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Discussion Starter · #1 ·
Have a 2400 mile Levy Stage 5 408W. Was driving at low revs (2500-3000) when I heard a metallic clanking noise and then engine sounded really rough and then died. I pulled it over about 150 feet after I heard the noise and got it towed to a local speed shop.

They just called and told me there was no compression in the #8 cylinder and that they couldn't get it started. What are some of your thoughts on what could have possibly gone wrong with such a low mile engine and low RPM? Spring break or valve issue? Timing and carb was just tuned up.

I just bought the car 150 miles ago! Place I bought it from mentioned that they had pulled the heads when it first came in to replace a gasket... which has me suspicious.

All thoughts / comments welcome.
 

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The person who did the work on the gasket would be the first person I would talk to. Who knows what the did or did not do in the re-assembly...or for that matter, what blew the gasket in the first place.
 

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Discussion Starter · #3 ·
Agreed... will be some of the first questions I ask. Hoping it is just something simple like a rocker that came loose.
 

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I'd pull the valve cover first and hope it's just a rocker, but in that case it would still run (badly). If nothing obvious, a leakdown test would tell you where the compression is going. I'll guess it sucked a valve. :(

[edit] I'm not quite sure why the shop wouldn't pull the valve covers even BEFORE they tried to do a compression test??
 

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Rocker arm would be my guess. Pull the valve cover on that side and take a look.
 

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My first thought was a rocker arm or valve too. However, the shop should not have tried to start it. They may have done more damage to the engine cranking it for a compression test. Hope for the best. The fact that it wouldn't start also leads me to the distributor gear destroying itself.
 

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If it won't start, there's more to it than just loss of compression in one cylinder. I drove this engine off the track (about 1 mile), then off the trailer and into my garage.


When a distributer gear gets eaten, the engine just dies, like turning off a switch. The distributer and oil pump suddenly stop spinning. If you look down the distributer hole, the cam gear looks something like this.



A blown head gasket will lose compression in two cylinders. But the engine will will still start and run, although a bit rough.


If you lose a rocker arm, you generally don't hear much. It just starts running rough because it only runs on 1 or 2 cylinders.


Unless something like this happens. Then you might actually hear this lifter bouncing around a little bit. Maybe.


This engine ran really well. The compression was good, but just a little bit low on cylinder #6. And it did seem to burn a little bit of oil.


A loud clanking noise, and then the engine doesn't start.... that sounds bad. If the engine won't turn over, I would consider that a rod broke??????

As said above, the first thing to do is pull off a valve cover and see what you get. A good shop will have a bore scope. They can inspect the lifter valley and cylinders without doing more than pull valve covers and spark plugs. The bottom end can be inspected through the oil pain drain hole.
 

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Yeah, I have a nasty habit of finding the limits of certain components. There is definatly a learning curve. :)
 

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Discussion Starter · #12 ·
Okay guys.. the wait is over. Went to the shop today...not good! When I got there they only had one of the heads off showing chunks of the #4 & 8 cylinder missing. They told me the only thing that could have done it was detonation. The heads are in good shape so it looks like I shut it down before I scrapped the entire engine. Here is my problem. I bought this car about 200 miles ago (my first cobra). It ran like a top when I got it. I brought it back in to this shop (which is connected to the place I got it and a well respected place in the St. Louis area) because it was hard to start. They told me they took some timing out of the motor. When I get it back from them it seemed to be much better! I drive through one tank of gas, no issue at all - VERY fast and great fun. Filled it up and put it away. Take it out 3 days ago and after 10-15 miles this happens. I was not getting on it hard, just cruising around. (not that it would matter I guess since detonation can happen at low RPM just under load). I had it immediately towed to the same shop.

So my options here are:
1) Have them continue their work, pull the engine, and have the short block rebuilt and put everything back together ($3-4 k in total)
2) Tell them to stop everything, and ship it down to Levy Racing to have him re-do everything ($6-7k in total)

The only thing I can think that happened was they didn't tighten down the distributor when they took timing out, and it worked its way more and more advanced until it blew up. (they claimed it could have also been bad gas...which sounds like a bit of bullshit to me)

Love to hear the thoughts of everyone because I am beyond bummed with all of this. Also, any REALLY good shops in the St. Louis area that you think are good with 408 / 351 strokers may also be an option.
 

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$6-7k for a rebuild is silly unless the bottom end and heads are trashed. From the pics, it looks like you trashed some ring lands. If your heads aren't junk, you should be able to have the block machined and a new set of pistons.

Flat tops in a 408? That's probably well over 12:1 compression ratio, which is way too high for practical use on the street and with pump gas. Find a reputable local machine shop and have them rebuild for a nice streetable 10.5:1 and you'll be happy and will have a lot more money left in your pocket. :) :beer:
 

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Chicago,
Sorry about your luck. Since you are new here let me give you a tip; there are some people here that you should listen to and some that you should not. Two who fall into the "should listen to" category are Wade Chamberlain and Bob Cowan.

Jeff
 

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(they claimed it could have also been bad gas...which sounds like a bit of bullshit to me)
Out of curiousity, what gas were you putting in it?

Levys' website says it should be Ok on 91 octane (so I'd say the pistons are minus a few cc's of flat tops).

Street Engines


I have one other thought - Did the shop that had the heads off put head gaskets on that were significantly thinner than what Levy had on???

Or did they trade out the Victor Jr. heads that were supposed to be on it for some other performance heads with smaller combustion chambers???

Those sorts of things start getting really tricky in stroker motors...


Mike
 

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Discussion Starter · #16 ·
All good thoughts here - really appreciate it. I was running Shell 93 octane (use to run that in a blower mustang I once had with no issues). Question about the head gasket thickness is a really good one - not sure. I am thinking that I will just leave it at this shop and have them rebuild everything. The owner is also a huge cobra guy and he is sending my motor to the same guy that does his.

That all said, I am going to make sure that this information get to them (10.5 compression, etc).

Hope to have her up and running in a few weeks, just as the weather breaks. Hopefully I will have far less issues with her.

If there is any other advise you guys have on what I should tell the machine shop, I am all ears.

Thanks again!

-Ryan
 

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Wade, that was included shipping the car both ways.
We build, installed and dyno tuned that engine about 10 years ago and everything worked great. I haven't heard anything about it since it left here.
 

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have the short block rebuilt and put everything back together ($3-4 k in total)
If the heads are ok, and if the cylinders are all ok (?), and if the rest of the pistons are ok (?)...

I'm not sure I'd go all the way into a ground up rebuild.

Bearings, rings, a couple pistons (if they're still available???), hone the bores, clean it all up. Bring compression down to ~10:1 with thicker head gaskets.


Of course, paying (knowledgable) somebody else to do it all, that's still pretty safely headed toward $4k...


Mike
 

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:001_tt1:That must be why you're so smart!!


Bob
I don't know about smart - but certainly experienced! * Maybe if I was smarter, these things wouldn't happen. *

Good decisions come from experience. *Experience comes from bad decisions. *


Okay guys.. the wait is over. Went to the shop today...not good! When I got there they only had one of the heads off showing chunks of the #4 & 8 cylinder missing.

Broken ring lands are from detonation. When that chunk of ring land started bouncing around in there, it damaged the heads. The heads can usually be repaired, though.

Flat top pistons, near sea level, and (probably) a some what aggressive street roller cam. Your static compression is well over 12:1, and dynamic is probably around 8.5. That's a recipe for disaster.

Where did you buy the car from? A higher altitude location? If it was some place like Denver, CO, it will run forever on 91 octane pump gas.

It's hard to tell from the pictures, but some of the pistons appear to have some spalling. That's also from detonation. And I would bet that the heads show the same thing.

You'll need to resurface and maybe weld up the heads. Then a complete rebuild with new valves, valve seals, and probably new springs.

As you rebuild the rest of the engine, keep in mind what detonation is, and what it does. Think of a bunch of tiny construction guys with big hammers. Every time the piston comes near TDC on the compression stroke they use their hammers to try and force it back down. All that banging force is transmitted down through the pistons, rods, and into the crank and main caps.

Also, before doing much of anything, I would call Gordon and get the specs for that engine. I'm sure he still has them. He can tell you pretty much everything you need to know about that particular engine.

You will need to replace all the pistons. Used dished this time, to bring your static compression down around 10'ish. Check the rods for straightness.

Replace the bearings, they're probably scored. Be sure and check the cam bearings.

The crank probably doesn't need more than a light polish. But if it's a cast crank, you should probably have it balanced and straightened. Consider having it checked for cracks.

Align bore the block, if needed.

The block probably only needs a honing, and not an overbore. It's a 408 in a stock block, you may not have enough cylinder material to bore it out again. If not, you might consider throwing that engine in the trash, and buying a new short block. You'll spend more money on new parts, but less on labor. If you're not planning on racing, there's really no sense in using a Dart or Boss block.

BTW, the passenger/right bank is numbered 1-4. It doesn't alternate like a SBC does.
 

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Discussion Starter · #20 ·
Bob - great info in your post! Thanks for taking the time. To Gordon's point, he was super competitive on the price and I would have preferred him to rebuild everything - but the shipping was a killer! I should move to AZ and get out of the cold!

As I get further along with this rebuild I will keep everyone posted on the progress - hopefully I am pleasantly surprised with everything.

Question for the group. When I get it up on the dyno for a re-tune, what are peoples thoughts on timing and air/fuel ratios. It will be run in Chicago (500-600 ft above sea level).
 
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