Engine rebuild questions
Thread Starter
Instructor
Joined: Jan 2012
Posts: 193
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Engine rebuild questions
Well guys it looks like I am going to have to rebuild this thing.
I hadnt planned on it but with possible fried rings it looks like I might have to.
I did a compression test and was reading 90-96 psi in all cylinders except 1 and 5 read 0 psi.
First off is that psi correct? What are the stock head castings? Mine said they where a 306. Are those stock? Could that be why so low?
I also have a supercharger on it now with a stock bottom end dont know if that makes a difference.
I had just bought some 317 heads and this camshaft. http://www.compperformancegroupstore...Category_Code= Cuase I had planned on just building up the top end. but now with this issue not sure if this will work.
I was thinking about stroking it (not sure what cu.in. to go with) but am unsure as to whether or not the stroker kit, camshaft, heads and blower combination is good or not. And if it is what rwhp would I expect.(right now stock bottom end and blower Im at 420 rwhp)
If I do stroke it can I use the aluminum block? I have read stuff about it being weak with a stroker. I have also read that I can steel sleeve it or something of that matter.
If not a good combo is there anything that I could reuse?
I really appreciate you guys input.
Thanks
Robert
I hadnt planned on it but with possible fried rings it looks like I might have to.
I did a compression test and was reading 90-96 psi in all cylinders except 1 and 5 read 0 psi.
First off is that psi correct? What are the stock head castings? Mine said they where a 306. Are those stock? Could that be why so low?
I also have a supercharger on it now with a stock bottom end dont know if that makes a difference.
I had just bought some 317 heads and this camshaft. http://www.compperformancegroupstore...Category_Code= Cuase I had planned on just building up the top end. but now with this issue not sure if this will work.
I was thinking about stroking it (not sure what cu.in. to go with) but am unsure as to whether or not the stroker kit, camshaft, heads and blower combination is good or not. And if it is what rwhp would I expect.(right now stock bottom end and blower Im at 420 rwhp)
If I do stroke it can I use the aluminum block? I have read stuff about it being weak with a stroker. I have also read that I can steel sleeve it or something of that matter.
If not a good combo is there anything that I could reuse?
I really appreciate you guys input.
Thanks
Robert
Tech Contributor
Joined: Jan 2007
Posts: 19,360
Likes: 1,128
From: Dyer, IN
Well guys it looks like I am going to have to rebuild this thing.
I hadnt planned on it but with possible fried rings it looks like I might have to.
I did a compression test and was reading 90-96 psi in all cylinders except 1 and 5 read 0 psi.
First off is that psi correct? What are the stock head castings? Mine said they where a 306. Are those stock? Could that be why so low?
I hadnt planned on it but with possible fried rings it looks like I might have to.
I did a compression test and was reading 90-96 psi in all cylinders except 1 and 5 read 0 psi.
First off is that psi correct? What are the stock head castings? Mine said they where a 306. Are those stock? Could that be why so low?
Good compression should be 100 psi minimum.
What's the history here? What is your specifc problem?
Thread Starter
Instructor
Joined: Jan 2012
Posts: 193
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Sorry I didnt put all the basic info
It is a '98 coupe six speed. Every thing else thst I know should be stock. I hope.
I swear when I looked it said 306. I could be wrong though. I can double check again when I get a chance. If it is an 806 are those stock?
The whole reason I started looking into this was because the dipstick was flying out like no ones business. And then of curse since it was doing that I was losing all kinds of oil.
Some said get a catch can to prvent blow by and I almost did but then read that this would be a bandaid. So I then found out it could be bad piston rings. Did a compression test and those were the results.
Thanks
Robert
It is a '98 coupe six speed. Every thing else thst I know should be stock. I hope.
I swear when I looked it said 306. I could be wrong though. I can double check again when I get a chance. If it is an 806 are those stock?
The whole reason I started looking into this was because the dipstick was flying out like no ones business. And then of curse since it was doing that I was losing all kinds of oil.
Some said get a catch can to prvent blow by and I almost did but then read that this would be a bandaid. So I then found out it could be bad piston rings. Did a compression test and those were the results.
Thanks
Robert
Tech Contributor
Joined: Jan 2007
Posts: 19,360
Likes: 1,128
From: Dyer, IN
Yes.
That tells me you either have excessive blow by, an improperly vented crankcase.....or.....based on your compression readings....a combination of both.
Before calling it a day, I would perform a leak down test on the two cylinders reading 0 psi. If you have two dead cylinders, the engine should run horrible.
Before calling it a day, I would perform a leak down test on the two cylinders reading 0 psi. If you have two dead cylinders, the engine should run horrible.
Melting Slicks
Joined: Jun 2012
Posts: 3,163
Likes: 6
From: Oceanside California
Yes 806 is stock. And as Lucky suggested, get a leakdown test done. This will tell precisely where its coming from. It is most likely the rings or possibly pistons due to the high crankcase pressure blowing the dipstick and oil out. Good luck
Thread Starter
Instructor
Joined: Jan 2012
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Ok I will look into how to do the leakdown test.
Yeah weird thing is that the engine seemed to run fine.
My oil pressure was higher than it had been. Previously it was pretty low like 20 -30 and then I noticed the day this happened it was around 50-60.
One thing I did notice when I pulled the spark plugs they had some oil on them. As soon as I saw that I already new and then the compression test confirmed.
Yeah weird thing is that the engine seemed to run fine.
My oil pressure was higher than it had been. Previously it was pretty low like 20 -30 and then I noticed the day this happened it was around 50-60.
One thing I did notice when I pulled the spark plugs they had some oil on them. As soon as I saw that I already new and then the compression test confirmed.
Thread Starter
Instructor
Joined: Jan 2012
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Havent gotten a leak down tester yet. My buddy says his brother might have one. so got to find that out.
But got some semi decent news still possibly not 100% great but better than before.
I used my buddies compression gauge and the numbers were considerably different.
1=75
3=140
5=65
7=170
2=165
4=160
6=170
8=160
I am alot more happy knowing that all my numbers werent below 100.
I hope that when I do the leak down it is a screwed up valve...
Fingers are crossed big time.
I am still betting on rings but ehh...
But got some semi decent news still possibly not 100% great but better than before.
I used my buddies compression gauge and the numbers were considerably different.
1=75
3=140
5=65
7=170
2=165
4=160
6=170
8=160
I am alot more happy knowing that all my numbers werent below 100.
I hope that when I do the leak down it is a screwed up valve...
Fingers are crossed big time.
I am still betting on rings but ehh...
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Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
If you do leak down test, check 3 things, exaust leaks which clearly you can see from rear of your exhaust (air escaping), Intake leaks (hissing sound), and take off engine oil cap and see if air escape from there, if so thats cylinder rings bad as air escaping past rings.
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
Thread Starter
Instructor
Joined: Jan 2012
Posts: 193
Likes: 0
If you do leak down test, check 3 things, exaust leaks which clearly you can see from rear of your exhaust (air escaping), Intake leaks (hissing sound), and take off engine oil cap and see if air escape from there, if so thats cylinder rings bad as air escaping past rings.
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
I really appreciate you guys help. And I will need all the luck I can get thanks again.
Thread Starter
Instructor
Joined: Jan 2012
Posts: 193
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Well it is quite possible I am an idiot fellas.
I am trying to do the leak down test but don't think I am doin it right. The pressure on the gauge only goes up to about 15 psi before the % gauge says set. And I can hear air like as if a tank was being filled up but looked everywhere and can't find a leak. Rockers are loosened and I can wiggle them around so....
Please tell me what I am doing wrong. Anybody???
I appreciate it guys.
I am trying to do the leak down test but don't think I am doin it right. The pressure on the gauge only goes up to about 15 psi before the % gauge says set. And I can hear air like as if a tank was being filled up but looked everywhere and can't find a leak. Rockers are loosened and I can wiggle them around so....
Please tell me what I am doing wrong. Anybody???
I appreciate it guys.
Team Owner
Joined: May 2001
Posts: 87,302
Likes: 1,583
From: Western NY
Tech Contributor
Joined: Jan 2007
Posts: 19,360
Likes: 1,128
From: Dyer, IN
Well it is quite possible I am an idiot fellas.
I am trying to do the leak down test but don't think I am doin it right. The pressure on the gauge only goes up to about 15 psi before the % gauge says set. And I can hear air like as if a tank was being filled up but looked everywhere and can't find a leak. Rockers are loosened and I can wiggle them around so....
Please tell me what I am doing wrong. Anybody???
I appreciate it guys.
I am trying to do the leak down test but don't think I am doin it right. The pressure on the gauge only goes up to about 15 psi before the % gauge says set. And I can hear air like as if a tank was being filled up but looked everywhere and can't find a leak. Rockers are loosened and I can wiggle them around so....
Please tell me what I am doing wrong. Anybody???
I appreciate it guys.
1) Water jacket
2) Intake manifold
3) Exhaust manifold
4) crankcase
Thread Starter
Instructor
Joined: Jan 2012
Posts: 193
Likes: 0
If you do leak down test, check 3 things, exaust leaks which clearly you can see from rear of your exhaust (air escaping), Intake leaks (hissing sound), and take off engine oil cap and see if air escape from there, if so thats cylinder rings bad as air escaping past rings.
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
Before you started leak down test, get the pen and paper ready for each cylinder, and pull of both coil packs/valve covers/rocker arms...that way you know all valves are shut closed.
Dont worry about top dead center as we cant turn motor as rack will be in our way.
well good luck, leak down is the way to go.
Sami
You have a choice, either set the cylinder being tested to TDC, or REMOVE the rockers. If both rockers are off, both valves should be closed. If you have an air leak, it's then up to you to determine where the air is going, with four possibilities:
1) Water jacket
2) Intake manifold
3) Exhaust manifold
4) crankcase
1) Water jacket
2) Intake manifold
3) Exhaust manifold
4) crankcase
The noise I heard was the sound you get like an empty tank was being filled (which I guess was the cylinder bore) but air just kept going in.
I did try a few cylinders and even one with the rockers on(of course when I did that air came out of the intake) so on that same cylinder I removed the rockers and heard all kinds of noise like on the others but couldn't find a stupid leak.
Arghgh I'm so annoyed by this. I am going to try tonight again.