250x How Tight

[Anonymous]

A question for you gurus out there Ive just rebuilt a crosflow 250 (rope seal) and its the tightest motor Ive ever had to turn over by hand. Every thing has been measured up correctly and is within factory specs, but you build up a real sweat just setting up dizzy and thats without plugs, plus starter has trouble if battery isnt fully charged. I havent run it yet my engine machinist says its okay but Ive never had to build a Ford motor before

 

[addo]

Seven main bearings and a stiff valve train will do that. The Infernational V8 is a real bugger to turn likewise, as the seat pressures are enormous compared to most engines.

You could try slacking your rockers right off...

Adam.

 

[Anonymous]

I thought about that and this thing was a pig to turn before the head even went on, its nothing like the other brand motor, have built heaps of them with no stress. I cant wait to see what the next ones like higher comp, double valve spring etc.

 

[xctasy]

There is a 7 lb pullout factor in each piston to factory spec, and the rope seal is very much a high drag item.

Read David Vizards book on how to modify your Small block chev. It covers the rope seal drag by giving a torque spec.

Its quite a lot of force from memory.

 

[Anonymous]

Mate I have built more than a few crossflow and i will tell you it is the rope seal that you have fitted is possible an after market one and they dont seem to be the right size to start with go with the later block you cant go wrong.

 

[Anonymous]

Don't use a rope seal. You will find the 302 Windsor 2 peice neoprene seal is a perfect fit. Its what my engine builder uses and recommends. It's ACL part number HN064. Much less drag than a rope seal. I have had the same trouble with rope seals. Rope selas take preparation and skill to install reliably, the neoprene is perfect for non-professional enthusiasts. To check everything is working properly I recommend the laborious process of putting your shortblock together without the seal checking all clearances with platiguage, make sure the shortblock turns relatively easily, then taking the crank out and doing it all again with the seal. You can leave the pistons in but watch the rods bolt damaging the crank on the reinstall.


Dom

 

[wagon]

The 250crossflow in my wagon was the same.. I could not turn it with a breaker bar+big pipe on the harmonic balancer bolt. An old flexplate and a big lever (eg wheel spanner) was the only way to turn it by hand!

 

[Anonymous]

Thanks for all the info its a bit late now to change the rear seal, motors all together and in the car. I have never had a problem with them in holden sixes, I will keep the info on the other seals and use them in the next motor though they are much easier to set up I know that.
You live and learn and hopefully dont make the same mistake twice

 

[xt falcon]

i have a rope seal and my motor is not to hard to turn 30ft lb but it is leaking some oil from the rear of the motor

 

[DYNOED250]

30 fp and it turns , are u sure u fitted a rope seal?

.My first ever motor i built and gues what it was a 250 cross flow for my mate, it was the famous over night re-build, out friday night and cleanned and striped, assembled sat morning, fit in car sat arvo, cruise sat night.

I never got any thing machined, we had a brand new reco xf alloy head for it so that was sweet, the crank was in a1 condition, and the bores were good, the cam bearings were pretty sad, but they wernt in the budget,

new rings on standard 250 pistons, new big ends and mains, all std size, checking clearnces or ring gaps were never thought off.
then there was the rear main, i didnt wand it to stuff up so i put the rope in the block and rolled pipe allong it to compress it into the block , then sliced of leaving al lil bit above. done same in cap...

*WE FITTED ARP ROD BOLTS, WITH A HAMMER AND A VICE, i mean thats damm scarry but didnt know any better at the time.
and also fitted a crow cam 224 and 500 lift

with the short motor together , you couldnt turn it over, i was shitting my self, ..., we put the short into the car with the gear box, put the starter in and cranked it it, struggled even with no head. it was about 11 pm sat night before we got to the starting stage with the head on, some how i dont know why it fired and scarred us all, it was a real real real real slug, that used over heat.
after 200 km so somthing weird happend it stoped over heating, and sudnely became a ball terror., this was basicly a stock motor just with alloy head cam and webber in a te cortina.
THAT WAS ABOUT 4/5 YEARS AGO, AND THE SCARY THING IS MY FIRST MOTOR IVE EVER BUILT WAS MY DODGIEST EVER, COST THE LEAST TO DO, BUT ITS STILL GOING HARD IN MY MATES CAR STILL DOESNT USE ANY OIL AND NOW WEARS A 600 HOLLEY, AND HAS MADE 133 RW KW. and gets reved over 6000 every day and still hasnt put a hole in the block

** this motor was so tight u breaker bar with a poll on the end couldnt turn it when it was built. so dont worrie about it its fairly normal for rope seals to b damm tight.

 

[Anonymous]

I've only seen 2 motors go tight. One was in a Nissan Patrol, one of the real early ones. We had to use a tractor with a bucket to get it out, and it took two of us to lift the crank. We went to put the main caps on, and after it got to 20 foot pounds it wouldn't turn over even with a bar. We had to get the block tunnel bored as it had warped and the old bearings were worn enough for it to still turn!
The other was a John Deere tractor and it was sent to a machinist who is into tight tolerances and it was tight after 20 pounds, and impossible to turn by hand at 40, so we did the caps up in 5 pound increments.
That motor was a dodgy one, as the owner just wanted it back in the paddock until his other tractor was rebuilt ( $18,000 bill for transmission parts!) so we reused the pistons and just honed the bores. The crank HAD to be ground though. He was going to retire it to occaisional light duties when the other tractor was going, but that was about 6 years ago and he still works it hard every day. It sits on the irrigation pump at medium high revs for hours at a time, but it is still going strong. It was a real slug too when it was first built, most good motors are because they are tight in the tolerances and need to bed in. They go better and longer though.

 

[Anonymous]

thanks for all the info motor has just turned 500 km and its a lot easier to turn had to jump start to begin with, nearly time to do first service and re tension everything. No oil leaks from rear seal and compression is excellent all cylinders same.
Once again thank you all for putting my mind at ease
Mark