Calling engine gurus, please help

[79cordoba]

I have a Frankenstein motor built by my grandfather and am unsure of all the parts used, he does not remember as he is very old. I was told is a 360 magnum from 1979 which I believe is true, but I was told is has "69 dart" heads , I don't know what that means. I think i saw an X on the head. He said it has a "hot cam 2 sizes up from the magnum cam". It has an edlebrock performer intake manifold. The reason I'm posting this is the engine used to start every time ( a year ago) and would make a little noise which I thought was just a bad water pump. Well I brought it to a shop to get the brakes done and they said they took off the water pump and it still made the knock and they think the engine is blown and a bearing is shot. I'm not sure if i trust them. The engine was just rebuild less than 5,000 miles ago. So I have good general knowledge on push rod v8's but I am no expert! Trying to keep this short... I pulled the valve covers and it looks brand new under there, I don't think I have solid lifters so I don't need to set lash??. Two of the rocker arms have side to side play on the rocker shaft, is this my issue? if so how do I fix it? Thanks so much in advance and sorry I may not know the correct names of everything, i can take pictures and look for codes if that helps! What do I have? What is wrong? And how can I fix it? Thanks!

 

[super-bee_ski]

Hi!
We have many engine experts here on the forum.
1. Side to side movement on a lifter (in my opinion, if it is significant) could be your noise
2. It seems to me you may NOT be very knowledgeable, engine savvy (that is okay)
3. Trust and integrity are very important when dealing with a "shop"
4. See if you can drive the car to a fellow "For B-bodies only" forum member for more advice
Fox Lake Illinois sounds like you may be in luck with fellow Mopar guy's in your local area (50 miles?)

NOTE: I always thought DART was a Chevy and FORD aftermarket race head
THE X head is MOPAR Performance!

DART HEADS? and X or J heads:
The 340/360 large port cylinder heads are much more desirable factory units for a performance build. These heads are most often found with the 1.88-inch intake valves, but were also produced with 2.02-inch intake valves in 1968 through 1971. The notable “X” and “J” heads (named for an X or J cast into the head near the spark plug hole) fall into the large port category, as do cylinder heads with “915” as the last three digits of the casting number. AAR and TA E-bodies with the 340 6-barrel option, while sharing the same casting as other X and J heads, were machined for relocated push rods and required special valve gear. It’s rare to find these heads today as they were very limited in production.

 

[PurpleBeeper]

Wow...that's not a lot to go on. What type of noise does the engine make that you "thought it was a bad water pump"? If you're hearing a "knock" that could be from a rod bearing (very bad & you're oil pressure will be very low) or something in the valve gear (rocker arm, pushrod - not so bad). Can you tell if the "knock" is coming from the top of the motor or down deep in the motor?

If it were me, I would buy & install a MECHANICAL oil pressure gage to see what my oil pressure is before I pulled the motor. If the motor is "blown" from a bad rod bearing, your oil pressure will be very low, like 5psi or something.

I would also keep inspecting the valve gear that you're already looking at. Stock rocker arms on a 360 are not adjustable (stamped piece of steel) so there's no valve lash to adjust. If you have screws/jam nuts on the rocker arms, then they're not stock & you will need to set your valve lash. (loose rockers "knock"). You can also pull out your pushrods, clean them & roll them on a mirror to see if they're straight. A slightly bent pushrod will "knock" too. While you're at it, you should inspect the ends of the pushrods & the "cup side" of the rocker arms for excessive wear (also causes a "knock").

 

[super-bee_ski]

And Purplebeeper,
The X head IS a MOPAR head correct?

 

[79cordoba]

Thanks for all the quick responses! I can't tell if it's upper or lower, it's a knock and gets faster as the engine speed increases. I Can't drive the car it needs brakes and the car is not registered.

 

[PurpleBeeper]

To super-bee.... I "thought" the X-heads might be the 1-year-2-car 340 six pack heads, but I was wrong. It appears X-head refers to the large port 340/360 standard heads (large or small valve).

OK 79cordoba....if you can't drive the car you can still fix it, but you'll have to spend more money "guessing" some things. Can you please send a picture of the heads under the valve covers? Or at least tell us do they have adjustable rocker arms? (a nut on each individual rocker arm in the center). For now, I will "assume" you have the stock-style rocker arms that have no adjustment possible.

Side-to-side movement of the stock type rocker arms is normal. What you should be looking for is up/down movement (not normal). If you try to rock the rocker arms back & forth like a "teeter-totter" you should have NO play at all. You will have to turn the engine over by hand (1-1/4" or 1-1/2" socket, clockwise, on the huge bolt in the middle of the big pulley at the bottom/front of the motor) since whenever a cam lobe comes "up", that valve will open & take out any slack in the valve gear. If you check a rocker/pushrod on a valve that is open, you won't be able to tell if anything is worn. In other words, you should not be able to find any rocker arm that rocks back & forth at all no mater what position you have the crankshaft in.

If you DO find a rocker arm that has play back & forth, you'll need to inspect the valve gear for that particular valve more closely. To do that, unbolt the 5 bolts on the rocker arm "bar" for that cylinder head, take all the rockers off at once & inspect that particular rocker arm, push rod & lifter where you found the back & forth play. NOTE: you should make sure to put all the rocker arms & lifters & push rods back in the same way they came out... this includes not getting any of the pushrods turned upside down. You'll be looking for any unusual looking wear or a collapsed lifter to determine exactly where that "play" is coming from & replace the appropriate part(s).

If you DO NOT find a rocker arm with back & forth play, even after turning the engine over by hand to several different locations & checking each rocker arm at each location....then you probably have a more expensive problem. As I suggested, install a MECHANICAL oil pressure gage ($35) and see what your oil pressure is. Spun rod bearings have a deeper "thud, thud, thud" than rocker arms "clatter, clatter, clatter" type sound and will cause low oil pressure.

 

[oldbee]

A loud "tap" or a knock sound kinda similar to uninformed. 79cordoba- a tap is usually in the top and a knock is rods/mains. Maybe you have a cracked flexplate/ loose converter bolts? Just throwing out something else.

 

[79cordoba]

If the rocker sliding sideways on the rocker shaft is normal why don't any of the other rockers slide? I will be working on the car later I will post later as well. hopefully get it running right!

 

[oldbee]

I think "purple" meant back&forth like they move when cam is rotating.With hyd. lifters there's always some tension on rockers.Idle it with v.covers off and if its top end noise it oughta be louder.

 

[happyjackdaddy54]

pull spark plug wires off one at a time to see if noise goes away. That will isolate the cylinder in question