Looks like I can get brand new aftermarket heads, made with thicker sections in all the crititcal areas, for right at $400.

What are the soft plugs? Are these the so called "freeze plugs"?

 

the '97 lean burn heads are different from earlier Aero 4L OHV engines...
you still have to have the valves lapped in for perfect surface seal on new heads or new seats...push rods and rocker arms still need to be examined and push rods measured for wear min. length also any oil tube plugging

i would just rebuild those good '97 heads...never heard of any problems with '97s...good strong reliable heads...took Ford 7 years to get the heads right...

buy new heads only if you have cracked head from overheating, damaged unrepairable valve seats or heads that are too warped for surface machining to correct

remember, new head bolts only...far cheaper than redoing a job

soft plugs aka freeze plugs

if you have a good reliable auto machinist engine shop in area with references, I would take the heads or engine depending on what you find in tear down to them and have them do the complete machine shop solvent tank dip, machinist inspection and any magnafluxing, and machinist work required such as crank , cam...have them also check rods for straightness and magnafluxed
if you have $200 extra bucks, have them balance the rods and crank with pistons and wristpins

use quality moly rings

have them do the engine assembly into a long block all ready for you to drop in....they usually will include a 1>3 year warranty with their full assembly....saves you the headache of a learners mistake and all the extra tools required

 

As Forrest Gump said, "Life is like a box of chocolates, you never know what you're gonna get." This is true when buying a used vehicle too! I finally determined the problem - valve recession. I pulled one head (so far) and found that the cylinder #5 exhaust valve has recessed at least .125 inch. Also, this was the head that had been replaced by the previous owner. It is the wrong head!!! It is an open chamber head and my van is a ‘97, which requires the smaller “fast burn” chambers. Doug Anderson’s site quotes the Ford engine guy that says this is an absolute no-no. The engine will “burn down”. This valve recessed so much that it bottomed out the lifter and wouldn’t close. The valve seat looks like it has been machined by the valve.

I think I’ll replace both heads. Ebay has a set that are new castings for about $400.

 

Glad you found the problem. Good luck in fixing it, it is worth it.

 

Rockers and push rods look good. What are the chances the lifters need to be replaced? Engine did not make rocker/lifer noise prior to tear down. Would recessed valves colapse the lifter to a point where it will not come back?

 

pull all lifters and set in holding rack oriented and numbered to hole they came out of.... check for roller OD" and wear on shaft...also check for egg shape oval wear in block roller hole....take to auto engine machine shop, most can pressure pumpup test for you
if you replace one lifter have to replace cam because of wear track in cam

i would stay away from most ePuke auto parts....too many are cheap Chinese knockoffs and branded fakes...have even seen socalled original FoMoCo parts on ePuke that are Commie phakes....

2 reliable US manuf. suppliers
http://www.alabamacylinderhead.com/fordproduct.htm
http://www.cylinder-heads.com/store_items_view.asp?itemid=16847

Alabama can supply bare heads and complete heads w valves and springs...usually don't come with rocker assemblys
these companies do advert. on eBay at times
they list 800 numbers on their sites...they are both good sources of head replacement info

$400 may seem like a good price but buying EPuke unknown quality cheap is not always a good idea....there is no state consumer protection laws....it's totally guts buyer beware, one born every day

have the original correct head magnafluxed and measured for straightness/warp....the lean burn HSC heads seldom fail or leak....wiil have to have valves ground 3 angle on it

the seller did a quick down and dirty cheap fix with the wrong head...lucky the open chamber head didn't snap a valve tulip and put it thru the engine....you caught it in time

check push rods side to side and make sure previous repair didn't put in wrong push rods

good luck with the repair

 

Hummm, So it was the Valve not closing tight. Just wasn't because of carbon build-up.

Aerostar1:
What you really want to hope for if someone did put on different heads that they didn't change the push rods for ones that we're shorter or longer then the original ones. If the other head hasn't been changed I'd use one of the rods to check the length of the ones on the changed head.

If it it was Me I'd replace the valve lifters just because I can with the heads off. That way you won't have to worry about a lazy lifter.

Oh and if you replace the freeze plugs.....Replace them with brass ones. They don't rust out like the Steel ones that were put in them.

JaY

 

Well, hopefully this will be the end of this post. I got the new heads on and the engine reinstalled back in the van. What a bear!! I remember the good old days when I thought pulling the engine in my V-8 Monza was difficult. The engine runs good. I'm going to check the fuel pressure just to make sure it doesn't run lean for any reason. Also, I might change the plugs for a different heat range.

Thanks to all who helped with this problem. I will continue to consult this forum anytime I have a problem with my van.

 

Aerostar1, this is a great thread Thanks for carefully documenting everything and following up. I don't post often here, but I read alot. This discussion was very helpful and informative.


Gary