Re-built engine might be too tight.

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Model T Ford Forum: Forum 2017: Re-built engine might be too tight.
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jonathan Delancey on Sunday, April 30, 2017 - 10:12 pm:

The engine is out of the Roadster and I am waiting until I graduate high school in June before I figure out where to take it for rebuild. One builder I talked to said most of the engines he does are so tight you have to tow the car in high in order to get it loose enough to start. My question is how does the builder set the valve timing if he can not turn the crank? What am I missing?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Longbranch,WA on Sunday, April 30, 2017 - 10:45 pm:

Very good question, Jonathan - I believe I would keep looking.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Andy Clary on Sunday, April 30, 2017 - 10:47 pm:

Don't go to that builder. If you have to tow the car it wasn't built properly.

Andy


Top of pagePrevious messageNext messageBottom of page Link to this message  By Spencer Vibert - Granby ,CT on Sunday, April 30, 2017 - 10:50 pm:

John call Ora at shwalms in Pa or Pat muste in ct they both know what they are doing as I tell many of my customers a properly rebuilt engine with correctly set bearings should turn over by hand and should start fairly easily


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stephen Bowers on Monday, May 01, 2017 - 12:11 am:

That guy sounds like a hillbilly


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Monday, May 01, 2017 - 12:43 am:

Jonathan, setting valve clearances on the bench with a rebuild is easiest with the timing gear off and just rotating the cam, setting the gears shouldn't be a problem either.
Ford publications stipulate that a rebuild should be able to be turned over with a 22" bar, any tighter could be a problem in a clearance on something.

Ford would burnish,(run in), a new engine on electric motors to make them free enough to crank start.

Smaller shops could buy and use the universal burnish running in machines, Fordson or model T engine driven.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Monday, May 01, 2017 - 12:54 am:

Whether a new motor can be crank started does depend on the strength of the crank on the handle. I would much rather drag a car down the road a bit, and back, and then turn it on for a tow start.

As Frank showed, Henry had machines to burnish the bearings to free up things before the motor was started. The 22" bar can be used to turn over the motor, but no way a 10" crank handle would allow the motors to be hand cranked at a speed fast enough to start the motor. Unless, of course, you are Hercules.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Monday, May 01, 2017 - 07:09 am:

Any mechanic that tells you can't get the proper clearances to get an engine to turn over easily with a fresh rebuild is someone you should avoid. If you can get tight clearances with a modern engine with proper assembly and machining, there's absolutely no reason why a Model T engine can't be similarly assembled. It all comes down to doing the job correctly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Monday, May 01, 2017 - 07:21 am:

I was able to crank start the one in my wife's '18 Touring after I rebuilt it. Boy, I must have left too much clearance or something, "'cause it crunk right up".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Monday, May 01, 2017 - 08:00 am:

It's not the bearing clearances which make hand cranking a T difficult on a newly reconditioned motor. The crank shaft should easily spin with a twist of the rear flange. Hook up a piston and rod assembly and it should not drag either. Put that assembly into a newly machined bore and it is a different story. Then add the other three. Then add a Prus high compression head. Then add the flywheel and the transmision. Hook it all up to the rear end, which the trans tries to drive unless the rear axle is jacked up,and you have too much for this 71 year old to crank start. What you end up with is nothing like a modern engine.

I don't know how one can equate this to modern engine reconditioning. Sure, all the clearances may be equated, but I know of no modern engine rebuilder who hand cranks his finished product.

I could be wrong, again!

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Wilson - Omaha NE on Monday, May 01, 2017 - 08:44 am:

My fresh rebuilt engine started the first time after it cranked over about 6 times on the starter. I agree with Allan, the fresh cylinder walls really stiffen it up to turn it over. I found in assembling the transmission, and other parts to the short block, it was hard to initially crank it if it had been sitting, but one you got it moving it was just kinda stiff to turn over.
Now one month and a couple of hundred miles later it still will take 4 or 5 cranks to start it cold. I figure that's it's just priming itself, as it now starts immediately when it is warm. My engine builder ran the crank in on his boring machine for hours before he assembled the block. I t is a lot easier to crank over by hand now, not as loose as an engine with many miles on it, but a lot different than brand new.
I had a previous rebuilt engine that had to be towed to start, it never did run right, and I broke the crank because the corners of the crank journals were not properly radiused. Other than the expense and lose of the car for months, breaking the crank was a gift, as I now have a very well running car to enjoy


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chadwick Azevedo on Monday, May 01, 2017 - 09:02 am:

I can remember on more than one occasion helping my grandfather tow to start a freshly rebuilt engine. Bear in mind that these were engines with no starter. When working with aftermarket parts often times it is much easier getting a turning engine to start before dialing in the carbs etc.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ed in California on Monday, May 01, 2017 - 09:04 am:

Has anyone ever found one of those original run-in machines as seen in the previous picture?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Miller, mostly in Dearborn on Monday, May 01, 2017 - 09:05 am:

One major difference between a modern engine and a T engine is the bearings. A modern crankshaft is directionally tape burnished after grinding and the bearings have a similar surface finish.

Since poured bearings are bored to size, there are always going to be microscopic peaks and valleys from the boring process that cause "ridge ride" of the crankshaft until these peaks roll into the neighboring valleys. After this happens, the bearing clearance increases dramatically.

I personally appreciate when my builder sets them up a little tight.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Eyssen - Abilene TX on Monday, May 01, 2017 - 09:19 am:

Ed: I have the one pictured in the lower photo.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, May 01, 2017 - 11:10 am:

All the engines I have rebuilt have been able to turn with the crank, but it is very hard to get it started with the crank. I have a long rope about 30' and I tie to the front frame or the spring where it is attached to the frame and the other end to the pickup. I tow in high gear and when it starts honk the horn and the pickup driver stops. I let it run just long enough to warm up. After that it will start fine with the crank or the starter.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Thompson, Sudbury MA on Monday, May 01, 2017 - 11:14 am:

I have a 1918 engine on a stand. It turns with crank, but not fast enough to start. Any ideas how to turn it a little faster?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Monday, May 01, 2017 - 11:18 am:

I use Time Saver to finish up all the bearings in the block. It's great stuff, and Langs sells it now. Stay away from the 100 grit though, it's too fine. What makes the engine so tight is the initial drag on everything bolted together, and especially the new rings on all four cylinders. The last engine I built for my '13, I did like Norman says above. A tow around the block was enough to get it running.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem - SE Michigan on Monday, May 01, 2017 - 11:24 am:

Some rebuilds are just a little tight. It's an "old school" approach to bearing fitting. A few of mine were that way too. Once run-in they were never a problem. It's more common when you have an engine who's bearings have been scraped and re-fit. I tend to make those a bit tight too, because the high spots, created by the scraping process, will soon wear away. An engine with newly poured & bored babbitt really should not need to be tight in the bearings. There will be drag on the rings and freshly honed bores however, until the rings fully seat. That's normal.

How do they adjust valves when bearings are so tight? They loosen the bearings a bit by backing off the rod & main cap bolts. Easy peasy!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Monday, May 01, 2017 - 12:09 pm:

There are two ways of crank starting a Model T. Starting on MAG, yes, you do need enough speed to generate sufficient current to fire the coils. But on BAT, here's how fast you need to "spin" the engine.

https://www.youtube.com/watch?v=3pv6HWWOGYA

I never had to tow this car after the rebuild.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Barker, Somerset, England on Monday, May 01, 2017 - 12:29 pm:

My rebuilt engine started with BOTH crank and 6v starter together. Neither was enough on its own. It quickly loosened up and it's fine now


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dewey, N. California on Monday, May 01, 2017 - 01:36 pm:

hmm, I'm on the fence on this one. When I worked for a car collector, he thought the first start of an engine should be on the crank. However, freshly honed cylinders and new rings do provide a resistance to movement. Yes, bored bearings will have a microscopically rough surface. It depends on the shape of the tool and the speed of the feed as to how rough it can be. The timesaver might be a way to smooth that out. The engine that is in my model A has bearings poured by a long-lost friend who was meticulous. When the crank was in the block, with nothing else on it, it would take a bar on the flywheel flange to start it turning, but then you could keep it turning with your finger on the flange. You had to break the cohesion of the oil film to the bearings and crank. He told me he'd never set it that tight for anyone else, other than himself, but he knew me well enough to know that I would break it in gently, and that engine has been wonderful for decades. It wasn't hard to start on the first start either, although I think I did it with the starter motor.
I think a tight engine, properly broke in, will work, but I also think you're putting a lot of stress on parts that likely don't need it. However, I also think I would avoid the rebuilder this thread started with; it shouldn't take that much effort to get a fresh engine to start.


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