jdmadam

iTrader: (2)

Okay, me and my buddy just built a motor. Its a b18c1 bored to 81.5 using 8.5:1 pistons. We used torco engine break in oil for start up and has since been using torco synthetic oil 5w 20. The motor sounded good for like the first 50 miles then it started to sound kinda rough and develop a bad idle kinda like when one spark plug is not firing. So we decided to do a compression test. When we pull the plugs the number 2 spark plug had oil on it and so did the piston. We did the test and got 195 135 195 198. So obviously there is a problem. I guessing its the piston rings on that piston but could it be from something else?

jdmadam

iTrader: (2)

forgot to mention that the motor is not boosted yet.

PyroProblem

Do a leakdown test next to determine WHERE you're losing compression...

Hopefully its something easy.

riceburner700

sounds like the rings didnt seal in that cylinder because of the synthetic oil

rich7777

Thats exactly what come to my mind.

wolve

strange everything i correct except for 1 cilinder...

what's even more strange, i've had the excact same thing happen to me.

oil on the #3 plug and low compression in that cilinder...

only i found out after running 300+whp on spray...

planning on leakdown test myself to find out what's up, i triple checked my ringclocking. engine is running hard! did a 1/4 and ran 100+mph on a stock cr GSR with stage1's....

i you find out what the cause is please update us, i will if i find out!!!

jdmadam

iTrader: (2)

Thanks for the help guys. We are gonna buy a leak down tester today. Most parts stores don't carry them so we gonna probably have to order one. I will update after the test results.

PyroProblem

You could probably rig up something with a blow gun and some rubber grommets to see where youre losing compression if you dont want to purchase one.

jdmadam

iTrader: (2)

Meh, I rather do it the correct way and plus, I could see myself probably having to use this tool again.

I picked up a leak-down tester from northern tools and I will be performing the test after work today. I never done this test before but I have read the directions and it seems pretty straight forward and easy. If any body has some tips or pointers for me on performing the test I'll be glad to hear some.

wolve

i'm curious to what the outcome will turn out to be !

PyroProblem

I hear ya man, it's definitely a useful tool. I was just suggesting options in case you were super tight on money.

just make sure your at top dead center, introduce air pressure slowly with the regulator, and watch your hands in case the engine wants to turn over.

jdmadam

iTrader: (2)

Okay, did the results and the leak is in a strange place.
The result were =

1)12% flawless
2)33% air leaking out of cylinder 1 spark plug hole
3)12% flawless
4)10% flawless

When I tested cylinder 2 the leak was coming out of the cylinder 1. There was no bubbles in the radiator coolant and no leakage any where else. I then pulled the valve cover off and confirmed that it was in fact coming out of the cylinder 1 spark plug hole. It was really blowing out of there too, so much that it would blow paper out of cylinder 1 spark plug hole. I did the test on a cold engine and I made sure and double checked that ever piston was at TDC before testing them. How is this possible? I cant figure it out, Im open to any possible solution at this point.

EpHatchy

headgasket maybe?
cracked sleeve at the joining of the 2 cylinders..
that is weird though

jdmadam

iTrader: (2)

This is the conclusion I keep coming up with also, but I just can't figure out why cylinder 1 doesn't leak into cylinder 2 like it does vice-versa. It's really weird to me. I think we are gonna pull the head tomorrow and check the head gasket and cylinder walls.

wolve

Hg leak or cracked sleeve will ALWAYS show in the coolant as the cilinderwalls are completely surrounded by coolant.

Only way I can see this is a headproblem, crack in th combustion chamber...

Strange!!!

jdmadam

iTrader: (2)

Like Ephatchy said and like I was thinking, If the crack is directly at the point where the cylinders meet then it will probably not show in the coolant. I think we are gonna pull the head today and see if we can see anything wrong.

wolve

offcourse

Mindfart :p

Still strange it's one way only tough. a cracked sleeve would explain the oil on the plug tough

PyroProblem

Sounds like a headgasket. They wont necessarily always show bubbles in the cooling system. Depends where the HG lets go. In your case, its leaking from cyl 2 into cyl 1. The gasket is the narrowest between the cylinders. Remember the coolant jackets go around the cylinders and not in between them.

jdmadam

iTrader: (2)

I just pulled the motor and head and there is no cracked sleeve, no blown head gasket, and no bent valves. I couldn't see anything out of the ordinary until upon closer inspection of the head combustion chamber on cylinder #2, I see what looks to be some damage. It kinda looks like a piston smacked the head. That combustion chamber is also not sealing properly because I tested it with a straight edge So I went back to check the piston in the block and the piston is not damage and still looks pristine. So my guess is that the previous owner who sold this head to my buddy sold him a damaged head. We gonna send it to a machine shop to test and see if it can be fixed. I'll post some pics later.

Put-In-A-Kill-Switch

I hadn't bothered to check the date on this, but does anyone know if there is a way to make your own leak-down tester? this is my first post.... so don't make fun of me to bad folks.

PyroProblem

Airplane in the haaaaangerrrr!!!


https://encrypted.google.com/#hl=en&...w=1920&bih=947

wolve

where do you think the oil has come from?

jdmadam

iTrader: (2)

I cant figure out where the oil on the plug came from. I also didnt see the plug with oil on it. My friend told me that the plug had oil on it, Im hoping it was just alot of unburnt fuel he mistake for oil. The head is going to the machine shop friday. Over the phone the guy at the machine shop said it sounds like it can be fixed.

wolve

i have to fix my compressor so i can leakdown mine...

curious as **** as to where it comes from....

ToniJ

what is the most leakage a cyl can have before i need to pull head. at 50 lbs of air, im at around 30 percent leakage on number 2. (h22)