my challenger and a broke 383

[t2h_68]

2 1/2 weeks ago i bought a nice 70 challenger. It has a "warmed over" 383, 727 trans, vitamin C orange. The day i bought it i was driving it home and it broke. it was running fine and then all of a sudden it started rattling real bad and then it felt like something let loose(serious vibration and alot of noise). When i broke in to the motor i found that 2 of the rocker arms(crane aluminum roller rockers)were broke on the #2 piston and there was a bent pushrod on the #8 piston. I put a new set in and was adjusting them and found out that i could only rotate my motor about 90 degrees. It sounds like it is "butting up" against something on the #8 piston(im thinking a broke rod or something like that). What i want to know is what caused all this damage. I was running about 55 and my tach was turning about 2500rpm. Could my oil pump have quit working on me? It was dark and i couldnt see the oil pressure guage. Any ideas would be greatly appreciated.

[92whitedak]

Justin,

Go a step further and remove the engine from the bay. It isn't doing you any good in the vehicle so just pull it. Then pick apart the rotating assembly. How do the bearings look? When you pull the pan, does it smell horrible? From doing this, you'll be able to see exactly what happened to your engine. Before you rip the pan off though, drain it and see exactly how much oil you had to start. Check your camshaft. I'm willing to bet that there are atleast 3 stripped lobes. In such a case like this, its fair to say your pump may have crapped out on you or something pertaining to the oilling of your machine failed. Take a look. You owe me lunch if I'm right.

-Fox Deacon

[6 packin]

I agree down the engine. It sounds like it jumped time or somthings bent

[dave571]

Since you're bent on two holes, and you can't turn the motor over, I think there is little doubt that timing chain failed/ jumped. something. 383's run a domed piston to get up over 9:1 comp so valve clearance is minimal.

No need to pull the engine out yet(it may come to that)

Pull the intake and timing cover. I doubt the cam is wiped although it most likely out of time.

Since you've got the VC's off you can check the lash on the remaining cylinders. If you find a really loose one, the valve is bent. I'd be very surprised if there wasn't a bent valve. This will require head removal, but is still an in car job.

I just finished putting a set of heads on a 3.0 l gm for that reason. The timing chain stipped off. There were marks on every piston, where every last valve had hit.

Set of head's on it and it's good to go.

This does give you a chance to pull the motor and hop it up, if you were looking for an excuse to do so.

[1972roadrunner]

i agree with Dave... sounds like a valve getting caught on the piston and not letting it move...

i'm curious as to how it actually did happen. is it a one or 3 bolt cam? if it's a one bolt, the pin could have sheared and messed up valve timing, but theres no telling. if it were me, i'd pull the whole thing apart, just to see what i had. that way, you can make sure EVERYTHING is ok...

good luck!

[t2h_68]

thanks for the replys, i have the intake off and the cam seems to look ok from the topside. I will probably go ahead and pull the motor to see what i have. Like i said i just bought it and the guy didnt build the motor, the previous owner did. All i know is it is(was) fast and sounded great. It has a pretty radical cam(mechanical) and solid lifters. i tried to post a picture but its too big.

[polarapete]

Five years ago, when I bought my Polara, it had a tired 426 Street Wedge motor.

The day after I bought it, I spun a rod bearing while running it hard on the freeway with low oil!

In your case, I would take all the plugs out of the motor and spin it over on the starter. If it were to spin smoothly, I would feel a little more confident in putting it back together without a complete inspection, but, I would always have that worry in the back of my mind!

Good Luck!

[t2h_68]

i had thought about using the starter but when i was rotating the motor to adjust the rockers it would only rotate about 90 degrees. and that is with the plugs out and 2 people pulling on a breakover bar. the crank nut was tightening more than the motor. it turn freely counter clockwise and clockwise but it "butts up" on something both ways. The motor is full of oil and it doesnt have any water in it. I was following behind my wife and she said we were going about 55. Another thing, the guy i bought it from said all he ran in the car is high octane, and since i was broke from buying the car i put a tank of medium grade in it. Would that have caused any problems??

[polarapete]

From what you are saying, that motor is seriously wounded!!
The grade of gasoline will not do that!! At worst you would hear detonation under load and wisely back off the throttle.

Time to pull the motor and do the autopsy.

Keep us advised as to what you find.

[t2h_68]

i will be starting on my motor this week if i can take a day off. I had a guy offer me a running 440(30,000 on a stock rebuild) in exchange for my 383 and 600 dollars. I dont know if i will take the offer since i already have 450 tied up in new rockers and pushrods but im still debating. I found the phone number of the guy who built the motor but havent had the time to call him. When i talk to him i will find out more about what he put in the motor. thanx again for the help

[dave571]

All you're gonna need is a set of heads and a timing chain(most likely)

That said, the trade for the 440 is a terrible waste.

[t2h_68]

ok ive pulled the motor..... it only took about 4 hours(next time i know that the dust shield at the bottom of the tranny has to come out before the motor). When i took off the oil pan i found 2 broken rods (all in pieces) from there i took off the heads and i found 2 pistons with holes in them and 1 that had a serious gouge in it. So far the block looks a-ok (so far that is) The crank looks to be ok other than being a little bit scored. The heads are ok no bent valve i dont think. it has forged .60 over dome topped pistons looks to be about 11 to 1. How much would it be to have the crank fixed(built up and turned down?) and do yall think i could get individual pistons and rods?? (i dont know the brand yet) ill keep everyone updated. Ill be pulling the crank out next weekend and see exactly what i got. Any advice would be appreciated. thanx
Ben

[t2h_68]

ive had a couple of people tell me i need to have my block checked for hairline cracks. ive also had people tell me that itll be fine. Which should i do??????

[5th_Ave_Sleeper]

When rebuilding a motor that has made metal inside, you really need to take the block to the machine shop and have it cleaned and checked for cracks. they will have to put new cam bearings in also because the cleaning process will destoy them.
Take the crank too, and have it turned to whatever it needs, then buy the appropriate sized bearings to match.
Might as well take the heads to and have them checked for cracks/bent valves. My goal is to have you take the engine apart ONCE! Yeah sure its a lot of money to sink into a machine shop bill, but is well worth it.
My dad always said; "if you cant find the time to do it right, you WILL find the time to do it over!"
Are the rods stock or aftermarket alluminums?
Who's pistons are in there?
I think you can buy some pistons /rods individually from summit racing (even though they dont carry much Mopar stuff)
A new oil pump is an absolute must! I would say that it was the cause of your engine failure.
good luck! keep us posted.
Building engines aint cheap (espesially Mopar engines) I hope this isnt a daily driver for you
5th

[dave571]

Broken rods and pistons with holes in them.

Probably cheaper to find a core block and start over.

I know I was the optimist earlier, but now that you've got it apart, and it's gone "worst case senario" the deal on the 440 is looking much better.

[Mr. Trans Am]

Get the 440. If he wanted the 383 and 600 I bet a grand or less will buy it outright. Get it and get back on the road.

Do not drop money in that 383, they are everywhere for nearly free. If you want one just get another.

I see 383/400 motors tear up all the time. Spun bearings usually.

[t2h_68]

surely it cant be that bad?? right??? hopefully????? its only 3 pistons and 2 rods and a little machine work? Right?? shouldnt take too much.RIght??? someone put my mind to ease. Ill get some part brands and part numbers so someone can help me figure this out.. Thanx for all the help ill keep ya posted
Ben

[dave571]

Dude, it's THAT BAD.

When engine parts physically break(like rods) it does damage to everything else.

You've already said that the crank is damaged. Expensive to build up and fix, much cheaper to replace.

Very good chance that the block is damaged from the rods whacking it.

With the valve train damage you've described, there is virtually no chance that you didn't bent a valve, you just haven't found the bent one yet. plus the possibility of guide/head damage.

So at minimum you'll need:

a couple of pistons
a couple of rods
a crank shaft
the block checked for cracks ect,
and engine kit with gaskets rings and bearings(to reassemble it)
a valve or two, plus the valve train parts you've already bought.

That's about $900 canadian(plus the stuff you already bought) assuming your block can still be used, and ignoring that you should have the assembly rebalanced when you do the crank change. If you need the block, there's the cost of that, plus you'll be boring it again. If the guides are whacked on a couple of holes, then you've got head work too.

Long and short of it, you're starting over and will most likely be spending 2-3 thousand dollars to have a hopped up 383 again.

Sorry man

[t2h_68]

thank you far all the responses im still unsure of which way ill be going. The person with the 440 says he doesnt want my 383 but will consider selling it still but hasnt settled on a price. Ive got everything off of my block except my distributor and the 2 pistons with the broke rods(#7&#8) they are hung up pretty bad. one of the rods knocked out a pretty good chunk of the bottom of the cylinder(about as wide as the rod) but its not into the water jacket or anything maybe i can have a sleeve put in. The guy who has the 440 also has a 383 block he might sell. would it be worth it to buy a new block to turn around and have it bored 60 to accept the pistons i have or what. or will the block i have be good. The gouge in it is about 1 inch wide and only about 1/2 to 3/4 inch tall. Im at a loss for thoughts here.
Pleeeeeeeeeease help me.

Thanx again Ben

[Mr. Trans Am]

It's not how big the gouge is, it's how DEEP. I'm betting it's junk and already at .060 over right? If so your done anyway.

Don't waste time on it. His 383 block should be real cheap. Real Cheap. But I think I would wait for a complete engine to come along. Much better deal for you.

I remember that car and if the body was in good shape you did good, even w/ the bad engine.

[Mr. Trans Am]

send me an email at cabner57@hotmail.com

all the message things are disabled here or I would have sent you one

[71383bee]

Sorry t2h, but these guys are right. A 383 at 0.060 over is way past the limit in my book. If the heads are salvagable I would set out to find a new block. 383's and 400's are pretty cheap still so a little scrounging can do you a lot of good. Your buddy who's selling the 440 doesn't want your 383 any more because he knows that it is toast.

If you aren't worried about keeping a stock year motor. I would try and find a 400. They are usually cheaper than a 383 and will take all of the same mods a 383 or 440 will take and it has the benefit of an extra 17 cubic inches. Besides, they make awesome stroker motors! My buddy and I picked up a running 73 400 for $100 bucks last year.

[cuda66273]

Sad...very sad......

Look at the valve guides, are they bronze?

A common mistake in building a Mopar, bronze guides set to Chevy 11/32 stem clearances...do it to a Mopar and the big 3/8 valves swell up, hang the valves, piston comes up and Boom!

Rods don't break unless they hit something, they usually pull apart.

Without seeing it I'd have to make a educated guess that somehow the piston tried to shove the valve into the seat and lost the battle.

or...are the bearings on the broke rods burnt? If so it may have seized...doubtfull as you would have noticed a loss of power, rods knocking and lifters rattling from lack of oil pressure.

Timing chains usually let loose when you've got it wound up tight and back off the throttle, the reverseing of the pull direction can snap them.

Whatever the cause does'nt matter at this point...go get the 440, but remember the 440 is wider...will your headers fit? The intake is different as is the distributor.

If you want to build it up more think about a 400 with a 440 crank...451 low deck block and all the bolt on's will fit.

MOST IMPORTANT....don't take it to a Chevy shop, they don't understand the valve job, always use the wrong honing stones and they have no clue as to how to grind the crank correctly.