View original topic: Exhaust/Heater Box holes Page: 1, 2, 3, 4  Next
Goach2 Tue Feb 06, 2018 12:39 pm

So as I'm going through the engine, collecting the missing parts I need and reassembling, I'm starting to put thought into my next steps. First off, there is no exhaust attached from after the heater boxes. Even the heater boxes are missing the flanges. I also see a few holes on the other side of the heater boxes, where they connect to the 'U' shaped pipes.

I have 'zero' exhaust experience, so I'm hoping for some advice here. Do I need to replace the heater boxes themselves, or can these holes/flanges be repaired? Do they need to come off the engine, if so I'll likely need to replace some of the other tubing. Does the engine need to be dropped to do this kind of work?

I can take some pics if it will help to assess.


orwell84 Tue Feb 06, 2018 2:35 pm

Yes pictures as well as year and engine type, Sounds like late 70's 2 litre...

Goach2 Tue Feb 06, 2018 3:48 pm

You are correct sir; 1977 2.0L

BUSBOSS Tue Feb 06, 2018 3:54 pm

This diagram should help you.

Engine does not need to be dropped although it saves the back if you can work with the bus on a lift.

I would replace the entire heat exchange/exhaust given the photos. (Edit: Although your J tubes look ok.)

orwell84 Tue Feb 06, 2018 3:54 pm

Your heater boxes still have their flanges. They are still attached to the flanges of the rest of the exhaust system. I'm not familiar with this system. It's more complex than earlier type 4's but there are work arounds and many options. I don't think you will have to drop the engine to repair it.

Others will be along shortly to sort you out. Cheers.

Goach2 Tue Feb 06, 2018 3:56 pm

Awesome, thanks Busboss. Is there a legend that goes with it?

orwell84 Tue Feb 06, 2018 4:14 pm

Your engine uses cylinder heads with square exhaust ports. Sometimes people replace them with the type of heater boxes pictured above. They are expensive but allow you to bolt on an exhaust system for a 73-74 bus which is ultimately cheaper and much less complex. I don't know what smog rules in Ontario are now, but when I lived there in the 90's they never smogged my bus and didn't have yearly inspections. There are also pipes that will fit your bus that eliminate the heater boxes entirely. Way cheaper, but of course, no more heat.

The above are pictured with oval ports, but I think they make them with square ports, which is what you would need.

Goach2 Tue Feb 06, 2018 4:21 pm

Thanks Orwell84, I will have to look into the feasibility of an earlier exhaust. Even though it says '78 1/2 this will fit my bus for sure?

They don't smog test vehicles this old, so that's an option...

Looks like a used system might be my best bet, just may take some time...

orwell84 Tue Feb 06, 2018 4:47 pm

Check the Samba classifieds for used heater boxes.

BUSBOSS Tue Feb 06, 2018 5:50 pm

Goach2 wrote: Awesome, thanks Busboss. Is there a legend that goes with it?


If your current set up is 77 model year then you will have round/oval exhaust ports and not the square ones noted above.

Wildthings Tue Feb 06, 2018 6:20 pm

As far as the big hole in the top of each heater box, you can just block that off if you like, the complete booster fan system adds only a tiny amount of air flow through the heater system when at idle. Above idle it does little at all.

orwell84 Tue Feb 06, 2018 7:08 pm

I am using the European motorwoks j-tubes. They fit well and I use a BN4 gas heater for all my heat. It keeps the bus warm enough to drive at about the freezing point with a light jacket. I am repairing a set of heater boxes and have found most of the heating system parts. Using the tubes has bought me the time it takes to get everything together and do a good job.

Goach2 Tue Feb 06, 2018 8:26 pm

I doubt that I'll be driving this in the winter, but in Ontario, the heating system has to be intact to defrost if it's going to pass safety...

Hoody Wed Feb 07, 2018 6:32 am

Given the condition of your original exhaust my advice would be to source the 72-74 engine tin necessary to switch to the earlier system. You will need two heater boxes a muffler and a tail pipe. This will be much less expensive than trying to source all of the pieces for the 75-78 system. All of the pieces are available new for the 72-74 system. The challenge will be the engine tin. Contact Scott at German Supply, he may have the tins you need. Your current system is completely shot.

Goach2 Wed Feb 07, 2018 8:28 am

Thanks Hoody, good suggestion.

I see Scott has a conversion kit:

I'm assuming I will still have to source the correct heat exchangers for my year?

Wildthings Wed Feb 07, 2018 10:17 am

Goach2 wrote: Thanks Hoody, good suggestion.

I see Scott has a conversion kit:

I'm assuming I will still have to source the correct heat exchangers for my year?

No you want the entire exhaust for the 72-74 including the heat exchangers.

Hoody Wed Feb 07, 2018 10:58 am

PM me if you need help. I just wrote 2 paragraphs twice only to have them disappear because of some stupid time limit on responding to posts! WTF???

Goach2 Wed Feb 07, 2018 11:20 am

Sorry to hear that Hoody, I'm sure it was wise advice you were trying to share ;)

Wildthings, I've read that my ports are square where earlier are round, does this mean new manifolds as well? ie everything after the heads?

edit: sorry I guess it was confirmed to be oval not square ports above...

orwell84 Wed Feb 07, 2018 11:53 am

Square ports refer just to exhaust. Curious about your bus; where it came from, new project or an old one. Does it have a gas heater. I think Canadian models came equipped with one. I found a few gas heaters in junkyard buses in the Montreal area. People don't know how to tune them and leave them for dead when they stop working. I found one with an old sock stuffed in it that was fairly easy to bring back to life.

Goach2 Wed Feb 07, 2018 12:00 pm

Ok, sounds like I need to look for everything from '72-'74 heat exchangers to tail-pipe with a conversion kit from GS.

I picked up the bus a few months back from Gatineau, Quebec. The engine was picked over, so it's a new project. It has the underside gas heater, which looks to be in pretty good shape, from the undercoating that protected the whole underside.

I haven't decoded the VIN yet to get all the history, but it's 2372058799.

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