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You do not have 245 psi. On a pump gas engine with a fairly large hydraulic roller, you will see about 170-180. I think your 180 psi number is correct and the others are incorrect. Were you holding the carburetor wide open when you did it?
On the valve guide clearance, the only way to do this properly is to use a micrometer to measure the diameter of the valve and then use a bore micrometer to measure the guide clearance. A brand new guide/valve will have a lot of wiggle in it because the clearances are .0015-.0020 right off the bat.
A clearance of .030" or .040" is THIRTY THOUSANDTHS or FORTY THOUSANDTHS and is not correct.
You do not have 245 psi. On a pump gas engine with a fairly large hydraulic roller, you will see about 170-180. I think your 180 psi number is correct and the others are incorrect. Were you holding the carburetor wide open when you did it?
On the valve guide clearance, the only way to do this properly is to use a micrometer to measure the diameter of the valve and then use a bore micrometer to measure the guide clearance. A brand new guide/valve will have a lot of wiggle in it because the clearances are .0015-.0020 right off the bat.
A clearance of .030" or .040" is THIRTY THOUSANDTHS or FORTY THOUSANDTHS and is not correct.
Well I've used a Facom tool to take compression 2 times, carb wide open of course.
I've made a video about my guide wears but cannot post it here. As I said.. I've got .030" to .040" wears !!!!!
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
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Quote:
Originally Posted by CLV8
Well I've used a Facom tool to take compression 2 times, carb wide open of course.
I've made a video about my guide wears but cannot post it here. As I said.. I've got .030" to .040" wears !!!!!
Post your video on YouTube. Then, to embed that video here on Club Cobra, copy the video identifier that is the funny looking letters and numbers at the end of the video URL and embed it in your message here by placing it in between two YT tags with brackets around them. The second has a slash before the YT. Here is an example that would embed a YouTube video about dogs and wolves but for the fact that I put dollar signs in the first copy of the embed code so you could see the actual code.
Ed, there are so much wear that no need to measure them. When you take a valve in hand you can move it very easily on the guide (0.03" to 0.04" wear).
If the valves can be noticeably moved side to side you probably have worn guides and they would be the source of the oil entering the intake ports.
If we accept the worn guides answer to the What question, the questions that remain to be answered are the Why did they fail and the How to fix questions so as to avoid a repeat performance.
BTW .003 to .004" stem to guide clearance while not desireable, on a street driven car it is also not that bad. The amount of oil you are showing in the ports belies .003 or .004" clearance.
Ed
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Last edited by eschaider; 09-12-2021 at 11:13 AM..
Reason: Spelling & Grammar
If the valves can be noticeably moved side to side you probably have worn guides and they would be the source of the oil entering the intake ports.
If we accept the worn guides answer to the What question, the questions that remain to be answered are the Why did they fail and the How to fix questions so as to avoid a repeat performance.
BTW .003 to .004" stem to guide clearance while not desireable, on a street driven car it is also not that bad. The amount of oil you are showing in the ports belies .003 or .004" clearance.
Ed
Ed, WHY is the question !!! and currently I still don't understand WHY my valve guides are worn !!!
That's a new one for me. Never seen anything like that.
I've heard of guys having a microscopically incorrect surface finish on the valve stems that acted like a file over time, but I've never seen that before.
I also know that GM had a batch of bronze valve guides that were incorrectly hardened on the Z06 Vette several years back. It accelerated the wear.
I'd change the guides and valves both. It will need a valve job as I imagine the valve head has been dancing around on the seat.
I'm surprised the valve heads haven't snapped off from bouncing off the seats at random angles. And how it even got compression test numbers like you have.
Regardless, your valve guide clearance is the largest I have ever seen on any engine in my 40+ years.
Location: Virginia Beach, Va & Port Charlotte, Fl.,
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Quote:
Originally Posted by blykins
That's a new one for me. Never seen anything like that.
I've heard of guys having a microscopically incorrect surface finish on the valve stems that acted like a file over time, but I've never seen that before.
I also know that GM had a batch of bronze valve guides that were incorrectly hardened on the Z06 Vette several years back. It accelerated the wear.
I'd change the guides and valves both. It will need a valve job as I imagine the valve head has been dancing around on the seat.
Trust me Brent, GM NEVER used bronze/brass valve guides in their LS/LT/Lx OEM (factory installed) engines the guides were ALL were powdered metal. The C6 valvetrain problems were (for the most part) caused By Linimar (Canada based contractor) who had the GM contract to CNC the ZR1/Z06 head valve jobs. They bore the powdered metal guides out of center, causing massive valve to seat mis-matches. This usually resulted in the exhaust sodium filled exhaust valve head to break off trashing the engine.
Just a few reasons that excessive guide clearance happens------wrong valves, wrong guides, incorrect rocker/pushrod geometry---- mix up of standard and metric specs---example would be use of metric valve stem and standard size guides-or wrong size reamer or hone for finishing the guide---wrong valve length to accominate springs/retainers causing issue with rocker geometry/pushrod lengths---
show us some of the seals and also port area near wear push rod is-------
angle of engine mount can cause poor drain back of oil in some cases ----
high volume oil pumps and lack of control of oil supply to rocker shafts can cause high oil level in valve covers-----
Also in that video it looks like those guides are too short-barely above head mass------
I'll see if I have time to photo graph some of the equipment needed to measure valve guide clearances--- also the diamond guide reamers for the guides--------
Last edited by Jerry Clayton; 09-13-2021 at 08:14 AM..
Reason: added comment about video
Today I brought my heads to a racing engine specialist and discussed about the valve wears.
For him my problem can be:
- Bad/wrong valve guides machining when heads have been built
OR
- too much camshaft lift incompatible with heads can accept. Edelbrock RPM Performer heads allow .600" maximum valve lift.
FOR BRENT:Do you have my camshaft specs when you built the engine ? I don't have any specs or camshaft reference.
Ok, here's where it's gonna get muddy, because you're taking it to the wrong people and getting incorrect information.
These were not assembled heads from Edelbrock. They do not have Edelbrock valves, springs, or anything else. These were bare Edelbrock castings, CNC ported by KCR, fitted with valve guides and valves there, then assembled by me with the valve springs to match the camshaft.
Location: Virginia Beach, Va & Port Charlotte, Fl.,
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Quote:
Originally Posted by CLV8
Today I brought my heads to a racing engine specialist and discussed about the valve wears.
For him my problem can be:
- Bad/wrong valve guides machining when heads have been built
OR - too much camshaft lift incompatible with heads can accept. Edelbrock RPM Performer heads allow .600" maximum valve lift.
FOR BRENT:Do you have my camshaft specs when you built the engine ? I don't have any specs or camshaft reference.
Thanks, OliveR
Let's hope you didn't understand exactly what the "racing engine specialist" said. It's either that or he didn't tell you the whole/correct story. Your "heads" don't dictate maximum lift. The installed valve springs accomplish that. Edelbrock was referring to the max lift on their installed valve springs. The valve springs are matched to the cam. My 482" aluminum Pond side-oiler has the FE Performer RPM heads (CNC'd) and I'm running a .650" lift cam. 20K miles in 12 years and zero oil consumption or valve/chamber coking. The guides are as new.
Location: Virginia Beach, Va & Port Charlotte, Fl.,
Posts: 2,285
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Quote:
Originally Posted by blykins
Ok, here's where it's gonna get muddy, because you're taking it to the wrong people and getting incorrect information.
These were not assembled heads from Edelbrock. They do not have Edelbrock valves, springs, or anything else. These were bare Edelbrock castings, CNC ported by KCR, fitted with valve guides and valves there, then assembled by me with the valve springs to match the camshaft.
I do not have your cam specs.
You answered while I was still typing. I think we said the same thing from slightly different angles.
Ok, here's where it's gonna get muddy, because you're taking it to the wrong people and getting incorrect information.
These were not assembled heads from Edelbrock. They do not have Edelbrock valves, springs, or anything else. These were bare Edelbrock castings, CNC ported by KCR, fitted with valve guides and valves there, then assembled by me with the valve springs to match the camshaft.
I do not have your cam specs.
Sorry but the guy who I brought the heads know what he's speaking about and your reply is not acceptable:
- You said Edelbrock didn't assemble the heads meaning that different people have work on them.
==> Are you sure that valve guides have been well installed ?
==> Are you sure that valve guides have been well machined ?
==> Are you sure valve job has been well done ?
==> Are you sure that valve lift don't go beyond heads maximum specs ? spring too soft ?
What I'm looking is a solution to my problem and today I have no reply. I can replace guides but will it be the solution for long term ?
GETTING MY ENGINE IN THAT CURRENT CONDITION WITH ONLY 13000 MILES ON IT MEANS THAT THERE WAS ASSEMBLY FAILURE / BAD COMPONENTS !
So after having spent $18000 on it I suppose I can have little more help from you.... I don't ask you $$$...
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