Steve Saunders Goldwing Forums banner

1 - 20 of 31 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter #1
Hi all,

Down here in New Zealand I own this little 1965 Hillman Imp that I restored from Feb 2018. I am now looking into the possibilty of fitting a 1990 Honda Goldwing GL1500 engine to potentially build my very own baby 911 :)

This is my Imp...

321460


Here's the Datsun 1200 engine currently fitted...

321462



My plan is to remove all of the transmission and most of the drive gears from the casing. I have been looking over my Honda workshop manual and have pretty much nutted out the engineering that I'll need to do . However- before I commit I need to find out a couple of things. I thought I would ask on here and hopefully someone here will have a stripped down engine that they can get me some measurements from.

First thing I need to check is the thickness of the flange on the crank that the alternator drive gear bolts to. It takes 6 bolts. Also- what size are the bolts? They look like they could be 10mm? This is all important because I'll be machining a boss to bolt onto this flange and those six bolts will take the loading of a custom flywheel.

Here's a shot of the crank flange I need to know the thickness of...

321461


Another question. What is the measurement from the centre of the crank to the bottom of the engine. This is important to work out just how far the sump will hang from the back of my car once installed.

I'll be back soon with more questions I'm sure !

Cheers
alex
 

·
Registered
Joined
·
1,521 Posts
I’m guessing somewhere around 8 inches
 

·
Registered
Joined
·
13 Posts
Discussion Starter #3
OK. Hopefully someone can measure up the bits/engine etc and we'll see how good your guess is ;-)
 

·
Registered
Joined
·
1,521 Posts
Here uu go,9 inches
 

·
Registered
Joined
·
13 Posts
Discussion Starter #5
Oh cool- you measured it? Thanks very much. Now hopefully someone with a spare crankshaft sitting about will pop along and can tell me that flange thickness/bolt size :)
 

·
Administrator
Joined
·
58,460 Posts
I can't recall of a 1500 motor that needed to be over-hauled.
the worst thing was folks bending shift forks, and even then, it cheaper to buy a surplus engine than to fix the tranny.
 

·
Premium Member
Joined
·
1,760 Posts
Rear wheel drive? Where is the radiator going to reside? Someone with access to a machine shop should be able to handle the job. Probably have more power than the stock engine. .
gumbyred
 

·
Registered
Joined
·
13 Posts
Discussion Starter #9
You might get better results with a service manual. The problem is, GL15 motors so rarely need to be dismantled.
Yeah this is one of the reasons I'm excited about the prospect of having a GL1500 up the backside of my car. Apart from the sound and smooth performance its also the reliability I like the idea of.

I do have the Honda service manual but it doesn't mention the thickness of that flange anywhere because its not an item that wears etc. So I have to rely on asking others.
I have asked a question on a Ebay listing for a crankshaft and await an answer from them....
 

·
Registered
Joined
·
13 Posts
Discussion Starter #10
Rear wheel drive? Where is the radiator going to reside? Someone with access to a machine shop should be able to handle the job.
Yeah rear engined. Radiator is up the front. Ive got the machinary (that's my trade) but need to suss these things out before I commit to an engine I've been offered.

I tried adding a link to my restoration and build thread into this thread but this forum platform wouldn't allow it?
 

·
Administrator
Joined
·
58,460 Posts
Yeah rear engined. Radiator is up the front. Ive got the machinary (that's my trade) but need to suss these things out before I commit to an engine I've been offered.

I tried adding a link to my restoration and build thread into this thread but this forum platform wouldn't allow it?
New Members are restricted from adding links until they have more than about 10+ posts.
forget the actual number.
go over to the Fun Forum and play with those guys.
you can post in 10 mores threads in about 20 seconds, and then come back here and post that URL link
 

·
Registered
Joined
·
13 Posts
Discussion Starter #13
Well yesterday I picked up this ....
321737


I was a very excited chap and quickly unwrapped it....

321738


It handily has come with this manual...

321739


Plus I picked up another Subaru box that might come in handy, this time from a 1600 Leone...

321740


So tomorrow I will start the strip down and assess what I will need to modify within the goldwing engine.

One thing I have already noted is how tiny the inlet tracts are and the exhaust headers! When it comes to re-fabricating that lot I'll certainly be making it all so the engine is allowed breathe a lot easier :) Throw six itbs and full bespoke engine management in for the party.

I'd love to know what other 1500 owners on these forums, well the ones who have played about with the performance side of their bikes, have done with there exhausts ?

Also- out of interest at this point in time (due to money ..lack of it) are there any after market camgrinds available for these engines- ie for the cafe racer modification type folk?

Cheers
alex
 

·
Premium Member
Joined
·
12,713 Posts
Mother Honda has designed the intake/exhaust system to work very well. Even altering the air filter box can lessen performance. Without hogging out the ports I expect a good cleaning,smoothing and polishing the ports could be helpful.
There have been some exhaust modifiers. Torque loops come to mind.
I don't have an awareness of camshaft grinds from aftermarket but that is possible. There was one fellow who was working on a fuel injection system . As I recall, after he began the tuning phase of that work he didn't keep updating his posting.
It is quite common on the four cylinder wings that 4 carbs were replaced with single one and two barrel carbs. In your application you may have space to experiment that way .
 

·
Registered
Joined
·
13 Posts
Discussion Starter #16
Yeah compared to the goldWing location I have loads of space above the engine. I'll post a pic later.

I'm not fussed about chasing big power but if I can get extra easily in my process of converting to efi and itbs then it's a bonus :) the extra torque and hp this engine already had over the Datsun engine I currently have fitted is going to make for lots of giggles anyway :) more then anything it will be the flat six sound in looking forward to most!
 

·
Registered
Joined
·
270 Posts
I think what he's saying is that bigger bore intake and exhaust pipes will probably not add performance, and may very well reduce it. The exhaust system in particular is probably tuned for a particular velocity of airflow that you won't get with a bigger pipe.
 

·
Registered
Joined
·
13 Posts
Discussion Starter #18
Ahhh yes I see what you mean. Certainly not much of an advantage if I don't touch the ports /valves or cam profiles.

I've looked on the Internet and there seems to be next to no info on hotting up these engines - this I attribute to the goldwings being perfectly suited to their job already and most riders not for want of any extra power?
 

·
Registered
Joined
·
558 Posts
Russ Collins used to make hot rod parts for them, but that was long ago.
Yeah, most riders would only want to increase peak torque, and Honda pretty much got a bullseye on that.
However, speed is just a question of money, how fast can your wallet go? There have been supercharger installs, or you could do a turbo. For drag racing there is always the bottle.
For a reliable daily driver I would just go with EFI and pretty much leave the rest alone. The stock tuning will be close to ideal for a lightweight car. (1500 pounds or so would be great)
 

·
Senior Member
Joined
·
1,648 Posts
Remember that each cylinder is only 250ccm and dosnt need much air in or out . ( the redline on these engines is around 6.000 rpm. ).
I know that the Valkyrie has 6 carburators and i THINK the camshafts are a little "sharper" .
The EFI project could lighten your wallet WERY much ! , - i vould go for the OEM GL1500 carburators .
 
1 - 20 of 31 Posts
Top