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Discussion Starter · #1 ·
I am in the process of doing a frame-off, clean-up, repaint of my 1984 CJ-7. I bought the Jeep in 1987. I converted it to an automatic with a Chevy 350 and a 700r4 with the stock Dana 300 about 20 years ago. The engine was from a 1985 Corvette. The engine smokes on the drivers side, but it runs good. I am trying to figure out what I need to do to the engine. I can't afford to do an expensive engine rebuild and I am planning on doing the work myself. I have not rebuilt an engine before, but I have watched some videos and I am sure I can do it.

I would like to change the cam for lower end power.

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Tire Wheel Automotive tire Vehicle Hood

I would appreciate any tips or suggestions.

Thanks.
 

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1974 Jeep CJ-6
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Buy a leakdown/compression tester before tearing too far into the motor. Check the leakdown and if those numbers are good, hopefully all you need is new valve seals. But likely your best route is to pull the heads and take to a machine shop for a good rebuild, valve job and new seals. Then you can stab in a new cam and put it all back together and enjoy it for another 35 years.
 

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Smoke from a single bank is helpful. I would start by inspecting the plugs. A single wet plug will isolate where the issue is.
Possible blue smoke issues:
Bad valve seals
Bad oil control rings
external input, such as a PCV line on a single runner

Blown head gasket (white smoke)
Siamesed plugs can indicate a blown head gasket as well

From there a compression test would be nice.

Insure you install new lifters on your new cam.
 

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Discussion Starter · #4 ·
Smoke from a single bank is helpful. I would start by inspecting the plugs. A single wet plug will isolate where the issue is.
Possible blue smoke issues:
Bad valve seals
Bad oil control rings
external input, such as a PCV line on a single runner

Blown head gasket (white smoke)
Siamesed plugs can indicate a blown head gasket as well

From there a compression test would be nice.

Insure you install new lifters on your new cam.
Thanks. It is white smoke. Can I use a leak detector on it if the engine is not running? Would it work if I reinstalled the starter and then used the starter to build compression in the cylinders?
 

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2023 Grand Cherokee
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I wouldn't always say this, but in this specific circumstance, I think I will...

Just pull the heads. You may very well have a bad gasket. But let's say that you don't...

Back in my day, which was about 2 months after we discovered fire, an engine refresh looked like this:
  1. Yank the heads and send them out for a cleanup & 3-angle valve job. Seats if you need them, stem seals as an automatic item.
  2. Rings and bearings. If the engine was kinda beat, maybe you send it out to a shop to be hot-tanked, bored .030, and do a ring & piston kit. If not, you just got a ring & bearing kit, ball-hones the cylinder walls, and put it all back together.
  3. Re-ring kit is probably $100-125. Full on piston kit is probably around $400. You can spend more, but if you're not on a budget, then you should just buy a warrantied re-man.
  4. You COULD put in a new cam, but even with a mild one, to make it pay off, you'd also want to put on a better intake manifold, and an Edelbrock carb if you don't already have one. I say Edelbrock, because those are basically Carter AFB's, and they are better for off-roading than Holleys. Oh, and shorty headers, unless you have a set of Rams Horn exhaust manifolds laying around.
That's a pretty good budget build right there. Remember, it's a Jeep, not a Car. You shouldn't really be spinning the engine all that fast anyway. Mainly you just need reliable low-end grunt.
 

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Discussion Starter · #6 ·
I wouldn't always say this, but in this specific circumstance, I think I will...

Just pull the heads. You may very well have a bad gasket. But let's say that you don't...

Back in my day, which was about 2 months after we discovered fire, an engine refresh looked like this:
  1. Yank the heads and send them out for a cleanup & 3-angle valve job. Seats if you need them, stem seals as an automatic item.
  2. Rings and bearings. If the engine was kinda beat, maybe you send it out to a shop to be hot-tanked, bored .030, and do a ring & piston kit. If not, you just got a ring & bearing kit, ball-hones the cylinder walls, and put it all back together.
  3. Re-ring kit is probably $100-125. Full on piston kit is probably around $400. You can spend more, but if you're not on a budget, then you should just buy a warrantied re-man.
  4. You COULD put in a new cam, but even with a mild one, to make it pay off, you'd also want to put on a better intake manifold, and an Edelbrock carb if you don't already have one. I say Edelbrock, because those are basically Carter AFB's, and they are better for off-roading than Holleys. Oh, and shorty headers, unless you have a set of Rams Horn exhaust manifolds laying around.
That's a pretty good budget build right there. Remember, it's a Jeep, not a Car. You shouldn't really be spinning the engine all that fast anyway. Mainly you just need reliable low-end grunt.
I agree about the low-end power. I considered a Chevy 400 but I already have the 350 engine, plus it sounds good to say it came from a Vette. Do you have specific cam you might suggest? I have a Holley TBI, but its probably 20 years old. I'm sure there are better ones available today. Thanks.
 

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I agree that you should get the heads done at a shop and then rering and bearing the short block. You can totally do a cam and nothing else - as mentioned above it won't give you as much but certainly will change the entire nature of the torque band. No matter how you slice it and dice it redoing an engine is not cheap. If you want to take a punt on it you could do a hone yourself (not advisable) and just slap in new rings and bearings. But it would be better to measure bores, determine if they need a bore or just a hone, and then have that done on a machine. On the bottom end, since its not making noise and I assume has good oil pressure, you could put in new bearings and check each one with plastigauge.
 

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Does the Holley TBI still work?
Because if it does, just stick with that.

As for a cam suggestion, I haven’t kept up on the latest stuff out there. Hell, I still think of camshaft specs at zero lift, not the .050” lift everyone uses today.

I can think of a good argument to make in favor of a regular flat tappet cam, and a different argument to make in favor of a hydraulic roller cam.

if I was in your shoes, I might just call a few different camshaft manufactuers, and ask them for a suggestion. You should see a clustering of suggested specs in a fairly narrow range.
 

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Comment?

$1,000 seems like a lot of money for a cam, when a traditional flat tappet cam is going to be around 10% - 15% of that cost.

Not criticizing roller cams per se, but I am questioning how that fits into your stated plans.
Plus, if I were going to put a $1,000 cam into an engine, I wouldn't want to put it into a budget rebuild.

Calling a parts SELLER like Summit or Jegs is not as useful as calling a maker like Comp, Lunati, Lingenfelter, etc.


That's just my opinion of course, which is worth exactly what you're paying for it. 😁
 

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Discussion Starter · #12 ·
Comment?

$1,000 seems like a lot of money for a cam, when a traditional flat tappet cam is going to be around 10% - 15% of that cost.

Not criticizing roller cams per se, but I am questioning how that fits into your stated plans.
Plus, if I were going to put a $1,000 cam into an engine, I wouldn't want to put it into a budget rebuild.

Calling a parts SELLER like Summit or Jegs is not as useful as calling a maker like Comp, Lunati, Lingenfelter, etc.


That's just my opinion of course, which is worth exactly what you're paying for it. 😁
I just got off the phone with a local machine shop and the topic of flat tappet cams and hydraulic cams came up. He said that across the industry people have been having problems with flat tappet cams and it is because the EPA mandated zinc be removed from oils. He said people either did not know that or did not add the appropriate additive for the break-in of the engine. But, I do agree that the Comp Cam is expensive. I'm going to tear the engine down this weekend and take it to the machine shop and start by getting everything cleaned and measured. They are good people and will, hopefully, help me through this process.
 

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Discussion Starter · #14 ·

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That’s a much more reasonable price, though I’d suggest you see what that same part number costs at Jegs/Summit.

I think your best bet is to see what your engine looks like inside, before deciding on parts.
Don’t forget that if your head are basically in good shape but your block needs a lot of work, you can get a short block, which will already come with a cam. Or vice-versa.

See what you’re working with first, THEN start making decisions.
 

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The best advice given so far was in post #2. Sometimes simply pulling and checking the plugs will identify a problem with a specific cylinder.

A leakdown test is easy, doesn't require a running engine, and will likely pinpoint the source of the smoking problem. It will also tell you the general sealing condition of all of the cylinders.

Some auto parts stores will rent a leakdown tester. You will need a compressor with the proper connectors.

Matt

Product Gauge Vehicle Measuring instrument Wood
 

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I am in the process of doing a frame-off, clean-up, repaint of my 1984 CJ-7. I bought the Jeep in 1987. I converted it to an automatic with a Chevy 350 and a 700r4 with the stock Dana 300 about 20 years ago. The engine was from a 1985 Corvette. The engine smokes on the drivers side, but it runs good. I am trying to figure out what I need to do to the engine. I can't afford to do an expensive engine rebuild and I am planning on doing the work myself. I have not rebuilt an engine before, but I have watched some videos and I am sure I can do it.

I would like to change the cam for lower end power.

View attachment 4179155
View attachment 4179154
I would appreciate any tips or suggestions.

Thanks.
One thing to always remember is when you put a bigger engine in the vehicle it is not what it was designed to use and it will inhibit the life expectancy of the rest of the running gear.Not to mention it is easier to damage it.
 

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Discussion Starter · #18 ·
One thing to always remember is when you put a bigger engine in the vehicle it is not what it was designed to use and it will inhibit the life expectancy of the rest of the running gear.Not to mention it is easier to damage it.
It is a 1984 CJ-7. I bought the Jeep in 1987 and it came with a stock 4 cylinder engine, which was an absolute POS. I had the 350 installed in the mid to late 90's. I have put it through quite a bit. However, I did quickly need to replace the two piece axles. I run 33" tires and I don't try to break things, but it is definitely stronger than the stock engine.
 
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