Drive Shaft ?

[placecrafttim]

I havn't posted here much at all. So after posting this on Banderlog and not getting a response I thought I would try here.
I'm putting a BBC in my Placecraft and the way the previuos owner had it was with a two peice universal shaft and I was told that this is a bad way to do it. So I bought a new shaft and flexplate button. Now I have to move the engine 2.5 inches forward. My question is. Can I machine some of the parts so I dont have to move the engine so far forward? The shaft on the jetaway is 1 1/2" long and the slip yoke on the drive shaft is 2". Can I machine a 1/2" off the end of the shaft and maybe an 1/8" off the flywheel button and an 1/8" off the front face of the driveshaft? I dont see any reason why I cant do it this way but if there is a reason not to please let me know. I'm getting kinda antsy to get it in the water.
Thanks

[sanger rat]

I can't answer your Q but alot of people are gone for the big weekend. If you don't get a anwser bump this back up on Tues. Or you could give Duane at HTP a call.

[Duane HTP]

You can thin the flywheel button. You can cut sometimes as much as 3/4" off the drive shaft yoke. You can even remove 1 u-joint on some applications, but DON'T cut the Jetaway shaft.

[LVjetboy]

"I'm putting a BBC in my Placecraft"
'bout time. :)
jer

[robk]

Long time lurker finally posting here....
I've been doing my due diligence searching for solutions to a similar problem I'm having with a hull I recently purchased, a '74 Tahiti.
I'm trying to install a 455 Olds out of a '71 19 ft Tahiti into the new hull, which appears to have had a 455 installed in it (judging by the parts installed when I got it, ie bell housing cover, etc). When trying to install the pump, I noticed that the driveshaft (2 u-joints and spline, 7.5" long) coupled with the PTO adaptor is too long to allow the pump to be mounted.
The way I see it, I'll either have to move the motor forward 2.5" (bad?) or find another type of driveshaft that is 2.5" shorter. So far, I haven't been able to find much in the way of driveshafts except like the one I have, but I've heard things here and there about a shorter type, but I can't find one. I've heard suggestions of taking one of the u-joints out, but I can't help but wonder about shortening bearing life by doing that. I plan on rebuilding this pump and would like the parts to last more than a season or two....
What is the better route? Help? I've been reading posts here and have had a lot of questions answered by hanging out and reading these forums, and it's the best advice I've seen around.
Thanks,
Rob

[robk]

Anybody ever experience this? I can't imagine a shorter driveline working, so are there any differences between a 12-JCAH and 12-JC that would account for 2.5" shorter distance between the pump and the motor?

[BrendellaJet]

if the 2.5" doesn't mess up your interior, you can move the motor. I doubt tahiti had it installed in the optimal location anyway. OR, you can attempt the trimmings mentioned above in an effor to decrease the lost interior room. A setback pump would fix this too.

[robk]

if the 2.5" doesn't mess up your interior, you can move the motor. I doubt tahiti had it installed in the optimal location anyway. OR, you can attempt the trimmings mentioned above in an effor to decrease the lost interior room. A setback pump would fix this too.
There is just enough room to move the motor forward enough and have it not hit the front cover. I wonder if I should do a little extra glass work on the stringers after moving the mounts -- I'm sure a bunch of extra holes can't be helping much, especially considering how short the stringers are to begin with.
Thanks for the advice.

[superdave013]

robk, take your drive shaft over to Orange County driveline (in Placentia) and ask them to shorten it up. They do alot of boat drive shafts over there. Tell Ray that Dave @ Sweet Performance sent ya.

[robk]

robk, take your drive shaft over to Orange County driveline (in Placentia) and ask them to shorten it up. They do alot of boat drive shafts over there. Tell Ray that Dave @ Sweet Performance sent ya.
That I would do, except I have what looks like a precursor to the H-bar driveshafts I see for sale now -- it's just two u-joints bolted together. The only way I can see to shorten it would be to remove one of the u-joints and I can't imagine that would work without causing tons of vibration.
Semi-off-topic, but they wouldnt happen to do regearing for trucks would they?
Thanks
Rob

[BrendellaJet]

maybe they can make you a new one.

[superdave013]

No they don't. The guy for that is "The Gear Man" in Stantion. Bill Slyvia is the guy to talk too. He has lots of used gear sets too if you are trying to keep costs down.
I bet if you showed the OC driveline guys that part they could whip up an H bar type in short order.

[robk]

No they don't. The guy for that is "The Gear Man" in Stantion. Bill Slyvia is the guy to talk too. He has lots of used gear sets too if you are trying to keep costs down.
I bet if you showed the OC driveline guys that part they could whip up an H bar type in short order.
I'll take it by there when I get a chance and see what they have to say. Thanks for the info.
Rob

[robk]

http://www2.***boat.com/forums/attachment.php?attachmentid=10391
What do you guys think? I was questioning whether it was feasible to use only one u-joint -- and the link above shows it being done.
Do you think that if my alignment is spot-on it'll be ok?

[Duane HTP]

I've run my boat, (blown 588 cid Chevy), with one u-joint for 7 years now. No problems yet.

[robk]

I've run my boat, (blown 588 cid Chevy), with one u-joint for 7 years now. No problems yet.
Awesome, that's exactly what I've been hoping to hear! Now I can move forward with my pump rebuild and getting everything fitted together and finished up!

[Duane HTP]

Robk,
When you do the one u-Joint deal, Put the drive line on the pump shaft, (be sure to leave about 3/16" end play), line the motor up where you want it. Then fasten the front mounts. That should pretty much do it as long as you are using a three point mounting system. If it's a four point, do the same. Then lift the back of the engine up just enough to take the weight off the drive line and fasten your rear mounts there.

[robk]

Robk,
When you do the one u-Joint deal, Put the drive line on the pump shaft, (be sure to leave about 3/16" end play), line the motor up where you want it. Then fasten the front mounts. That should pretty much do it as long as you are using a three point mounting system. If it's a four point, do the same. Then lift the back of the engine up just enough to take the weight off the drive line and fasten your rear mounts there.
Thanks for the advice! I appreciate how helpful everyone is on this board.

[NavalOfficer]

speaking from my v-drive experience. Everything stated above is exactly correct. The differnce is the h-bar would allow for some height differences as the engine and pump angle should remain the same. same basic theory as aligning a transmission and a rear end of a car. if the pump and the engine are not at the same angle the u-joint is forced to take the load and will entually fail.
just my 2 cents
frank

[Glencoe MiniDay]

I think you are incorrect on the inline U joints.
cars and trucks have the rear diff offset or angled down to work the joint to avoid premature failure.