I pulled my heads to clean them up and ream the valve guides. There were some assorted spring shims under the valve springs. When I went to put them back together things didn't seem right some springs were super tight when I tried to squeeze them in. I got a valve spring height mic and measured them out today. They were all around 1.740 to 1.800 without shims. I was going by the mel forum that lists installed height at 1.825" http://ford-mel-engine.com/viewtopic.php?t=14 I torqued the heads back on came inside and double checked the factory manual. It lists installed height at 1.625 -1.656 I am not sure what to do here. ~.200" seems like a ton of shim. Should I just run it as it is? @KULTULZ used to post on a few places but I haven't seen him in 10 years
@KULTULZ used to post on a few places but I haven't seen him in 10 years Check over on the Ford barn. He was on this morning.
Something has been changed. Maybe it's got the wrong valves or retainers? Are there multiple versions of MEL heads with different heights?
I know there are different version of the heads but not sure on the heights. It looks like someone has been in here before I think at least different valve seals than stock. Guessing it had valve seats maybe? MELs are kind of a mess with different piston designs almost every year and different heads port and valve sizes.
I set the shims to the pounds I want for the valve spring seat. I like to purchase new springs. Normally I buy from Competition Products because they have great pages showing height to psi. They also show different diameters, retainers, and keepers with various heights to get exactly what I want. I have found engines don’t know or care what’s stock or aftermarket. If correct the engine becomes trouble free. Good luck
I think you are going to have to go with Jimmy Six's advise and just order and set the springs so there is the correct pressure on the valve seat when closed and no coil bind under a fully opened condition. Hard to say what machine work has been done over the 60 odd years those heads have been around.
Valve springs aren't expensive, at least ordinarily. You want new ones. Is valve seat recession a possibility? That would bugger the installed height. Even bone stock engines btw, benefit from correct valve spring pressure. I think it's probably an often overlooked part of getting a good, sharp tune. You'll hear people talk about "valve float" in high performance high RPM revving engines, but what usually happens in any engine with weak valve springs is "valve bounce". The engine will often run out of steam as low as around 4000 RPM. There's always some valve bounce, but with incorrect installed height, or weak springs, the valves will bounce 6 or 7 times instead of say, just 2 or 3. Cylinder compression can't build unless and until the intake valve is closed for the duration. Even a Flathead where the valve spring pressure is spec'd at only maybe 50 pounds, whatever the spec might be you always want to make sure installed height is correct and use fresh springs.
Why would you pull the heads to clean them and to ream the guides? Sounds like you were putting the cart before the horse or you left a whole lot of info out. Reaming is usually only needed after installing new guides or when installing valves with larger stems. Why would you put the heads back on if you weren't sure if the installed hight was correct? Not enough info here. Enlighten us a bit.
Had a misfire/ occasional backfire out of the right bank. Tried everything I could electrically to eliminate it and it was still there. Seemed like a valve was staying open. I pulled the head it was full of the nastiest carbon buildup/ varnish I have ever seen years of bad gas and PCV system dumping oil into it I guess. Found a couple of sticky valve guides so I ran a reamer through them to clean out the crap basicly. I thought my measurements were correct till I came in a read the manual instead of the MEL forum. Went back out and measured them again today the exhausts were all around 1.74 and the intakes were all around 1.70 I shimmed the exhausts around .060 and the intakes around .030 still a little bigger than spec but it was the shims that were already in there.
Kultulz is also on the yblocksforever site, as is RB and Ted Eaton. Both RB and Ted have pretty good knowledge of MEL’s. If you want to pursue it farther, try over there.
The Jalopy Journal
