Crossflow tips!!

bookworm007":3ocdh8vx said:
Also is a 2 barrel carb going to be good enough to power this engine or would it require a 4 barrel? Just looking into what intake to get.
Click to expand...

Because of the distance to get replacements/upgrades, go with the 4Bbl intake. With an adapter, you could run a 2Bbl on it if you want. An Autolite 4100 would work on your engine.

Since the crossflow uses the same rockers as the Cleveland engine, stock ones will fit no problem. You get into clearance issues with roller rockers. What a lot of guys do is make or buy a spacer for the valve cover to provide clearance for rollers. Aussiespeed makes a tall valve cover for rollers, and spacers if you want to use your stock cover.
 
Also does anyone know what the standard replacement head gasket thickness is for these motors? And is there anything wrong with using standard replacement ones? I see that a lot people try to use the ACL gaskets but they are getting hard to find. thank you Rocklord I will start looking for a 4v intake, and some standard 351c rockers.

Oh and earlier someone asked why my town was called Battle Ground and I forgot to respond :oops: But when the area was being settle there was supposed to be a battle between the settlers and the local native americans, but a day or two before the battle the chief died and the native americans decided not to fight. So they still called it Battle Ground even though the battle was never fought. At least that is the story on the sign in the middle of town......
 
bookworm007":3hzgz78r said:
CNC-DUDE: And what are the flanges made from?
Click to expand...

That price is for 3/8" mild steel. Intake port flanges are also available if want to make your own intake manifold.
 
the crossflow head gaskets are differnt to the pre crossflow(log heads) - so need to organise a stash of them to be psoted over
 
Let me add my .02 to the discussion. I think I might be the only person to ever get a hybrid crossflow/US block together.

A lot of aussies ask, why. Well the answer is logistics. It's relatively easy to ship a 40lb head 12000 miles from Oz, but not so the 300lb block. Also, the internals and all the ancillaries are very different, so you have to import a lot of stuff to rebuild one and make it work. The Crossflow is a great engine but very rare in the US.

So, yes, you can make the head fit. Here are the issues you will face: First, the block needs extensive modification. You will have to pull it out, disassemble it, and start grinding. I outlined the holes you need to plug, the ones you need to open. Then you need to somehow extend the side of the block to support the gasket on the pushrod side. This turned out to be problematic. It is hard to get a good seal and the engine tends to weep a lot of oil. I tried bolting, welding, and using JB to seal that side but it is not easy.

Second, the head itself needs lots of mods. I sealed a couple with epoxy, but welding is preferred. One other thing I think needs to be done is to add some steam relief holes to somehow replace the ones that were sealed. I'm not convinced that the coolant flow is adequate without those passages.

The head uses a sled fulcrum rocker like a 351/460 and you should be able to use those if you don't have stock ones. The fulcrum base may need massaging to fit the recess on the mounting pedestal. Crane used to make a rockerstud/pushrod guide adapter that would bolt on, but those are no longer available. There is just enough meat on the rocker stud pedestal to machine for a 3/8" stud. A 7/16" stud might not leave enough metal around the pedestal so check carefully before drilling. The valves are canted like a 351, but at different distances and slightly different angles. The 351 guideplates will need welding to fit. . You need to use 289/302 lifters and you'll have to measure for pushrods because the stock ones won't work.

On a 250, you should be able to use any US 250 distributor. On a 200, there is no room for anything good.

On any 250, log or crossflow, you really MUST fix the quench issue. Jeep, 255 Ford, or other pistons can help fix the compression distance, but leave you with a very high compression ratio. It will take a combination of machine work on both the piston and the chamber to get it down to a manageable level. If you don't get the deck height right, you lose a lot of the advantage of the crossflow's chamber shape.

The bottom line is this; The easy way out, and probably the cheaper route, is to import a complete Aussie crossflow engine and all the rebuld parts. a US/Crossflow hybrid is a very custom engine. It takes a LOT of machine work to make it all fit together. It is not easy and not inexpensive.

If you really need 300hp, all you have to do is pull a roller cam 5.0 out of almost anything, stuff a B303 cam in it, top it off with a 600cfm carb and a durspark distributor, and voila, 300+hp for pretty cheap.
 
Well put Jack, then theres another problem to add, good crossflows are getting a bit scarce, since the last one was about 1988 theyre all pretty old and worn out.
I had a devil of a time getting a standard bore 200ci version and I had to pay , what I thought was "over the odds" for an engine. Ive got 2 crossflow alloy heads, but they both need fixing.
As to rocker arms etc Yellaterra does a good line in them, if your running under 0.5 lift (and I wouldnt run any more, given the length of the pushrods and the fact that the ports dont get any better over that anyway) you dont need them. ( Im working on an Idea to fit carbon fibre tubes over the standard steel pushrods to increase stiffness, as yet I havent sorted it out.
As Ive stated before the OHC is a much better proposition if you really want an inline six.
The OHC and the DOHC engines are cheap, $500 will get you one. They are completely bulletproof, have good power and quite a bit of aftermarket support.
The DOHC will be tight in the Mustang and its got double variable cams which might be a bit of a problem.
A7M
 
hmmm Thanks for all that info! Been processing it for a couple days to see if there is a feasible way to continue on.

First with the oil leaking problem. My block has what looks like unused bosses on that side of the block, if a guy had that whole side of the block machined smooth and then attempted to weld or braze on the deck extension do you think it would be more successful? And of course after you attach the plate have the deck machined so everything is flat and true. Where does your seal leak from and what do you think causes it?

Next cooling problems: The need for filling in the cooling passages makes more since now that i have looked at my head. And it would appear the cooling passages are on the opposite side on the aussie head? Most likely due to the larger area needed for push rod clearance. (or maybe because the toilets flush the opposite way down there? :LOL: ) Could the US block be modified to use the crossflow head cooling passages? Because i would agree those two little holes seem very inadequate to cool the head.

Valvetrain: I did not know that the valvetrain would also require modification. From your build up it sounded like the 351C parts were pretty much bolt on. A7M does yellowterra still supply those rockers for the crossflows?

Next quench: I was planning to use the 250 block because i thought it would make adapting a tranny easier, get me extra cubes, and allow me to retain my DUI ignition, but this quench deal is going to be a big hurtle. I have done some forum searching and here are the options i have found so far. Dishing the 255 pistons would be an option but would probably have to be used in conjunction with with a few other tricks like decking the block, offset grinding the crank, and carving a few more cc's out of the head. How many CC's can you realistically dish one of those pistons? Also i looked up the code on my head and its an aussie D code which i believe it has small combustion chambers in the 42cc range which is not going to be a great match for the 250. So next question is how much volume can i safely add to this head?

Option B: Use Jeep 258 pistons with the lunar crater sized dish of 21cc this plus the fact that they have a 1.63 pin height would completely eliminate the need to deck any surface more than what is needed to ensure a good seal of the head gasket. The big downside is i would be forced to over bore .070 which would not allow me to use this block again without sleeving it. But i might already have to do this because I noticed the soft plugs on the block look a bit too shiny to be 40 plus years old. This seems like the best option to keep the compression ratio down. With these pistons the deck zeroed and one of the .050 crush head gaskets i could come in right at 9.7 to 1 assuming i could open my head up to 52cc, if all i could squeeze out was 50cc then the ratio would jump to 10:1 too high for regular but with the right cam i could make it by with premium.

Yes a v8 would be the cheapest and easiest but i hate looking at them. I work on this car for fun, something to play with, and releave my appetent need to over engineer everything i touch.

OHC engines would be a great option to keep a six but once i get the fab work done on this one almost any part for it i can roll down to napa and pick up. Not the case with the OHC engine.
 
I think its going to defeat the purpose to put a head with this potential on your engine and then use such a large dish piston to correct the compression ratio that will have no quench to it just because the numbers work out. I would get some custom pistons made that would mirrror image the chamber and yield the correct compression instead of the AMC pistons. Once you get to this point you are going to be so deep into it with time, labor and money, a few hundred more bucks thrown in the right direction might make it worth the effort in the end as opposed to stopping short and not having a combo that can be all it could have been.
 
There is probably some truth to that, but if the 250 block becomes too unwieldy to make work for the pistons i also have a good 200 block i could use. Putting an EDIS megasquirt system on would be much cheaper and easier than having custom pistons made since for a set of 6 your probably looking at at least a grand! Also the combustion chamber size of my head would lend its self better to a 200. Just it drops the realistic power potential greatly without adding forced induction
 
I have a crossflow head that has around 57cc combustion chambers. It would have to be rebuilt. Maybe we could do a swap?

The ACL pistons for the 4.1L crossflow with 200 rods had 20cc recesses and didn't have problems making power.

As for the rockers, Crane Cams has started reproducing the kit that allows roller rocker arms to be used without machining the head, Crane Cams 52655-16 about $120 from Summit Racing
http://www.summitracing.com/parts/CRN-52655-16/
This would allow you to use locally available roller rockers, as opposed to the Yella Terra's that cost around $450 plus shipping from Australia.
 
I would be very interested in that! then maybe i could go with a smaller bore piston. I found some dished GM 250 pistons with a bore of 3.685 and a pin size of .927. If you sleeved the block to accept them and reamed the rods for the pins would these be viable? This is the link for the pistons: http://www.summitracing.com/parts/SLP-599P/ Then the block wouldn't be weakened and they have a compression height of 1.640 I would be at zero deck with no machine work on the decks. What other parts have you gotten for your build, do you have a plan yet? Then only thing i havent been able to find is how much these piston are dished. I'm hoping they are about 10cc, but the best part is they are only 18 bucks a piece!!! Oh and rocklord what code is your head?
 
Okay so a little bit of a mystery with these pistons. The application part of summit racing says the pistons are for a gm 250 inline 6 but the stock bore for that engine is 3.875 no where near the 3.685 summit racing says they are....... Since they are only 18 bucks I am tempted to buy one and check the size my self or maybe call but i dont know if the sales reps would really know anymore info.
 
Yep, the stock bore for the Chevy 230, 250 and 292 are 3.875", so these are way too big for the small Ford 6's. Must be a misprint or just bad tech advice for them to even think they can interchange.
 
Yeah I am guessing its a mistake on their part too, but new plan that wouldnt involve expensive sleeving. These pistons http://www.summitracing.com/parts/UEM-1743H-5MM/ have a compression height of 1.310 in and a bore of 3.720 only requiring a .040 overbore which is very conservative. If you used these pistons with 300 rods which have the same big end dia as the small six engines the piston would only poke out -.0057 inches before machining. Which is pretty darn close to zero decked. the piston pin hole would have to be opened up by .007 inches so very minor, and with a 62cc head 9.5:1 compression ratios are a possibility because these pistons have a 12.67 cc dish!
 
Oh Wow, oh wow oh wow! That econo piston is the answer! Bookworm007, you da man!

Silvolite has 'em listed too http://www.kb-silvolite.com/silv-o-lite ... s&S_id=552


In one Falcon swoop you solved
1.an 11 year old problem I had with my X-flow, and
2. have made a 221 stroker from a 200 possible and
3. Have fixed all the US 250 problems and made them strengths. L/R, the lambda length of rod to throw ratio, a problem with all Ford sixes except the Aussie 3.3 from 1971 on has been fixed. 1.5:1 where the rod is 5.88" and the stroke is 3.91" is not a good ratio for reving past the peak power curve.The US 200's has 1.5:1 too, with 4.71 to 3.126" and all 250's on both sides of the Pacific rim suffer an asthmatic halt past there power peak because of this ratio. Long rods unload the pistons at high rpm, reducing frictional losses under hard loads. The C/R problem with big stroke sixes from 221 to 250 has also been fixed.

What a Good choice, best one I've seen as this is the hardest nut to crack since the thin wall 250 has a huge deck problem that cannot be solved by decking! In my opinion, the decking of a block that has led its life with with that 103 thou short fall is a bad idea, it hairline cracks about the front head studs and on an engine that needs longer rods, why would you ever deck the block? The piston, mated to a longer, bomb proof 300 6.21" Ford rod with a nice brass bush, or earlier pre 69 rods with there stock 0.912 wrist pins would be ideal to bush down to 0.905". 1.31 compression height, 6.21" rod, 1.955" throw 3.91" stoke crank, perfect o deck, and a nice big dish to suit, this is a magic, or rather, anointed idea.

The 89-93 GM 3300 (LG7) engines were skipped because of the port EFI GM 3800 engines power and economy excellence. I spent 125 000 miles behind a GM 3800 Holden, an engine which made 177 hp in non emissions NZ spec, a 17 second flat quarter mile, 130 mph top speed, 25 US miles per gallon on coarse tar seal, and never less than 19 miles per gallon US ABSOLUTELY THRASHED. Our State Highway Ride Meter, housed in a 1993 VP Holden Commodore, weighed in at 3500 pounds with 200 pounds of steel over the back axle. Stock, with only 2750 pounds, and 700 r-4 auto could dip in to a 15.8 second quarter, and get 30 US mpg.

With a cam, and piston changes, unsupercharged Formula Holden GM 3800's made 315 hp at 6500 rpm with stock injection and ignition.

On the little 3300, the deck was shaved back to the old 215 Buick size. Pistons were 100 thou undersize at 3.700", but just fine for stock 4.0 Liter Rover strokers. When Rover rehashed the 215, they had a funny, un American policy of not supplying +10/+20/+30/+40/+50/+60 over size pistons in 3.5, 4.0 and 4.6 blocks. So Buick 300 and 340 pistons get used all the time. Everyone used to shove Aussie 1973-1975 4.4 liter P76 or Buick 300 cranks in this sucker, and then have to find some 229/305 forged pistons which were 3.736" stock...just about the limit of the stock liner and often a problem unless the block is resleaved.

Back before I joined Ford Six, I had a special block made up. My 229 cubic inch X-flow Falcon engine runs a cold run welded cast iron XT Falcon 221 crank (the 1968 to 1970 221 ran 200 Falcon main bearings, but the post 1971 non cross flow and crossflow blocks were all a similar to US 250 bearing size, and also ran the small 200 Ford crank pilot, which was 3.4" diameter rather than 250/240/300/Small Block Ford 3.625" crank flange).

For pistons, some 12cc dish 3.736" 305 and 229 TRW forged pistons which have two different part numbers but are the same piston. Each has a lot of meat in it as a forged piston, with 110 thou depth and an irregular shaped trough of 3.1" diameter on its longest side. Enough to take 110 thou or more off in a lathe. The 1971-1993 3.3 Liter Aussie rods were all 6.27" and are fixed to the 0.927" Chevy rod after a 15 thou hone out from the nominal 0.912 wrist pin. Then the pistons were decked to suit the 9.387" deck register our Aussie ohv 200/250 sixes had from 1971-1993. I had to add a much taller 62 thou head gasket, as the pistons had to be shaved right down a massive 140 thou to 1.39". 1.39 compression height, 6.27" rod, 1.73" throw 3.46" stoke crank, perfect o deck, but the stock nice big Chevy small block dish was totally gone, and the stock alloy head X-flow chambers are 53 cc, so compression was 10.75:1 to suit propane. It solved the L/R ratio problem, but then I lost heart, and as I was looking at supercharging, there was no way to get the C/R down unless I added a 140 thou plate and found another set of TRW Forged pistons as I'd already cut them down. I'd used the first four from the right bank from the 305 forging and the two of the right bank from the 229. The pistons have a 62.5 thou thrust left to right, and the V6 ones were designed for the semi even fire 229, which was designed to run offset conrods. The dish is biased, so you can't just get six the same. Long story short, my combo only works for a high compression engine on NZ 98 octane, and its layed dormant in my basement because of that reason.


Funny thing is that 1.39" is about the deck height of the 1988-1992 3.612 and 1993-1999 3.622" 3939 and 3984 cc Aussie I6 OHC pistons. If you sleave down to 3.622 from a 3.7" or 3.72" over bore, you can use the 3984 1993-1999 pistons at 1.39" or the 1.1629" 1999 to date DOHC pistons from engines that made anythoing from 197 hp right on up to a factory 422 hp in the low compression turbo version. There was a cross over when both OHV x-flow and OHC engines were made on the same tooling, but the OHC ran a 9.22" deck, 160 thou lower than the stock ohv block. The US 250 is 9.469". This means that you have a whole heap of options. Oh, and 3.622" is the Subaru WRX STi 2000 cc piston size, and using Subaru forged pistons and rings with a Chevy 6" rod made 1500 hp possible from a Nispro engine back in 2005.

Other pistons to consider?

Well, the Chev 250 piston at 3.685" is actually either one of the 60 thou over Holden 202 L6 pistons or a similar variant found in the 253 Holden with a bigger wrist pin. Stock bore is 3.625 for both engine, compression height is 1.75", and wrist pin is 0.866 or 0.927". The Holden 202 piston is also made in 80 thou over 3.705" versions if you do your homework.The good versions of these are okay up to 7000 rpm all day if they are XU1 GTR spec on the 202, or 6800 rpm for Commodore Challange part numbers. The ft per second on the 3.25" stroke 202 and 3.0625" stroke 253 are reduced when they are put into a US 250, as its stroke is longer, but each is okay to at least 78% of that 7000 rpm figure. A 250 reving to 5818 rpm with 202 pistons isn't out of the question, or 5305 rpm using the 253 pistons.

See the 253 Holden piston at http://www.kb-silvolite.com/silv-o-lite ... s&S_id=724 , wrongly listed as GM 250.

It lookes like there are a lot of young bucks doing dodgey data management. This piston is actually a 253 piston which will fit a stock bore plateau honed to 3.685". It is an excellent piston, hacks 6800 rpm and 290 hp and 150 mph in the Commodore Challenge using 4.2 liter 1978-1984 VB/VC/VH Vee-Eight Commodores. The 4.2 is just a destroked Holden 308 5liter V8, but unlike Fords 255/4.2, the Holden one is tougher than a goat eating a plastic bag. Shame the 202 is listed as 201, 202, 3.3 and the 308 as 4.9, not 304, 308, XT5 etc. Lots of errors, and lots of issues with supplying lower than standard deck height to drop compression. Looks like its cheaper to lower a deck than profile a good dish to make profit margins

And those 3939 and 3984 cc 3.9 and 4.0 Aussie pistons in early 1.394" deck heights. VIN code for engines are 1988-1991 EA and 1992-1993 EB Falcon Codes are:

A - 3.2 EFI CFI TBI 120 hp
D - 3.9 EFI CFI TBI 161 hp
P - 3.9 Multi Point Batch fire EFI 186 hp
H - 4.0 Multi Point Batch fire EFI 198 hp
X - 4.0 Multi Point Batch fire XR6 216 hp in XR6


http://www.kb-silvolite.com/silv-o-lite ... s&S_id=725

http://www.kb-silvolite.com/silv-o-lite ... s&S_id=726

http://www.kb-silvolite.com/silv-o-lite ... s&S_id=727
 
Thanks i have been google and searching summit racing with all my spare time to try and find a combo to make this 250 work without taking a huge chunk out of my wallet. The pistons are also availible from summit racing in a 3.7, 3.72, 3.73, and 3.739 which allow .020, .040, and .059 over bores. If the pin size was alittle larger i would think they practically made for our engines. So if you used this combo in a 250 bringing its rod ratio up to more or less the same as the 200 you would get the extra revs of the 200 with the extra cubes of the 250??
 
You may be able to use the later 300 rods with the larger pin opening (0.975) and bush it to fit the smaller (0.905) Buick pin.

The recess in the 3.3L Buick piston is about 12.68cc.
 
Alright i got some more input on the zero decking part of the build and think i have it more or less taken care of, at least until i start tearing into my block. I finally got a chance to cc my head it and came out to 45cc. So i am hoping to open those up to at least 50cc. What do you think i can get away with before hitting water jackets? and is there an ideal area to remove material from to improve combustion chamber shape?

Next thing i have been busy doing is trying to find a way to get more coolant from the head to the block. Jack previously voiced concerns about how much coolant could get through the drilled out passage.

I used an extra block i had laying around, I believe it is actually a 4 main 170 but since all US 6 heads a swap-able i am assuming the width of the deck is the same. I then took my head and used wooden dowels to center it on the block. Probably not perfect but it will do. From my test fitting today the aussie head is wider on both sides which causes the AU heads cooling passages to hang over the side of the block hence why they get blocked.

Here is a picture showing this


Originally i was thinking that a person could just drill holes in the deck to match the AU heads passages and seal up the old US ones, but that was before i realized the head is wider on both sides and since Jack had trouble sealing the non pressurized oil side i don't want to deal with the same problem on the coolant side.

So my other ideas are as follows.

First is deal up the old holes ideally welded and then tap holes at each cylinder into the water jacket in both the head and block and used small external tubing to connect the system up. Next would be my head has the following openings on it:

Two on the from in addition to the thermostat:


And one casting hold that already has a casting plug:


Using these preexisting holes a fella could either tap and use one of the freeze plug holes or link it into the lower radiator hose connecting and complete the circuit.

Another plus to this fitment test was that i was able to see what needs to be done to clearance the lifter holes. on my block there is the flat deck a slight bevel and then it drops straight off the side of the block. When i go to widen the block i am going to have the side of the block machined flat and the bevel filled in most likely vie brazing or welding so that when i have the deck cleaned up and trued it will all be one smooth hunk of metal and crossflow your fingers it wont weep oil :LOL:
 
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