[magnuman]

Welcome to the forum. I'd be surprised if it is the intake manifold gaskets on a 5.7, unless the bolts are very loose. If it were a 6.1, I'd bet that was the problem. Intake gaskets on the 5.7 are really good and the 6.1's are totally different and often the port sealing rubber parts get ingested into the engine and cause massive leaks at the ports, even if the bolts are tight. You can check your 5.7 by using soap bubbles when the engine is running. You won't be able to check under the manifold, but you will be able to check between the intake and the valve covers. Also, check to see if the bolts are properly torqued. If you have access to a smoke tester, you can try that too.

 

[magnuman]

OK, the design is different between the 5.7 and 6.1? I think I will pull that manifold and look anyway, I am no sure this engine is original to the car so maybe the manifold has been bodged onto the wrong kind of motor or something.

edit: for a smoke test, is it enough to block off the PCV and air balance tube and see if the smoke is getting into the manifold? If the smoke is getting past the rings or valve guides or whatever what could I do to narrow it down other than maybe pulling a few spark plugs?

What year is the vehicle? Can you see any evidence that the engine has been tampered with or possibly removed? What does the odometer say for mileage? Does it look like it has been properly cared for or does it appear to be neglected? Have you checked for Diagnostic Trouble Codes?

The design between the 5.7 and 6.1 are basically the same, but the intake manifolds and gaskets are considerably different....5.7 is plastic with o-ring type gaskets and the 6.1 is an aluminum manifold with real crappy aluminum gaskets that have lousy rubber seals surrounding the ports. See the pix below of when I took my 6.1 apart. Most of the rubber seals had been ingested through the engine, and the others were all distorted and half gone. The engine did have about 165K on it and probably never been touched.

Unless someone has grossly neglected the engine over a long period of time, I doubt you'll have a problem with the bottom end, the pistons/rings. If it has over about 100K you'll probably have some bad valve guides. If it's an 05-06 or early 07, dropped valve seats can be a problem, especially if the engine has been overheated.

The things you can do to determine the basic condition of the engine and find where the leak is coming from is to do a compression check first then, perhaps a cylinder leak down test if the compression is not real good and, finally, a smoke test if you're unable to find anything. You could also start with a smoke test if you wanted, but I wouldn't. Usually, a compression check and leak down test will tell you everything you need to know though.

FYI, 5.7's have an EGR Valve on the front passenger side head, as said, a black plastic intake with the PC Valve on top rear of the passenger side. 6.1's have the aluminum intake, no EGR Valve and the PC Valve is located on the front passenger side.

Smoke testing an engine is kind of redundant, a PITA and time consuming because you'll need to isolate each cylinder and check them one at a time with both valves "supposedly" closed....top dead center on the compression stroke. This is better done with the cylinder leak down test. IMO, the smoke test is best for checking for intake/exhaust leaks and such.

On a 5.7, the PC System and, especially the PC Valve, are one of the biggest weak spots on a 5.7. It's difficult to determine if the valve is good or bad, because the spring in it is so weak to begin with. After time it gets weaker and the old method of "shaking the valve" is not an accurate way of checking them. I've never seen one that didn't shake, no matter its condition. Just change it every 15-30K and be done with it. You'll be able to see how bad the PC System is by looking at the back side of the throttle body butterfly. It'll be all caked up with crud and, worst case, there will be oil puddling in the intake manifold plenum.

 

[magnuman]

I think I'd first take a look at the PC Valve and replace it. Have to go now but will be back later.

 

[magnuman]

It just seems like waaaaay too much oil for a PC Valve. I'm thinking valve guides/valve stem steals.

How hard is it to pull the heads with the engine in there? My next move seems like it should be compression test all the cylinders, and if they come up good (which is likely given it runs strong even with the oil getting sucked through it) then pop the heads and do a valve job. Thanks for the pointers so far!

Don't get too hasty about pulling the heads. Troubleshoot the easy, inexpensive stuff first. Do the compression and, if necessary, the leak down test before you start tearing into things. IMO, this should be the next order of business.

As far as the PC System goes, the Hemi's have about the worst system possible and it's not uncommon to have puddling in the intake plenum. If the valve is stuck open, that amount of oil would not be out of the ordinary. Many of us with the Hemi's put catch cans on them to catch most of the oil that gets past the valve. This catch can goes in series between the PC Valve and the intake manifold. The catch cans seem to work pretty well and keeps most of the oil out of the intake....as long as it's serviced properly. Winter months generate more oil/condensation than summer months, unless you live in a very humid/damp area.

Valve guides may be some of the problem, but not to the extent that would cause that much oil contamination. I would also be surprised if the valve seals are bad too, again, unless it has been grossly neglected, been overheated or has a zillion miles on it. The valve seals on my 6.1 with 165K on it were still good. When I changed valve springs on both of my 5.7's (both under 100K), all of those seals were good too.

If the engine is a 2005, pulling the heads at some point may be a good idea, if for no other reason, to replace the valve seats. IMO, this should not be done until you've fixed most of the other problems you find and have found, and insured that the vehicle is fairly sound and worth throwing more $$$$ at it. Pulling the heads and doing seats, and a valve job could end up costing you around $2000, including the top end gasket kit. R and R'ing the heads is not overly difficult or time consuming, but you'll need to have a pretty good assortment of tools, including a good torque wrench.

magnuman said: "I think I'd first take a look at the PC Valve and replace it. "

+1
Results of a compression test are good to know, no matter what. However, before pulling heads or any more dismantling.... a PCV valve is cheap and easy... and should be replace as part of routine maintenance anyway.

All of this is true. I do compression checks on mine about once every other spark plug change....while I am changing them. That is about a 60K interval. As far as compression goes, know that altitude and weather conditions both have effects on your compression pressures and, if they're a little low, may need to be taken into consideration. I live at nearly 3000 ft. elevation (most of my driving is at 2500-4500 ft.) and my "normal" compression pressures are lower than that of someone's who lives at or near sea level. I am so use to driving at altitude that, when I drive one of the Hemi's down near sea level, it's like someone put a new high performance engine in it.

 

[magnuman]

I'm going half way. New pcv ordered and will take a punt and just change the valve seals since its fairly simple and i have the tools handy.

I figure if the guides are bad the seals will still work ok for a few months until i get a chance to pull the heads.

Engine actually looks ok inside, no obvious signs of overheating or damage so far and it runs very quietly, no valve chatter or tick so I think the guides are probably ok.

The valve train "valley" does look pretty clean, so it may not be in as bad shape as you think. Good to start with the PC valve.

You won't be able to EASILY change the valve seals UNLESS you have compressed air and a special "heads on Hemi valve spring compression tool".....about $150-200. Otherwise the heads have to come off to do the job.

 

[magnuman]

Yep, that looks like a good one too. When I did mine about 10-11 years ago, the tools they had weren't that good. Be sure to have a some spare valve spring retainer "keepers" just in case you drop/lose one or two. Also, while doing the job, plug all the oil drain back holes and bolt holes that are big enough for one of them to fall into.

 

[magnuman]

No preference really. The ones in the picture look more "high end" than the ones on both of mine. Mine look the same but don't have the little spring tensioner on the top where it seals the valve stem. The factory ones are like the ones I have on mine. FWIW, when I pulled my 6.1 heads with 165K on it, the valve seals were all still good, pliable and no oil getting past them.

 

[magnuman]

You really should do the compression check first.....and a cylinder leak down test if needed. Yes, the only way you can do the valve seal replacement with the heads on is with the special tool. You'll also need a compressor and a way to pressurize each cylinder you're working on. Pull one spark plug from each cylinder, bring the piston to top dead center on the compression stroke, insert your spark plug to air hose adapter, pressurize the cylinder and have at it. The most difficult one is the exhaust valve on the No. 8 cylinder.

 

[magnuman]

You're right, that's definitely the wrong type seal. The hat type are the correct ones.Can you see any of the others without tearing into it any more? Maybe someone just changed one or two for some reason.

 

[magnuman]

All of the heads will pretty much interchange. It's pretty east to tell the 09's and the SRT8's from the early ones. The later and SRT8 ones do not have an EGR Valve on the front of the passenger side head. The early 5.7's all had the heads drilled and fitted with EGR's. Port sizes are also larger and different, "D" shaped ones on the later/SRT8 ones. The valve springs in your picture look like stock early springs with the skirt on them to keep them from distorting. Stock, my 05 Hemi had the skirts and stock on my 06 5.7 didn't have the skirts. The later ones, SRT8 ones and aftermarket springs don't have the skirts on them. I have aftermarket springs with the hat seals on both of my 5.7's.....6.1 springs on one and PAC 1232 ones on the other...no problems at all.

 

[magnuman]

Yep, that'll for sure cause problems. If the cylinder wall is not damaged, and the rest of the engine is sound, you may be able to hone that cylinder and install a new piston to make it happy again. Be sure to check EVERYTHING though, before you go forward.

 

[magnuman]

I think, based on your findings and the fact that you're going to end up pulling the long block, I'd pretty much do a complete rebuild.....at least all new pistons and rings, either stock or a slight bore to increase the displacement. If the vehicle has had relatively good care in the past, especially oil changes, the rest of the rotating assembly is probably good and may not need anything. Just be sure to take your time and check everything.

 

[magnuman]

Yes definitely new pistons/rings at the minimum. Needs a water pump and some of the water jacket looks a bit clogged so will rod that out. Bought an engine stand yesterday so just have to phone a friend to help me pull the block. Had a mechanic take a quick look and he said the bores were fine, can still see the factory cross-hatching on them so it's good to go with just replacing the pistons.

The cylinder head on the other hand will need some polishing work to try and get it as smooth as possible, and one of the valves has some slight seat damage so will need to address that (potentially the valve itself is bent but more likely the seat damage is causing problems). In an ideal world I would put a stroker kit in there but money is an issue with this vehicle so a decent repair will do for now.

Hone the cylinders again to rough up the cylinder walls and remove any glazing that has happened over the years. IMO, no on the stroker unless you're going to get "all in" on hopping it up. You can get good power out of the stock rotating assembly and heads with a good cam, header back exhaust and tune....plus a few more "low yield" performance goodies. I am talking 425-450 hp. and maybe more. If you install forged pistons you can even go with forced induction and/or nitrous oxide injection and get over 500 hp. out of it. All it takes is $$$$$.

 

[magnuman]

It really depends on your ultimate plans for the vehicle and your pocketbook. Going "all in" is not an inexpensive endeavor. A good set of forged pistons will run you close to $1000, U.S for Mahle or Wiseco's. If you go .020 in. over, you'll be adding the cost of re-boring, but you'll also be able to get pistons with a slightly higher compression ratio, if you desire and are going to remain normally aspirated. Then, of course, you'll want to get a performance cam, pushrods and lifters, and that'll run you another 1200-1600, U.S. You're already doing the heads at whatever cost. Once together, you'll need a tune (or tuner) and a good header back exhaust system. Those can quickly get up over $2000-3000, U.S. in a big hurry. Then, if you want to go with forced induction or NOS, you'll be spending another $600-1000 for a complete NOS system or probably $7000 plus U.S. for a complete positive or variable displacement forced induction kit.....IMO, preferably a positive displacement one. Personally, I've stayed away from forced induction and NOS because I didn't want to go to the expensive when the rotating assembly is still in great shape. If I were in your circumstances, I'd probably at least think about forced induction.

Also, if you end up getting it all, you'll need to make modifications to the transmission too, so it'll support the added power. Depending on how much power you're adding will dictate how much you'll have to do to the transmission. A shift kit and AMG shift solenoids, and tune will cost less than a complete performance overhaul. Here you're looking at about another $2000-5000, U.S.

Going to be interesting and fun to see which way you end up going with yours.

 

[magnuman]

"Stick to the original plan?" I don't know about you, but I have always found that to be a difficult thing to do when I am modding my vehicles. More power to you, if you can. For me, it always seemed to be, "since I am doing this, I might as well do that or, while it's apart, I might as well do this too." Heck, I've had my Hemi Magnum since new (over 18 years now) and I am still messing with it periodically, just not as much. On my Hemi Grand Cherokee Jeep, I spread the "serious" modding out over about a 10 year period, spending about $1000-1500 a year on it. Fortunately, I have them both just the way I want them now.....and that has made my wife very happy......and me too.

 

[magnuman]

Good show, keep winning streak going. You should have a good runner when done.

 

[magnuman]

1978 VB Holden Commodore this morning, really sweet little car with a 5 litre V8 / TH400 combo. It's not running right so we might chase up some plug leads and plugs and give it a tune. Somebody replaced the original points ignition with a modern electronic one and didn't bother to hook up the vacuum advance so I assume the timing is out completely -

Be sure to hook that vacuum advance up to "ported" vacuum......very slightly above the throttle body. If you don't you'll have full vacuum advance at idle (much faster than it should be) and it'll never run like it should. At idle it should run at the initial idle advance setting before top dead center. Once the throttle is opened (takes very light throttle) you'll get both centrifugal (mechanical) and vacuum advance. At higher throttle settings and wide open throttle (lower vacuum), you'll just be running only on certrifugal advance.

Many folks used to just hook the vacuum advance up to any vacuum source and think it should work fine. Vacuum advance is there mainly for economy purposes. Running without it is not a problem but, if he's after performance, he should have the distributor set up on a distributor machine (by someone that knows what they're doing) so that the advance curve (how much and how fast [RPM] it advances) is optimal for the cam timing, the type fuel and other engine specifications. Probably not too many of them around these days though.

In the "old" days (60's through about early 80's), they used to sell generic pre-set advance "curve kits" that kind of worked, but usually not optimally. They usually just brought full advance on quicker (at a lower RPM) but, in many cases it would cause pre-ignition because of being too much, too soon.

 

[magnuman]

Do you know the "List No." on the carburetor? Is it a spread bore type? Ported vacuum (Holley calls it "timed spark") will always be on the butterfly base (throttle body) on the primary side of the carburetor. Depending on which model Holley he has, it's normally under the primary float bowl or maybe slightly at an angle near or under the float bowl. Holley's description is as follows:
"On carburetors equipped with timed spark advance (no advance at closed throttle) a port in the throttle bore is exposed to vacuum as the throttle plate moves past the port....usually slightly off idle."

On your Hemi, be sure to follow the FSM torquing procedure and at least double torque the heads, as if you only do the sequence once, the center bolts will end up with less torque than the bolts toward each end. On the final step I usually do the sequence 3 times, just to make sure all bolts are torqued evenly. Also, be sure to use engine assembly lube on all contact (metal to metal) points on the valve train, including push rod ends, rocker arms and valve heads. At least double torque the rocker shafts too. If you're using new lifters, do not run the engine above about 1400-1500 RPM for about the first 15-20 minutes. This will insure the lifters are pumped up enough to avoid any piston to valve collisions.

Good luck on the reassembly and have fun!!

 

[magnuman]

Will grab the part number off that Holley. Trying not to get too involved got enough problems of my own, fun toy though.

I think the chrysler is lubed right. That 90 degree final torque is quite the effort at step 3!

I really like the older stuff.....easier and more fun to work on, plus not nearly as frustrating. Also, none of the electrical/electronic mumbo jumbo stuff on them. Does the Commodore have the GM HEI distributor on it? I am guessing yes, unless someone went back to the old style one.

 

[magnuman]

You sound too ambitious. You should relax on your holiday and have a beer or two....or three or more. I used to be that way (ambitious) too but have slowed down a lot over the years. Now it's, "tomorrow is another day."

That distributor sounds like the stock GM High Energy Ignition (HEI) unit. They were pretty good units and, for sure a lot better than the earlier ones with breaker points. The centrifugal advance mechanism in them is almost exactly like the earlier GM distributors that ran external coils and breaker points or electronic ignition modules. The ignition module in the HEI is also similar.....no breaker points. to wear out.

A little gee whiz side note on these ignition systems, FWIW. Back in the mid 80's I bought a 77 Cadillac Seville for $700 U.S. that wouldn't run and the owner was told needed an engine overhaul. The "so called mechanic" even wrote the compression pressures (all good by the way) on the fender wells. After I paid the owner for the vehicle, he even had it towed to my house. Once home I did a little troubleshooting and it turned out to be the electronic ignition module. Cost to repair was under $20.00 and took about 15 minutes. It ended up being a good vehicle for quite a few years.