Externally balanced crossflow 250? Question on flexplate - now epic journey through the crossflow

hucklburry

Well-known member
This flexplate came off a rebuilt 76da block, I was told it's the flex plate that was on it when it arrived in the states prior to rebuild. I pulled it off in preparation of installing a zero balance flywheel, but this doesn't look like a zero balance flex to me. It might be off a 82 falcon?? I'm not for sure on that.

I can take it to a shop and see what it's balanced at, but my internet searches don't show any externally balanced 250s, is it possible I have one? Pic of front of crank as well





 
I did some research on the flexplate you have. It is for a SBF 289-302. The 250 inline six flexplate does not have any weights on it. I've attached a couple of pictures to show the difference.
250 Flexplate
Ford250Flexplate.jpg

SBF Flexplate
SBF289Flexplate.jpg


All Ford inline six cylinders, US and AU, made during this time are internally balanced.
I wouldn't worry about using a zero balanced flywheel or flexplate on the Crossflow.
I would an externally balanced one.

Using the SBF flexplate may be why the PO was having a "rear main seal" leak.
 
Dan, I was able to talk to him, and he thinks that was the flex plate that came with it. But really, it could have gotten lost at the machine shop and this one put on, who knows, right? Or it could have been the wrong one that came with it from Australia.

I might pull the front pulley and have them both checked, if they match, then I'm confused as heck. If the front pulley is neutral, than I can be pretty sure the wrong flex was installed. And your right, maybe that is why there was a leak. He said it can't have 200 miles on it. I saw he was asking questions about a distributor on here, maybe it was running rough and he thought it was ignition and it was really an imbalance?? Maybe that was before he installed it, I didn't ask him that.

the only markings I saw on the front pulley where "CAL" I think, how could I confirm its not weighted?

I'm just trying to cover all the bases before I install it, I'd rather not deal with the transmission AND transfercase or pulling the engine to figure it out later.

I appreciate your help! --Jim
 
:unsure: Yep that for sure is the wrong flex plate for your six it would be ruff running with that much imbalance. :nod:
 
Since I will have the pan off to replace the rear main seal, I will be looking at the crank pretty good and see if it looks stock or has had work done to it - that would be the only way it would be externally balanced now I think. Pics to follow....
 
So here are some pics of the crank, it has 8 weights, and looks factory, with some holes drilled for balancing, I don't see enough gone to think its changed to external balance. - Note part of dipstick found in one pic, more later on that:



 
When I got this, the dip stick seems short. I had one from a US 250 that seemed right.

I found three pieces of the short one in the oil pan, that total length is the same as the US 250. I am trying to figure out how it did it, maybe it needs bent to miss the counter balance weight on the crank?







 
On the flex plate your two choices are to either replace it with the correct zero balance one or have the weight removed and rebalance your current flex plate to zero. With the design of the Ford inline six'es there would never be a case to try and rebalance them so it could use a weighted flex plate or flywheel that had an imbalance. Of course if it was a V6 engine design we were talking about then that would be a different story and it would be possible to use a weighted type flex plate just as the Ford Small Block V8's used.

As far as the Dip Stick goes if you have your engine on an engine stand you can try to fit it so it clears the crankshaft counterweights. Ie it may need to have a slight curve it going back some so it's near the outside of the oil pan and near the sump centerline. It maybe that the dip stick tube going into the block has also been bent (could have happen during its shipping) which may cause it to be to close to the crank counterweight. Good luck :nod: edited
 
Dan,

It was a good thing I pulled the rear main, it was a 2 piece seal, installed a little different than everything I've read, but it got nicked up. The pin was still in. I used a nice fel pro 2 piece, pulled the pin, and installed 3/8" offset from the bearing cap, with a dab of sealant in the pin hole.

I had to pull the oil pump to loosen the crank, one bolt in the way of the pump, so I am waiting on a gasket for that, and cutting a new oil pan gasket, here are some pics:









 
hucklburry":36rbogmf said:
Dan,

It was a good thing I pulled the rear main, it was a 2 piece seal, installed a little different than everything I've read, but it got nicked up. The pin was still in. I used a nice fel pro 2 piece, pulled the pin, and installed 3/8" offset from the bearing cap, with a dab of sealant in the pin hole.

I had to pull the oil pump to loosen the crank, one bolt in the way of the pump, so I am waiting on a gasket for that, and cutting a new oil pan gasket, here are some pics:










Wow that rear main seal looks in bad shape it is a good thing you pulled that apart! How are the bearings looking?

I use to install the oil pump to block gaskets found in the a rebuild gasket set but most people don't use the gaskets now days even Ford didn't alway use them. If you want you could use a small amount of silicon or make a paper gasket if you can find one. You for sure need to use the gasket for the oil pump to pick up tube though. Good luck :nod: (y)
 
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