Advanced timing ****ed my pistons

[Kyle1983]

Long story short. Bought my Blazer with a freshly rebuilt 4 bolt main 350. It was bored from 350 to 383. Pretty much every damn part is new. Every pump and hose. Everything. The dumbass that owned it was driving around with over advanced timing. He didn't know it was over advanced. He only told me the timing was "off" and I should "get it fixed" but it was ok to drive.

Like I said, long story short. 700 dollars later the custom shop finished the full motor inspection and fixed the timing but told me I now have "piston slap" and possible internal damage from engine spikes or rather engine detonation.
Now I have a big knocking noise, it's a regular fuel motor and sounds like a ****ing diesel.

I found a shop that will possibly swap my 383 out for a stock 350.

Here is my question: When doing an engine swap, what parts can I keep or what parts should stay with me and what parts have to follow the 383 to the shop?

I want to keep as much of my brand new performance parts as I can. Thanks for the help!

 

[Kyle1983]

 

[Blue85]

It was stroked. Max bore on a 350 will still be less than 360 cubic inches. It probably has something similar to a 400SBC crank (3.75"). The best parts of this engine would be the crank, rods and pistons, but wherever the bearing are wasted, those parts are probably junk now. Almost know way to know for sure without a complete teardown. All of the external parts should still be good, though.

Are you sure they are right though? Have you taken a stethoscope to it, checked for loose torque converter bolts, cracked flexplate, etc.? How about taking a video with the sound and post it up?

 

[Kyle1983]

It was stroked. Max bore on a 350 will still be less than 360 cubic inches. It probably has something similar to a 400SBC crank (3.75"). The best parts of this engine would be the crank, rods and pistons, but wherever the bearing are wasted, those parts are probably junk now. Almost know way to know for sure without a complete teardown. All of the external parts should still be good, though.

Are you sure they are right though? Have you taken a stethoscope to it, checked for loose torque converter bolts, cracked flexplate, etc.? How about taking a video with the sound and post it up?

Well the engine shop will let me know if they are interested in the swap and I will take it to them and have them look at it and they will tell me exactly what is wrong. It was another classic car shop that told me about the piston slap. I had it yo a transmission shop. A classic car shop. And next is a motor shop that oy des with motors. They will tell me exactly what is wrong, especially if they are going to swap it.

I will take the video tomorrow and upload. It sure does sound like engine knock but the sound gets quieter as the engine warms up.

They said that engine detonation super heat the motor and the pistons. And when the pistons gets over heated it effects it in some way producing the piston slap. Not really sure.

But back to my original question, looking at the pictures I uploaded. What parts in the engine bay will hook up to the 350? What can I keep?

 

[Blue85]

Everything swaps - headers, valve covers, intake, brackets, accessories. A 350 may take a different flywheel/flexplate, depending on if your stroker motor was internally or externally balanced.

 

[K85 Octane]

Yeah, damn near everything swaps over. That 383 started its life a regular 350. To build a 383 on the cheap is just the rotating assembly.
In fact, don’t do the engine swap if the cylinders are ok. Throw parts at it and go.

 

[Kyle1983]

Everything swaps - headers, valve covers, intake, brackets, accessories. A 350 may take a different flywheel/flexplate, depending on if your stroker motor was internally or externally balanced.

So I am looking at just swapping the actual motor block itself? So I will have to get the timing re-done for the new motor? So basically my engine bay will look exactly the same but with a 350 block?

Yeah, damn near everything swaps over. That 383 started its life a regular 350. To build a 383 on the cheap is just the rotating assembly.
In fact, don’t do the engine swap if the cylinders are ok. Throw parts at it and go.

So if it's piston slap then don't do the swap? The shop wants like 2,000 USD to pull out the motor and tear it apart. I really have no way of knowing how bad the motor is unless they disassemble the motor.



I am not really what the smart move is. I am worried about internal damage to the motor and the obvious knocking sound. I was thinking it's easier to swap it out

 

[Russell]

Kyle - For $2000 USD you can fix that engine yourself. Even if you have to replace some hard parts.

Start by getting yourself an engine hoist and some tools then pull that engine out of your K5. Put it on an engine stand and take the heads plus oil pan off. Then we can help you figure out what happened to your 383 and get it fixed up. You'll learn a lot about engines and save yourself a huge amount of money. Worst case you may need to replace the rotating assembly bearings and the pistons. If you take the heads off, you'll need to get the block decks and heads re-surfaced before you re-install the heads with new head gaskets. Once you get the rotating assembly fixed up, we can help you degree the camshaft then set the ignition timing properly yourself to make sure this doesn't happen again.

 

[centexk5]

The block in your truck now is a 350 block. The parts that make it a 383 are the crank, rods, and pistons. Literally everything will switch to a 350 block that's been prepped for a stroker kit. And get a second opinion.

Had a custom car shop tell me they needed to pull the brand new motor I had built and re-hone and re-ring the cylinders and that I might have collapsed lifters or a wiped cam lobe because it was breaking up over 4000rpm and the compression and leak down on the back 4 cylinders indicated something damaged. They wanted $5000. I brought it home and did some inspection. The brand new coil was cracked and arcing across the terminals, they had replaced the brand new fuel pump I had installed with a higher flowing version and the fuel pressure was 12psi instead of 5psi, and the float on their "custom" carb was ****ed off and flooding the back cylinders. Got all that fixed up in a weekend and almost a 1000 miles later it's still running like a champ. It pays to do some investigation yourself.

 

[1-ton]

Like I said, long story short. 700 dollars later the custom shop finished the full motor inspection and fixed the timing but told me I now have "piston slap" and possible internal damage from engine spikes or rather engine detonation.
Now I have a big knocking noise, it's a regular fuel motor and sounds like a ****ing diesel.

Sounds like another so called "custom shop" blowing smoke up your ass. Charging you $700 (Krona) to adjust timing, and then sit and listen to it run so they can blow smoke up your ass with guesses about what is wrong with your engine. incorrect timing does not cause piston slap. You probably have a cracked head or blown head gasket that let some coolant and crud into the combustion chamber, and hydrauliced it. Now the piston wrist pin is slapping. The PO knew the engine was toast, and wanted to sell it fast before it completely blew.

There could be any number of things wrong if you are not the one who rebuilt the engine. This engine may not even be a stroked 383. The PO only told you that because someone else told him that. The pistons could be in up-side down with the valve reliefs in wrong, or any type of thing for that matter, which is why I only trust myself to rebuild an engine for myself.

 

[Kyle1983]

Kyle - For $2000 USD you can fix that engine yourself. Even if you have to replace some hard parts.

Start by getting yourself an engine hoist and some tools then pull that engine out of your K5. Put it on an engine stand and take the heads plus oil pan off. Then we can help you figure out what happened to your 383 and get it fixed up. You'll learn a lot about engines and save yourself a huge amount of money. Worst case you may need to replace the rotating assembly bearings and the pistons. If you take the heads off, you'll need to get the block decks and heads re-surfaced before you re-install the heads with new head gaskets. Once you get the rotating assembly fixed up, we can help you degree the camshaft then set the ignition timing properly yourself to make sure this doesn't happen again.

I wish I had the tools and a shop to undertake my own rebuild but I do not. I am an American living in Sweden. You sound super knowledgeable. I would expect this information from an engine shop.

The block in your truck now is a 350 block. The parts that make it a 383 are the crank, rods, and pistons. Literally everything will switch to a 350 block that's been prepped for a stroker kit. And get a second opinion.

Had a custom car shop tell me they needed to pull the brand new motor I had built and re-hone and re-ring the cylinders and that I might have collapsed lifters or a wiped cam lobe because it was breaking up over 4000rpm and the compression and leak down on the back 4 cylinders indicated something damaged. They wanted $5000. I brought it home and did some inspection. The brand new coil was cracked and arcing across the terminals, they had replaced the brand new fuel pump I had installed with a higher flowing version and the fuel pressure was 12psi instead of 5psi, and the float on their "custom" carb was ****ed off and flooding the back cylinders. Got all that fixed up in a weekend and almost a 1000 miles later it's still running like a champ. It pays to do some investigation yourself.

I suppose if I was more knowledgeable I could do more investigating. I am at the mercy of the motor shop that will be looking at my knocking motor.

Sounds like another so called "custom shop" blowing smoke up your ass. Charging you $700 to adjust timing, and then sit and listen to it run so they can blow smoke up your ass with guesses about what is wrong with your engine. incorrect timing does not cause piston slap. You probably have a cracked head or blown head gasket that let some coolant and crud into the combustion chamber, and hydrauliced it. Now the piston wrist pin is slapping. The PO knew the engine was toast, and wanted to sell it fast before it completely blew.

There could be any number of things wrong if you are not the one who rebuilt the engine. This engine may not even be a stroked 383. The PO only told you that because someone else told him that. The pistons could be in up-side down with the valve reliefs in wrong, or any type of thing for that matter, which is why I only trust myself to rebuild an engine for myself.

I agree it's best to do it yourself, but I am not very knowledgable.

I was told that the engine detonations from over advanced timing was the reason I am now having piston slap. Not sure how they are connected. I will probably take the Blazer to the engine shop just to see what they can find wrong.

 

[Kyle1983]

It's good to know that all I need is a 350 block and i can hook all of my other parts to the motor

 

[1-ton]

If really do have a stroked 383 it is best to have that engine rebuilt because if this has decent 383 stroker crank and rod kit this is something you want to keep. Getting a set of aftermarket aluminum heads would be something you should do because rebuilt stock GM iron heads with a lot of miles on them are too much of a liability on a good quality stroked 383 small block bottom end.

If this is just an old remanufactured 350 small block, then it could be nothing but junk.

 

[Kyle1983]

If really do have a stroked 383 it is best to have that engine rebuilt because if this has decent 383 stroker crank and rod kit this is something you want to keep. Getting a set of aftermarket aluminum heads would be something you should do because rebuilt stock GM iron heads with a lot of miles on them are too much of a liability on a good quality stroked 383 small block bottom end.

If this is just an old remanufactured 350 small block, then it could be nothing but junk.

It's the 350 that came with the Blazer from 1988. It was broke all the way down and built up. No expense was spared. I have all the receipts. Very expensive build. Maybe not a big powerhouse but it was quality. So with that being said, I should invest the money into a rebuild of the internals. What does that run. 5,000?

 

[1-ton]

It's the 350 that came with the Blazer from 1988. It was broke all the way down and built up. No expense was spared. I have all the receipts. Very expensive build. Maybe not a big powerhouse but it was quality. So with that being said, I should invest the money into a rebuild of the internals. What does that run. 5,000?

I was under the impression it was a stroked 383 because you cannot bore a 350 out enough to reach 383 cubic inches. As I said the old cast iron GM heads probably cracked. You should just get a new crate engine that is an all brand new cast iron heads, block, crank, valves and all. You can go cheap with a GM Goodwrench engine Henhco in Mexico, or a good quality GM Performance crate engine Made in U.S.A.

 

[blazer74]

Questioning about how it was running and sounding prior to going to this shop. Went in for timing and came out sounding like a diesel.

 

[Wes Harden]

if this motor is a 383 you should fix it. the labor to r&r the old motor and repair it will be less than r&r and buy new motor. 383 make more torque then the 350, more desirable for a 4x4 truck. If the pistons were damaged by detonation, it is possible there might also be some combustion chamber damage, I expect the cast iron heads would survive. you might only need new pistons, gaskets and fluids.
setting/checking timing should be done at every tune up. this is normal maintenance item. while the motor is out and apart top dead center #1 cyl should be verified. The timing marks on timing chain cover should be lined up with the top dead center line on the vibration dampener. Then you can be confident that the motor can be timed correctly when installed and at routine maintenance.
If you do go with the 350 long block, you will need a new fly wheel/flex plate and vibration dampener. 350 and 383 are balanced differently. 350 crank is internal 383/400 crank is external.
if you have access to a bore scope you can inspect the piston tops through the spark plug holes.

 

[wasted wages]

Are the current pistons cast hypereutectic or forged...???

 

[diesel4me]

I know someone who took their truck in for a tune up and had it return pinging and spark knocking,turned out the harmonic balancer had slipped,threw the timing marks way off,but the shop assumed it was OK and just set the timing with a timing light using the mark on the balancer..

The timing was at least 20 degrees too far advanced!..and the truck did not want to crank over and re-start after shutting it off fully warmed up,and letting it cool off only a few minutes..the same shop then told the owner it was the starter,and had him buy a gear reduction "mini-starter" ,and it still bound up during hot cranking..

The truck ended up at my friends shop for a "engine swap"--he just turned the distributor back about 1" to retard the timing and the spark knocking went away and it would start hot no sweat..he had to replace the harmonic balancer ,then re-set the timing with a light,and it ran good again..luckily it hadn't been driven too far with the timing so far off..

 

[Kyle1983]

I was under the impression it was a stroked 383 because you cannot bore a 350 out enough to reach 383 cubic inches. As I said the old cast iron GM heads probably cracked. You should just get a new crate engine that is an all brand new cast iron heads, block, crank, valves and all. You can go cheap with a GM Goodwrench engine Henhco in Mexico, or a good quality GM Performance crate engine Made in U.S.A.

I live in Sweden. We have American crate motors that are turn key and a 350 is like 7,500 USD. That is half the cost if the entire blazer with the 383. I don't have money for that.

Questioning about how it was running and sounding prior to going to this shop. Went in for timing and came out sounding like a diesel.

It had the knocking sound after the over advanced timing problem. Over advanced timing + 2 hours driving at high speed. Had the vehicle towed and timing fixed. Now a knocking noise.

if this motor is a 383 you should fix it. the labor to r&r the old motor and repair it will be less than r&r and buy new motor. 383 make more torque then the 350, more desirable for a 4x4 truck. If the pistons were damaged by detonation, it is possible there might also be some combustion chamber damage, I expect the cast iron heads would survive. you might only need new pistons, gaskets and fluids.
setting/checking timing should be done at every tune up. this is normal maintenance item. while the motor is out and apart top dead center #1 cyl should be verified. The timing marks on timing chain cover should be lined up with the top dead center line on the vibration dampener. Then you can be confident that the motor can be timed correctly when installed and at routine maintenance.
If you do go with the 350 long block, you will need a new fly wheel/flex plate and vibration dampener. 350 and 383 are balanced differently. 350 crank is internal 383/400 crank is external.
if you have access to a bore scope you can inspect the piston tops through the spark plug holes.

You sound just like the guy I need working on it. Too bad you aren't here.

The engine repair shop can't pull motors so Inhave to pay a shop to pull the motor. Then transport it to the motor shop. Then pay for the tear down and rebuild. Serious money. Just paid 15K for the Blazer. Don't have another 5k for a engine rebuild.

Are the current pistons cast hypereutectic or forged...???

Forged pistons

I know someone who took their truck in for a tune up and had it return pinging and spark knocking,turned out the harmonic balancer had slipped,threw the timing marks way off,but the shop assumed it was OK and just set the timing with a timing light using the mark on the balancer..

The timing was at least 20 degrees too far advanced!..and the truck did not want to crank over and re-start after shutting it off fully warmed up,and letting it cool off only a few minutes..the same shop then told the owner it was the starter,and had him buy a gear reduction "mini-starter" ,and it still bound up during hot cranking..

The truck ended up at my friends shop for a "engine swap"--he just turned the distributor back about 1" to retard the timing and the spark knocking went away and it would start hot no sweat..he had to replace the harmonic balancer ,then re-set the timing with a light,and it ran good again..luckily it hadn't been driven too far with the timing so far off..

It's a bored out 350. To a 383.

The engine was ok except for bad timing. After 2 hours driving on over advanced timing it now has a horrible knocking on startup but gets less noticable after the engine warms up.

Damage was done. I suppose it will have to sit until I have the money to pay a shop for a tear down and rebuild. That's like 4-5,000 USD.