Bronco Forum - Full Size Ford Bronco Forum banner
1 - 20 of 26 Posts

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #1 · (Edited)
After letting them sit 75% finished for the better part of a year, I finally wrapped up porting my GT40 heads and collecting the supporting parts needed for the upgrade. I had a machine shop do a basic cleaning, inspection, and pressure test of them initially, and they gave them a thumbs up on everything except deck flatness and one valve's seal. I believe I now have everything addressed with the heads... I've been somewhat fearful of diving into this project, if I'm being honest, as it's by far the deepest I've gotten into engine work. That's largely why I was dragging my feet on finishing up the porting. It's too bad my neighbor moved out of state last year. He's a Chevy guy, but he knows engines inside and out...literally.

Please take a look over the below list and let me know if I need to acquire, or change direction on, anything:

Purchased:
  • Comp Cams 35-512-8 cam
  • Comp Cams 942-16 valve springs
  • Comp Cams 7905-1 pushrod length checker (6.125"-7.5")
  • ARP 154-3601 head bolts
  • stainless steel lower manifold bolts
  • FEL-PRO 9333PT1 head gaskets
  • FEL-PRO VS13264T valve cover gaskets (current ones leak)
  • Autolite 104 spark plugs (longer length than Autolite 25's, for GT40's)
  • Pioneer DA3021 harmonic balancer (50 oz) ... garbage
  • MAHLE T27802 timing cover gasket
  • Ford M-9439-G50 intake-head gaskets (regular ones too narrow for GT40 ports)
  • rocker shims
  • cam degree kit, includes checking springs
  • assembly lube, cam/lifter installation lube

Still needed / Uncertain:
  • proper length pushrods (once determined)
  • harmonic balancer
  • timing chain set




Answered below. I held off on purchasing a new timing chain set and hydraulic roller lifters. The engine was likely rebuilt shortly before I bought it <5000 miles ago, so I'm assuming the timing chain isn't stretched. I'll know when I disassemble... I haven't been able to confirm it, but I believe I have hydraulic roller lifters already with my '95 block, and this indicates any roller lifters should be okay to re-use unless obviously worn. Some say stock is roller lifters, others say they're hydraulic lifters, but none that I've found specifically refer to them having hydraulic roller lifters from the factory.

Answered below. Do I need softer checking springs for pushrod measurement? Opinions seem to vary widely on that. At ~6.3", I'll be near the bottom of the 7905-1 checker's range, so it should be less prone to bending than in many reviews. Could I just use my weak GT40 springs for that?? I think I saw somewhere the GT40 springs are around 80 lb seat pressure, while the Comp 942 springs are 115 lb. Comp Cams recommends the 942 springs for the 35-512-8 cam, but Mustang guys say more spring is better. (That leads me to believe I won't stress the pushrod checker as much as people running stronger springs, who are likely the ones recommending checking springs.) I suspect I won't be revving high enough (north of 5k RPM) for that to be an issue. The Comp 4758-2 "low tension" checking springs have no rating that I can find anywhere.

I also have a Felpro MS 94951 gasket kit from RockAuto. Summit and the parts stores say it's a 5.8L set, but RockAuto lists it for all Bronco, obviously including my 5.0L. Is there a difference in the lower manifold seals, or am I fine using those on mine if there is indeed an engine-kit disparity?

I was able to open the exhaust valve throats to 1.30" to 1.31", which is ~85% of the 1.54" valve diameter. The general rule of thumb is 90%, and I was using 87-89% as my goal for a street-driven vehicle, per a hot rod article. But, 89% is exactly the inner diameter of the exhaust valve's wide seat and barely less than the intake's. I didn't want to risk grinding/sanding that close to the seat and knicking it, so I left a tiny margin all the way around. The exhaust valves started at 1.26" to 1.27" (82%). I got halfway from starting point to ideal... (The intakes started at 1.56" to 1.59" = 85.5%, so I left them basically as-is for consistency with the exhausts.)

The machine shop told me the decks were 0.007" warpage, with a max allowable of 0.004". However, they conveniently overlooked the gasket remnant at the edges effect on that. I got my own precision straight edge (+/- 0.001" per foot, so 0.0015" over the ~20" span), cleaned the surfaces up much better, and measured both at 0.003" to 0.0035" (my feeler gauge's closest increments). Only a sliver of daylight is visible below the straight edge, which from what I've seen in videos, is consistent with decks in the 0.003" neighborhood. Would people agree that I'm okay at that reading, or should I consider something much more time consuming like this method? I still have the head gasket texture imprinted in the metal, unlike a machined deck.

BTW, the machine shop was recommended to me by a couple people as the best in town, but I wasn't impressed by the work or service. I've since talked to two other people, one of which who owned a performance shop at the time, who say none of the shops in town are to be trusted, including that one. (One shop was caught putting used parts back into a performance build.) They both send all their work 1-2 hrs away. So, doing everything myself without leaning on a machine shop is the goal. I did manage to get the one broken and badly seized lower manifold bolt extracted during my resumption of porting activities this fall -- the machine shop neglected to perform that requested task. I hope to never deal with that again (!), thus the SS bolts for at least the four corners by the coolant passages. I'm leaning toward using the stock bolts for the inner locations, since SS doesn't really have a torque rating, but I'm open to feedback on that.

The bulk of the below pictures were taken prior to lapping the valves. One of the seats never got smooth and shiny like the others (looks pitted, but doesn't really feel like it), but all of them are sealing well now, including the one intake valve that the machine shop highlighted as leaking. Each of the chambers holds water for several minutes, with the sacrificial old spark plugs threaded in to plug the holes. Some of the valves keep the runners below them bone dry, while others allow a drip out of the port every 1-5 seconds. Seems like that should be good to go, from what I've read, but I could lap them a bit more if people think that's wise.

The timing cover gasket was only a buck and change with other stuff, so I ordered it just in case. That was the only one RockAuto had listed. My water pump is nearly new, having been purchased at the time the '95 engine was installed. I'll be putting in a new thermostat. I suspect my current harmonic balancer has slipped, but I haven't verified distributor position and piston #1 TDC to rule those out, but I'll be replacing it with the Pioneer, anyway.

Tuning-wise, I got sniped on a Quarterhorse/BE package...still need to acquire something there. I have a new AEM wideband I bought several years ago for another project. I may go ahead and weld an extra bung on my Magnaflow y-pipe for it, so I can at least get some air:fuel monitoring going as a baseline. I have the MAF setup in place already.

Here's a sampling of the state of the heads:



Intake ports done. I didn't get super aggressive with the pushrod bulges, opting instead to just level (vertically) the wall's contour through there.




Close-up of one of the intake ports. You can see the walls aren't perfectly flat, but I didn't want to take off too much material in trying to reach that point that's mostly for aesthetics, anyway.




Close-up of one of the exhaust ports.




Exhaust ports.




Intake/exhaust bowls ported. The valve throat has been opened up as far as I dared go on the exhaust side, reaching 85% of valve diameter.




I also smoothed out the EGR passage's transition on each head.




Valves lapped ... plus a little flash rust from the water leak test. They all seem to seal well enough at this point.




Intake/exhaust bowls, before and not-quite-after porting. Most notable is how needlessly thick the valve guides are, and how restricted the exhaust throat is.




Lots of casting slop for carbon to grab hold of.




The infamous exhaust port thermactor bump.


Full-size pictures at: 1992 Ford Bronco GT40 Heads pictures, videos, and sounds | SuperMotors.net

The last thing I need to do is get the heads cleaned, to rid them of all the grinding and sanding gunk. A friend's dad has a workshop with that equipment, but who knows how long it'll take for schedules to align. I figure I'll fiddle with semi-polishing the exhaust ports in the meantime.
 

·
Registered
1986 Bronco Eddie Bauer 5.0 bone stock
Joined
·
999 Posts
Looks good, are you planning on gasket matching the intake and exhaust ports as well? From the pictures it looks like theres still a good bit of "meat" left if you wanted to match it to the gasket, do this on both the lower intake manifold and the intake side of the head to make a nice smooth flow through without interruption. Also, not as big of a deal, but you could do the same on the exhaust, at least go down in grit and get those exhaust ports slick as glass (leave the intake rough for swirl).
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #3 ·
I'll check the lower manifold against the heads when I have it off, but I already compared my old '92 manifold to them (via gasket matching) and there's not a lot of material that can be [safely] removed to match the GT40's big ports.

See previously uploaded pic at: 1992 Ford Bronco GT40 Heads picture | SuperMotors.net

Most of the excess is down around the injector holes. When inserted, they're deep enough still (from the inside perspective), that I assume some of that metal can be shaved away without exposing them adversely from a fuel spray standpoint.



Playing around with the old lower manifold to see how much material can be removed for gasket matching to the heads.

I'll work on the lower manifold when I'm waiting for the proper length pushrods to arrive, after taking everything apart and measuring.

I'm not sure how much the exhaust ports can be opened up to match the headers, but it's not worth taking any more off, from what I've read and observed. That's not the limitation there (the roof prior to it is), and as long as it's going small-to-big at the transition, there's no obstruction to worry about. Plus, you don't want to get greedy removing material and hit water jackets... I just wanted to even them all up and get all the wavy lip stuff out of the way of airflow.
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #4 ·
I may just finish up polishing the exhaust ports before people weigh in on my remaining questions in the first post. ;) Although, it's true what they say about polishing: it reveals all the little things that can be improved upon, resulting in a never-ending perfectionist process.

The shopping list should be completed now, once everything arrives: Ford M-9439-G50 intake-head gaskets & M-6529-A302 rocker shim kit, Comp Cams #152 Pro Cam Lube, and Permatex 81950 Ultra-Slick Engine Assembly Lube.

I finally read up on cam degreeing, and realized the full kit is needed, not just the degree wheel. I waffled a bit, but decided to go ahead and do it right and not rely on the "dot-to-dot" alignment method. This article was among those that convinced me.

According to Comp Cams..."If your cam phasing is off 4 degrees, the loss of performance is going to be in the neighborhood of 10 lb-ft on a 400 lb-ft/400 hp application, but only on the ends of the torque curve. This is a big deal in racing, but probably not dramatically bad on the street. That same 4 degrees could reduce piston-to-valve clearance by 0.030 inch. If you were already on the tight side, this is where checking the camshaft intake centerline can save you."

I'm hoping to gain ~40 HP between the heads and cam, which would equate to 6-7 HP being left on the table according to the above info. Maybe not the end of the world, but significant enough to beg the question of why go to all the trouble if leaving that much slop?

In a practical sense, size does matter. "Anything over 230 degrees duration at 0.050-inch tappet-lift on the intake side should probably be degree'd unless you know something about the piston valve reliefs. Anything under 220 degrees at 0.050 is probably safe. In between is a coin flip." [Comp 35-512-8 is 206 degrees intake at 0.050", well under that threshold, which contributed to the waffling.]

I was close to pulling the trigger on JEGS' 81621 kit, which is $97 regular, less 10% stacked promos last week, then went on sale for $88 the day after ordering when 4% of the promos had expired. But, I settled on Summit Racing's SUM-G1056-16 kit ($100 regular, $90 on special, less 5% cash back) which includes the magnet base for checking camshaft end play.

Both kits include checking springs (and TDC checker), so that killed two birds with one stone, and they seem fairly comparable otherwise. The Summit kit appears to be identical to Trickflow's $120 TFS-90000-16, but with a sticker (same as JEGS) on the degree wheel instead of it being laser etched. Reviews of the JEGS kit say the sticker gets pinched and twisted at the center by the bolt, so I might trim that area in advance, although having it my hands now, it's hard to see that being an issue.

The Pioneer DA3021 harmonic balancer turned out to be a dud. It appeared to have etched timing marks in photos, but they ended up being painted on. When I inquired, I was told they're powder coated, but the marks rubbed off with hand soap... I thought about etching them myself with a scribe, but then I noticed the elastomer band had a split in it. The stock-style balancers have a bad enough reputation for slippage without any help like that out of the box. So, I ordered a Dayco PB1084SS...which arrived as a Dayco PB1106N (Ranger/Aerostar, entry level). Still waiting to see if they can send me the right one or will it have to be a refund and back to looking for an alternative. AutoZone has by far the best price on the Pioneer DA-3021-HD (clearly etched marks in photos) at $92 less their ubiquitous 20% on $100+ orders, but it says out of stock when I try adding it to my cart... If I were to get a stock style balancer, I would scribe the outer and inner portions prior to install, so there'd at least be some way to verify down the road that it hadn't slipped, since slippage seems to be a design element.

I saw somewhere that a new cam bolt and washer, and thrust plate is advised with a cam swap?
 

·
Registered
Joined
·
221 Posts
i cant find my custom grind cam card
i just put my ported gt40 with larger chevy valves on with a custom cam, edelbrock upper/lower, bbk twin 56, shorty headers, custom exhaust etc.......so far so good.
i got a cheap ebay balancer that fit like a champ and the timing marks were etched in. got a timing set for dirt cheap as well, the good one (not with the cheap bicycle chain but a real chain) from canada. the links are like a motorcycle chain, quality is far better than stock or most aftermarket cheap ones.
i ran the stock cam bolt and plate. stock roller lifters, custom length pushrods, 1.72rr's, big valve gt40's with all the bolt on's........

lol, funny thing is i had timing off 180 when i went to start it which i guess was good, it just cranked and cranked.......but got everything primed up with oil first, fixed timing, went to start it again with gas filled cylinders and exhaust.....................lets just say all my neighbors came out. "its ok everybody............im a mechanic, i know what im doing!"..........lol
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #6 ·
Thanks. I'm not so keen on a no name balancer and timing set -- too much trouble to quickly replace if durability becomes an issue -- but good to know you found what looks like good quality for cheap. Good to know the stock cam bolt/plate and roller lifters worked for you. I'll figure those are getting reused unless I see any problems upon removal.

You ran 1.72's with a custom cam? I thought it's generally only recommended to go over 1.6 on stock cams for mild builds? Then again, you went with BBK TB, Eddy intake, and oversized valves...
 

·
Registered
Joined
·
221 Posts
they came with the heads when i purchased them so i ran them, you don't need 1.72's though. the cam was suppose to be ground with that as part of the equation and for $350, it was the same as an off the shelf with shipping. i think the specs were 272/280 .480 lift with 112 deg lobe seperation.........they originally wanted 110 degrees lobe seperation but im not running maf anymore so they upped it for the speed density.

i havent had time to drive it yet, its only done a few heat cycles in the driveway since life is too busy right now but i'll let you know how it goes, before the cam swap, the power was pretty decent with just all the other bolt on's and the stock cam.

the timing set is a high end unit i just ended up getting cheap, i wish i took pics of it first, its what you need to look for when looking for a quality timing set.
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #8 ·
Ah, I see, your cam accounted for the rocker ratio. Makes sense. Oh, cheap price, not cheap quality. Gotcha. I lucked out that way with several of the items on my list, such as the Comp cam being open box for ~$150 (guy opened it but never installed it), less than half price. What brand did you go with, in case it looks like I should change out my timing set once I have a gander at it?
 

·
Registered
Joined
·
221 Posts
these chains are longer lasting and can hold stupid power according to guys at the track. notice they are not like the cheap looking bicycle type. again.............i've never ran this until now, im just going off of what i was told from built 351's from going to the race track in san antonio when i lived close by.

heres a pic of my stock one, i have two of these which are worn out but have a ton of miles on them so i can't say they don't hold up because they did although they just had a lot of slop in them but i would guess thats normal with the amount of miles
171246
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,371 Posts
Looking good!

Yes, a 95 will have hydraulic roller lifters from the factory. And yes they can be reused if no significant wear is present.

Dont buy a dorman balancer... The one on my 300 only lasted 1200 miles before delaminating.

Any ratio of rocker can be used with any cam. The issue is most all cams for fords are ground for 1.6 rockers. When you go changing ratios, you change the valve timing events. The valves open and close at the same time, but will move a longer distance, which means they are moving faster. This changes the duration slightly. It is generally recommended to buy the correct cam and use the correct rockers. As you said, 1.7s are really only good for a stock cam when someone wants a bit more oomph without taking the heads off.

Jetski: that upgraded chain is the same type used in our transfer cases, so yes, they are very strong.
 

·
Registered
78 Custom 460 NP435 NP205 Sniper EFI HyperSpark Ignition 4.56 Gears Front/Rear Grizzly Lockers
Joined
·
3,450 Posts
That "upgraded" chain looks like the stock type chains Ford used on the 429/460 and probably others. I was under the impression that double roller timing chains were the upgrade and they do indeed look like two bicycle chains put together and the sprockets look like bicycle sprockets.

Here's the timing chain I removed from one of my 460's. Once this one gets rebuilt it's getting a roller timing set.


 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #13 ·
I definitely see the difference...will be interesting to see what mine has in it currently. That looks like the transfer case chain.

Yes, a 95 will have hydraulic roller lifters from the factory. And yes they can be reused if no significant wear is present.
Excellent, thanks for the confirmation.

Dont buy a dorman balancer... The one on my 300 only lasted 1200 miles before delaminating.
Yikes. Factory-style, I assume? Dorman also has some high end balancers, but I suspect they're not the actual manufacturer. I've been trying to figure out if the Dorman 594-024R ($180) and Professional Products 80007 ($80) are the same item, and who actually produces them. I read one review that says at least some of the Dorman SBF balancers are also offered under the PP line.

Any ratio of rocker can be used with any cam. The issue is most all cams for fords are ground for 1.6 rockers. When you go changing ratios, you change the valve timing events. The valves open and close at the same time, but will move a longer distance, which means they are moving faster. This changes the duration slightly. It is generally recommended to buy the correct cam and use the correct rockers. As you said, 1.7s are really only good for a stock cam when someone wants a bit more oomph without taking the heads off.
Good, educational explanation!

Jetski: that upgraded chain is the same type used in our transfer cases, so yes, they are very strong.
Ha, exactly my chronological thoughts.

That "upgraded" chain looks like the stock type chains Ford used on the 429/460 and probably others. I was under the impression that double roller timing chains were the upgrade and they do indeed look like two bicycle chains put together and the sprockets look like bicycle sprockets.
I had the same understanding of double rollers, but I hadn't compared photos to see if there are different styles within the upgrade realm.
 

·
Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
16,371 Posts
Yes, factory style for the 300 is a bit different than SBF though.

This little bandaid got me through the first half of Fins n Things out in Moab before it too broke.

 

·
Registered
Joined
·
221 Posts
5.slo's from I think 86 or 87 on up are all roller, same time they went to the 351 fireing order. 5.8s didn't get em till 94 f4te blocks and yes, mine were fine with 200k+ on them unless someone rebuilt yours flat tappet which i doubt and I've got plenty if you need any.
My pushrod checker did just fine pushing my 280# installed height springs with no signs of bending. Mine is an Elgin.
I got 10 pairs of head gaskets I found online for $6 ea, same felpro as yours which are my favorite besides the older part number one's which seem the same.
Luckily your already maf so you shouldn't have any surprises.
 

·
Ford Hoarder
78 & 92
Joined
·
7,740 Posts
I agree on the thrust plate. Espeically if the old one is extremely worn. Also if you put a different material cam into the engine then what it had. Just like the distributor gear, I feel the cam thrust plate needs to match.
Ford sells a billet steel one, there are other options too but this one is usually very flat, and the thickness is consistent.
also for the new bolt this kit has few odd parts that are harder to find if you need them
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #18 ·
mine were fine with 200k+ on them unless someone rebuilt yours flat tappet which i doubt and I've got plenty if you need any.
Referring to hydraulic roller lifters, I assume? I wouldn't mind having one or two as spares to put a stack of quarters in to make them solid lifters for pushrod measuring... Though, it's not a big deal to do that temporarily on one being reused, then just soak it in oil again to fill up.

My pushrod checker did just fine pushing my 280# installed height springs with no signs of bending. Mine is an Elgin.
Damn, that's either a stout checker or other peoples' technique sucks. Of note, the checking springs in the Summit cam degreeing kit are simple hardware store springs that are too narrow to slide over the spring seat, but that shouldn't matter with how weak they intentionally are. 3/8" x 3", easily compressible with two fingers. That should save someone $5-10 if needing a set...

I got 10 pairs of head gaskets I found online for $6 ea, same felpro as yours which are my favorite besides the older part number one's which seem the same.
Whoa, where'd you find those, and what's the older part #? I think I paid $32 for the pair.

I agree on the thrust plate. Espeically if the old one is extremely worn. Also if you put a different material cam into the engine then what it had. Just like the distributor gear, I feel the cam thrust plate needs to match.
Thanks for the links. Hopefully I won't need them, but I know where to start shopping if so. How do I determine if the cam is a different material from stock? It's not billet or anything, so I assume it's the same.
 

·
Premium Member
Joined
·
4,164 Posts
changing the cam and adding ported heads should get you a pretty nice little bump! won't the factory computer handle those changes, though? it's MAF so it should be able to handle quite a bit.

also, what about exhaust / headers?
 

·
Registered
'92 Custom w/ '95 MAF 5.0 M/T, 33's, 4.10 LSD
Joined
·
3,341 Posts
Discussion Starter · #20 ·
changing the cam and adding ported heads should get you a pretty nice little bump!
My goals are modest, sort of out of necessity. Assuming the engine is healthy enough currently to be near its rated power, I can give it a 23% bump before it reaches the M5R2's torque limit. So, a nice little bump should be just the ticket. :)

won't the factory computer handle those changes, though? it's MAF so it should be able to handle quite a bit.
Are you referring to my comment about getting out-bid on the tuning software? If so, yeah, I'll be fine without, and the argument could be made I'll be better off without, since maximizing performance via a tune could put me over 330 ft-lbs.

I did get a clamp-on O2 bung so I can run the wideband for monitoring, since I can't weld stainless myself. It's annoying that they're sized for 2.25" and 3" exhausts, leaving 2.5's to be stretched at the end of the range. Hopefully, I can make it fit.

also, what about exhaust / headers?
Already done. JBA headers, Magnaflow y-pipe, 3-way cat, old Flomaster muffler.
 
1 - 20 of 26 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top