Intake plenum cover

[Tsapnin]

Been lurking in the shadows. This place has done me quite a service. I've been wading through a lot of POW and replacing and repairing what feels like, and may be, every component of my steering, suspension and braking systems. The bad news was it all needed replacing. The good news is the last guy only ran bolts up finger tight so disassembly is a breeze. Pulled the power steering pump out with no wrenches an one hand. Pretty neat. But pretty scary.

So now that I've addressed the issues of steering and stopping (oh yeah and replacing the bailing wire throttle linkage) I figured I'd try to sort out some of the other Frankenstein problems. For this post: intake plenum cover.

The truck is a 91.5 ic 4x4 manual swap with a 93 gas truck body. I noticed that my master cylinder interferes with the piping from my turbo inter cooler to the intake horn. The horn wants to connect about a half inch to the rear of the front of my master cylinder. "No problem" said the PO, "we'll just stick a longer rubber boot in there that will press against the master." Thanks again friend.

From looking at pictures it appears that I have the intake plenum cover from a non I/c truck--I believe the difference is that non ic intake ports are located with their center between the third and fourth valve cover- exactly halfway front to back-- whereas I/c trucks are about 2.5 inches forward which gives clearance for the master cylinder.

This theory is based on google image searches.
Here are my questions:
1. Does this theory hold water?
2. Why can't I find first gen plenum covers-- let alone ic or non ic specific ones?
3. Do second gen covers work? Their intake appears to be at the second valve cover back. What kind of effect does the location of the intake port have on the flow to the cylinders?
4. Where can I get a bad boy intake plenum cover and or an oem one that will give me the clearance I need?

Any info would be appreciated!
Thanks,
Tsapnin

[Nughuffer]

Non-ic plenums are set rearward towards the firewall. Not 100% sure why as I have a IC truck but maybe to clear the hood and/or line up square with the compressor outlet?. They can be found on ebay from recyclers or aftermarket ones can be found from a few different vendors. Not sure on $$ though.
Pick up a 2nd gen airhorn preferably from a 24v. 2nd gen 12v horns will work but you will have to cut off the large mount that extends outward towards the radiator as it wont quite clear the 1st 3 injection lines. As far as I know the 24V air horn bolts right up and they are both offset forward to account for hydroboost in the 2nd gen so they should easily clear your master if you only need 1/2". I saw one on cumminsforum.com the other day for $30 shipped.

Edit: Def look for a 24V horn. I don't think a 2nd gen 12V will work in your situation unless you want to cut it all up. Sorry..

[Tsapnin]

Found this: https://puredieselpower.com/dodge-produ ... oduct/7664

The installed picture on that page looks like the port is even further forward than the stock ic plenum covers. Pictured here:
http://i116.photobucket.com/albums/o28/ ... 009572.jpg

The routing on my injector lines would interfere. So looks like ill need to find a set like the ones in the second link there that all pass behind the first valve cover. How do I specify that and where can I buy them or should I just bend them up myself?

What effect on even-ness of flow to the cylinders will the intake port being so much further forward have? Anything appreciable?

[Tacoclaw]

I wouldn't sweat the $300 intake unless you're building some sort of ridiculous race truck.

Does your truck have a fan shroud? My neighbor had a cummins swapped into a gasser and they used the gasser piece that goes between the mount and engine block. It set the engine up too high and not only made contact between the fan and shroud, but also the intake horn and MC. It's worth a check.

[cmann250]

1. Welcome!

2. Do you have a picture of the issue? It almost sounds like the intake plate could be flipped around to get things to line up.

Just an FYI, there is a huge hump the air has to go over inside the head to get to cylinder 1. That's where the bulk of the restriction is.

For reference, here's what I have:



It's 9-1/2" from the front of the cover to the grid heater. This is a non-intercooled engine originally.

[RCCUMMINS89]

We need a "thank you" button.... good post Caleb.

[Tacoclaw]

The second one of those turns up I'm outta here.

^...is that going to make one show up sooner...?


Regardless, I knew Caleb had this on lockdown. He showed me that handiwork when I was at his place.

[RumbleFish]

All i know is, somebody need to keep him from the rattle cans. Did helen keller pick those colors??

[RCCUMMINS89]

[cmann250]

I am at fault for the valve covers and the valve covers alone. Everything else is the same color as it was when purchased. Do not fear, I hung up my aerosol cans long ago

[PToombs]

Nice gay purple wire on the dipstick. What's that all about?

[cmann250]

It's gone. That piece of fender is holding the dipstick tube now.

[Tsapnin]

Thanks guys. A mans valve cover color choice is a private and personal one that ought not be discussed in civilized company.

Looks like I have the plenum cover and injector line routing off a non ic truck... Which is strange. It would make you think that it started out as a non ic truck. But I got injectors off the engine serial number and they are for sure the ic 7mm. I thought about flipping the plenum around but there's little details like bracket mounts for the throttle linkage and injector lines I'd rather not deal with.

I called crazy carls turbos and his fancy plenum cover won't clear my lines BUT he is sending me a stock ic plenum cover he had lying around. Pretty awesome.

I am in fact missing my fan shroud. What a world. The life this truck has lived is one of abuse and half-assery. I believe the engine and frame were originally one unit and the gasser donated only it's body. How would i go about proving or disproving that? Many mysteries to unfold.

Caleb, where did that intake horn come from?

For my next trick I will attempt to post photos in the body of this very message:





Don't mind the cowboy wiring. I was on the road trying to ground my regulator to quite literally everything. Didn't work. Still charging high at almost 16. Not a bad reg. not a bad alt. and all my grounds check out....but that's another post for another time

So on a second gen plenum is the port so far forward to compensate for the hump to get to cylinder one? I just want to educate myself a little more... Or rather be educated by y'all as long as I've come this far.
Thanks again guys.

[cmann250]

Caleb, where did that intake horn come from?

A 1994 Cummins-powered Ram.

I see now that flipping the cover around will do you no good. It enters right in the center.

Also, to thicken the plot, it looks like you have a non-IC injection pump and an intercooled vacuum pump.

[PToombs]

Definitely some abuse and 1/2 assery going on there! Something is wrong with the intake tube /master cylinder deal. I almost think the brake booster is wrong, it looks too deep or something.