all the feedback- keep it coming.

mvh
Jax/Fl

D.spencer · May 25, 2009

Re: Head Gasket Sealer for pitted block

Looks good so far. Have you checked the deck with a straight edge just to see how flat it is? check in an "x" pattern as well to check for warpage as well as legthwise to look for low spots/high spots. might should do this before re-assembly to save some potential frustration later. Use a feeler gauge to see how much "out of flat" it is, if any. Usually the rule of thumb is .007" max combined out of flat.

aclmvh · May 26, 2009

Re: Head Gasket Sealer for pitted block

Thanks D.Spencer.....I checked the deck of the block as soon as the head was removed.....it looks perfect from every cross section. After using the wet/dry on the head in a figure eight pattern it looks like the center (area between cylinders) is a 'high' spot...but it is less than .007, so I'm thinking it will be okay- hopefully. More to come after I find my replacement bolt....I'm pretty sure the head bolts are not factory. They are 5/16" coarse threads, 2 1/4" long...but they have 1/2" hex flange heads. The ten head bolts on the port cylinder bank have smaller heads (maybe 3/8"). So I'm headed to a good fastener place to match up what I have.

mvh
Jax/Fl

Head Gasket Sealer for pitted block

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