New engine has loss of compression

-
DartVadar said:
Yea I am going to do every check possible for this build and for any other builds that I do. I now fully understand why you check parts over before using them, in the end it's alot more work. Well you learn from your mistakes, just won't make this one again!

So while the motor is out should I just leave the shortblock together and just rebuild the top end? Or should I check that out too.
Click to expand...

When you consider having to do it all again, it does not seem like all that MUCH extra work. lol
 
RustyRatRod said:
When you consider having to do it all again, it does not seem like all that MUCH extra work. lol
Click to expand...

Very true! Imagine I go through all this and put it all back together and I still have a lame hole...I'd probably just give the car away LOL
 
you gotta love an engine.

reminds me of one of my favorite dogs: skidboot R.I.P.

awesome video if you have the time. can be applied to engine building lol.
just like you gotta love a dog, you gotta love a horse...
[ame="https://www.youtube.com/watch?v=P2BfzUIBy9A"]The Amazing Skidboot (Texas Country Reporter) - YouTube[/ame]
 
Was about to pull the motor out and leave the trans in place...I couldn't get the trans to separate from the motor because the stupid oil pan was hitting on the cross member! Definitely something I am changing when its out.

I'll do some more wiggling on the trans tomorrow so I can get the motor out, But I was just thinking when I was doing that. How delicate is the flexplate/converter/crank etc? like is there any chance that I could bend something? because one dowel pin easily comes out while the other seems to get stuck (all bolts are out everywhere lol).
 
duster360 said:
Do you have the flexplate unbolted from the converter?
Click to expand...

Knew somebody was going too ask that lol. Yes I made sure I did, and spun the converter around to ensure I got all this bolts, I also verified that I have all the bolts out connecting the trans and motor.
 
RustyRatRod said:
When you consider having to do it all again, it does not seem like all that MUCH extra work. lol
Click to expand...


My philosophy is do it right the first time, or you will be doing it over later.... :banghead:
 
AJ/FormS said:
Ok, heres the math; c/r= (CV+cv)/cv. Where; c/r is compression ratio,C/V is swept volume of one cylinder, and c/v is total chamber volume.
C/V=(360/eight)x2.54cubed = 737cc
c/v=0(for deck)+5cc piston+8cc gasket+63 head =76
So.....c/r = (737+76)/76 = 10.7
With those numbers your approximate compression ratio is 10.7:1.
My engine runs the same numbers and she generates 165psi, easy.
However,when I do a compression test, I dont stop at the 4th revolution.Some lazy(dry, or long not run) engines require 6 to 10 revolutions to peak. Also I block the Throttle blades full open to speed things up.After the baseline test I squirt a bit of oil in each hole and crank it over maybe 10 or 15 seconds to distribute and disperse the excess oil.(sometimes makes a mess). Then I repeat the test.I also watch the compression build after each shot.Im looking to see each cylinder building at a similar rate.
Whoa, I musta fallen asleep at the keyboard.We are on page 3 already.
I have 125000 miles on my Eddies.
Click to expand...


Nice calculations.

I like to use bore x stroke to get a little more accuracy instead of 360/8.


DartVader:

If you want to know the true compression for your components, you can check it with the info in this thread on how to check your compression. It's a basic, cheap, easy way to check your parts. This procedure eliminates part stack up and variation and tells you exactly where your parts are:

http://www.forabodiesonly.com/mopar/showthread.php?t=278215
 
Be sure to put jack with a block of wood under the transmission pan. This will keep from binding everything up. It is very easy to pop a trany case if you don't. That would really ruin your day.
 
krazykuda said:
Nice calculations.

I like to use bore x stroke to get a little more accuracy instead of 360/8.


DartVader:

If you want to know the true compression for your components, you can check it with the info in this thread on how to check your compression. It's a basic, cheap, easy way to check your parts. This procedure eliminates part stack up and variation and tells you exactly where your parts are:

http://www.forabodiesonly.com/mopar/showthread.php?t=278215
Click to expand...

Thanks for the link of the guide, I will do that to see exactly what I have.
 
67cudafb said:
Be sure to put jack with a block of wood under the transmission pan. This will keep from binding everything up. It is very easy to pop a trany case if you don't. That would really ruin your day.
Click to expand...

I was sure to do that, I think part of my issue was I was alone when doing it, I will have help today, so that should make things it easier.
 
To Crazycuda; Yeah me to. Thats why I said approximate, and in this case, with rounding, comes out to the same. And you dont have to know about; pi times(r squared). Its even hard to type.
Then after the engine is built, I roll it over on the stand until one plughole is up. Then with piston at true TDC I pour a measured quantity of oil into the hole, to see if it matches the math.I use a motoroil hoping I can get the job done before any leaks past the ring-gap.I tried other liquids, unsuccessfully.As a sidenote; Plasma Moly file fits seal pretty nice.Next time around, I might try gapless.
 
AJ/FormS said:
To Crazycuda; .I use a motoroil hoping I can get the job done before any leaks past the ring-gap.I tried other liquids, unsuccessfully.As a sidenote; Plasma Moly file fits seal pretty nice.Next time around, I might try gapless.
Click to expand...


That's why I put grease in the gap between the piston and cylinder wall to help seal off the gap. It doesn't affect the readings enough to make a difference and helps keep the leaking to a minimum.


It's good to check your engine like my write up, you never know if the block and heads have been decked enough to affect the compression, and this will let you know where your parts stand.
 
Got the engine and trans out finally.

Will take the heads into get a valve job and looked over tomorrow. And have decided to go hydraulic roller cam. Just have a few questions about installing ine though, I want to use comp retrofit lifters, as far as I know those just fit in like normal lifters, but what about the camshaft? I have heard about something called a cam button? And can I use the stock fuel pump eccentric for a mechanical fuel pump?

I just want to get parts ordered, I am planning on looking through everything still, and want to go through krazykudas thread to figure out all the specs. I am still deciding if I want to re-ring it just to be sure.

Gunna go slow with this, thought I covered everything when i first built it, but now I am going to be even more careful!
 
DartVadar said:
I am still deciding if I want to re-ring it just to be sure.

Gunna go slow with this, thought I covered everything when i first built it, but now I am going to be even more careful!
Click to expand...


For $200, you can get a mancini racing "A" or "B" klt in Federal Mogul or Sealed Power.

A kit = Main bearings, rod beairngs, Fel-Pro gasket kit, cast rings. $200 - $210

B kit = Main bearings, rod beairngs, Fel-Pro gasket kit, moly rings. $205 - $230

http://chucker54.stores.yahoo.net/enrebkit.html

You may consider getting one of these kits to replace the rings and bearings for piece of mind. Unless you want to go for round 3.... #-o
 
I just found this picture on my hard drive, and it reminded me of this thread and the issues that you had pulling the engine.

Just for laughs.... LOL!!

View attachment Hoist.jpg
 
krazykuda said:
For $200, you can get a mancini racing "A" or "B" klt in Federal Mogul or Sealed Power.

A kit = Main bearings, rod beairngs, Fel-Pro gasket kit, cast rings. $200 - $210

B kit = Main bearings, rod beairngs, Fel-Pro gasket kit, moly rings. $205 - $230

http://chucker54.stores.yahoo.net/enrebkit.html

You may consider getting one of these kits to replace the rings and bearings for piece of mind. Unless you want to go for round 3.... #-o
Click to expand...

Now bearings I can't see being a problem, I will take a look at them to be sure then. Now if they are bad I think i wouldn't just replace them I would want to figure out why it happened in the first place. The rings may be a good thin to do, the motor is out, may as well do a bit of rebuilding just to make sure it's sealing good.

If the bearings are good should I just leave them and replace the rings. I was told to check 2 main bearings and the tops of the rod bearings for wear. But if those look good as well as the journals is it even worth it to replace them?
 
The motor is dismantled, everything looks pretty good in the bottom end, but while its out I am just going to completely rebuild it again.

I am taking the heads in on Monday to get fixed, and the valvesprings installed. Now I am looking at cams, I have a comp cam and a lunati cam that I am deciding between. Who makes the best retrofit roller lifter? I know the lunati lifters are a bit cheaper than comp, but I'd rather get the best one and not just get the cheaper one.
 
Get the MRL lifters from Mike Liston. They are supposed to be the best.
 
I will look into those lifters, what makes them better? Just make well?

And when I took the cam out I took a look at the bearings, I don't know if they look good or not...
 

Attachments

  • cam bearing.jpg
    32 KB · Views: 192
That bearing's fine but if you're rebuilding it (and so you can clean out the oil gallies) you're replacing them anyway... So just make sure the new cam bearings allow the new cam to be turned by hand.
 
You must log in or register to reply here.
-

Back
Top