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Look what else I found

3K views 32 replies 16 participants last post by  freddie 
#1 ·
Looks like I also had some valve contact. Guess I wont be using that machine shop again.:mad:
 

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#2 ·
Man it seems like you have no luck at all with your engine. :mad:Are you goning to rebuild it or are you gonna do a cummins swap? Whatever you decide to do I hope it goes better for you the next time:fordoval:
 
#3 ·
I know it is just one thing after another. Definately not doing a cummins swap, so Im just going to build the spare block I have and hopefully have something that will be what I want it to be, horsepower wise, and stay together.
 
#6 ·
What is your boost levels, what valve springs are you running, how many RPMS, are you still running hydraulic lifters......? Many things can cause the valves to (kiss) the pistons. Yes, it is a good idea to have plenty of piston/valve clearance, but if other things can attribute to this issue....

Let me clarify by saying I am not at all trying to argue, but I have went round and round before, chasing a problem when I found out later it was something else causing the issue.

Hope you get-er figured out man.
 
#11 ·
Found the specs from comp. These are comp # 26120-16 1.445" Beehive Springs.

Seat load: 155lbs @ 1.880"
Open: 370lbs @ 1.280"
Coil Bind: 1.230"
 
#13 ·
that spring with a 1.95" installed height, is less than 130lbs seat load.

If you were running 80 pounds per square inch of boost...on a valve that is 1.65" seat width, then your valve had 132 pounds of force trying to open (or keep open) the valves, without any help from the rocker.
 
#16 ·
I did but not the heads. I sent them out to have em completely re built and I got them back without new guides or seats in them. They said the guides and seats were fine. So all they did was put new valves, valve seals and put my springs on and apparently f'ed them up. Oh forgot they cleaned up the deck a bit too.

I wasnt too happy with their work when I got them back but not much I could do, and to say the least Im realy not happy now.

Any way thanks for pointing out the spring height to me. I wouldnt have checked that because I thought they could handle it.
 
#18 ·
Exactly my thoughts too but like I said I thought they could do the job. I had all new parts and provided them to them when I took the heads over and told em to do everything.

So looks like Ill be adding heads to the list for the new engine.
 
#19 ·
I dont know that much about clearances and tolerances on the heads , but whenever I bought my valve springs I asked a lot of questions about springs . A lot of guys run the comp 9.10 's . I came across a credible guy telling me to call comp or crower maybe and have them spec some for me . Then he proceeded to tell me that he ran the 9.10's and had a lot of piston contact like they couldnt handle the load . So instead of doing like I was told I got some 9.10's . I havent had any problems yet , but I am running under 40 lbs of boost and under 350rwhp . A lot of other guys assured me they would be sufficient . Are they capable of holding it ?:confused:
 
#20 ·
We run the 910 springs with the factory rotators, and the 942's (?) without the factory rotator.

with any valve spring, the most important thing is to match the installed height with the application.

When we do a VS install in our shop (or are assembling a set of heads), we will measure each valve springs installed height, and shim them to the desired seat load.

There is no one spring that can just "drop in" and be perfect for every application...especially when boost and rpm are increased significantly from stock.

The 910 spring will have more seat load than the factory spring...but to ensure that proper seat load is achieved, the only way is to individually measure each springs installed height, for each valve...and shim them individually to the load that you want.
 
#22 ·
Good read...
 
#25 ·
This is a hijack, and I apoligize.

Dave, at what point will the 910's let the valves begin to float? I'm running ~42psi and 3800rpm, but I'm looking to go more of both, with your help. :D

Dave
 
#26 ·
...at what point will the 910's let the valves begin to float? I'm running ~42psi and 3800rpm, but I'm looking to go more of both, with your help. :D
the 910's won't be an issue, as long as you KNOW what your installed height is...and calculate (or measure) the seat load at that installed height.

(Going off of memory...and being an office beotch...)

I *think* we set the 910s up at 1.77-1.80 installed height for ~70lbs of boost...more shim (for more seat load) for more boost.

The only reason to not run some crazy amount of seat load is going to be the limit of the hydraulic lifter to resist collapsing under the pressure being transferred from the spring through the rocker & pushrod...and increased valve seat wear from the valve slamming shut.
 
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