I need a new exhaust mixing elbow for the 1980 Perkins 4.108. I have the elbow that connects to a five bolt flange via a short piece of 1.5" pipe with external NPT on both ends. I fabricated my own elbow from standard natural gas fittings but I cannot get the connection to the flange leakfree. I asked TA diesels for a quote and they want $ 271 plus shipping for just the elbow. When I read that I remembered why I fabricated my own elbow in the first place.
Does anybody have a Perkins part source with more friendly prices? And with shipping to the Netherlands?
This is a photo of the flange on the back end of the watercooled exhaust manifold (I already have this flange):
And this is the elbow I need (including the 1.5"NPT pipe connection and the 3/4" raw water hose connection):
Thanks for suggestions.
Unfortunately these parts for early Perkins 4.107 and 4.108 engines are becoming difficult to obtain, particularly the flange, and therefore dealers pricing has become expensive.
The flange has “standard” NPT. Those mixing elbows, like the one pictured, I think are aluminum. That’s a really poor choice of material for something you are going to run hot saltwater through. You would be much better served to have one built of stainless pipe (just my opinion). There are cast iron versions which work better and a Yanmar one would work well in your application.
The key to getting a good seal is the tapered thread and sealant. I use permatex ultra copper and it handles the heat fine. Make sure and use a stainless nipple between the flange and the elbow and it’s a good idea to wrap that with a heat shield. I use the same heat shield used by race car guys for header exhaust and it’s readily available from car parts places here stateside.
Last of all, I’ll look through my scrap yard and see what I have in terms of spares. If I have something you can use I’ll try and get it to an airline pilot buddy of mine and see if we can get it across the pond at least, I know he ends up in Amsterdam from time to time, England more often. I have another friend who has access to international shipping who sometimes does me a favor so with a little gultching we should be able to come up with a better solution for you. Let me do a little digging and get back to you.
Update: I don’t have one in my junk. The one on Marquesa looks like the one pictured (including the mounting spot for a temp sender) but ours is bronze with bronze pipe nipple connection.
Thanks for your replies, and George, many thanks for your visit to your ‘spare parts center’. As far as I know, the red painted elbow pictured above is cast iron. Aluminum elbows also exist, but these are unpainted, according to the photo’s on the TA Diesels website. The mixing elbow is no Perkins part (Perkins stopped at the flange) so there is no part number. There are numerous different mixing elbows used as you can see at TA Diesels.
I redid the exhaust gas leaking NPT pipe today with Locktite 570 (steam pipe sealant) but left out the hemp this time, so the threads have more contact with each other. All other connections on my mixing elbow (10 different parts all with NPT) I did two years ago with Locktite 570 and hemp wrapping (that’s how 570 has to be used, they tell me) and they are still tight.
The leaking connection however is turned loose time and again by the weight of the mixing elbow (actually it’s an S-pipe) hanging down. Vibrations turn the S-pipe so it becomes undone half an inch. Without the hemp, the S-pipe hangs straight down so it does not turn loose, I hope.
I indeed wrapped it in glass cloth heat wrap like they have on industrial engine installations with dry exhausts. I would have preferred an asbestos wrap because it looks more ‘marine’. ;^)
I will go through Robert’s links and see what I can find.
