Jake Brake valve cover question

richard5933 · February 19, 2018, 12:46:36 PM

Found a complete set of Jake Brakes for our 8V71. They came from Central Truck in MN, and they should be here soon.

The guy said that the tall valve covers he had were aluminum and included breathers. Our current valve covers do not have breathers.

Question is this...

Any reason to do anything about the breathers? Assuming they don't bump into something, can I just leave them in place. Or, should I follow his suggestion and have the openings welded closed by someone that can handle the aluminum welding?

I know that I'll have to fabricate a bump-out in the engine cover, but I have no idea how the breathers will play into things.

Geoff · February 19, 2018, 01:23:56 PM

They made covers for the breathers, but they usually come with the valve covers so you can switch the breather location. It wouldn't be hard to make one using the existing retainer ring and bolts.

luvrbus · February 19, 2018, 03:04:24 PM

Don't worry about the breathers the old 8v71 didn't have enough breather any ways,the only problem you will have is the location if the breather is on the top then it will interfere with the tail gate dog house and the upper bulk head.
You want the covers with the breathers on the side not the top those are not fun to cut a 4 inch hole in.
Like Geoff said you can try and find the relocation covers but I haven't seen any in years since the valves covers stopped coming with 2 holes.
Let me know if you need the side breather I have 8 sets of side covers with side mounted breathers and will trade you for the top mounted.
Keep the breathers on the valve covers then you don't need to worry about removing the breather on the back of the V71 to service it lol most people don't worry about it anyways I get those here no one has ever serviced caked solid because they never knew it was there

richard5933 · February 19, 2018, 03:38:57 PM

Quote from: luvrbus on February 19, 2018, 03:04:24 PM
Don't worry about the breathers the old 8v71 didn't have enough breather any ways,the only problem you will have is the location if the breather is on the top then it will interfere with the tail gate dog house and the upper bulk head.
You want the covers with the breathers on the side not the top those are not fun to cut a 4 inch hole in.
Like Geoff said you can try and find the relocation covers but I haven't seen any in years since the valves covers stopped coming with 2 holes.
Let me know if you need the side breather I have 8 sets of side covers with side mounted breathers and will trade you for the top mounted.
Keep the breathers on the valve covers then you don't need to worry about removing the breather on the back of the V71 to service it lol most people don't worry about it anyways I get those here no one has ever serviced caked solid because they never knew it was there

Thanks - I'll let you know when they get here if they are side mounted or top mounted when they get here. I also will probably need to swap the solenoids for 24v versions, since these are most likely 12v. Hopefully those are still available somewhere.

Otherwise, I think I've got a complete setup coming.

chessie4905 · February 19, 2018, 05:31:04 PM

On my 4905 with Jakes the breather is on the top of the upper cover, not on side of upper cover. Lower cover has none. Upper cover also has a plugged approx 1 1/2 inch hole. The upper breather has a 1 inch hose attached to it that runs down on back side of engine. I can remove upper cover if I disconnect hose. Tight fit, but it'll come out.

luvrbus · February 19, 2018, 05:51:06 PM

Quote from: chessie4905 on February 19, 2018, 05:31:04 PM
On my 4905 with Jakes the breather is on the top of the upper cover, not on side of upper cover. Lower cover has none. Upper cover also has a plugged approx 1 1/2 inch hole. The upper breather has a 1 inch hose attached to it that runs down on back side of engine. I can remove upper cover if I disconnect hose. Tight fit, but it'll come out.

The 1-1/2 inch hole is a oil fill hole

luvrbus · February 20, 2018, 05:07:50 AM

Quote from: richard5933 on February 19, 2018, 03:38:57 PM
Thanks - I'll let you know when they get here if they are side mounted or top mounted when they get here. I also will probably need to swap the solenoids for 24v versions, since these are most likely 12v. Hopefully those are still available somewhere.

Otherwise, I think I've got a complete setup coming.

If those came from a 92 series you are going to need bridges for a 71 series the 92 series bridges will not work on a 71 series

richard5933 · February 20, 2018, 10:35:15 AM

Confirmed today that the covers have the breathers on the side, and the bridges are from a 71. Should be good to go on both of those counts.

I did get a NOS fast idle buffer switch for the setup, at cost, from another shop in MN. Lucked into that. I think that the only thing I'll be missing are the solenoids, as the ones being sent are thought to be 12v and not the 24v needed. My assumption is that they can be found, perhaps even new if needed.

Anyone have experience making the needed extension on the engine cover to allow the taller valve cover to protrude? Or, does it just fit into the slight bump already present where the license plate mounts?

chessie4905 · February 20, 2018, 11:25:14 AM

The factory bulge won't even come close to fitting. Mine is rectangular shaped with no ends. Allows more engine heat to exit, I guess. Made out of aluminum.

richard5933 · February 20, 2018, 11:36:28 AM

Quote from: chessie4905 on February 20, 2018, 11:25:14 AM
The factory bulge won't even come close to fitting. Mine is rectangular shaped with no ends. Allows more engine heat to exit, I guess. Made out of aluminum.

How much further does the cover need to protrude? Am I correct in thinking that the opening from the factory bulge will be large enough to mount the new bulge, or will I need to open the rear of the engine cover further? If the taller valve cover will fit through the opening left after removing the factory bulge, it shouldn't be difficult to fabricate a new one that looks similar to the original but sticks out further.

chessie4905 · February 20, 2018, 03:48:29 PM

I went out and measured it. It sticks out 3 inches, is 34 inches long and 12 inches high. The attachment screws are out of site on top and show on bottom. License plate is mounted on it. This gives 1 inch clearance to valve cover with tailgate closed.

richard5933 · February 20, 2018, 04:07:32 PM

Quote from: chessie4905 on February 20, 2018, 03:48:29 PM
I went out and measured it. It sticks out 3 inches, is 34 inches long and 12 inches high. The attachment screws are out of site on top and show on bottom. License plate is mounted on it. This gives 1 inch clearance to valve cover with tailgate closed.

Thanks. That sounds like it's in about the same place as the factory bump. Were you able to keep the oil dipstick access door?

chessie4905 · February 20, 2018, 05:20:09 PM

The factory bump is removed and this cover, which is same length and almost same height, replaces it. The tailgate is not modified. Oil door and everything else unaffected.

richard5933 · February 20, 2018, 05:40:20 PM

That's great to hear. Thanks.

I've been slowly putting this project together, and I'm just about at the point where I've got everything in place. If the valve cover will fit through the opening left from the stock bump, then I should be able to remove the factory bump before having the Jakes installed so that I'll be able to close the engine cover on the way home.

My plan is to fabricate a new bump that mimics the factory one but sticks out far enough to house the new valve cover. I think if I do it right I can even maintain the license plate mounts and maybe even the lights, although the license plate lights may need to be aftermarket. I've worked with a really great fabrication shop in town and I'm sure that they can get this done with no problem. It's a smaller mom & pop type shop and they are pretty willing to work on oddball projects like this.

richard5933 · March 06, 2018, 01:40:57 PM

Just about to get this project install underway. Before I have a new bump out made for the engine cover, I thought I'd give one last effort in finding a factory bump out that will clear the taller valve cover.

I've seen photos online engine covers with the bigger bump out, so I'm assuming that they were available at one time for buses running Jakes.

Anyone know of any salvage yards that might have such a thing? Anyone have an engine cover for a 4108/4903/4905 with the bigger bump out that they don't need?