My Budget 250 build

Just a bit of calculations.

The deck height of a 250 is 9.469". This is stock and doesn't take into account any milling.
A US250 rod is 5.880" long
A 2.5L Taurus rod is 5.990" long.
A 200/250 piston has a compression height (CH) of 1.50"

If you rebuild a 250 with stock rod and piston, the piston will be recessed 0.134" down the cylinder.
(3.91"stroke/2) + 5.880" + 1.50" + 0.134" = 9.469"

If you rebuild a 250 with a 2.5L rod and 250 piston, the piston will be recessed 0.024" down the cylinder.
(3.91"stroke/2) + 5.990" + 1.50" + 0.024" = 9.469"
This will help with your quench, and increase compression. The rod ratio also goes from 1.504 to 1.532.

If you go with a flat top 2.3L HSC piston (1.50"CH), the recess will be the same 0.024", but the compression will be significantly more.

Since you already have the 2.5L Taurus rods, this is the best way to go.

Another way to improve quench and increase the rod ratio in a 250 is 1965-68 300cid rods, and +1.0mm flat top pistons from a 2002-04 Jeep 4.7L OHC V8. The early 300 rods have a 0.9122" pin diameter, the Jeep piston has a 0.946" pin diameter so the small end of the 300 rod would have to be enlarged 0.0338".

And now the math:
65-68 300 rod is 6.210" long
2002-04 4.7L +1.0mm flat top piston is 3.701" in diameter with a CH of 1.24"
This rebuild will give you a recess of 0.064", less than half the stock depth.
(3.91"stroke/2) + 6.210" + 1.24" + 0.064" = 9.469"

This setup will increase the rod ratio from stock 1.504 to 1.588

The 65-68 300 rod does have a larger big end (2.2758" vs 2.239") so the 300 rod bearing would have to be used.

Hope you find this interesting.

Excel spreadsheet can be such a time-waster.

Thanks Dan, I am intending to use these pistons in either .020 0r .030 over

lavron":2qtsn3fo said:

Silvolite 3332H pistons .030 oversized, dish measure 2.843" dia. .276" deep (equals 12.863cc) the Compression height = 1.530

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If I figured right that should give me just .010 deck height to mill off and keep the CR in check.

See Ya,
Mike

lavron":29ygzyus said:

I was messing with comparing the rods today and pulled one of the rod bearings out, pretty sure they are the original.

And I know this is a crude way to show the difference in length but I don't have a way to press the wrist pin out, so the "precision" ruler is sitting against the pin and then you can see on the other one I was measuring from edge to edge on the holes.

A bit of difference in length, hopefully I have solved my quench issues if I can keep from getting the CR too high.

I also was checking to see if the rod bolts were the same because I am wanting to have ARP bolts installed and I wasn't sure what to order, looks like regular SBF bolts will work, have to see if I can find a 6cyl set so I don't have to buy the 4 extra, expensive bolts - I think we know why that is :roll: I switched the rod caps and nuts as suggested here to see if they were a match, I was pretty confident they would but better safe than sorry.

Everything looks good for ignition!

I really need to order pistons soon so I think I need to do some more measuring.

See Ya,
Mike

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Thank you for the pictures comparing those two rods! Yes you are correct that's a stock Ford Std. (Standard) size Rod bearing. Adding the ruler is an excellent touch showing off the differance of almost .120 that's close to an 1/8 inch improvement in the length. Most 250 blocks that haven't been machined (decked) since they left the Ford assembly plant are going to measure taller than Fords stated 250 engine spec though. I think my on 77 Maverick 250 the stock pistions were at .180 down the hole, stock compression was rated at about 8.0 to 8.5 to 1, but I doubt it was that much. Good luck on your 250 build the new rods should be a great help in getting better performance from your 250 while fighting off the detonation problems high compression 250's are know for.

Anyone know if the 300 rod bolts are the same as the 250/sbf? Summit sells a kit for the 300 and it is $20 less than the SBF set, I was assuming that was because there were 4 less bolts and nuts but I can't find anything to confirm it, like what size the 300 bolts are. I know I can use the SBF set but if I can save $20 I am all for that, of course I am assuming they are different otherwise ARP and Summit would show they fit a 250 as well.

See Ya,
Mike

I would get the sbf ones and use the best 12 ,but that just me.

lavron":3fv0449s said:

Anyone know if the 300 rod bolts are the same as the 250/sbf? Summit sells a kit for the 300 and it is $20 less than the SBF set, I was assuming that was because there were 4 less bolts and nuts but I can't find anything to confirm it, like what size the 300 bolts are. I know I can use the SBF set but if I can save $20 I am all for that, of course I am assuming they are different otherwise ARP and Summit would show they fit a 250 as well.
See Ya,
Mike

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Hit up Matt at vintage inlines dot com as he's on here all the time, specalizes in these motors (all 'falcon' i6s).

Here is a 300 rod big end measurement

https://www.dropbox.com/s/0g3zz2x906suk ... h.JPG?dl=0

pmuller9":330kn54s said:

Here is a 300 rod big end measurement

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Thanks for that, you wouldn't know the bolt size, I think small six/SBF are 5/16"

See Ya,
Mike

The 300 bolts measure .374".
3/8" bolt.

I used the ARP 152-6001 connecting rod bolts.

pmuller9":19eej2r8 said:

The 300 bolts measure .374".
3/8" bolt.

I used the ARP 152-6001 connecting rod bolts.

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Thanks, maybe I should just stick with SBF bolts because it would probably cost more than $20 to have the holes enlarged.

See Ya,
Mike

Glad I am in no hurry my pistons are backordered until November, I guess Silv-O-Lite has to make them for me.

Oh well lot's to do in the mean time.

See Ya,
Mike

I've got to say Mike, you're doing a h*ll of a build here. I'm loving this. If I'd have known about those rod's, I'd have probably gone that way to. I can't wait to see how this works out.

Thanks Seth.

This site certainly has always been a big help, I was a member way back in 2002-2003 before everything went bad and all the memberships got toasted at least twice, I took a hiatus from working on my Comet way too long, even though I still haven't touched my car I have been working on collecting and rebuilding components for the last two years or so (not counting stuff stored away from 10 years ago), so one day I can get her back on the road with a, hopefully, short shop/garage time. makes it tough to build something before you actually touch the car but I figure it would be a pain to wait two months for pistons when that is all I needed to get it on the road and it was scattered all over my garage, right now I can wait and do other unpleasant things like clean grunge off of old parts Lots of research and searching for just the part I want on the cheap

I am finally "finished" cleaning up my block, I think, now waiting on pistons so I can take it too be bored and decked and I still need to run down a machine shop they are pretty scarce around here. :roll:



More parts still have to be cleaned, it feels like that is all I do

See Ya,
Mike

Here is the dirty pig when I brought it home, still just a happy as could be to find it close by, paid way too much for it :roll:



See Ya,
Mike

Your still making some great progress towards your goal congratulations on that! Keep up the good work

Econoline":1zxitd7c said:

I've got to say Mike, you're doing a h*ll of a build here. I'm loving this. If I'd have known about those rod's, I'd have probably gone that way to. I can't wait to see how this works out.

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it was discussed, often. The 1983 to 1992 OHV valve 4 cylinders had a lot of other parts, first it was pistons the I6 guys used, then we looked at timinag chains and eventually, the 5.99" rods.



Its always a risk to self promote, but I've done it only because a lot of people just didn't get it the seventh or fifteenth time over....


"US 250 Owners: Nuclear Timing Chain HSC/US 250/Oz 250"

Post #7 by xctasy » Fri Nov 02, 2012 to Post #15 by xctasy » Tue Jan 21, 2014

viewtopic.php?f=1&t=69097&p=547594#p547594

xctasy":1zxitd7c said:

Invectivus":1zxitd7c said:

What can you tell me about the connecting rods? I've been looking at NAPA online (just to get a ballpark) and they don't tell you too much. Are they forged by nature or something? or maybe lighter? i guess i'm asking why you think there'd be a benefit in using them.

Also, since these parts look pretty expensive, is there an engine code i can look for to just poach the entire engine from the salvage lot for fitment and comparison purposes? i can probably get a whole engine for the cost of one of these connecting rods...

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The rods on four cylinders and the pistons, have to be much heavier duty than the I6 items due to power per cylinder. 2.3's are 5.45", but the 2.5liter rods are 6.00" centre to centre, rods are forged as far as I know, and same as the 6.06" non turbo Aussie 4.0 OHC/DOHC after 1998 till date. Wrist pins and crank pin diameters are the same as any 1960-1983 I6, and the 1976-1992 X-flows and 1988-1998 over head cam 3.2 and 3.9's.

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xctasy":2ld9e7t3 said:

Its always a risk to self promote, but I've done it only because a lot of people just didn't get it the seventh or fifteenth time over....

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That is ok I caught it along the way somewhere

xctasy":2ld9e7t3 said:

then we looked at timinag chains

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Did we like them? I haven't really looked for one yet but that is in my future sometime, something else to collect maybe.

See Ya,
Mike

lavron":1vb0bt0g said:

xctasy":1vb0bt0g said:

Its always a risk to self promote, but I've done it only because a lot of people just didn't get it the seventh or fifteenth time over....

Click to expand...

That is ok I caught it along the way somewhere

xctasy":1vb0bt0g said:

then we looked at timinag chains

Click to expand...

Did we like them? I haven't really looked for one yet but that is in my future sometime, something else to collect maybe.

See Ya,
Mike

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No one got back to me. Its like the old 164 teeth flexplate big bell low mount 200 block, and the 9 years of wrong info. Asking the same question, over and over before getting a response...the solutions came from new people asking the same questions, and then being able to provide a partial part number, and then,


Seams like its was a good idea, Ford wouldn't have blown away a couple of million reworking the stock 250 timing chain unless it had a want to.

But, you know, the 250 to 302W timing chain set-up by Does10s and mike1157 was better if your already machining something. Like 1986 onwards "WCP 351" SVO NASCAR Cleveland Windsor race engine made on the Windsor lines for Winston Cup engines, some people never minded an afternoons machining the block and crank on a lathe to get the 300 too long snout machined back. The six cylinder 250 was the first engine to copy the unshouldered crank, and its that aspect that screws over a cheep 302W timing gear and chain swap.

Does10s had the same upset response.....seams like people really need to read some of the old Ford Six posts.


I gotta say the scheduling of details on these special items of knowledge really ticked off my a$$ from 2011 to 2015, repeating the same stuff over and over.

viewtopic.php?f=95&t=71986&p=584193#p584193

Does10s":1vb0bt0g said:

Mike1157,
Funny that this is the first time I've seen this tread!! It's been here for 2 years and it just got bumped to the "new posts".

I would've commented on your timing chain way back when for sure! Nice to see someone else give that a try! I assume it was a success?

The one in Kelly's car is still working just fine!

Later,
Will

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THE FRENCHTOWN FLYER":1vb0bt0g said:

Hello Mike. I just discovered this thread and read through it - very interesting. I usually hang out on the 240/300 forum and neglect the rest. Your build-up reminds me of some of the issues I had to work through to put a crossflow head on a 300 (oil pan, damper, keyway, valve springs, rocker arms, valve cover, yadda, yadda). I missed a lot of what plans you have for the vehicle, what type of vehicle, etc. so I don't know how high you plan to rev it, how much boost etc.

Did you ever consider a belt cam drive like a Jessel setup?

Some 300 racers who run crossflow heads to the extreme have bored the cam journals to a larger size, enabling a larger base circle on the lobes and a stronger cam in bending. With extreme spring pressures the cam billet has a tendency to deflect and not deliver the advertised lift to the valve. They also add additional bearing supports inside the block. Not saying you'll need all that (some of those guys have valve lift in excess if one inch!), just an FYI.

Good luck with your project. I for one find it interesting.

EDIT: I JUST READ YOUR VEHICLE DESCRIPTION ON YOUR SIGNATURE LINE

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lavron":1aqj7cci said:

Glad I am in no hurry my pistons are backordered until November, I guess Silv-O-Lite has to make them for me.

Oh well lot's to do in the mean time.

See Ya,
Mike

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Hey, I’m following your build and thinking about taking a run at building one myself. I was wondering if you could share where you are sourcing your rods and pistons?

Thanks,
Harlon

Harlon":dtytxmil said:

Hey, I’m following your build and thinking about taking a run at building one myself. I was wondering if you could share where you are sourcing your rods and pistons?

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Sorry I have not replied sooner Harlon, I haven't had anything to post since the last time because it has taken this long to get my pistons.

Saying that these arrived today;



I got my rods from Clegg Engines and the Pistons are Silv-O-Lites via CARiD

I can finally start thinking about machine work now.

See Ya,
Mike