4.0 OHV Persistent Hard Start. Looking for ideas

[Brain75]

Couple thoughts on what ruined seats you have... SBI sells both cast and sintered, the sintered have the suffix "PM" ("Powdered Metal").. SBI came up in my search for GSI, I think because they are one of the biggest mfg. (I read everything SBI had to say on their sales page when you linked it)

If you could find your old receipt from when the engine was built they might have an itemization of all parts and you could catch the part number there....

Otherwise a destructive test (it's a PITA to get the seats out without machine shop tools), take a seat to the anvil and (while wearing a full face mask) smash it as hard as you can with a sledge, if it chips cleanly into 2 or 3 pieces with a janky fracture line it is cast, if it splits into 18 pieces and some tiny bit of powder residue it is sintered. The powder most likely will stick to the face of the sledge.

Beware though they split and rocket out at 100 mph, hence the full face mask, probably long sleeves/gloves/apron/etc.

 

[Brain75]

Your comment that sintered was more expensive along with the fact that every oem is putting sintered in "most" new cars bugged me, I had to dig. When mfg started using sintered we all though it was cause it was cheaper - yet another way to shave a 1/10th of a penny off the cost meaning you could save $1 mil on production costs and give yourself a 6 figure raise.

Anyhow, I dug a little.. engines are getting smaller, valves bigger, and clearance around the valves smaller, pushing the tiny 1.9L's to get performance like it was twice the size. A few articles I read all backed this up - that mfg. used em because they could stand up better. Completely ass opposite of what I was taught and I said a couple posts back.

Engine Builders Magazine had a deeper dive into this and the closing punchline at the end was check all your valves that none of them are burnt, you may have gotten lucky and dug into the engine just in time.

Understanding Today's Valve Seats - Engine Builder Magazine

Understanding How They’re Made, How They Work and What Can Happen When They’re Wrong

www.enginebuildermag.com

One thing I took away from it sintered or cast, go for hardened unless it is ridiculously expensive.

 

[bobbywalter]

i remember that article. one of the best places for detailed data....been reading it for years.

 

[Kirby N.]

S.B. International e-Catalog

S.B. International is the premier worldwide supplier of cylinder head components to the aftermarket in terms of quality, service and product offering.

sbi-e-catalog.com

Here are the ones from my invoice.
It is attached:

 

[Brain75]

From SBI's decode a part number I gather this...
1437 size, high chrome universal insert for cast iron head, NOT powdered (so cast).

Product Details - SBI

scroll down to "PART NUMBER EXPLANATION"

 

[Brain75]

Unfortunately I only have a few engines worth of knowledge on this, someone who has built hundreds could probably steer you better.
My bank of knowledge includes fewer than bobby I bet but it does include a 1981 F-150 (300 straight 6 aka the indestructible motor) that was converted to dual fuel gas/propane (yes hardened valves), but I do not remember anyone saying there was such a thing as hardened seats back then. It was built by a shop and we ran what they put in, I didn't see the receipt (wasn't my project).

Unfortunately that vehicle made it 80k miles and started acting like yours, it was eventually just parked. We never opened the engine up so don't know what the cause of the poor stability was. Every time you gapped the plugs, etc etc - basically a tune up, it would make it another 250 miles before acting stupid again.


I rebuilt a 302 and put high compression heads off a 289 onto it, and in the course of the valve job (I did it all), the college instructor said we needed to replace some particular valve (bent or something) and when we pulled it, saw it was hardened so he said we needed different seats too... he ordered everything and I just put em in, once again did not see the part numbers, just paid cash no receipt. (Side note on that - those heads sparked a leaded gas engine debate, and the whole "You need lead in the fuel or hardened seats one or the other" argument... I think it closed out with both hardened valve and seat)

That engine I can not tell you how it ran even 1 day.. I moved before I finished building it, and quickly put the last bits together tied a ribbon on it and sold it on craigslist cause I did not have the vehicle for it to go back into anymore.


So... maybe (and this is just my conclusion from reading several things now), the fact you have hardened valves means you needed hardened seats AND the machine shop did not want to install hardened seats. I have read that it is harder to do, and you risk ruining the head screwing up the adjacent water jacket.

From everything I have read so far I would say don't run the hardened valves again without hardened seats, and to make life easier all around and not risk having $800 door stops just get new (not hardened) valves to go with your other new parts.

Take that for what it is worth, an OPINION from a marginally experienced guy, not a professional engine rebuilder.

 

[Brain75]

If you are dying for a performance rig and you want to spend the money on new heads or new valves+seats etc that's fine, it's your project. If you just want a running truck I can keep an eye out at the junkyard for a 4.0 OHV, there has to be some around - course with their known issues a guy probably wants to magnaflux em for cracks...

 

[Kirby N.]

ok. I don’t know for sure that they are hardened valves, that was just a theory- but I do think it makes a lot of sense. It’s interesting you say you knew yours were hardened because they had a mark on them? Perhaps I can look for that on these valves.

 

[Brain75]

The "auto tech" college prof (I took 1 year while working on other stuff) knew they were hardened, I think from a combination of things... how they tink/ring when you bang em on a metal table, markings, etc - I didn't know as much back then and other than looking up part numbers I wouldn't know for sure myself at this point.

And now that I think of it, a 2000 explorer with a 4.0 is as common as beans in the yards where I go... I keep forgetting to look at explorers cause mostly I have needed body stuff. I can't swear it for 100% sure, but I bet I can lay my hands on half a dozen heads from 95-2001 explorers.

I read a couple postings like that enginebuildermag on what causes valve seats to recess and a couple common things came up... 1) constantly lugging the engine/overloading it and 2) hardened valves without hardened seats.

 

[Brain75]

sintered seats are smaller, hardened seats they have to mill out a bit of meat and press in the bigger seat. (They call that "making a recess" for the seat) That meat they take away is the risk of making a doorstop, get too close to the water jacket and it will either open up immediately or fail (crack) soon after. To tell if you have hardened seats is easy, compare a non hardened seat to what you have, if what you have is much deeper / larger OD it is a hardened seat. This also means once you go hardened you have to replace em with hardened.
Note: factory seats (at least on chevy's since like '72) are induction hardened small seats, they zap em with electricity to heat em up and harden em - but they are still small. I also don't know for sure when chevy quit doing hardened and switched to sintered. I have no clue if Ford factory hardens any seats or what years they did or when they switched to factory sintered seats.

I'm cheap and not willing to "learn the hard way" what is a bad combo... just me, I would get a set of 2000 heads to match your 2000 block and run a known combo

 

[Kirby N.]

Hmm. All this is interesting. I know the yards around you, Brain. I spend a lot of time at the ones in Denver. I like the littleton Pull and Pay the best (its not sold out to the conglomerate), but as of lately they dont have much of the 90s rangers and explorers.

I still really like the idea of a 95 head with these pistons because it has the same exhaust ports. I dont even run a cat, so I dont see any reason for smaller exhaust ports. I dont really want a "performance" engine, just want a stock one that will go another 300 miles. It has plenty of power for me.

Weird, the guy at the machine shop did ask me if I over loaded it. I didn't even know what that means. I told him I drove it everyday on the highway.

The more we talk, the more I think the valves are probably hardened and they put incompatible seats with them. I think the heads are probably fine and could be rebuild with hardened seats.

I might go get them from the and take them to another shop.

 

[Brain75]

don't leave em set too long, they will consider em scrap and get rid of em for you.

I really used to like the Aurora one (very east end of town), when they had handwash stations, no soap but also didn't charge an entrance fee - before they changed the name to LKQ.

Martin's supply was the classic collector's dream - the back 40 had all 40's and 50's classics.


Since I don't own an 4.0 OHV and don't wrench on one right now, you got to tell me where all would a guy find the 95tm heads?
Is it just 95 and 96 ranger/explorer/aerostar?
I read this first before asking:

Rebuilding The Ford 4.0L Pushrod V6 - The Ranger Station

The Ford 4.0L/244 cid is the big brother in a family of Ford V6 engines that were built in Cologne, Germany, and have been used in domestic Fords since the early ’70s. The original 2.6L engine was replaced by the … Continued

www.therangerstation.com

 

[Brain75]

I ask because the very same explorer eddie bauer that I got my seats out of is still there and I wouldn't swear to it, but I think it is a 4.0 ... it is a 95, and last I checked the engine bay was unmolested (it wasn't a 2.9, so I glanced and moved on)... might be a pair of 95 heads right under my nose AND I plan on going back sometime in the next week or 2 to get my core on something else, etc etc... kinda tired of going to the yard, but seems it is required to get it all put together right.

Only issue with that one is you can't tell for sure why it came to the yard, not an obvious T-bone or blew a radiator or transmission grenaded all over... when you can't tell why I am a little leary of pulling engines (heads) out of em, rather find one that had a good solid T-bone and the engine bay without any intrusion.

 

[Kirby N.]

Yeah 95-97 explorer and rangers. Not Aerostars if I understand correctly. These came out of a 95 at the local pull n pay in south colorado springs. Its funny they typically have the most 90s fords out of any of the ones in denver. When I pulled them and took them to the machine shop the guy said, "all 4.0 heads are cracked." Except he looked close and didn't see any cracks and then magna fluxed them and they didn't have any cracks. I doubt they have any now either. It hasn't ever been hot. I dont know if they are fixable. Ill go get them tomorrow. I might take them somewhere else and see if someone can make sense out of it that doesn't have a dog in the fight. Right now I just want to get my truck back together.

Last time I went to that one in aurora I wasn't impressed. I used to like it, but it wasn't well organized anymore and kind of a dump. I guess it was actually a dump. Ha.

Colorado Auto Parts over off Santa Fe used to be so rad. He had that old f150 dent side wrapped around tree and the old filling station out front. Then they also had an old truck with a radial airplane engine they were working on in the back they let me gawk at. I guess it was on some shows and in some magazines more recently. They were also on roadkill. Last time I was in there they had like 0 inventory.

 

[Brain75]

Did you ever go to Denver Ford Parts, they got sued by ford for using the name, now their sign reads "Denver af-Ford-able Parts" Not a u-pull-it, but back when had the best chance of finding... These heads at my yard are gonna be $31/ea ($25+6 core) with a 30 day warranty that's why I mentioned, cheap and back on the road immediately if you skip magna and just inspect em real well... it would be 3 times as much gas just to deliver em or meet ya half way as the parts.