Volvo 225D engine block water drain plugs stripped-gctid815550

[sandt]

Im not sure what the best course of action is here... Last summer I bought a 1986 Bayliner Capri 1950BR with a Volvo Penta 280 outdrive, and Volvo Penta 225D 5.0L engine. I removed the water drain plugs to winterize the boat, and when I tried to put the plugs back into the bottom side of the engine block I saw that they are terribly stripped, and wont go back into the block. When I try to screw them in, they basically start threading, then just break loose and start again, break loose and start again, and wont go in deep enough to stay. The two on the back of the manifold at back of engine went back in fine. There are pictures of the drain plugs below. At this point Im not sure if a previous owner tried to drill out and tap the engine holes to increase the size of the plugs, or if these are the original plugs. I cant really get close enough to the holes to see if they are badly stripped. I've done a little reading and I think I understand the concepts of thread chasing and tapping a LITTLE, and it sounds like something I dont have enough experience to do, and also like doing it with the engine in the hull is a problem... The local boat repair shops in Colorado Springs basically sent me packing when I asked them about checking the engine over last year, but they gave me the name of a retired guy who worked on old boat engines, who I can no longer get in touch with...

Any suggestions or advice? Should I first try getting replacement plugs in the original size, and see if they will go in? Where do I get new drain plugs? how much does the length of the plug matter? I saw a couple of posts about putting in a petcock that with loctite that looked great, but Im not sure if that's too much of an unknown at this point (http://www.baylinerownersclub.org/in...-volvo-aq260)? How do you go about trying to use a thread chaser, and should I try? If you have to use a drill or something, seems like that's going to be problematic on the port side since there is not a log of space there.

Any advice would be greatly appreciated...


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[Guest]

you need a 1/4 NFTP plug. This is tapered pipe thread, not straight thread. you should find them in the plumbing section of your local home depot/lowes/menards. Do not try to chase the threads unless you've worked with a pipe tap before. you run them to deep and you won't be able to seat the plug.

[2850Bounty]

Steve, these are 1/4" Tapered Pipe Threads, not machine threads. The 1/4" refers to the ID of the pipe that uses this tapered thread.

The taper is what allows this style thread to seal against leaks...... air, water, oil, etc.

I would first buy a 1/4" tapered pipe thread "tap" and see if you can gently get it to chase the existing threads. You will actually be making the threads a dad bit deeper as you chase them. The new male threads will accomodate!

Make certain that the tap will not bottom out within the cooling jacket. Also, it must be aligned correctly before chasing.

If you are able to chase the threads, clean and dry them out, and install a Marine style fully removable "stop" style petcock.

https://newcontent.westmarine.com/content/images/catalog/full/15358_F.JPG

The "stop" can be removed so that the drain port can be probed during winterizing.

Use a Loc-Tite product when you install them!

[sandt]

Thanks for the suggestions. Forgive my ignorance, but I've never done this before.I;ve got a couple of ignorant questions:

0 - Doesnt say anything about tapered pipe threads, but this looks like the right part, right?? https://www.westmarine.com/buy/sierr...7?pCode=361891

1 - Woodbutcher suggested trying to use a tap might be a bad idea since I've never done it before. If I do it, how do I know what is "too deep"?

2 - how do you clean and dry out the threads? WD-40 and just wait for it to dry?

3 - I read about thread chasers as opposed to taps, which sound like they do less cutting? Would that be better to try?

4 - When you use a chaser or tap, since there's not much access, are they just shaped like a bolt or something, that I can use a socket wrench to do? My ability to maneuver around and be sure that I've settled it into the existing threads (as opposed to mangling them) is a bit limited unless I do it with just my hand...

5 - Is it going to hurt anything to just try using the new plugs first? (other than maybe strip them...)

[Guest]

[color]red wrote:
[/color]

"sandt" post=815570 wrote:
Thanks for the suggestions. Forgive my ignorance, but I've never done this before.I;ve got a couple of ignorant questions:

0 - Doesnt say anything about tapered pipe threads, but this looks like the right part, right?? https://www.westmarine.com/buy/sierr...7?pCode=361891

[color]red wrote:
I'll let Rick answer this.

[/color]

1 - Woodbutcher suggested trying to use a tap might be a bad idea since I've never done it before. If I do it, how do I know what is "too deep"?

[color]red wrote:
You don't want to cut the threads any deeper than they already are. If you chase the threads, cover the tap with a thick grease, it will catch any metal chips that break loose.[/color]

2 - how do you clean and dry out the threads? WD-40 and just wait for it to dry?

[color]red wrote:
Oil up a rag and stick it in the hole and twist it around, do this several times[/color]

3 - I read about thread chasers as opposed to taps, which sound like they do less cutting? Would that be better to try?

[color]red wrote:
I've never seen a thread chaser for tapered pipe thread, but they may exist.[/color]

4 - When you use a chaser or tap, since there's not much access, are they just shaped like a bolt or something, that I can use a socket wrench to do? My ability to maneuver around and be sure that I've settled it into the existing threads (as opposed to mangling them) is a bit limited unless I do it with just my hand...

[color]red wrote:
taps are usually driven by a t-wrench. It's very important to run it straight in, using a socket wrench is not a good idea, puts to much angular torque on the tap and will be very difficult to keep straight.[/color]

5 - Is it going to hurt anything to just try using the new plugs first? (other than maybe strip them...)

[color]red wrote:
I'd give it a try after cleaning out the threads. you should be able to turn it almost all the way by hand. you only want to use a wrench to tighten the last 1/2 to 1 turn.[/color]

[sandt]

Im going to get 2 new plugs and see if they can will go in before trying to get someone to tap the threads, and the local boat repair place said they dont have the brass petcocks in the picture Rick posted, but they've got the mercrusier type with same 1/4" pipe threads one the brass base and a blue plastic plug instead of the brass petcock that screws in. The mechanic there said that it would be fine and he prefers those. Any opinions or reason that I should wait instead and order the all brass one online???

[2850Bounty]

"sandt" post=815586 wrote:
Im going to get 2 new plugs and see if they can will go in before trying to get someone to tap the threads, and the local boat repair place said they dont have the brass petcocks in the picture Rick posted, but they've got the mercrusier type with same 1/4" pipe threads one the brass base and a blue plastic plug instead of the brass petcock that screws in. The mechanic there said that it would be fine and he prefers those. Any opinions or reason that I should wait instead and order the all brass one online???

[color]blue wrote:
If you attempt to re-install the same type of Bronze 1/4" TP plugs, you may further damage what's left of the existing female threads.

Also, the blue plastic plugs are inferior..... I could not recommend using them!

See if your local NAPA store has the correct Marine style petcocks. The stops must be fully removable!

MY suggestion:

Pick up a 1/4" Tapered Pipe Thread tap.

Be very careful to align the tap into the existing female threads properly.

Gently run the tap into the existing female threads.

You will be cutting into the rust and removing a very small amount of cast iron.

DO NOT re-install 1/4" TP plugs!

Instead, purchase two of the true Marine Engine drain petcocks that I linked us to in my previous post. These have the fully removable stops!!!!!

Clean the freshly chased threads out and make sure that they are free of any WD-40 or any oily products.

Using Loc-Tite, firmly install the Base portion of the new petcocks.

With the base portions locked into the cylinder block, and by now using the removable stops........ you will not have any issues in the future.

Again...... if you continue using 1/4" TP Plugs........ you will have issues in the future![/color]

[Chief_Alen]

Give this a peek ...

http://baylinerownersclub.org/index.php/forum/search?query=Nipple&searchuser=Chief%20alen&searchdate=all&searchatdate=07/01/2017&childforums=1

[2850Bounty]

Give this a peek ...

baylinerownersclub.org/index.php/forum/s...1/2017&childforums=1

[color]red wrote:
DO NOT....... repeat..... DO NOT extend the petcocks out from the cylinder block by using brass pipe nipples!

If I need to explain why......... then go ahead and do it! [/color]

[Chief_Alen]

Read it again.

In place of the petcock the nipple and a cap all brass.

You explain why it won't work, seeing as it's a sbc block.

[2850Bounty]

Attached files

[Chief_Alen]

Looks to be jimmy is going to pop a vein in his neck ....

[Guest]

"Chief Alen" post=815734 wrote:
Read it again.

In place of the petcock the nipple and a cap all brass.

You explain why it won't work, seeing as it's a sbc block.

Short answer: Open cooling, brass has a significant amount of zinc in the alloy....will be rotted out by electrolysis in a matter of time.

[2850Bounty]

"Woodbutcher" post=815812 wrote:

"Chief Alen" post=815734 wrote:
Read it again.

In place of the petcock the nipple and a cap all brass.

You explain why it won't work, seeing as it's a sbc block.

Short answer: Open cooling, brass has a significant amount of zinc in the alloy....will be rotted out by electrolysis in a matter of time.

[color]blue wrote:
I agree. Brass is not a good choice. Bronze would be a much better choice, and the ultimate choice would be the fully removalable stop Marine petcock that I have shown us.

But..... the reason for NOT installing a brass pipe nipple has not yet been revealed![/color] :P

.

[706jim]

I'm not sure how easy it will be to get to these loose threads. But the problem I see here is accessibility for tapping. It's one thing to do this on a bench but another altogether to do it in a restricted area in the bilge.

I find that if you start a tap with your fingers instead of a wrench there is less chance of cross threading.