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-   -   Model A engine transplant, drivetrain elignments (http://www.hotrodders.com/forum/model-engine-transplant-drivetrain-elignments-143533.html)

pcoghlan 08-15-2008 03:25 PM

Model A engine transplant, drivetrain elignments
 
I decided some while back to switch out the SBC in my steel '29 highboy for a 292 Y Block.

I have the new engine nearing completion and am looking to mock up some mounts etc to get it and the top loader in within the next week or three.

My question relates to alignment between the engine/gearbox and the driveshaft/rear end. I dont yet have a driveshaft and will need to scratch my head and work out how to get one made up after the engine/gearbox is in place so I have the correct length.

So, is it simply enough to get 'visual' alignment or are things so critical that there is some scientific method to ensure EXACT alignment? Bear in mind that the car is a cruiser, not a racer.

Thanks,

F&J 08-15-2008 03:33 PM

You should add info on the rear suspension and or type of traction bars. Some setups can't "wind-up" and change the pinion angle under acceleration, and some types do.

On my cars, I eyeball :D

Ujoints won't last long if there is zero angle. That's because the needle rollers must move to spread the grease.

pcoghlan 08-15-2008 06:02 PM

Thanks for the reply. I will take/post a few photos in the morning. I haven't a clue what the rear end is so I should learn a bit about it at the same time.

It is promising that things may not need to be more than eyeballed. The guy that tuned the engine on my Cobra had a look see and freaked me out telling me that I would need jigs to get it exact or the bearings would fail quickly.

dalesy 08-16-2008 06:53 AM

What was previously said, should apply here, since it is not a race car. Many times in the past, we would put the vehicle on jackstands, or on blocks, to where it is sitting at ride height. Then, lay a steel rod or piece of conduit on top of the tail housing back to the top of the yoke at the rear end. If it was fairly straight, that was good enough. Never had a failure. Some 'purists' have become over sensitized by details....

Frisco 08-16-2008 07:30 AM

Quote:

Originally Posted by pcoghlan
My question relates to alignment between the engine/gearbox and the driveshaft/rear end. I dont yet have a driveshaft and will need to scratch my head and work out how to get one made up after the engine/gearbox is in place so I have the correct length.

Place the engine at the height you wish it to be and as far back as you wish.

Center the engine between the side frame rails. Measure this at the center of the harmonic balancer and the center of the trans tailshaft.

NOTE: Sometimes the engine/trans unit will be offset to one side to allow clearance for the steering. If this is done; the engine/trans centerline should still be parallel to the centerline of the pinion shaft.

The 'Y' block assembly is longer than the SBC so you may have to recess the firewall some.

Level the assembly using a level on the carb mount surface on the intake manifold from side to side and front to back. You will see that the rear of the engine / trans assembly is slightly lower than the front of the engine. This will be about 3 degrees and is normal.

Fabricate your engine and trans mounts at this time.

To measure for driveshaft length; install the front transmission yoke all the way in. Then slide it back out about 3/4" - 1". Measure from the u-joint bearing centerline of the front yoke to the center of the u-joint centerline of the yoke on the pinion shaft. This is the measurement you will need to have your driveshaft made. The pinion shaft of the rear third member may be offset (not centered) from side to side between the frame rails. This is OK.

Eyeball measurement is NOT good enough. Use a tape measure. Looking from above the engine/trans, frame, rear axle assembly; the centerline of the engine/trans should be parallel to the centerline of the pinion shaft in the rear axle assembly. They can be offset.

Looking from the side view of the same assembly; the centerlines once again should be parallel. For drag racing alignment the rear pinion centerline may actually be pointed down from the engine/trans centerlines and not be parallel.

pcoghlan 08-18-2008 12:39 PM

2 Attachment(s)
Thanks for all the feedback guys. It does sound like the process laid out by Frisco (much appreciated) is the one to follow.

Here is the current rear end setup in the event is it is material.

speedydeedy 08-18-2008 01:56 PM

FRISCO laid it out well.I do mine the same way.You have 4 bar rear suspension with what appears to be a 8" Ford rear end.

pcoghlan 08-18-2008 01:59 PM

Thinking about it the only snag is that I currently have the bare block, without heads/intake. Sounds like I will need to await the final assembly of the engine prior to mocking up mounts then.

Thanks,

Frisco 08-19-2008 07:20 AM

Quote:

Originally Posted by pcoghlan
Thinking about it the only snag is that I currently have the bare block, without heads/intake. Sounds like I will need to await the final assembly of the engine prior to mocking up mounts then.

Thanks,

I suggest waiting until you have the heads and valve covers as well as the timing cover, water pump and fan. This will allow you to set the engine to clear the radiator and also let you see how much firewall recess you may require. For the Ford Y-block I don't think the intake will interfere at the firewall area.

For overall appearance, you will find it to be best to keep the radiator in the original Model 'A' location (directly above the front crossmember) rather than moving it forward to clear the waterpump/fan assembly. More work to recess the firewall and set the engine to the rear, but will be much more satisfying in the end. :D

I like your rear axle setup. :thumbup: The coil spring rear should give a good ride.

pcoghlan 08-23-2008 09:36 AM

Thanks guys, I have a spare Y block that I might use for mockup purposes. It is complete.

I will post photos as I progress this.

Thanks for the comments on the rear end. I have no idea how long ago the car was rodded but the inclusion of the SBC didn't float my boat.

Thanks again,,,

pcoghlan 08-25-2008 12:27 PM

Mockup in place
 
5 Attachment(s)
So I removed the cross member (to be cleaned up this weekend) and lowered the backup engine into place.

These shots show the situation. I think it is pretty good but the fan does slightly impact the cross member.

The only thing that hits the firewall is the distributor which if I recess a small part of the firewall will give me another 1-2 inches.

The oil canister is an issue (3rd picture) but I purchased this (http://cgi.ebay.com/ebaymotors/ws/eB...284483056&rd=1) last night so I think I am OK there as I can remote the oil filter.

Anything else look odd/bad? For example, is the engine low enough?

Based upon what you see am I way off in my assessment?

I am starting to think others might tread a similar path in the future so I am starting a project journal in the event it is useful. I will add some of the things I have tackled previously like painting the firewall which was a pain!

Thanks,
Paul

Brian_B 08-25-2008 01:01 PM

I do not have my truck here to compare...but something looks odd on the front of that engine (to me). :confused:

Mine has a pulley on the water pump and a spacer for the fan which puts it out about half way in the shroud.

My only belt goes around the crank, water pump pulley, and the generator.

Maybe I am wrong.........

I will look closer tomorrow when I get up. I won't get home until around 1 AM. LOL

pcoghlan 08-25-2008 01:03 PM

Brian, yes of course, silly me. I just threw the fan on without sticking the pulley on too!

I will dig out the fan pulley and see what difference that makes.... :(

Brian_B 08-25-2008 01:11 PM

I was just asking. I know you are working on clearance everwhere. :thumbup:

pcoghlan 08-25-2008 01:27 PM

OK, fan pulley on. Makes almost no difference to be honest. Maybe pushed the fan out about 1/8". The thickness of the pulley metal where it mounts.


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