68 170 Head rebuild

[ledslinger29]

I pulled the head off my old Bronco last week due to a leaky head gasket, decided to take it all apart and have it magnafluxed and the deck checked. I have a good head with a flat deck and no cracks. HOWEVER, all but two of the valves need replacing and the seats are so worn out they need replacing too. Total cost is gonna come out to about 860 bucks. Not sure if it's really worth it for a truck that I drive when I feel like it. Was thinking about swapping out to a 200, but who's to say all this work won't need to be done on IT when I find one. WWYD?

 

[bubba22349]

If you can find a mid 1970's or newer 200 than it should be in better condition being as they were designed to operate on unleaded fuel. Or if you rebuild your original head and later swap to a 200 then that head could be reused again just depends on your goals for it. Good luck

 

[ledslinger29]

I have read where some people are putting 170 heads on 200s. My falcon six performance book is inbound. If I do decide to rebuild this head, I'll likely go ahead and do it right, so I don't have to take it apart in the future. Does anyone have any experience with the little divider people put in the Siamese exhaust port? Ill certainly get the throat bored out to take a 2 barrel, if the generally accepted practice is to upgrade, but I read somewhere else that the small log head limits he amount of fuel and air you can get into the motor with a single carb, and questioned the value of switching to a 2 barrel. Like I said, I'm new to the i6 world, and I'm all ears. I dropped an EFI 351W in my last Bronco, and while quite awesome, I'd like to play with the six for sure.

 

[CZLN6]

Howdy Slinger:

"I have read where some people are putting 170 heads on 200s."
That was a mis-interperatation of a statement by Ak Miller in an early Hot Rod article (1964 I believe) when the, then new 170 head had bigger intake valves, slightly bigger intake tract volume and slightly smaller combustion chambers than later heads. This was an improvement over previous heads and can add slightly better economy than later heads. The smaller ports tend to generate greater velocity of the intake charge. Your '68 head all ready has1.65" intakes and 1.38" exhaust. They won't see an increase until about 1977 castings (D7). D7 and later casting will have induction hardened seats and a 1.75" carb hole too. The only down side of switching to a later head is the need to mill it to reduce the 62 cc combustion chambers to match the 52 cc chambers of the earlier head.

"Does anyone have any experience with the little divider people put in the Siamese exhaust port?"
Yes, I and many others have as well. Is it worth it on a lower performance engine? Marginally, at best. If one goes to the enth degree to get maximum performance out of one of these heads, along with a header, they are probably worth it. They must be properly fitted and welded into place.

The cost you quoted for new valves and hardened seats is a bit steep. I'd check around.

Your '68 170 should have an 1100 Autolite carb with a ported vacuum source to the distributor. That year should have a distributor with both vacuum and centrifugal advance.

Questions?

Adios, David

 

[ledslinger29]

Howdy Slinger:

"I have read where some people are putting 170 heads on 200s."
That was a mis-interperatation of a statement by Ak Miller in an early Hot Rod article (1964 I believe) when the, then new 170 head had bigger intake valves, slightly bigger intake tract volume and slightly smaller combustion chambers than later heads. This was an improvement over previous heads and can add slightly better economy than later heads. The smaller ports tend to generate greater velocity of the intake charge. Your '68 head all ready has1.65" intakes and 1.38" exhaust. They won't see an increase until about 1977 castings (D7). D7 and later casting will have induction hardened seats and a 1.75" carb hole too. The only down side of switching to a later head is the need to mill it to reduce the 62 cc combustion chambers to match the 52 cc chambers of the earlier head.

"Does anyone have any experience with the little divider people put in the Siamese exhaust port?"
Yes, I and many others have as well. Is it worth it on a lower performance engine? Marginally, at best. If one goes to the enth degree to get maximum performance out of one of these heads, along with a header, they are probably worth it. They must be properly fitted and welded into place.

The cost you quoted for new valves and hardened seats is a bit steep. I'd check around.

Your '68 170 should have an 1100 Autolite carb with a ported vacuum source to the distributor. That year should have a distributor with both vacuum and centrifugal advance.

Questions?

Adios, David

Thanks David, the work seemed a little pricey to me as well. I know good work comes at a cost, but I intend to shop a bit. He did note that the job included a three angle grind on the valve seat. I have an 1101 carb, and it is hooked up to the distributor with a vacuum line, the distributor was changed over to Pertronix a few years back, at which point I had it blueprinted. The carb was built in 66. Im not looking to build a race motor, but wouldn't mind getting a few more ponies out of it. Im toying with the idea of strapping some Clifford headers on, as they are made to fit inside of the Bronco frame. In my limited experience with getting more hp out of a motor, headers have given me the most bang for my buck. I'd just like to know that Im doing all the right things to this head so I don't have to disassemble it again in the future. I may skip the siamese port divider. Is there anything special I should take into account in the head if I should choose to put a big cam in it in the future?

 

[chad]

...the idea of strapping some Clifford headers on, as they are made to fit inside of the Bronco frame. In my limited experience with getting more hp out of a motor, headers have given me the most bang for my buck. I may skip the siamese port divider.

The tacked in divider goes widda headers. Headers on this motor only = 5 - 10% improvement. Most is in the ignition & carb.
UNLESS
U want the "cross flow" (that can = 500 HP).
But Y in a bronk?

I like the bigger 6s for low rev tq…
Years ago a MABR member put the LPG in one in the Allegheny, Cumberland & Blue Ridge & that wuz kinda torquie .

 

[ledslinger29]

[imagecap][/imagecap]

...the idea of strapping some Clifford headers on, as they are made to fit inside of the Bronco frame. In my limited experience with getting more hp out of a motor, headers have given me the most bang for my buck. I may skip the siamese port divider.

The tacked in divider goes widda headers. Headers on this motor only = 5 - 10% improvement. Most is in the ignition & carb.
UNLESS
U want the "cross flow" (that can = 500 HP).
But Y in a bronk?

I like the bigger 6s for low rev tq…
Years ago a MABR member put the LPG in one in the Allegheny, Cumberland & Blue Ridge & that wuz kinda torquie .

How big a six are we talking about? I had an 86 f150 with a 300 in it, I don't know if that thing would fit between the firewall and radiator in this little truck. I like that it sounds kinda like a sewing machine, but I'd like it to have a little more power than one. Maybe this valve job will put me at ease. I'm at a "while I've got it apart" stage, where a younger, wifeless,
childless, ledslinger with little to no time constraints was more of a "let's slap it back together and see what happens" guy

 

[chad]

"...the bigger 6s for low rev tq…"
the Falcon motors = 144, 170, 200, 250 known as the "sm 6" /and/ known as "the big 6s" the 240 & same 300 U mentioned.
The vee dub Bug wuz decimatin the American auto industry & ford came up wid da above (the 144 which kept morphin) as a response.
Sure it became the 'stang & bronk but that's the start.
UR vehicle is just a 4WD falcon or stang….

Ck out the cross flow. When the falcon motor went to OZ they kept with it while we went bent8 for the muscle cars. The cross flow is Down Under puttin a nice head on our (USA & Oz) bullet proof bottom end (7 mains!). Ta 4edoublel wid da 'log intake' !

The CI archive &/or "the Handbook" might both have a lill history 4 ya...

 

[ledslinger29]

My handbook is in the mail. I'll do a little reading and see what I can figure. That crossflow head looks like a bear to mount to a US block

 

[cr_bobcat]

A crossflow isn't really an option unless you've got a fat stack of cash available to you. If you do, go for it! However, you've got to find one stateside which isn't the easiest thing to do. Otherwise, you have to buy one from Australia then pay another $400+ in shipping costs then wait for a month or longer. Then you start getting into the fab work that you'll have to do and other custom order parts (ie. cam). So I wouldn't consider the x-flow to be a realistic approach for too many.

As far as the 170 head goes though, there was someone on here a year ago or so that posted some pics of a late model 170 head that had the larger intake volume but still had the small combustion chambers. Something along the lines of 48 cc if memory serves me correctly. I don't know how common they were but I think this one may have come off of a Maverick. Probably a D0 or later casting, if I had to guess.

In general, yeah, you could use the 170 head and potentially save yourself some milling of the head surface, but you're going to suffer from intake log volume issues. Late model heads can be gotten for a reasonable price if you've got the time to look and/or wait for one to pop up for sale.

 

[ledslinger29]

Thanks again for the response. What , amongst this crowd, is considered 'late model'?

 

[cr_bobcat]

Check out this link:
https://fordsix.com/archive/www.classicinlines.com/SmallSixSpecs.html#SSgeneral

In the "general specs" table, you'll see a compilation of the different heads. Generally speaking, most folks around here refer to the "late model" as the '77 and newer. These have the 1.75 intakes, larger log plenum, and hardened exhaust seats. There is what is commonly referred to as the "hex log". This is due to the hexagonal shape to the intake as opposed to the more cylindrical, earlier versions. There appears to be some additional challenges associated with making one of these work with some of the common upgrade tricks.

 

[ledslinger29]

That's a great table.

 

[ledslinger29]

So I decided to bite the bullet and get the head rebuilt. This is why I quit working on trucks, because I can't help myself when I start. It always turns into "well, while Im at it..." SO, I'm having them take .020 off the deck, and looking to put a cam in it. I've read a few threads, and I've seen the Comp 260H mentioned a few times as a cam that will give me a little more torque and still give me a smooth idle. I'm thinking I may as well go ahead and pull the rest of the motor and replace the crank bearings in and the main seals and the rings. And I'll probably drop the tranny and replace the shift linkage seals. Who likes what cam for the 170??

 

[chad]

rbohm is about the best - PM him if not showing up…
get all the parameters dialed in 1st then bring them to him.

 

[ledslinger29]

I got my handbook, and it's more fun to read than Animal Farm. AND it's left me with more questions than answers. As mentioned above, I'm sticking with the 170 head, mostly because I have it. I sent it to the shop for a three angle seat job, new valves, mild milling(020), and wallering out the carb hole in the top of the manifold to 1.75. What should I do with the stock 1.5" bored carb spacer? Book says I don't need to run the heater hose through it anymore, easy enough. In my past experience throttle body and carb spacers were desirable. Should a I ditch the spacer? What carb fits a round 1.75" hole? Also how do you take apart the adjustable rocket arm shaft for cleaning and boring out the oil ports? I can't get the first and last arm off, but that's about it . On a side note, I tried calling the number on the classic Inlines site today and it didn't work.

 

[cr_bobcat]

The spacer re-orients the carb right? So you could hog it out as well. Otherwise you need to mod the throttle linkages.

 

[CZLN6]

Howdy back:

Q- "What carb fits a round 1.75" hole?"
A- With a '68 distributor an 1101 Autolite would be a great choice. It will be stock appearing and all hookups are the same as your bigger T-bore. '69 and later 200 came with a good carter YF with a 1.75 t-bore but would require adapting for linkage, fuel line.

Q- 'Also how do you take apart the adjustable rocket arm shaft for cleaning and boring out the oil ports?"
A- Yes. The inside of the shaft needs a thorough scrubbing and cleaning. The holes in the rockers should, at least, be cleaned and cleared of built up crud.

Sorry to hear the Handbook is causing more questions. How can I help? Did you get a shop manual for your car?

Adios, David

 

[ledslinger29]

Howdy back:

Q- "What carb fits a round 1.75" hole?"
A- With a '68 distributor an 1101 Autolite would be a great choice. It will be stock appearing and all hookups are the same as your bigger T-bore. '69 and later 200 came with a good carter YF with a 1.75 t-bore but would require adapting for linkage, fuel line.

Q- 'Also how do you take apart the adjustable rocket arm shaft for cleaning and boring out the oil ports?"
A- Yes. The inside of the shaft needs a thorough scrubbing and cleaning. The holes in the rockers should, at least, be cleaned and cleared of built up crud.

Sorry to hear the Handbook is causing more questions. How can I help? Did you get a shop manual for your car?

Adios, David

Thanks everyone for your continued interest in my rookie head thread!
David, don't think I'm complaining about the book, its a great read and well written, and has certainly answered a lot of questions for me and given me some ideas. I've read it three times so far.
I don't have shop manual for my car, which is a 68 Bronco. I believe, according to what I've read, that I have a 66 Autolite 1101, as the tag reads C6TF F A 7AD. the bore is 1.5, as is the bore of the spacer. I rebuilt it, and sent it to distributor dynamics to have the carb and distributor matched and a Pertronix module added.
The block stamp starts with C8, so it should be a 68. The book indicates that after 65 all 170s came with hydraulic lifters and non-adjustable rockers, I've got solid lifters and an adjustable rocker. Is the difference perhaps due to the fact that it's in a truck and not a car?
How do I get that rocker shaft apart?
Thanks again David for a great book and advice!

 

[CZLN6]

HOwdy:

Glad to hear the Handbook is helpful.

The Carb- "C6TF F A 7AD" is a 1968 Autolite 1100, The "T" indicates "Truck". It has NO Spark Control Valve (SCV) and is rated at 156 cfm.

The Autolite 1101 is a 1969 only piece used on 250 engines, most commonly in a Mustang. It has NO SCV and is rated at 210 cfm. It looks identical to the 1100, and is a direct swap in your case since you've already opened up the carb hole. '69 1101s are getting very scarce and hard to find. All this is moot if you are planning to go to a two barrel at some time.

Your '68 block is most likely a hydraulic lifter block. The adjustable rocker arms are most likely a carry over from earlier years. They are a nice additions to be able to get the most out of the cam and to compensate for machining changes in the engine. Adjustable rocker arms were a common carry over item to later years.

Getting the rocker and stanchions off of the shaft can be challenging. Use lots of solvent, twisting and cussing. A stuck rocker arm could be an indication of wear on the shaft so inspect it carefully once you get it apart. It's the inside of the shaft that can get really gunky if the engine has been sitting a long while and/or poorly maintained. Generally, it's the front rockers that show the most wear because they are the last to get oil on start up.

You said you carb and distributor were matched. What does that mean? Centrifugal advance recurved?

Be sure to specify that you want the intake valves back cut with a 30 degree cut. This is an inexpensive and cost effective upgrade so long as the head is being done.

Adios, David