Exhaust leak

waughoo · October 08, 2023, 10:13:02 PM

That 170 dollar price point vs breaking off a bolt in the manifold or lighting something on fire with a torch seems pretty inexpensive to me. Sometimes it costs money to get a job done even when it is a DIY job.

KWKloeber · October 09, 2023, 08:29:43 AM

Quote from: waughoo on October 08, 2023, 10:13:02 PM
That 170 dollar price point vs breaking off a bolt in the manifold or lighting something on fire with a torch seems pretty inexpensive to me. Sometimes it costs money to get a job done even when it is a DIY job.

Sounds like it might be a use it and eBay or Craigslist it situation.
Been there before!

junaido · October 15, 2023, 09:55:36 AM

Well the riser is off. The recalcitrant bottom nut finally yielded to a L handle wrench coupled with a 6 point 9/16 socket. This L-handle is narrow enough to fit on the socket. Breaker bars and conventional ratcheting socket wrenches don't fit on the bottom nut due to the narrow clearance of the exhaust riser. https://www.amazon.com/dp/B07XY1HJJ8?psc=1&ref_=cm_sw_r_cp_ud_ct_4RMK52ARYZQYYGTZHXKZ

When I say the nut yielded -- it went down fighting. The stud came out with the nut still attached. My question is, can you just screw this back into the engine side when the new exhaust riser is ready to install? Or get a hex bolt of same thread as the stud engine side and appropriate length? What is the advantage of this stud/nut arrangement? The studs are $27 at Catalina Direct. https://www.catalinadirect.com/shop-by-boat/catalina-38/engine/exhaust-system/exhaust-flange-studs-and-nuts-universal-3-hole-flange/

Thanks,
Junaid

KWKloeber · October 15, 2023, 11:50:04 AM

***Correction I was thinking of the exhaust manifold studs, which are metric x Imperial.
Mcmaster probably has the studs if you want to hunt something cheaper.

The studs are ~~metric x~~ imperial thread UNC x UNF. Why they didn't just use single thread studs is obvious - they're a little harder to find so they can charge 3x the cost.

I suppose you could use a metric bolt if you can fit it in there.
I'd **guess** the reason they use studs is, if the bolt seizes and snaps off, you're screewed. Presumably a frozen nut could be split or a slit ground in it? to get it off a stud, then the stud replaced if necessary.

Stu Jackson · October 15, 2023, 02:18:18 PM

Quote from: junaido on October 15, 2023, 09:55:36 AM

>>>>>>>>>>>>>>>>

The stud came out with the nut still attached. My question is, can you just screw this back into the engine side when the new exhaust riser is ready to install? Or get a hex bolt of same thread as the stud engine side and appropriate length? What is the advantage of this stud/nut arrangement? The studs are $27 at Catalina Direct. https://www.catalinadirect.com/shop-by-boat/catalina-38/engine/exhaust-system/exhaust-flange-studs-and-nuts-universal-3-hole-flange/

Thanks,
Junaid

I'd get the stud. The very last thing you want to be dealing with to replace the flange and ever remove a nut again is a bolt, especially with the tight clearances.

You could get a stud for next to nothing from a Kubota dealer. The tech wiki has an M25 engine manual for tractors with all the parts #s. I use Kubota regularly for this stuff. Put some blue locktite on the inside threads.

junaido · October 15, 2023, 02:34:40 PM

Quote from: Stu Jackson on October 15, 2023, 02:18:18 PM
Quote from: junaido on October 15, 2023, 09:55:36 AM

>>>>>>>>>>>>>>>>

The stud came out with the nut still attached. My question is, can you just screw this back into the engine side when the new exhaust riser is ready to install? Or get a hex bolt of same thread as the stud engine side and appropriate length? What is the advantage of this stud/nut arrangement? The studs are $27 at Catalina Direct. https://www.catalinadirect.com/shop-by-boat/catalina-38/engine/exhaust-system/exhaust-flange-studs-and-nuts-universal-3-hole-flange/

Thanks,
Junaid

I'd get the stud. The very last thing you want to be dealing with to replace the flange and ever remove a nut again is a bolt, especially with the tight clearances.

You could get a stud for next to nothing from a Kubota dealer. The tech wiki has an M25 engine manual for tractors with all the parts #s. I use Kubota regularly for this stuff. Put some blue locktite on the inside threads.

I am happy to get the stud from Kubota. How does one screw the stud into the engine ?

Noah · October 15, 2023, 02:40:10 PM

Double nut it to screw it in?

junaido · October 15, 2023, 03:25:36 PM

Quote from: Noah on October 15, 2023, 02:40:10 PM
Double nut it to screw it in?

Thanks, I just googled it. That will solve the stud installation.
Thanks!

KWKloeber · October 15, 2023, 06:12:14 PM

Quote from: Stu Jackson on October 15, 2023, 02:18:18 PM

You could get a stud for next to nothing from a Kubota dealer.

The exhaust manifold is a Universal part, not Kubota. So it's not a Kb part.
CD gives you the stud thread size so, again, McMaster might have them.

IIWMB I'd run a bottoming tap in and set it with locktite as Stu said.
Make SURE the exhaust gasket isn't put on backwards, that will ruin your boating day.

T

waughoo · October 15, 2023, 10:44:49 PM

Junaido,

As Ken says (in different words) chasing the threads is likely a good idea. The bottoming tap is a special tap for cutting threads all the way to the bottom of a drilled hole. If you go that route, make SURE to get a bottoming tap (not a regular one). What might be a better solution is a thread chaser. A chaser is yet another tool that will straighten the existing threads without cutting new ones. This will avoid damaging the threads that are already there. Sometimes running a tap in an already cut set of threads can damage them by cutting new ones.

KWKloeber · October 16, 2023, 08:28:27 AM

***
in different words
***

Yeah, in confusing ones, as well. In re-reading those not-so-clear words, I didn't mean to locktite the tap in place!!

Thx Alex!

Unless all the studs were pristine looking I'd replace them, but that's just my overkilling things.

Ron Hill · October 16, 2023, 03:23:27 PM

Junaido : You might just want to pull the engine (mentioned in another post - to replace the Xmission) to replace that stud!! It will make access MUCH easier!

A thought

Stu Jackson · October 17, 2023, 07:48:45 AM

Here's another reason to NOT use a bolt:

https://www.cruisersforum.com/forums/f54/sheered-bolts-exhaust-flange-280511.html

Shearing the head off a bolt seems harder to repair than cutting off a nut and clamping what's left of a stud. But maybe that's just me...

junaido · October 17, 2023, 05:02:05 PM

I went to the local plumbing store, the guy has various black iron nipples, elbows and a tee for about $50. I was thinking about maybe getting a short section of flexible hose and/or an adaptor to connect the water into this T. Is there any reason why the angled "Y" connection is a must-have for the water injection? Or will a "T" work OK ?
Thanks,

Junaid

Stu Jackson · October 17, 2023, 08:43:26 PM

I have seen a few Ts used for just that purpose on the internet and one in person: a friend bought a used M25 to replace his Atomic 4 in his Pearson 30; he put it on a dolly in garage to get it all set up and serviced before he put it in his boat...awesome, and that's what he used. All he did was thread a short piece of smaller pipe into the end of the T, to have the OD of that nipple to mate with the ID of the 5/8" HX output hose from the vented loop, ask your plumber friend how to do that. First time I ever saw it but have seen others online. Functionally see no reason it shouldn't work on our boats.

A few years ago I saw a nipple section of pipe offered for sale online. Maybe Westerbeke, don't think it was CD. You could look to see if it's still around - just a nipple into a short pipe section, but I don't know if the pipe was threaded at the top end.

Good luck.