Htp (the tech only version)

[miketsouth]

I am suspecting loose splines as the cause of some light vibration in my P/F.
I have about a 7deg rise in the 7"(ujoint center to center) crankshaft that connects the motor to the pump.
The vibration starts at about 3800rpm and continues to 4700(my max so far)
There is also very loud pump rattle from 1000 to 1100 rpm. I have a jet with pump rattle but no vibration but the close coupled shaft has only a degree of offset, and that by accident.
The spline connection has radial play of about 1/32" at the ujoint end
The spline connection is well lubed.
The motor and pump are parellel, dead nuts.
The spline is engaged 95%, leaving just 5/16" for thrust
The u-joints are not very loose, if at all and lubed.
I researched the part i needed and found it to be a specific spicer part,
part# 2-4-2401
1310 series
10 spline
1.375 spline major diameter
1.069 u-joint cap diameter
2" spline length
ubolt design bearing cap hold downs
et cetera
I called my local bearing company, who have been very knowledgabe in drive systems before, and i might as well have been talking to a (censored) dealer.
I called Dana-Spicer and they found the part number, but did not know if they still made them...and said they would get back.. another (censored) dealer.
I called your shop. The gentleman not only knew what i was talking about but had them in stock, assured me by direct measurement that it was the right part, offered me some vibration troubleshooting information and shipped them out RIGHT NOW.
This is service. This is excellent unparalleled service, and i wish to display my profound pleasure in dealing again with your shop.
Thank you
.................................................. .................................................. .
I dont know if this is the source vibration or not. Could be uneven power, but i cant find it. Maybe i'm being to critical. I thinks not.
I moved the motor a little back to engage just a little more splines and the vibration, as well as the axial play was not as bad.
I mic'd the OD of the shaft and the ID of the major diameter of the splined coupling. .006" @ .003 per side. I probably made a mistake. The splines wear on the side of the spline. If the sides are close, the coupling will be tight regardless of the major OD, i think.
I tried to think of all kinds of ways to tighten the coupling, from shimming to electroplating. Didnt have to. For the price and availability this will work.
Thanks Duane
mikeT

[miketsouth]

My next effort is to get someone to give me some SBC headers.
I know, Rots of Ruck.
I used logs because i dont like the idea of water injection and i just cant pay more for jacketed headers than i did for the motor.
Seems i miscalculated the restriction that logs give even with the OT trumpets.
I been searching E-bay, pondering Lightnings and dreaming of making my own. Got to look good, which leaves out some of the cast aluminum manifolds, but seems i just cant bring myself around to making the plunge for CMI or Stellings. Im just too cheep(spent all of my money already). Sucks.
Water jacketed is the way to go. I burnt myself TWICE in the same day on the OT extensions. (thick, like i said).
mikeT

[miketsouth]

Ok, got the new coupling. Major OD measures the same. Teeth on the old one were worn. Just a little, but at the driveline angle of 7degrees probably enough to matter. It is the teeth that hold the damn thing straight, not the OD.
Thanks again Brian and Duane.
mikeT

[pops1]

Originally posted by miketsouth
I am suspecting loose splines as the cause of some light vibration in my P/F.
I have about a 7deg rise in the 7"(ujoint center to center) crankshaft that connects the motor to the pump.
Thanks Duane
mikeT
Mike, if I am reading this right-are you saying you are 7 degree's angle on universal spline or straight. If you are either spicer say's you should have some load on the bearing caps of between 2 & 3 degree's- Not straight or overload. I have seen both conditions cause noise problems. Dave

[Blown 472]

Originally posted by miketsouth
My next effort is to get someone to give me some SBC headers.
I know, Rots of Ruck.
I used logs because i dont like the idea of water injection and i just cant pay more for jacketed headers than i did for the motor.
Seems i miscalculated the restriction that logs give even with the OT trumpets.
I been searching E-bay, pondering Lightnings and dreaming of making my own. Got to look good, which leaves out some of the cast aluminum manifolds, but seems i just cant bring myself around to making the plunge for CMI or Stellings. Im just too cheep(spent all of my money already). Sucks.
Water jacketed is the way to go. I burnt myself TWICE in the same day on the OT extensions. (thick, like i said).
mikeT
Just a little food for thought, I had fresh 472 in my boat with center rise manifolds, didn't turn the rpm I thought it should so I tried a set of lightnings, no change in rpm or speed what so ever, my wallet was alot lighter thou.
I took them off and sold them and put my center risers back on and have been happy with them.

[miketsouth]

Pops1: I was not clear. Let my try to get this right:
My engine is coupled to the pump with a short driveshaft.
The driveshaft has only two universal joints.
The seperation between the two universal joints' centerline is about 7inches.
The power(engine) end of the driveshaft is coupled to the PTO adapter via 4 finethread bolts. It is centered on the engine end by a boss that fits into the adapter.
The powered(pump) end of the driveshaft is, of course, coupled with a slip spline adapter. This is a nightmare thing. Failing part of the drive system, no matter how you look at it.
The pumpshaft and crankshaft centerlines are parallel. Not inline, but parallel. The angle is only in the vertical direction, engine above the pump.
The motor sits some .7inches (or whatever makes about 7deg, i forgot) above the pump.
This is more angle than is recommended by typical driveline geometry, but i did not think it should vibrate. I expected the chatter as it is normal, and more rapid wear. I did not like the mild vibration.
When the spline coupler gets even a little loose, or even brand new, they can chatter out of the water. This was chattering in the water. 1000-1100 rpm. Vibration started at 3800 and increased with more revolutions, but silent (or rather cant be heard above the megaphone exhaust)
The spline coupler had some visible movement when shook by hand. That is, radial movement (up,down,left,right)
I replaced it. It is tight now. Very close. My calculations indicate that the coupler was allowing about 1.5 degrees. Not much, i thought, but with the 7deg driveline angle i am hoping it did matter.
The exhaust (for those who care).
Logs. I ran DTD to size the pump impeller initially. The one thing i could not run was the exhaust. There is not a "logs". Using pump curves to indicate HP, i selected the exhaust system that seemed to fit my present conditions. "high performance manifolds" seems just about right.
Plug in "small tube headers with mufflers" yields great gains. It will put me where i need to be, i think. "Open small tube headers" even more.
Now, how to do that, look good, and afford it. Im workin on it.
Thanks Pops1 for the attention. Of the many there are few that have offered me some sound advice. I have been offered some BS though. Maybe i was not explicit in my questions.
Oh, yeah, a little pump work and i will should get 70+mph with an almost BONE STOCK sbc. Got to love the tunnel. It rides like a dream.
HP rules.
Math Works
Forget Torque
(you hear that Jer)
mikeT
Originally posted by pops1
Mike, if I am reading this right-are you saying you are 7 degree's angle on universal spline or straight. If you are either spicer say's you should have some load on the bearing caps of between 2 & 3 degree's- Not straight or overload. I have seen both conditions cause noise problems. Dave

[miketsouth]

It seems that proper center rise manifolds (the long ones) do a pretty good job of seperating the pulses. I am thinking that if the cam is not sized to take advantage of the exhaust velocity for scavanging, longer tube headers will not net any gains.
Center rise mans is an option. They pretty ugly though, and good ones are $750 or so. I am still looking for an exhaust solution. I have even thought of getting some cheep chebby "hugger" headers ($60) and welding on a drypipe to them to try it.
My wallet is floating right now, if it gets any lighter i can use it for air travel.
Originally posted by Blown 472
Just a little food for thought, I had fresh 472 in my boat with center rise manifolds, didn't turn the rpm I thought it should so I tried a set of lightnings, no change in rpm or speed what so ever, my wallet was alot lighter thou.
I took them off and sold them and put my center risers back on and have been happy with them.

[miketsouth]

it is not the chatter. I'm pretty sure i know what causes that. I think it is just what riodog said, and maybe a little more, like crankshaft instantaneous speed changes at low rpm, especially with some cams and more with flexplates than flywheels.
It is the vibration
i think lots of people just live with the vibration. The people who drove my boat didnt notice it, until i pointed it out.
I've felt the vibration on other boats too. I just dont want it in mine. I want it sewingmachine smooth. I know it can be achieved as i have another jet that is smooth and have rode/drove in lots more smooth ones.
I just wonder if it is available with that much angle, no matter how balanced (drive/driven angle) the shaft alignment is.l
Could it have been the loose coupling? Cant tell until i get it out. Work today, rain tomorrow. Sucks.

[LVjetboy]

MikeT, just keeping the thread on top so someone who knows more than me can read it and help you.
Until then, you mentioned parallel and 7 degrees, but are both angles (engine and pump joints) equal? Small variations no big deal but any difference will cause some degree of vibration.
jer

[miketsouth]

Originally posted by LVjetboy
MikeT, just keeping the thread on top so someone who knows more than me can read it and help you.
Until then, you mentioned parallel and 7 degrees, but are both angles (engine and pump joints) equal? Small variations no big deal but any difference will cause some degree of vibration.
jer < controversial a**hole
Yes, i made sure of that. When a level is level on the pump, it is level on the engine. The engine is at 4degrees, just as is the pump to the bottom of the boat. The engine and pump centerlines are parallel.
I am dying to try it out again, but someones dancing, i suppose.
ASAP though.
Thanks Jer