Blowing 3 Gees on my Six

Luke, It is much easier using a valve spring tester to do it but, really the .060 min. is the total amount of clearance needed over the cams lift. IE all the gaps between coils added together the goal is so that the spring coils don't totally all bottom out at max lift (or stacked) as this would cause bent push rods. You can just install the retainer on the valve stem without the spring to measure the guide seal clearance and also the spring install height using a snap gauge or a like a 6" steel machinists ruler. Sometimes you can also swap the parts around if you find you need a little more for a tight one.

Looking at your direct mount intake it looks like was done fairly well good catch on the cut off stud. That maybe could have been filled in with some epoxy (or better yet welded) and at the two places were is a little narrow not sure there would be any danger of the heat effecting the epoxy that high up on the intake. How did the gasket look any signs of a vacuum leak anywhere?
 
Well, I finally ran into the issue of degreeing the cam on a 250. I'd read all about degreeing the cam but most of the threads I was looking at had to do with the 200... as it turns out the timing set for the 250 doesn't really offer any adjustment. It would be good if CI added a note about this in their tech section.

Fortunately in searching the forums I came across the most common solution, a Mr. Gasket offset crank key, which they sell in 2* and 4* versions (part number 987G and 988G respectively). I've ordered both but haven't decided yet which to use. CI recommends the Clay Smith cams be installed 4* advanced but they also say 2* is a good alternative if you want more power at highway speeds. But I'm not sure I'd even be able to tell the difference from the seat of my pants...

Anyway, not a big deal in the end, just sets me back another week waiting for a teeny, tiny part! I think I'm going to ask that the machine shop not degree my cam since there isn't really a whole lot that can be checked - that will save me a bit of labor cost. I can always do a degree check myself afterwords just to make sure it wasn't installed retarded or something... :roll:

PS: Bubba, my two carb gaskets have looked fine, no vacuum leaks that I can tell. I'm also surprised I haven't had the problem some people have found of excessive heat in the carb, since I have no phenolic spacer (just the aluminum). However I never really got a chance to drive it very far on the new carb so maybe I didn't notice.


Luke
 
Well, I finally ran into the issue of degreeing the cam on a 250. I'd read all about degreeing the cam but most of the threads I was looking at had to do with the 200... as it turns out the timing set for the 250 doesn't really offer any adjustment. It would be good if CI added a note about this in their tech section.
Click to expand...

The tech for degreeing the 250 is the same as for a 200 except for the timing chain set is longer because the cam sits up higher from crank center line than a 200. This below video is quite good on degreeing a 200 cam. The offset key's and dowels where in use for many years before there were multi key way crank gears & double roller timing sets. Only bright spot is that the early 250 timing set (1969 to early 70's) is not retarded like the late model set I believe this is only in the crank gear though have not checked mine out yet.

Mustang 200 Rebuild Part IV Degree cam

http://www.youtube.com/watch?v=zj-GA494SJQ&feature=plcp

I'm also surprised I haven't had the problem some people have found of excessive heat in the carb, since I have no phenolic spacer (just the aluminum). However I never really got a chance to drive it very far on the new carb so maybe I didn't notice.
Click to expand...

Luke I would recommend using the thick carb base gasket stock on the mid 70's up Ford 2V V8's is about a 1/4 inch thick there is also a thicker 3/8 one too. :nod:
 
Hi Bubba, I've seen that video and it is very good. However the 250 is unfortunately different from the 200 in that there are no multi-keyway crank gears, nor any double-roller timing sets available for it (see this post by Gene Fiore and this one by Does10s).

I thought it would a simple matter of adjusting the crank gear the way everyone talks about, but come to find out that's not an option on the 250! For whatever reason most people actually have the 200 here in the forum, and most of the information is geared toward it. I suppose the 200 must have been more common in Mustangs/Falcons, which are the cars most people here are running.

Anyway if there is a multi-keyway crank gear out there that someone has found, I'm all ears! Otherwise it's the offset crank key for me (the whole idea of an offset key seems a bit dodgy to me, but I guess they must work ok...)

As for the carb gasket - if I end up with some problems I'll check it out, but hopefully I'm ok because my air-cleaner is already touching my hood! (But I could maybe go to remote induction).


Luke
 
Anyway if there is a multi-keyway crank gear out there that someone has found, I'm all ears! Otherwise it's the offset crank key for me (the whole idea of an offset key seems a bit dodgy to me, but I guess they must work ok...)
Click to expand...

I can tell you that the offset keys work great when the damper is bolted down the timing gear is tight against the crankshaft and is not going anywhere. Another way would be to have a new key way or mutli ones cut in the crank gear, if you have a well equipped machine shop near you. Other than that I was going to check to see if they might be making the double rollers 250 sets over in Aus.
 
with the auto trans I figured you wanted straight up... oh well, but yeah I agree never to have an engine shop degree my cam again, just install it and I'll do the chain. the early model timing chian set would be ideal for your application.

the multi key for the 200 is only from classic inlines double roller chain, I haven't heard of one for a 250... would be interesting if you could use a 200 crank gear with a 250 timing chain and cam gear... but I'd bet if that was the case I'm sure CI would have already done something like that.
 
I really have no idea if I want straight up, 2* or 4*. I was basing my decision on nothing more than what CI recommends, which is 4*. But I'm not really sure how to make the best determination for my own purposes.

I do in fact have the early timing chain set (I believe), anyway I ordered it from CI and it says on the website they default to shipping you the early set. Of course it comes with zero documentation.

I'm tempted to just tell the machine shop to finish installing the cam, crank and pistons and I'll do all the timing stuff myself... I ordered a Moroso degree wheel and I already have a dial gauge. I think the main things I wanted the machine shop to do were the bearings and such, as I really didn't want myself to have the chance to screw myself when installing such vital components. ;)


Luke
 
Ok, got the block back. Tried measuring lobe & valve lift so I can decide what I need to do with my springs.

I can confirm that lobe lift on the 264-112*cam is indeed 0.29". I measured this with my dial calipers set on a pushrod as I turned the crank by hand. Measured it on four different lobes and got exactly 0.29" every time. This is good because it matches exactly what the CI Cam Spec page implies (click here).

However, measuring valve lift is much more tricky and I was not very successful at it. I will go back out tomorrow in the daylight and try again. Of course the roller rocker is touching the top of the valve so you can't really put a dial indicator right on the valve tip. I tried putting the dial indicator needle at various points at the tip of my rocker arm, the roller itself, or on the valve spring retainer - but in all cases I kept getting measurements way short of what I would expect, and also, measurements that would vary quite a bit from one try to the next.

Supposedly these CI rockers are supposed to be 1.65 ratio, which would imply a valve lift of: 0.29" lobe lift X 1.65 ratio = 0.4785". I never got anything above 0.36"

I will make a better effort tomorrow and see if I can improve on my readings. The head wasn't really torqued down so maybe it was scooching around every so slightly while I was turning the crank... This wouldn't have been a problem when I was measuring the pushrod, but could have affected the valve reading. Also I am using testing springs on the valves but even they are pretty stiff, and I'm wondering if that is causing my lifters to compress slightly. I tried filling them with oil but maybe I didn't quite get them "filled" up completely.



Luke
 
Since the rocker swings in an arck the ratio is always changeing it's only going to be 1.65 when it's 90 degrees to the valve stem. You might need to use a solid lifter to measure max lift that way the hydrolic lifter is not collapsing. Good luck
 
I "converted" an old hydraulic lifter to a solid lifter by filling it with JB Weld. Then I got the head on good and tight and was finally able to get some repeatable measurements of valve lift.

I get 0.474" which is very close to what we would expect if the rockers were 1.65 ratio: 1.65 ratio X 0.29 Lobe Lift = 0.4785" valve lift.

I'm going to chalk up the 4-thousandths difference to my measuring inaccuracy and say with confidence that my rockers are 1.65 ratio.

In other news, I am afraid to say that the Tempo flat-top pistons are not exactly the same installed height as the regular 250 pistons, as has been claimed. They actually sit a bit lower. I know this because even though we milled 0.020 off the top of the block, with the Tempo pistons my piston-to-deck clearance actually increased, whereas it should have decreased by 0.020".

This will change my CR calcs... I think now my compression ratio will end up closer to 9:1 instead of the 9.5:1 I was shooting for. I should have measured the pistons before installation rather than make assumptions. I could mill more off the top but at this point we'd have to completely dis-assemble and then re-assemble the block and I'm asking myself if it's really worth it...

I'm also asking myself if it's really worth it to install the cam with advance because the Mr. Gasket offset crank key does not look like it will fit the crank without some mild-to-medium modification. Richard was suggesting I might just keep the cam straight up due to the auto trans and the fact it will be run on the highway.

Decisions, decisions... And it's so hot outside my brain is addled.


Luke
 
the lift sounds about right, nothing is perfect but at least it's consistant.

the pistons, they sit lower, but were your other pistons dished? if so, it might compensate in your favor. 9.1 is what I have and I was aiming for 9.3, with 9.1 I can run 91oct safely, and 89oct safely, but 87oct I have to run little richer to no ping.

the CAM, IMO, engines with autos rev higher naturally, because you aren't using the lower rpm torque. and you have a torque converter so your lower RPM's are taken care of. so that's why I suggested straight up to help top end.

either way you should make more power than me with your 50 extra cubes.

for the heat in that storage place, why not get a 36inch shop fan, moving air really helps!!!
 
Yes, my previous pistons were dished so I got rid of that volume at least by going to the flat-tops. And we did mill 20 thou off the block which is better than nothing, even if I would have done more had I known in advance the new piston height.

Prior to any work on the block my CR was 8.6:1, now with the new pistons I'm looking at about 8.9. Seems a shame not to go higher but I'm not about to redo the whole block now. It just goes to show how important it is to measure everything and never take published specs from the manufacturer for granted. The piston height was probably the only thing I didn't measure and of course, that's the one thing that ended up being different.

But at least it wasn't too different the other direction, giving me some crazy CR or interference between valves and pistons. That would have been bad news bears for sure!!

Richard I've decided to go ahead and install this cam straight up. Your reasoning sounds good :thumbup: plus it's just too much work to start whacking on the crankshaft now. This is another area where if I'd informed myself better ahead of time we could have modified the crank while it was out, and now it's just too much hassle. But it sounds like straight up may be best for me anyway. I'll still degree the cam to make sure I have the old timing chain that's not retarded.

The head is getting the spring seats machined now... meanwhile I've painted the oil pan and getting ready to paint the block.


Luke
 
I guess don't understand on The old crank key it should come out with punch fairly easy, did they send one that is to wide or too long to fit the grove? Most Fords will use same width. As far as the compression that's is a pain since it's off so much. One thing you could maybe do is look for a copper head gasket in .025 or .030 range you could maybe pick up a 1/4 point that way and copper head gaskets are reusable.
 
I'll try to take a picture of the replacement crank key and the one already in the crank. You can kind of see a picture of the Mr. Gasket key here.

The Mr. Gasket key is maybe 1 inch long, if that. The key in the crank is at least twice as long and maybe closer to 3 inches. It looks like the Mr. Gasket key might be just long enough to engage the crank gear, but wouldn't even come close to engaging the harmonic balancer. I guess the balancer doesn't care if it's offset or not, but you'd still need to key it with something to keep it from spinning. I suppose we could cut the crank key in half, and press in the Mr. Gasket key behind the front half so it engages the gear. But this seems kind of kludgy... and given the half moon shape, maybe not very effective.

Or are you supposed to pull the crank key and cut a half moon into it? I guess I don't know what the crank key even looks like. I wacked on it pretty dang good but couldn't get it to come out.

I guess it's all besides the point if my build would be just as well with the cam straight up...


Luke
 
If you do some pricing of the rod bearings and crank grinding, you'll most likely find the solution for US 250's is the do what Kelly and Does10's does...run the 4.6 Modular conrods.

I use the Aussie Ford Corsair/ US market Nissan 240SX rod on my supercharged and turbo Aussie block engines, and this is almost the same, and being Nissan, just as tough.

Our Aussie blocks are the same height as the US 250 based 1986-1992 HSC 2500 four cylinder engine (The Taurus 2.5 liter base engine, and the optional engine on the 1986-1992 Topaz before the Vulcan V6 option), and its 9.38" tall. The HSC 2500 has a 6" rod, but only a 3.585" stroke. The pistons and rods fit the 250, but with the 3.91" stroke and a nearly flat top piston, the compression ratio is up in the 10.8:1 bracket even with a nice thick composite gasket. But with some 3.3/200 X-flow 15.5 cc Aussie Duralite or Repco/Mahale items, its fine. There used to be a US 12 cc 200/250 piston listed too.

See "250 with hsc 6 inch rods zero deck flat tops and 62 cc head with 41 thou gasket"


Compression is a massive 10.85:1. With the 15.5 cc pistons, its 9.07:1 for a 30 thou over engine.

If you go modular, its much easier to get lower compression ratios

Both Modular and Nissan rods are a lot longer, and you need the Ford 5.0/5.8 Coyote piston, but it'll do just fine for a fraction of the costs, and you can keep that nice 9.469" tall deck. Never, ever deck a US 250 block...the thermal stress of the heated ledge can cause cracks about the head stud radius. Seams to be a very common problem.

Then you can use the larger 62 cc chamber and a composite 41 thou gasket and select a piston which has the right cc to make a target 9.5:1 compression ratio. If your advance is wound back enough, even an iron head will cope with that. You'll need an anti dieseling solenoid when C/R go above 9:1
 
Hmm , My Deck is cut .200 Yep no Typo , the motor has 12.3-1 and about 50-65 passes , no leaks , no cracks , so I respectfully disagree , I would not Deck that much , on all combos but again Ive had no problem , but I als run 100 octane fuel and keep it out of Detonation , as that is the KILLER of a normally otherwise healthy motor , NO Timing By Ear or Vacuum Gauge , I know the numbers , just saying
 
The key Looks fine!

It looks like the Mr. Gasket key might be just long enough to engage the crank gear, but wouldn't even come close to engaging the harmonic balancer. I guess the balancer doesn't care if it's offset or not, but you'd still need to key it with something to keep it from spinning. I suppose we could cut the crank key in half, and press in the Mr. Gasket key behind the front half so it engages the gear. But this seems kind of kludgy... and given the half moon shape, maybe not very effective.
Click to expand...

Correct if you did decide to use it, for it to work all you need is it be just for the crank timing gear width and cut off the other key (org.) to fit that keeps the balancer timing marks right. You want the offset key to not stick past the crank gear face. I usually soak the old keys if engine had a lot of sludge or varnish with some spray penetrate or other cleaner. Than with the key pointing straight up, drive the key down on one end (1/4 inch or so from tip) this will lift and other end of the key than you can get something under it (screw driver or punch etc.) to pry it out. The wood rift or half moon keys are very effective and been in use on machinery probably over a hundred years very seldom is there ever a problem with them.
 
I thought an offset key to change timing is directed on the cam key, not the crank key...

oh well, just install straight up and call it good, IMO I really think you'll be happier with it straight up than advanced...
 
MPGmustang":1soumovu said:
I thought an offset key to change timing is directed on the cam key, not the crank key...

oh well, just install straight up and call it good, IMO I really think you'll be happier with it straight up than advanced...
Click to expand...
True for a 200...a 250 cannot be degreed using the timing set...must be done at the crank.
 
You must log in or register to reply here.

Similar threads

phipplet
All Small Six 1962 Falcon Wagon C4 & 200
Replies
13
Views
750
bmbm40
B
AZstang66
All Small Six Export and Monte Carlo braces for VI cylinder head
Replies
11
Views
775
Jmustang_65
J
F
All Small Six Block identification help.
Replies
3
Views
366
John Ha
John Ha
J
All Small Six High altitude jet size autolite 1101
Replies
19
Views
554
Frank
Frank
awasson
All Small Six Ford Six Mustang Offset/Dual Muffler
Replies
3
Views
290
Kritas
Kritas
Back
Top