Engine shudder/vibration

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Model T Ford Forum: Forum 2018: Engine shudder/vibration
Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Wednesday, January 17, 2018 - 04:50 pm:

1914 engine in Runabout
Just after shifting into high gear, as I accelerate under normal load, I get a bad engine /shudder in a narrow rpm range, but once past that shudder rpm range the engine smooths out. This vibration/shudder whatever has caused the upper inlet fitting on the rad to cause a leak for the third time. The rad is now in the repair shop for the third time.
The shudder is so bad you can see it vibrate the rad during that short period of acceleration.
I plan to pull the engine in Apr and do a careful balance on everything possible.
Any suggestions what to look for would be appreciated


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Bourgeois on Wednesday, January 17, 2018 - 04:53 pm:

Are you sure that it is in the engine and not the tires being out of balance?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Warren F Rollins on Wednesday, January 17, 2018 - 04:53 pm:

Clutch adjustment? No shutter in low?


Top of pagePrevious messageNext messageBottom of page Link to this message  By William Dizer on Wednesday, January 17, 2018 - 04:55 pm:

Broken/loose motor mount? If everything is bolted as solidly to the frame as usual, would the engine move enough to damage the radiator?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Wednesday, January 17, 2018 - 05:22 pm:

Motor mounts checked all OK
Warren, haven't checked that, good thought!
Steve, good thought but shudder stops if I back off on throttle!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Marshall V. Daut on Wednesday, January 17, 2018 - 05:27 pm:

Bad or loose universal joint? That causes vibration more at certain RPMs than at others. A bad U-joint will make you think your car is falling apart and the world is coming to an end at various RPMs.
Is your U-joint pinned to the drive shaft the way it should be?
Marshall


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Wednesday, January 17, 2018 - 05:33 pm:

Motor mounts checked all OK
Warren, haven't checked that, good thought!
Steve, good thought but shudder stops if I back off on throttle!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Wednesday, January 17, 2018 - 08:37 pm:

Sometimes an ignition miss will only show up on a hard pull. Could be missing when you first shift into high and then smooth out as the engine speeds up and you back off the throttle. Check your spark plugs, the coils and the timer.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Lloid on Wednesday, January 17, 2018 - 08:50 pm:

I had a bad u joint and that was my shutter problem on up shift.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Wednesday, January 17, 2018 - 09:46 pm:

When you retard the spark going into high gear you will not have any shutter as the engine will easily pick up the RPMs due to the gear change


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adam Doleshal on Friday, January 19, 2018 - 11:36 am:

Poorly re-ground crankshaft, or huge flywheel imbalance. Could also be loose flywheel to crankshaft bolts (but less likely).

I had the exact same vibration circumstances in an engine over 10 years ago. Turned out that the shop who had ground the crank centered off the worn front & rear main journals to make a quick grinding job instead of the gear area and the outside of the flange to do a quality job. When disassembled, the flange had .024 indicator runout. The installation of a properly re ground crank eliminated the vibration.

I had 2 more cranks on the shelf from the same re-grinder. I checked them and they had the same errors. Took them back and they happily refunded the grinding charge and paid for the core value.

A couple years later, one of the guys from that shop had both those cranks for sale in the swap meet at the dodge county antique tractor show. He was telling people they were cranks they ground for somebody who never showed up to pick them up. They were gone by the end of the show, so I imagine whoever bought them has the same vibration issues!!! If I remember correctly, they were both 26-27 EE cranks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Saturday, January 20, 2018 - 02:13 am:

I've heard this story quite a few times and, to an extent, my own car behaves the same way. -The know-nothing-newbie thinks this is the very common consequence of building a low-power car without an intermediate gear between low and high. -The symptoms appear to varying degrees depending on the individual car in question, but every Model T I've driven grumbles at least a little bit on acceleration right after up-shifting. -Retarding the spark and throttling up very gently is a common way of dealing with this annoyance, but if you're getting a very heavy, low-frequency vibration, it's possible there's something wrong with your car. -Check the easy, inexpensive suspects first.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Saturday, January 20, 2018 - 08:51 am:

Thanks all for the input
Wilf


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Saturday, May 12, 2018 - 06:55 pm:

Now that we are home from wonderful sunny Gilbert AZ, in cold Ontario, I have jacked up the right rear wheel. With the brake off,( in high) rocking that wheel back and forth I hear a notable 'Clunck" sound from the universal area. The rear end is quiet.
Could this be causing the annoying shudder when under load at lower RPM?


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Saturday, May 12, 2018 - 07:13 pm:

My engine does that when the gas is set too rich or it is going too slow for the carb setting.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rich Bingham, Blackfoot, Idaho on Saturday, May 12, 2018 - 08:38 pm:

Similar but not the same problem, I couldn't get a smooth shift from low to high. I rebuilt the rear axle and driveshaft, now she's smooth as silk. U-joint was bad, pinion carrier in trouble and differential thrust washers shot. No wonder !

Unless the engine is in trouble disengaged from drive, idling or revved up, or obviously rough in low, I'd think shuddering when taking up the load in high indicates drive line problems.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Saturday, May 12, 2018 - 08:54 pm:

Wilf,I agree with others above.Plus....
If it was mine,I'd tighten up the clutch discs a half turn.Sometimes they ' catch and release'.
I had one with Turbo 400 discs in it that would occasionally do this.
I do not believe you have any severe internal balance problems.
If it did,it would rattle your eyes in their sockets most or all the time.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Saturday, May 12, 2018 - 09:04 pm:

Jim
This maybe the problem. I have turned in the finger screws as far as I dare,( so far that the split pin doesn't touch the screw heads. Now the spring is only compressed to 2.5 in, not 2 as recommended. I'm convinced that the rebuilder did not put in enough clutch plates with the turbo 400 to allow proper compression of the clutch spring.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Daren Carlson on Saturday, May 12, 2018 - 09:44 pm:

Clutch.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Saturday, May 12, 2018 - 11:12 pm:

Old T guy, RIP,I knew well put in one pair too few discs.
Slipped.
So,after realizing what he did,and getting over the urge to take a maul and a sledgehammer to the "whole damned shooting match",he made longer adjusting screws.
I think he may have also shimmed the spring shorter.
That was about 1980.Several owners later,last I heard,still works.
To those that have always fixed things 'right',I doff my cap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Doolittle on Sunday, May 13, 2018 - 11:54 am:

Is the clutch the problem? Maybe.

Personally, I think that if the rebuilder installed a NEW Turbo kit, why would he have left out a disc? When the new set was ordered, why not install them all?

My thinking is a weak clutch spring may be the culprit. The difference between 90 pounds and 115 pounds is great. A weak spring slips or stutters. A strong spring knock your teeth out upon engagement.

Ask him if he checked the poundage on the clutch spring.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Sunday, May 13, 2018 - 12:15 pm:

If everything is up to snuff re the clutch, the 2" is for checking the strength of the spring. It is the finger adjustment that is of concern. You need to set the distance of the through out collar to the drive plate. 13/16", then from there adjust as needed to get full engagement of the disks. The fingers on the ring should be at or just above the drive plate with the clutch engaged. My OP is, with the three pins too much below the drive plate you can risk enlarging the holes. The pins are hard the plate is not.
Another point of concern is the bosses in the brake drum, they need to be smooth for good action of the disk. If they are too worn the disk can hang up.
From the the description that the adjustment tops screws are below the cotter pins, sounds like missing disks or the tubo400 disks are very worn.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, May 13, 2018 - 12:19 pm:

My money is on u joint or driveshaft bushing being worn. My experience with slipping clutches is they keep slipping until you let back off the throttle. I never noticed any roughness or vibration during the slippage. Only a racing engine, but no acceleration to go with it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wilf Bradbury on Sunday, May 13, 2018 - 05:39 pm:

Thanks Hal I agree. Rear end is coming out next week!
Thanks to all for the great feedback
Wilf


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rich Bingham, Blackfoot, Idaho on Sunday, May 13, 2018 - 05:53 pm:

You won't be sorry Wilf ! That said, I always have to wonder at the "side-long" difficulties non-stock "improvements" throw into the mix. The Model T was its own level of perfection as built, and performed admirably that way, and continues to do so.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eviston on Sunday, May 13, 2018 - 06:55 pm:

Since it sounds like its coming apart in any event,try this,just for kicks.
Put a dose of Tranny Honey, or similar friction modifier in it and see what happens.Make sure whatever it is doesn't have any metallic components, or it's good-bye magneto.
My Roadster with T400 clutch discs would usually shudder to beat hell if it were intentionally slipped---say to turn a corner at a speed to high to shift all the way into low.If it had been a normal steel disc clutch car,that would have been accepted driving practice.
Finally, I got tired of that and I added a bottle of some snake oil or other,and that reduced that about 90%.
I had forgotten that.
Worn driveshaft bushings go bump bump bump right under the floor boards when you close the throttle quickly on level road in high gear.
Badly worn ujoints cause the car to rock back and forth,more than they normally do,
when braked to a firm stop without easing up on the brake pedal.And go clunk clunk,usually.
Got to be pulled apart,anyway.
Don't keep it a secret what you find.
ALWAYS remember. The LAST resort with these damn things is teardown and throwing money at the pieces.


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