There you go , never buy a cheap gauge , to bad you stripped the threads in the spark plug hole , if not you could have waited for a good gauge to test before tear down . At least next year you'll be sure everything is working well . Maybe once the heads are off a bit of winter porting ?
New engine has loss of compression
- Thread starter DartVadar
- Start date
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Something just don't make sense.
I am with Rusty on this one.
I think the off shore gauge is not reading correct, but at least you know #4 is low.
Sounds like a valve was not adjusted right.
Also why did it it not start right up, the heads and pistons look really nasty for 3,000 miles. With a motor with a low cylinder it should have fired right off.
Maybe running too rich or rings not seated???
FYI my 360 mag with KB 107 with Eldebrocks has around 200 psi cranking compression.
I am with Rusty on this one.
I think the off shore gauge is not reading correct, but at least you know #4 is low.
Sounds like a valve was not adjusted right.
Also why did it it not start right up, the heads and pistons look really nasty for 3,000 miles. With a motor with a low cylinder it should have fired right off.
Maybe running too rich or rings not seated???
FYI my 360 mag with KB 107 with Eldebrocks has around 200 psi cranking compression.
I don't have any mineral spirits, I will get some tomorrow and then test that way.
Also I was looking at the valves, I understand that an exhaust valve would be sooty, but shouldn't intake valves be clean? Number 4 (issue cylinder is all full of soot around and under the valve, number 2 is nice and clean, and the last two are kinda sooty, but cleaner than 4.
Also I was looking at the valves, I understand that an exhaust valve would be sooty, but shouldn't intake valves be clean? Number 4 (issue cylinder is all full of soot around and under the valve, number 2 is nice and clean, and the last two are kinda sooty, but cleaner than 4.
I doubt it's the gauge, be willing to bet my snap on gauge would read the same + or - a couple pounds. if you are sure the squeeze is 10.1, I would be looking at cam timing as a cause for the low numbers. jmo the current figures are more in the range of 8.5 to 1.
if the valves were adjusted to tight, causing a non seat condition, I would think the motor would run poorly. good luck !
if the valves were adjusted to tight, causing a non seat condition, I would think the motor would run poorly. good luck !
It usually fires right up, it was sitting for a while so that would be why I would think it didnt fire right away. So being dirty looking what would have caused that? I have been trying to fight a rich issue, still working on the carb for that. But A few weeks ago all the plugs fouled and were completely black! so I would guess it was from that crappy fuel that I had, I looked at that too and could see that it was starting to clean up a bit as it was clean in some places (could be completely wrong about that).
And yea I am still wondering why mine is so low, if the rings weren't seated wouldn't I have other issues? Like oil consumption. It doesn`t burn any oil.
I adjusted the valves I dont know how many times so I doubt thats the issue. And it should be around 10:1 and higher, but thats not what I am seeing. The car seemed to run good too.
When I installed the camshaft I degreed it and everything so it should be good there.
Yea exactly, well at least it happened now and not during the summer when I should be driving it! And possibly, may as well do something like that since the heads are already off!
From the pics you posted its hard to believe you only have 3000 miles on it. My feeling is your carb was way rich and rings never seated properly. Pics look like you been sucking oil past the rings. Did your oil look really dirty and diluted?
It was abit rich I am pretty sure. And if the rings never seated wouldn't I be burning oil? and it doesn't burn any oil at all, alot of coolant spilt into the cylinders when I took the head off. The spark plugs also looked pretty clean. And the oil was fine, and not diluted or anything.
Pistons look okay for 3000 miles , some strange patterns on them , but that might be from the bad gas you had . You would have known if the rings did not seat with all the driving you did .
Here is a pic of my pistons after around 10,000 miles , yours are a lot cleaner(except for the coolant ) . Hope there is nothing wrong with the heads , good luck.
![>](https://www.forabodiesonly.com/mopar/<img src="<a href=http://img.photobucket.com/albums/v398/jerry666/cars/100_0762_zpsfbc37000.jpg" target=_blank>http://img.photobucket.com/albums/v398/jerry666/cars/100_0762_zpsfbc37000.jpg"</a> border="0" alt=" photo 100_0762_zpsfbc37000.jpg"/>)
Here is a pic of my pistons after around 10,000 miles , yours are a lot cleaner(except for the coolant ) . Hope there is nothing wrong with the heads , good luck.
In what ways would I have noticed if they didn't seat? Because I always thought the thing made great power.
After the bad gas I intentianally left the plugs in to see if they would clear up, when I pulled them for the compression test the plugs did in fact get clean, I would guess that the Pistons were slowly getting clean again. After the bad gas I stepped on it once and it left a black cloud behind me, only did it thag time, never had any more smoke after that. After the bad gas I only put about 50 miles on it so it never had a nice long drive to clean crap out.
The coolant went everywhere too, it filled up the cylinders completely, that's why they look wet, same with the heads, it was sitting there for quite some time and the level stayed the same as well.
I hope the issue is the head...I am kinda thinking that it is, I wouldn't think that one piston would be bad already. I talked to my local machine shop and they told me that they have had issues with eddy heads, recently lots of warped heads and bad valve runout is commonly seen when they buy them. I also looked more into the compression readings, altitude (I'm at 2200 feet) and how the cam was installed can effect the reading, so I will just take the variance as the important factor I guess.
After the bad gas I intentianally left the plugs in to see if they would clear up, when I pulled them for the compression test the plugs did in fact get clean, I would guess that the Pistons were slowly getting clean again. After the bad gas I stepped on it once and it left a black cloud behind me, only did it thag time, never had any more smoke after that. After the bad gas I only put about 50 miles on it so it never had a nice long drive to clean crap out.
The coolant went everywhere too, it filled up the cylinders completely, that's why they look wet, same with the heads, it was sitting there for quite some time and the level stayed the same as well.
I hope the issue is the head...I am kinda thinking that it is, I wouldn't think that one piston would be bad already. I talked to my local machine shop and they told me that they have had issues with eddy heads, recently lots of warped heads and bad valve runout is commonly seen when they buy them. I also looked more into the compression readings, altitude (I'm at 2200 feet) and how the cam was installed can effect the reading, so I will just take the variance as the important factor I guess.
So I took the head into my engine shop. They need a complete overhaul, the seats were pretty bad on a few of the valves too. Another issue that he saw was the excessive wear on the valve tips, he thought that one was odd (I know I had the valves adjusted correctly). But said that it is common for the eddy heads to have these issues, more so recently actually (Not the wear on the valve tip).
I then showed him what some of my camshaft lobes look like, he wasn't too thrilled about that either, some of the lobes looked like they had some excessive wear as well. He was thinking the valvesprings weren't quite right for the cam (I used the stock ones that came with the heads) Or something was out of adjustment (I did the adjusting right I though) So it is probably a good idea to change out the camshaft as well :banghead: If I am needing to do that I am going to spend the extra cash and just put in a roller cam!
I then showed him what some of my camshaft lobes look like, he wasn't too thrilled about that either, some of the lobes looked like they had some excessive wear as well. He was thinking the valvesprings weren't quite right for the cam (I used the stock ones that came with the heads) Or something was out of adjustment (I did the adjusting right I though) So it is probably a good idea to change out the camshaft as well :banghead: If I am needing to do that I am going to spend the extra cash and just put in a roller cam!
info on cranking pressure and elevation http://www.not2fast.com/turbo/compression/cranking_pressure.shtml
fratzog lover
Well-Known Member
The valves are surely one area of cost cutting with these heads.
Seems they cut cost on a few things...
He said that he has recently been in contact with edelbrock reps due to the issues that they are seeing. Well on the plus side I will have all of this stuff fixed over the winter.
He said that he has recently been in contact with edelbrock reps due to the issues that they are seeing. Well on the plus side I will have all of this stuff fixed over the winter.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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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.
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.
mderoy340
Well-Known Member
IMO Edelbrock will do nothing to improve the quality until they can't sell their heads to anyone.
Both lucky , or the heads were installed and adjusted properly , right pushrods , rockers adjusted properly . Unless the shop I go to is giving me BS about not seeing problems with the heads , but I doubt it , more money in telling me they need extra work if true .
moper
Well-Known Member
If the heads were just installed when new, that's part of the problem I'm sure. The valve job on a shaft rocker system sets the geometry, which in turn provides either normal wear or poor geometry and faster wear. If the bore in that weaker hole looks good, and the piston is not damaged on the ring land, I'd say it was the heads. The Edelbrock springs hsould have been good enough for the XE268. Maybe not perfect, but usable. So my feeling is it's probably the valve job issues that led to the sealing problem. Wise choice to bring them somewhere.
Yup bought the heads, took one valve out to put in a flimsy spring to check piston to valve clearance, and then put them on the engine, so they were essentially ran right out of the box. And yea that could have been due to the bad valve job. The weaker hole bore looks identical to the others, and they look really good, no scrapes or scuffs anywhere, so yea it was probably the heads, and the fact that I couldn't get a good seal with the compression tester due to the bad spark plug threads. I also only spun the motor over about 3-4 times, and the throttle closed and air cleaner still on, so that probably didn't help the numbers.
I got somebody to look at the cam and just like the guy at the machine shop said, it didn't look too good, two lobes had much more wear than the rest (wore through the parkarization and through another layer it looked like), and a cam change would be a good idea. Its easier so I am going to pull the motor out to work on it, I need to change the oil pan anyways as it is too close to the ground, and its just easier to work on the engine on a stand.
While its out I will take a look at the bearings (I expect them to be fine but its not hard to check). Put a different pan on, fix the heads, maybe get some light porting done and install a retro-fit roller cam, just gunna bite the bullet and pay the extra cash for the piece of mind. Dont wanna go through all this and end up having to worry about the cam again.
I guess next time I wont just throw parts on!!!!!!!! At least I got to drive it all summer.
I got somebody to look at the cam and just like the guy at the machine shop said, it didn't look too good, two lobes had much more wear than the rest (wore through the parkarization and through another layer it looked like), and a cam change would be a good idea. Its easier so I am going to pull the motor out to work on it, I need to change the oil pan anyways as it is too close to the ground, and its just easier to work on the engine on a stand.
While its out I will take a look at the bearings (I expect them to be fine but its not hard to check). Put a different pan on, fix the heads, maybe get some light porting done and install a retro-fit roller cam, just gunna bite the bullet and pay the extra cash for the piece of mind. Dont wanna go through all this and end up having to worry about the cam again.
I guess next time I wont just throw parts on!!!!!!!! At least I got to drive it all summer.
Not trying to pour salt on the wound......but all of these issues are covered all over the forum. Do yourself a favor this time. Don't put it back together until you are 100% sure everything is right. You have some nice parts there. It would be a shame to do it a third time. If it's right this time around, it has the potential to be a killer combination. Good luck!
moparlover
Well-Known Member
i'm glad you caught it when you did. that's the plus side to the story, along with the fact that you found it during the offseason 
that is the key what triple R said^^^
you can never bolt on any heads without checking, partially because of manufacturing processes and partly because no two blocks are the same either. a set of heads with valves and geometry all set up for one short block might have piston/valve clearance issues on another short block.
that is the key what triple R said^^^
you can never bolt on any heads without checking, partially because of manufacturing processes and partly because no two blocks are the same either. a set of heads with valves and geometry all set up for one short block might have piston/valve clearance issues on another short block.
moper
Well-Known Member
...and there will always be some who will say just throwing parts on is easy and works "just fine"...lol
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.
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.
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