Timing cover dilema

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Model T Ford Forum: Forum 2012: Timing cover dilema
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 09:30 am:

Ran into an issue while installing the timing cover on the front of the engine. I cannot center the cover to the cam so the timer will be in the middle. The machined area for the crank seal is touching the top of the crank snout. Has anyone ever seen this before?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn on Sunday, December 16, 2012 - 10:19 am:

You will have to use the tool that properly centers the cover on the cam shaft. Lang's sells a K R Wilson Repop that is super! It slides over the cam and fits where the timer fits holding the cover in the proper place while you tighten all of the bolts.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, December 16, 2012 - 10:28 am:

Follow what Mike said. Also, you don't say much about your engine. Has it been rebuilt? Have you installed a different crankshaft? Have the main bearings been replaced since you had the timing cover off? Some engines have been bored to fit a crankshaft with a different stroke which necessitates moving the main bearings so the crankshaft will not hit anything inside the crankcase or block. In that case, you will need to modify the timing cover to accept the new location of the crankshaft.

Anyway, unless something radical has been done to your block, it should fit by using the tool mentioned by Mike. Install the timing cover first and bolt it up tight. Then bolt up the crankcase to the timing cover.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 10:41 am:

Just got the motor back from being rebuilt. My crank had a crack (of course)and it was replaced with a stock crank.010/.010. New bearings poured with and a stock cam and crank gear. The problem is I can't put the KR Wilson alignment tool on, the cover needs to move further but the seal area is touching the crank. Seems like the cover needs to machined out a bit to slide it down about a 1/16th or 1/32nd.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Sunday, December 16, 2012 - 10:48 am:

It doesn't make sense that the cover is hitting the crank. If the mains were bored off center the timing gears wouldn't fit together. I am guessing you just need to wiggle things around.
If you've done that to no avail, then machine the lips of the felt area as best you can.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn on Sunday, December 16, 2012 - 11:19 am:

Jim - If you are using a rope or felt seal sometimes it helps if you put the cover in place and tighten the bolts on both sides of the crank shaft. This will give the seal some shape that fits the crank, then loosen the bolts and use your alignment tool to install the cover, again tighten the two bolts on either side of the crank first then tighten the others, I have had some that I had to play with for a while before everything fit like it should.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Sunday, December 16, 2012 - 11:27 am:

Be sure you have the correct cover for the year block. Do you have a rope seal or felt seal in the cover? Can't think of any reason the cover is metal to metal contact with the crankshaft nose.

If the seal is hitting the crank you compress it by using round stock or the side of properly sized socket wrench, then fit the cover in place on the block. Then use the timing cover alignment tool, to align, then bolt down the cover. The seal will squeeze down, but not if it is sticking up too high, soak the seal in oil too.





Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn on Sunday, December 16, 2012 - 11:31 am:

Something else that I have done to help get the seal to fit so that the alignment tool can do its job is to use a drift through the hole the fan shaft goes through, you can use the drift to pry the cover in the direction you need to allow the alignment tool to slide into place. It usually does not take much pressure but as you have already seen the rope or felt does give you some restriction and it needs to be shaped and compressed to fit the crank shaft.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, December 16, 2012 - 11:35 am:

The really early covers may look the same at first glance but the "timer cavity" was never actually used for the later style timers that began in late 1911. What happened is that Ford designed the new timer to fit a cavity that was already in place for a felt donut seal but those early timer covers have that cavity and it was not precision located or bored to a tight tolerance as are the later timing covers. I doubt you have the timing cover I am talking about but you didn't mention what year the motor is.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 11:47 am:

it's an early '26 motor and early '26 cover, it has the boss for the fan adjuster but not drilled or tapped. I haven't even put the seal in the cover yet, was just checking to see if I had all the correct bolts and it is touching the crank. I have .030 on each side of the cover to the crank. It needs about .030 ground out for the cam to be centered.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn on Sunday, December 16, 2012 - 11:56 am:

Did you have any gaskets in place for your dry fit?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Sunday, December 16, 2012 - 12:25 pm:

Jim:

Go slowly here. You need to be absolutely sure of what the problem is before you modify anything. Incorrect timer fit will plague the performance of the motor for its entire life.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, December 16, 2012 - 12:30 pm:

Jim
I know you said K.R.W., but what kind of timing cover alignment tool are you actually using? There are three different types I know of and two of them could cause this trouble.
Is it like this one?
1
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Sunday, December 16, 2012 - 01:02 pm:

Jim

You posted "It needs about .030 ground out for the cam to be centered"

The cover will not be centered over the cam until you position the cover, and then use the tool to align. That 'centers' the cam in relation to the timing cover recess for the timer case.

Maybe we have misunderstood your need to center the cam on first placing the cover?

The tool does that.


Pic of 'non tool' placed cover, on a cutaway non function engine, there is a gap or offset, that goes away when you bolt on the cover using the tool.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 01:42 pm:

Here is a picture of the cover, as you can see there is .030 on each the left and right side of the cover. The top of the crank is touching the cover. I can't move the cover any further down to make the cam line up in the cover hole.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier on Sunday, December 16, 2012 - 01:57 pm:

Jim, it appears in your picture that you have the bolts in the cover and it is touching the crank, that can only mean that the line bore was off when the engine was rebuilt as you said it was. I would be getting in touch with whom ever did the machine work. Good luck, KB


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ed in California on Sunday, December 16, 2012 - 02:03 pm:

Try another cover before you panic.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Sunday, December 16, 2012 - 04:53 pm:

I fear Keith B may be right. But one question first. Did you happen to tighten the bolt on the right (manifold) side of the engine first? The bolt holes allow a bit of slop and adjustment for the cover. If it happens to be too high on one side and too low on the other, this problem can occur. Usually, the pan edges of the block and cover should line up fairly close on both sides of the block. I usually set the manifold side first, then align the cover to center the timer and bolt it down.
You may be able to adjust that cover by removing the cover bolts. Then push the manifold side of the cover in the down direction just beyond the pan edge lining up with the block and bolt tight with the one right side end bolt. Then try to adjust for timer centered by moving the left side down till the adjustment is correct and put the rest of the bolts in. This has the effect of rotating the cover slightly around the cam and raising it over the crank. If something is off only a couple thousandths, this should work (it has for me once or twice). If the mains line bore is off more than that, this probably would not work without a lot more fiddling which I would not recommend anyway. If the line bore is off too much, even if you can get it together and running, you could likely end up with serious timing gear troubles. (Depending upon just which direction it is off.)
Good luck.
Drive carefully, and enjoy the holidays! W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Richard Gould on Sunday, December 16, 2012 - 05:54 pm:

If the line bore on the mains were off center enough to cause this, the timing gears wouldn't mesh. That's not the problem.
Another thought, even though the cam is not centered in the hole in the cover, the recess for the timer may still be concentric with the cam. Try the tool that Ron illustrated.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Woods, Katy, Texas on Sunday, December 16, 2012 - 06:15 pm:

The timing gears may mesh, but I think the align bore could still be off a fraction. The question is; do the timing gears mesh correctly? Just like the fit between the ring and pinion gear, the timing gears need to have the correct lash. According to the Ford Service manual, page 116 in the 1925 version and figure 457, "New time gears are assembled with from .0005 to .003 backlash (space between the teeth). The picture Jim posted, shows a lot of clearance on both sides of the crank, but none on the top. If I were a betting man, I would look here.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, December 16, 2012 - 06:40 pm:

Jim,
This is what I would try. Get the tool from Langs. Then with all the bolts loose put the tool on the end of the camshaft and center in the recess in the cover. The recess is the one for the timer not the one for the seal. Once that is in place, then tighten the bolts. The cover can be rotated around the timing gear, so the side over the crankshaft can be raised for proper clearance. The cover might be lower or higher from the crankcase rather than flush with the block, but that difference can be made up by gaskets and or sealer. Also, the camshaft might not be centered in the hole in the cover, but it must be centered in the recess in which the timer is set. This should work.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 07:36 pm:

I just checked the backlash on the gears, there is .001 between the teeth, which is correct. Just enough to where I can turn the cam gear cam back and forth enough and barely see a movement. But I did notice that the tip of the crank tooth rides deep into the cam gear. There is .001 from the tip of the tooth and the recess between the cam teeth. which makes me believe the line bore is a bit high. Is this acceptable or do I need to do something?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Sunday, December 16, 2012 - 07:43 pm:

Is there any babbitt in the block?

If you have the means, measure the center-to-center distance between the crank and cam. It should be 100mm or 3.937".

Remove the cover and shoot a picture of the crank gear and cam gear meshing. I think the crank is sitting too high.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, December 16, 2012 - 07:52 pm:

Jim
During line boring the main bearings the location of the hole in the babbitt for the crankshaft bearing is indexed on the camshaft bearing bore in the block. This is normally done with a false camshaft rod which is inserted in the cam bearing bore which is then precision spaced to the crankshaft centerline.
I cannot immediately lay my hands on the exact decimal number, someone will have it at their fingertips, for the nominal distance between these two centers, but it is critical for proper cam/crank gear mesh.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, December 16, 2012 - 08:22 pm:

Jim
Ken has the number, before going too much further some precision measurements are in order. Do not be disheartened, it is certainly better you get to the bottom of this problem now than later.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeff Hood on Sunday, December 16, 2012 - 09:12 pm:

Just a thought, is the end of the crank bent? turn it over 180 degrees and see if there is any difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Sunday, December 16, 2012 - 09:17 pm:

Rotated the crank and it is straight. I measured the distance between the crank and cam centerline and came up with 3.926", so it appears it is off by .011" Cam gear.JPG
Now for the big question, is this acceptable or does it need to come apart and be done over?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kerry van Ekeren (Australia) on Sunday, December 16, 2012 - 10:24 pm:

ouch!! that looks tight Jim, may be try some well worn gears to give you some lash or it's a repeat job on the mains.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, December 16, 2012 - 10:44 pm:

Jim
If I had this problem I would discuss with and get the opinion of Dan McEachern before doing anything else.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Sunday, December 16, 2012 - 11:13 pm:

Using worn gears isn't going to solve the original problem. The crankshaft isn't on the correct centerline. This could to lead to rod and piston problems. And for sure, fast gear wear and noise. It wouldn't take much heat or dirt to lock those gears up and break the cam. I wonder if the crank is even parallel to the cam? Did you check the rear center-to-center distance?

A Band-aid won't work on this. The block mains need re-poured and line bored correctly. The caps will probably be ok. (Enough babbitt to re-bore.)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Woods, Katy, Texas on Monday, December 17, 2012 - 12:30 am:

As my Dad used to say, "That's tighter than Dick Tracy's hatband".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan McEachern on Monday, December 17, 2012 - 12:44 am:

This is just speculation, but from the last picture, that crank gear is meshing pretty deep in the tooth space of the cam gear. Odd that a rebuilder would mesh a new cam gear with an original(probably worn) crank gear. In fact, about the only way you could mesh a gear set that deep is if the crank gear is badly worn given the center distance that was posted.

If that set has .001 backlash as was posted, you will most likely be having timing gear problems shortly after starting the motor. If you want to dig in the motor a little, pull the front cap and check if the journal is centered in the vertical direction. Thats an easy check with a depth mic and two blocks of known size. Good luck with this. Dan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Monday, December 17, 2012 - 01:50 am:

The tolerance on the cam to crank measurement is less than +/-.001". Leniency to the larger side is .0008" and only .0003" on the short side. Ford wouldn't have this spec if it wasn't critical to the engine design. It's not just the gear mesh that's affected.

Wonder how many broken cranks can be attributed to out-of-spec block main bearing alignment that gets blamed on the 4th?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Monday, December 17, 2012 - 02:11 am:

This is an extreme exaggeration but you can see what other problems can arise if the crank isn't on the design centerline.

Crank Alignment.jpg


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Monday, December 17, 2012 - 02:20 am:

And it gets worse. I drew the piston pins on the wrong side.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kerry van Ekeren (Australia) on Monday, December 17, 2012 - 03:02 am:

First, you would have to ask what sort of line borer was or is used, mine is set to run parallel with the cam, dummy cam shaft and tool setting front and back on the block, I don't know what was set up on Jims block but something is not right, I believe the machinest should have picked it up that something was not right just with the gear lash, even if he could get .001" that's too tight, Ford specs are .003 to .005 for new steel gears and I think a few more is safer with brass or aluminium.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Alan Woolf on Monday, December 17, 2012 - 06:18 am:

I had similar problem with a fresh "rebuilt" engine. The rebuilder had not set the cam to crank to centerline properly. The fix was to get Dan McEachern to make a custom cam gear to make up the difference in the center to center distance. That engine has been run 10k miles with no problems.

Jim in your situation get a timer alignment tool and make sure you can get the timer located properly. Once the cover is located to suit the timer talk to Dan McEachern about making a custom bronze camshaft gear to match up with whatever centerlines you have. It won't cost a lot more than a new gear.

Alan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Monday, December 17, 2012 - 10:26 am:

If you are using a rope seal, I get a socket that is about the same diameter as the crankshaft, and lay it in the cover, and c-clamp the socket to the cover overnight. This seats the seal in the cover, and makes it easier to get the bolts in.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Monday, December 17, 2012 - 02:25 pm:

This is the OP's problem: http://www.mtfca.com/cgi-bin/discus/show.cgi?tpc=257047&post=484132#POST484132

All the clamps and new gears in the World won't fix this.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Monday, December 17, 2012 - 07:14 pm:

I contacted the engine builder this morning and he said to bring it back for him to look at and determine what needs to be done. This shop came highly recommended and Babbitt engines is all he has done for almost 30 years. He has done a few for people that I know and have heard no complaints. I also contacted a member from this forum that was recommended. And I was hoping to have this fired up during Christmas break.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Hycner on Friday, December 21, 2012 - 11:00 pm:

Had a friend come over to look at the problem who is a quality inspector for a large machine shop. He determined that the line bore is not parallel with the deck of the block. It is off by .070" with the front of the crank too high which is why the cover does not fit right and the timing gear mesh is too tight. The crank to cam center is .025" to close. Looks like the engine needs to go back.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Friday, December 21, 2012 - 11:29 pm:

Jim
In my view there is no excuse for that quality of work!
I suggest you find another engine babbitt and align boring shop who understands how to properly set the initial camshaft and crankshaft centerline clearances for pouring the bearings and align boring the main bearings of a Model T engine.
Ron the Coilman


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