250ci dual roller chains.

[AzCoupe]

I'm working on the 250 dual roller chains (finally) and need to verify a measurement. Unfortunately I don't have access to a 250 block.

What I need is the center to center (crank/cam) measurement. I think it is 4.257", but wondering if anyone can confirm if this is correct?

Also need to verify the diameter of the crank snout?

 

[CoupeBoy]

I'd love to help, how would I measure this? Just stick a caliper in the center holes? measure the distance from between the closest point on the crank snout to the closest point on the camshaft?

-ron

 

[simon]

Ron, ideally, you measure from center to center.

Mike - I just took a quick look at my 250, it appeared to be more like 4.5" - roughly. I ain´t sure though `cause I´ve been in a hurry somewhat.

Maybe one of the Schjeldahl bros. comes to chime in?

 

[AzCoupe]

Still trying to get a confirmation on the measurements?

 

[rbohm]

8) i would love to help you mike, but my engine is in az and i am in va. if you were willing to drive to tucson, and try to convince my mom that it was all right, you could pop by my house and open up the trailer in which the engine sits and do what was needed to take your measurements. be a fair amount of work though as there is a bunch of stuff on top of the engine, and the engine is turned the wrong way to make the job easy.

 

[WhitePony]

LOL with Mike's schedule I doubt THAT will happen.

 

[alloydave]

Sorry i havnt got those measurements ,but i know my suppliers make a set to suit to suit the canadian block as they call it. The chain is 50 link double roller versus the 52 link in the aussie 250. Do you need a sample?

Dave

 

[rbohm]

LOL with Mike's schedule I doubt THAT will happen.

8) yea i kind of figured that, but since mike is a friend i would give him that option.

 

[AzCoupe]

Thanks Rich. If that's my only choice, then I may take you up on it. But I would think someone here should know. :

Dave, I think we are talking about the same supplier. They do make a Canadian 250 roller chain, and they are the ones which supplied the measurements I posted. If it is correct, I can have these in stock in a couple of weeks. But their not sure if they will fit the US blocks either.

I'm having a sample sent over, but I'll still need to locate a 250 block that I can test fit it on. Guess a Saturday trip to my local boneyard may be required when it gets here. Thanks for the offer though, it was appreciated.

 

[Javabean]

Mike I will Open my 250 up & measure over half time if possible. I KNOW I will be needing a nice timing chain for it in the future. I'm putting it on a stand this weekend, might as well get a start on it and get some measurements tonight. GO PISTONS!!!!

 

[Javabean]

Was able to get everything unbuttoned and pulled off the water pump. Now I'm down to a stubborn Dampner/Pulley that doesn't want to slide off easily. I'll be able to get a puller tomorrow after work and get the timing cover off. Sorry I would've liked to get you the measurements before the weekend, but it's getting late and the Pistons blew game 1.....time to call it a night before the drinking gets too heavy .

Jay

 

[Javabean]

Who would've thought the local parts store would've had thier one loner rented out this weekend? I'll check back in when I locate one to finish the job. You willl have the measurement by Monday.

Jay

 

[AzCoupe]

No problem, thanks very much for the assistance. I'll take care of you when you order one.

 

[Javabean]

Finally got the pulley & timing cover off last night. I measured the distance between the gears to be 4.375" center to center & the end of the crank to be 1.375" in diameter. FYI - The block is a 1970 casting.

My most reliable measurement came from the timing chain itself, once I removed it from the block that is. I don't know how old the chain is, so it's possible that it's tired & stretched. I'll try to get a better measurement from the center of the crank & cam themselves. But the means of doing so made the accuracy a bit suspect. Any tips besides eyeballing the center of each?

I don't claim to have the most precise instruments, although the calipers & a straight edge both measured down to the 32th of an inch.

Jay

 

[addo]

Can you measure outside to outside on each of the shafts with the Verniers? Then subtract half each diameter.

 

[Javabean]

Thanks Addo. I was hoping to use that methodology. I should've mentioned the real problem is my calipers/verniers only open up to 5" which is just shy of making it around the outsides of both shafts to get the outside to outside length.

You know thinking this through again jogged an idea, if I just reinstall the bolts in the end of the shafts and use that same methodology it should work. I love it when the answer is simple....too bad it's usually the hardest one to find.

 

[80broncoman]

Have you tried inside to inside measurments?

 

[Javabean]

Mike, my final answer is 4.375".

I've now measured from the inside of each shaft & backed into the center to center, reinserted the bolts and backed into the center to center, and measured the timing set itself. I came up with 4.375" every time.

Hope that helps,

Jay

 

[AzCoupe]

Thanks much. That sounds like it took quite a bit of doing.

I'll forward the info to the manufacturer and see what they have to say.

I think the sample is on its way already, so maybe I should just send it off to you when it arrives. Then you can test fit it (since yours is already all apart). If it fits, its yours.

 

[Javabean]

Hard to consider that work! I just wanted to be sure to get you the most accurate measurement I could.

Of course I'd be more than willing to test fit it, take pics and whatever else you need! Also, I'm close to placing an order with FSPP, so the least I could do is pick up the additional freight on it. I'll PM you and we can discuss offline.

Jay