Vibration and blow by (engine tear down)

Hi folks


I did rebuild my Buick 455 engine and put it in my car. The engine did not accept WOT or fast step on pedal. Stumble and backfire was the result. Timing was 36 total and with vac was 50 or so. After a short ride my Mallory distributor was gone, so i replaced the magnetic unit with a new one. After another 50 Miles the Mallory cap was burned in the center. I replaced the petronix flamethrower II coil with a Mallory pro master. After several 100 miles the coil was gone.
After this i bought a MSD 6530 PC programmable box and an crank trigger with a ati damper ( i know not the best idea, but i assembled it with hammer..)
The box has a MAP sensor which is direct connected to the intake manifold vacuum. I love this ignition, and the engine runs great and the timing is very accurate and correct ( total 34 with Map 45). But since the first start with the crank trigger the engine began to vibrate. It vibrate through the entire RPM range. It does less vibrate when the engine is raising / decrease the RPM. It vibrate in P N D .... it doesn't matter which gear is in. I put the torque converter 1/2 back in the direction of the transmission and the issue was still there ( torque converter spins slowly). The whole car is shaking, the car vibrate more than the engine. I saw my headers touch on the passenger side the frame, first drive a year ago it hammered loud when car was acceleration stronger, after few miles later it stops. So i guess the problem was solved. But now im not sure... My engine mounts has 2 holes and now i use the upper one, can i use the lower? but for this i should underlay 3/8" the pads on the engine the right horizontal position.



Here are the engine specs:

455 0.38 over
11:1 SCR 8:1 DCR
230/240 at .05 Lift 118LSA
Zerodeck
JE forged pistons
Crower rods


I did a compression test, and cylinder 3 and 4 was way off compression the have only 123 PSI and 116 PSI others 178 PSI -190 PSI and number 8 has 200 PSI. So why are those two different? Test was with a warm engine but i not used oil for the rings. And here come the second misstake i used synthetic oil 5-30W with ZDDP .But i heard with a synthetic oil, the rings cannot seat in so fast as with a mineral. It has to less friction on the ring and the cylinder wall (Have moly rings).
When the engine is running there is a lot of air coming out the valve covers, but the air is not hot and it has not a pressure. So there is a chance that i have a wrong pcv valve? The pcv valve is connected stock location direct into the manifold


In this video can u see the air and how the engine is vibrating: (see the heaterhose how much it vibrate)

http://youtu.be/o79tTKh9NIM


Here is video in P and 1000 RPM Idle 16" hg vacuum (900 RPM 14"hg) There is a little fluctuation of 1"hg.

http://youtu.be/RGzmUX2-Uos


Timing is: (vacuum plugged in map sensor)


800 RPM 20 advanced
1000 RPM 24 advanced
1200 RPM 28 advanced

I guess its not a timing or fuel problem (idle 4-6 PSI fuel pressure), the engine runs good in all condition now, but it vibrates
Can create two weak cylinders this vibrations? My engine was fine balanced (internal) . Are the new pulley and balancer to much add of weight in the front?( not balanced with them)

Next step was:

Checking the valve lifts and compare they with the compression rate.

1 I 0.318" CR 12.8 Bar
1 E 0.320"
2 I 0.319" CR 12.3 Bar
2 E 0.318"
3 I 0.316" CR 8.5 Bar
3 E 0.314"
4 I 0.315" CR 8.0 Bar
4 E 0.327"
5 I 0.314" CR 10.9 Bar
5 E 0.320"
6 I 0.311" CR 12.0 Bar
6 E 0.326"
7 I 0.314" CR 11.6 Bar
7 E 0.317"
8 I 0.315" CR 13.9 Bar
8 E 0.317"

So there seems to be no relationship between the valve lift and the CR pressure.
So i pulled engine out of the car and disassembled the heads and there was not a funny to see that:




















What happened? I guess there were some detonation inside. The rings of number 3 was stuck, number 4 moving free but why he has also a lower compression?
On 3 different piston are these small pieces off. I'm lucky that the cylinder wall has only few strips and which i cant feel it with the finger nail so they aren't deep


Rod bearing shows:






So there are no metal in the oil...


And last but not least, here a question about the balancer and his position on the crank
I guess he's not mounted right, its too far from the timing gear...



what you mean? can this vibrate my engine? or is the piston ring an reason enough?

Tomorrow i will pull the other pistons...

advices and tipps for proceed are welcome

Kind regards

Robert

 

The compression numbers could cause the vibration pretty easily.

Did you check the ring gaps before installing the pistons? I've seen butted rings break the ring lands. And it's typically the rod side bearing that is hammered from detonation, though the crank journal looks pretty decent to me.

 

Yes i checked the ring gap after Pauls advice, but i didn't use the hone plate :/ . IMO crank journals looks good, no stripes or hammer scars...

 

Robert

The cranking cylinder pressure seems too high.

It should not be much over 160 PSI.

I think the cam timing is advanced too far.

Would you please check the cam timing and record the .050" (1.27mm) intake lobe lift opening and closing points.

The intake lifter should lift 1.27mm at 1 degree BTDC and return to 1.27mm at 49 degrees ABDC.

Thanks

Paul

 

8:1 DCR is roughly 185 psi (12.7 bar) cranking pressure, see here:

http://victorylibrary.com/mopar/cam-tech-c.htm

So, some of those results apppear in-line with what you should be expecting

 

Scott

Thanks for the correction.
Robert's actual DCR is 7.75 and he is around 1500 ft in elevation.
That should put the cranking pressure at 178 psi.

It's a concern that he was able to get 13.9 bar from cylinder #8

I still would like to have the cam timing checked anyway just to eliminate it as a problem.

Paul

 

Paul and Scott thanks for your advice. Im pretty sure that the crank was right installed but i will confirm. Last time i only checked the cylinder 1 and not all lobes.
Intake was 114* and exhaust 122* @ max valve lift. This time i want to do exactly what you want 0.05" readings.
First i want to be sure that i'm doing it right:
So the .05" readings are the sure way to know where begin and end the intake lobe?
The intake lifter should lift 1.27mm at 1 degree BTDC = Piston is very close before top dead center and the lifter begins to open, correct?
and return to 1.27mm at 49 degrees ABDC = Piston is move 49 degrees after his direction turn from bottom and now the compression will begin ?
And a last question, 180 ABDC = Piston is Top center?

thanks

Robert

 

Robert

That is correct
When you check it this way it also tells you that the cam lobe duration is correct.

Thank you

Paul

 

Had the same problem with my mallory distributor. I had to use a ballast resister from a mopar application.

 

My distributor cap was burned with 0.8 Ohm a preresister.
After that i bought the promaster coil from mallory with an internal resister but the coil was after 100 miles gone ...

So my pistons with rings are ordered with all another necessary stuff. The degree wheel and balancer puller should be deliver next week so i can start to confirm proper timing on all lobes.

I research several hours on detonation problem and sound.

Detonation how sound it?

The detonation sound has 6400 hz frequency and some folks say it would hear like a pinging and some say it would sound like rattling? Now whats correct, because i never heard any of this sound from my engine.
The worst sound i ever heard from my engine was an 1 time hammer knock on a hard metal "like hard dog" at very high rpms 5500+ with no loads. But after that the engine runs like before...


What happens?

I just want to be sure of the cause that which broke a little of my piston crown on the edge of the valve reliefs. So my thoughts are following:

Piston to valve clearance:

Pro:
- Wrong cam position
- Wrong crafted cam or just
- Timing gear to much slack in the chain

Counteraction:
- Piston to valve was measured out
- Cam position was confirm with cylinder 1 intake and exhaust lobe but not all
- Timing chain has a proper tight fit

I will recheck all the points to get sure the cam is sitting right and the pistons has enough clearance.

Detonation:

Pro:
- Lean fuel mixture
- bad timing ???? bad ignition ( weak coil) or to much advanced 60 BTDC?
- To low fuel octane
- To hot combustion temperature
- Hot spots in the CC
- Wrong oil rings, they allowed to suck oil in the CC

Counteraction:
- right jetting the carb, proper idle mixture ( confirm that wich black sparkplugs)
- Refuel only with high octane fuel
- Never run hot, stay near of 180 Fahrenheit
- Never heard a rattling or pining sound
- Polisched CC removed all sharp edges
- No smoke in the exhaust, nice combustion

Im not sure about bad ignition and the conventional damages, with the bad coil from mallory the engine pops out of the carb during fast mid opening the throttle blades.
And im pretty sure the air which is pushing out of the valve covers is since my engine pops out of the carb. So this was straight after installing the engine int the car.

My thoughts about the vibration:

The difference crank pressure from the compression test can't create so bad little hard vibrations.
And they wasn't early there like the steam out of the valve cover.
The engine began to vibrate after i instlled the ATI Super damper, i guess the balancer sit not in the right place on the crank.

So what you guess about my thoughs?
Any advice or opportunity for my cause of detonation or piston to valve clearnce?
Or is there a complete different point that i not observe?

Kind regards an thanks for reading

Robert

 

Update:

today i spend 3 hours to confirm the valve timings. To get the right TDC from the piston i did following:
First i mounted a dial indicator on center and top of the piston zeroing the highest position.
Now set the crank degree wheel to zero. Turn clockwise until .05" reads on the dial indicator, now set the needle to 12 ATDC.
Turn the engine counterclockwise until the indicator reads again .05" this point shows near 12 BTDC. Now i did correct the needle until both side have the same number.

In the picture can you see the 0.05" from Cylinder 1 intake

Cylinder 1 :

Intake .050 Lift
Intake open 3 BTDC
Intake close 52 ABCD
Exhaust open 58 BBDC
Exhaust close 2 ATDC

Intake center line 114
Exhaust center line 118?!

Cylinder 8 :

Intake .050 Lift
Intake open 1 BTDC
Intake close 50 ABDC
Exhaust open 61 BBDC
Exhaust close 0 ATDC

Intake centerline 115
Exhaust centerline 118?!

Cylinder 8 seems little confusion, so i rechecked the TDC from this cylinder 3 times and it was always correct 12 and 12 ... So i cant explain whys the intake 8 BTDC opens ( 2 degree to late) and closes 3 degree to soon?
The exhaust valve opens and close 3 degree to early. I guess this measure was not right, but i repeat 6 times... i will try it tomorrow again.

I guess the cam is right installed, because the cylinder 1 reading are 100% correct except the exhaust 118 center line...

Im not sure whats going on and an advice from an other person will be very appreciated

thanks for the time

Robert

 

Robert

The cam timing is good.
Even though the .050" durations measure differently for different lobes, the intake lobe centers are close to 114*.

The angle between the intake and exhaust cam lobes are 116* instead of the 118* that you specified. No problem.

The reason I like to check the cam lobe timing is to see if the cam was ground to specifications.

If you are still set up would you mind taking the .006" lift intake lobe readings.
I would like to see what your Dynamic compression ratio is.

Thank You

Paul

 

Thanks Paul you are a great person! Today i did check the 0.006" timing and they are correct 288 intake and 296 exhaust. I guess the cam is good, but just checked cylinder 8 with 0.006" .
Now i know that TA Performance didn't send me a cam with 118 LSA for a smoother idle as i order it. But anyway i'm glad to know that i did degree the cam right. And i have new inputs for the detonation causes. My thoughts are:
Detonations is influenced by chamber design, heat, engine timing , cylinder pressure and mixture . My chamber was optimized (no sharp edged s, quench area), no heat and not to high cylinder pressure. So what left? The mixture and the timing. I know my engine has a lot of advanced timing 55 degree and part throttle.. Engine created backfire ... Too much spark advance ignites the burn to soon so that it increases the pressure too greatly and the end gas spontaneously combusts. A detonation will start at the widest distance to the spark plug, in my case the left and right border of the piston crown. Exactly on the sharp edges of the valve reliefs. Paul what you think about my thoughts?

kind regards

Robert

 

Im no ignition expert but Id say thats waaay to much timing. Most buicks like 34 deg or so total. "all in" at 3k rpms. Id back off that timing and go from there...
Someone else may chime in...:Smarty:

 

Robert

You are correct in your thoughts.

I also agree with dirtrider546 that the total timing should be 34 degrees at the most.

Paul

 

What is the part number on the ATI balancer? Sounds like you added an external balanced balancer to an internally balanced engine.

 

Update:

First i found the cause of the vibration. It was a misunderstand with my engine builder. He did balance the crank for the JE Piston and crower rods and corrected they counterweights internal but there is still an external balanced harmonic balancer required. I bought a new one with the corrected weight, so that was a really stupid error but i'm happy that i solve the vibration problem.

The block is now rehoned with a 320 Grid brush and looks great.

The new set of JE Piston has a different weight as the older one:

Old 696 grams and the new are 702 grams
Piston wrist pin is 6g lighter so the total weight will be the same.

But why are the new piston heavier? another composition?
The piston valve reliefs are on the piston land side very very thin, should i take it out? file down the thin sharp wall? Last time the broke of, so i guess there is a big indicator for a hot spot?


Kind regards

Robert

 

Yes, I had a feeling that was your issue. 10 points for me! You sure are learning a lot through all of this!

 

Sean you are right, it was a harmonic for internal balanced engine on a external balanced engine
Yesterday i took the crank back from balancing and the new balancer just need 30g additional weight and now its all balanced.

Before i put the engine together i want to be sure what was going on in my engine.
I read a lot about pre-ignition and detonation and these are two very different things.

The definition of pre-ignition
The ignition of the fuel/air charge prior to the spark plug firing. Pre-ignition caused by some other ignition source such as an overheated spark plug tip, carbon deposits in the combustion chamber and, rarely, a burned exhaust valve; all act as a glow plug to ignite the charge.
Keep in mind the following sequence when analyzing pre-ignition. The charge enters the combustion chamber as the piston reaches BDC for intake; the piston next reverses direction and starts to compress the charge. Since the spark voltage requirements to light the charge increase in proportion with the amount of charge compression; almost anything can ignite the proper fuel/air mixture at BDC!! BDC or before is the easiest time to light that mixture. It becomes progressively more difficult as the pressure starts to build.
Other signs of pre-ignition are melted spark plugs showing splattered, melted, fused looking porcelain. Many times a "pre-ignited plug" will melt away the ground electrode. What's left will look all spattered and fuzzy looking. The center electrode will be melted and gone and its porcelain will be spattered and melted. This is a typical sign of incipient pre-ignition.
My engine has not this signs of damage, thats the reason I thought it must be detonation issue. But I didnt hear a ping or rattle so im a bit confused

Paul or someone here, what you guess detonation or pre-ignition?
I dont want this issue again and its better to research than say later sorry

Thanks for your advice

Robert

 

Robert

Stuck piston rings are a sign of detonation

If detonation occurs when the engine is running with a lot of throttle you may not be able to hear detonation over the engine noise.

It looks like the timing may be coming in too soon.

You don't want full 34* till 2500 rpm

If you can get the engine to idle with less initial timing that would help. Maybe 15* instead of 20*

Paul