Engine destroyed.....

Hey guys, you may have noticed I have been posting questions about the 753901 cam and other things on my rebuilt 87. Well, we have been having problems with it so we took the head off to see if I bent a valve. Well, to make a long story short, the cam has eaten the lifters (all of them but cylinder #1 & 2, and the last lifter on cylinder 6) and the shavings/debris from the lifters made its way to the cylinders and scored each one, ruining everything in the bottom end of the engine pretty much. I had trusted a mechanic friend to help me rebuild the engine so he had stepped me through it and he majorly screwed me over. I now realize he is a moron and when he saw this, he was like "I have never seen that before..." even though he has built numerous engines before. He said "I guess thats what happens when you put an aftermarket camshaft in" Anyway, I am extremely pissed and I have lost a lot of money/time as I needed the car to be running by the end of the week, and that is not going to happen. We believe what happened was that the stock pushrods that were used with the Crane Cams 753901 and the recommened lifters and springs were too long, creating too much pressure on the lifter and cam. I advise anyone who is putting a cam in there car to make sure all your clearances are checked out before you try to run the engine. So my next question is, I will end up having to rebuild the engine again, having no choice but to bore it to .060" over. I still want a cam in it, but I am thinking of buying the 750501 instead, as I want more low end. Has anyone successfully put this or the previous cam in their car and what did they do with pushrod lengths and such? Thanks!

Also, I still want to use 87 octane fuel, so is having it bored to .060" going to hinder me in anyway? I want the most performance without having to run higher octane fuel (with gas prices what they are).

Did you lube the lobes on the cam when you built it? Crane actually provided a special lube for that purpose with my cam. Are you sure you used new lifters on the new cam? Did you preoil the engine by spinning up the oil pump before starting? Did the oil pressure come up immediately upon starting the engine.

I ask because these are all things that can cause premature failure on cam lobes. Did the valves hit the top of the pistons? If not and you did all the things above, either you had spring bind or you had a faulty cam.

I base my opinions on the fact that I've been building diesel and gas engines for almost 40 years.

Build tip:
On engines I build that have hydraulic lifters, I have someone run the drill running the oil pump while I take a wrench and turn the motor over at least a half dozen revolutions. That lets the lifters purge any air and get pumped up. I don't get even a second of lifter clatter when I start that way and the oil filter is completely full.

Sorry to hear about your delima. LOL

I'm about to put that cam in my motor (finally!) and was told by people who should know that it would run fine with the stock push rods and valve springs. Any other thoughts on this?

Real sorry to hear that you had a problem........major bummer.

Tom, my motor is already assembled and is about one year old. I'm just going to pull the head and replace the cam. Anything special you'd recommend in that situation? (I have new lifers)

Well, when we first noticed a problem, it seemed the engine was backfiring through the intake, which made me believe that a valve was bent, especially when I found a pushrod was bent as well. So instead of being smart and doing a compression test to find out, I just took the head off and didn't see any sign of the valves being hit by the pistons. Another thing that was odd was that pistons 5 & 6 were quite dark with carbon and didn't appear to even be firing (plugs were fouled). We did prime the engine with a special priming tool we stuck where the distributor goes and using a drill. We did it enough times where oil was flowing through the pushrods. I also suspect coil bind, but can't figure out what could have caused this. I doubt it was a faulty cam, visually it looked fine, and I do believe the lube that was sent with the cam was used. We lubed the cam and lifters, so I know that can't be it. I am completely stumped, and it worried me as I still want to put in the 750501 cam and don't want the same thing to happen. The spring rate was supposed to be 1.70 and 1.24 on the intake and exhaust, but I know there weren't exactly there. The stock spring height is 1.64" from what I have read, so in order to achieve the 1.70 that Crane recommends, you must machine the spring seats. I was told that having it at 1.64 shouldnt make enough difference to cause what has happened though...

Were you using stock valve springs? I went to Mopar Magnum 360 springs to avoid coil bind with a similar cam.

Edit: Nevermind, just read your previous post, see that you used the springs from Crane. Ed's post regarding the timing chain being off may be accurate. Have you checked it?

CRASH

karter74 said:

Hey guys, you may have noticed I have been posting questions about the 753901 cam and other things on my rebuilt 87. Well, we have been having problems with it so we took the head off to see if I bent a valve. Well, to make a long story short, the cam has eaten the lifters (all of them but cylinder #1 & 2, and the last lifter on cylinder 6) and the shavings/debris from the lifters made its way to the cylinders and scored each one, ruining everything in the bottom end of the engine pretty much.

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It seems to me that the problem from the outset might have been excessive lifter preload causing the cam lobes to wear them out prematurely. The question is why?
I very much doubt that the stock pushrods could have been too long unless the head/block surfaces were milled. In that case, it would have been wise to shim the rocker arm bridges or use shorter pushrods.
As Tom said, it's important to lube the cam lobes and journals before installing it, but the cam lobe contact surface of each lifter must also be lubed before the lifters are installed.
Was the proper cam break in procedure followed? If not, that could be another reason for the premature lifter wear.
The installed height of your Crane springs was almost certainly insufficient and that would have caused excessive spring tension. The result of that would have been rapid wear of the rocker arms on their pedestals, rapid wear of the lifters, cam lobes, and possibly bent pushrods.
The stock valve spring installed height is indeed 1.64" and the Mopar Performance 5249464 springs that Crash refers to have the same 1.64" installed height, so the spring seats don't need to be machined for these.
If your cam is still good and doesn't have any lobe wear, you can reuse it and get a new set of lifters. If you've milled the head/block, shim the rocker arm bridges so that the lifter preload isn't excessive. The thickness of the shims will depend on how much the head/block were milled and the thickness of the head gasket that you use. You could get a set of shorter pushrods but shimming is the cheaper option.
As far as springs go, you could either retain your Crane springs and machine the spring seats, or get a set of the aforementioned Mopar springs and avoid machining the spring seats.
Whichever route you take, make sure that the lifter preload (0.020-0.060") and the valve spring installed height (1.70" for Crane springs, 1.64" for Mopar springs) are within spec.

Will the Mopar springs be within spec of my cam? I haven't tore the engine down to actually look at the cam, but from the looks on how badly my lifters are chewed, I would most definately assume it is trashed. If I were to go with the 750501 cam, would the Mopar springs be a wise choice? Another question, Crane recommends a compression ratio of 7.75-8.75 compression ratio, and I know that stock is 8.8, and since the head has been milled ever so slightly, would it be ill advised to use this cam?

Not trying to thread hijack but I thought others might be interested in the response to Goatman's question.

How many miles on your motor? If it is high miles, I worry about loose cam bearings. If the cam you are going to is a high lift cam, any slop in the bearings will speed their demise. Most people don't do the cam bearings but I would really rather be safe than sorry. The hassle is that it is a hassle changing those bearings and getting them in wrong happens way too often and yields a toasted motor.

The same things that effect a first time build effect a re-cam. If the cam is high lift, you have to worry about valve springs. Old stock springs don't take well to high lift cams. There are two problem modes. First is spring bind. In otherwords the spring isn't designed to compress as much as the new cam will force them to. The second is that old springs used this way can loose the bulk of their spring force, causing lifter chatter against the cam. Not a good idea.

Using the old push rods will normally be fine, just make sure and clean them out with carb cleaner and make sure they are straight. Inspect the old rockers for wear as well.

Has the head been milled on your engine? This is where you can get into trouble with a high lift cam. Depending on the amount of milling and the amount of lift, you can get into a situation where the valves hit the top of the pistons.

The old trick is to put a piece of putty in the cylinder, put the head on, and then turn the engine over with a wrench after you have pumped up the lifters. You then pull the head and see how far the putty was squashed and if the valve hit.

I'm running a 4.7L stroker I built. I had the block decked .025" and I am running stock pushrods. I am using the Crane stroker low rpm cam. I am running the H802CP pistons along with the thin Mopar performance head gasket. I had no clearance issues.

Just like I said before, you need to preprime the oil with a drill and make sure to lube the cam prior to assembly. Also turn the engine over several revolutions while using the drill to keep up the oil pressure. That way the lifters go ahead and get pumped up so you don't have massive valve clatter when you first start. Any time you open up an engine like that, I do a oil change within a few hundred miles of getting it back together.

I would think the only way you would be having this problem is if the head or the block had been milled(as old man said). I have had a strange problem with my stroker since it was built, but it hasn't caused any internal problems yet. I used a Competition Cam in mine,the part number I can't remember, something from a stroker formula I found on the net.My problem is the lifters seem to lose their prime over night(2nd new set). They tap for a second on start up and then the noise goes away(no it's not rod bearings). Everything else seems to be great, just a little worried about it. I did take a lot of time measuring clearances from the rocker arms to the push rods and it seemed to be the proper preload on the lifters at the closed position of the valves.Everything in the motor is new so I'm pretty sure wear isn't an issue. I doubt I've been help, but after reading this thread I'm starting to get worried.

karter74 said:

Will the Mopar springs be within spec of my cam? I haven't tore the engine down to actually look at the cam, but from the looks on how badly my lifters are chewed, I would most definately assume it is trashed. If I were to go with the 750501 cam, would the Mopar springs be a wise choice? Another question, Crane recommends a compression ratio of 7.75-8.75 compression ratio, and I know that stock is 8.8, and since the head has been milled ever so slightly, would it be ill advised to use this cam?

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I'd be surprised if the cam lobes are still intact but you never know. Your engine's CR is probably close to 9.0:1 (depending on which head gasket you used) so I suggest you steer away from the Crane 750501 cam to avoid any low rpm detonation problems later on. You could either go for another Crane 753905 cam but if you'd rather forgo a few HP to gain some torque lower down, the Isky 133125/6 would be a good choice.
The Mopar 5429464 springs will do fine. The installed height is the same as the stockers at 1.64" and they are rated up to 0.525" of lift, so spring bind should be a non-issue. These springs have an outer diameter of 1.42" so your existing Crane spring retainers and valve locks should be OK.
Since only the head was slightly milled and nothing was done to the block, the stock pushrod length will be fine even if you use the thinner than stock Mopar Performance 4529242 head gasket. Just make sure your pushrods are straight and that oil flows through the holes. You shouldn't need to shim the rockers either because the lifter preload won't be affected enough to make this necessary.

strokedwoody said:

I have had a strange problem with my stroker since it was built, but it hasn't caused any internal problems yet. I used a Competition Cam in mine,the part number I can't remember, something from a stroker formula I found on the net. My problem is the lifters seem to lose their prime over night (2nd new set). They tap for a second on start up and then the noise goes away(no it's not rod bearings). Everything else seems to be great, just a little worried about it. I did take a lot of time measuring clearances from the rocker arms to the push rods and it seemed to be the proper preload on the lifters at the closed position of the valves.Everything in the motor is new so I'm pretty sure wear isn't an issue. I doubt I've been help, but after reading this thread I'm starting to get worried.

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It does seem that your lifters are bleeding down when left for long periods. Does this also happen if the engine's only switched off for a few minutes before restarting? You didn't say which lifters you used but I'll assume their CompCams units. It's possible that these may be fast bleed down units (especially variable duration lifters) in which case it'll be normal and you'll have nothing to worry about.

Tom, thanks.

The motor is one year old and ran about 20k miles. It was built by Jake's Racing Engines for his own use, and is very budget, and he scrimped and used the stock cam. It's a Renix motor, and has an adjustable MAP, and so it runs with the 10 to 1 compression of the 4.6L with stock pistons. I'm not satisfied living with the stock cam, and retarded timing of the knock sensor keeping it from pinging, although it runs fine the way it is. I'm going with the new cam (Crane 753901) to bleed off some cylinder pressure at lower rpms to help alleviate the potential for pinging. I was told it was built with new stock valve springs, for what it's worth. The valve springs are the only real question I have, although the last time I talked to Jake's I was satisfied afterwards that I could just replace the cam (and lifters) with nothing else needed. That is the cam that Jake's recommends for the stroked 4.0L, and it's the one they sell, so they are familiar with using it.

Any thoughts?

Experience is the best judge. If they have good history with the combo, then I would go with it.

Goatman said:

Tom, thanks.

The motor is one year old and ran about 20k miles. It was built by Jake's Racing Engines for his own use, and is very budget, and he scrimped and used the stock cam. It's a Renix motor, and has an adjustable MAP, and so it runs with the 10 to 1 compression of the 4.6L with stock pistons. I'm not satisfied living with the stock cam, and retarded timing of the knock sensor keeping it from pinging, although it runs fine the way it is. I'm going with the new cam (Crane 753901) to bleed off some cylinder pressure at lower rpms to help alleviate the potential for pinging. I was told it was built with new stock valve springs, for what it's worth. The valve springs are the only real question I have, although the last time I talked to Jake's I was satisfied afterwards that I could just replace the cam (and lifters) with nothing else needed. That is the cam that Jake's recommends for the stroked 4.0L, and it's the one they sell, so they are familiar with using it.

Any thoughts?

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The Crane cam that you mentioned is now sold under the part no. 753905. The Summit Racing part no. is CRN-753905 and they have it for $105. They also have the Crane lifters for $74. In my mind, this is the best cam for a stroker with a CR close to 9.5:1 and that's the one that I have for the stroker that I'm building myself.
The stock valve springs might be OK as long as you avoid high rpm where the risk of spring bind is highest.

Dr. Dyno said:

The Crane cam that you mentioned is now sold under the part no. 753905. The Summit Racing part no. is CRN-753905 and they have it for $105. They also have the Crane lifters for $74. In my mind, this is the best cam for a stroker with a CR close to 9.5:1 and that's the one that I have for the stroker that I'm building myself.
The stock valve springs might be OK as long as you avoid high rpm where the risk of spring bind is highest.

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I got the cam from Summit for just over $100. I was told that the stock springs would be fine for all but the highest rpm. I have an auto trans, and rarely shift it manually, so I figured the automatic shift points are well below the rpm that could cause a problem. I also figure that the automatic shift points are below the peak power range of this motor......

I could get the Mopar Performance springs if that was a better and safer way to go. Does anything special need to be done to install those springs?

The Mopar performance springs are a good way to go if you can get them cheap, but personally, if you check for spring bind, I would probably just stay with stock springs, especially for a stroker or a trail rig. I took a year to build my stroker and surfed the web and ebay for a year cherry picking parts.

Goatman said:

I could get the Mopar Performance springs if that was a better and safer way to go. Does anything special need to be done to install those springs?

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There's nothing special as far as installation of the MP springs goes but you'd also need the MP spring retainers and valve locks so these will add to the cost. You can at least be safe in the knowledge that you won't get spring bind or valve float if you run the engine up to the 5250rpm rev limiter. With the stock springs, you don't know what the effective rev limit is.
I bought a full set of MP springs, retainers, and locks for a total of $153. The springs and retainers are much beefier than the stock items.