Belt tensioner mount 1300/1500

bmck

bmck

True Classic
I have just read here...

http://xwebforums.com/forum/index.php?posts/101856

...that there is a difference between 1300 and 1500 timing belt tensioner mounts.

I have just swapped the mount from my old 1300 to my new 1500 Regata engine. I have placed the smaller 1500 bearing on the 1300 mount.

What's the difference between the two mounts?

Regards,

Brian
 
You and I are talking about completely different parts. I'm referring to the tensioner nub on the snail mount, NOT the timing tensioner mounted to the block.
 
The link is to my reply to your post

Hi Mike,

Brian's link was to my reply about the difference between 1300 and 1500 parts.

Brian,

I know there is a difference between 1300/1500 regarding the bearings and tensioner mounts. Unfortunately, I do not know the specific differences in the mounts.

I am in the process of building a 1500 with a performance head from Midwest-Bayless. Matt was very specific in instructing me to use a 1300 mount with a 1300 bearing, but a 1500 t-belt.

Hopefully someone will have the specifics on the differences in the mounts.
 
stock vs modified

bmck said:
Jim,

Thanks for your reply.

So you're using a 1300 mount and a 1300 bearing on a 1500 block?

It gets even more confusing given the reference here...

http://www.midwest-bayless.com/storefrontprofiles/DeluxeSFItemDetail.aspx?sid=1&sfid=208227&c=193014&i=250927908

...to "Not compatible for use on 1500 engines!" - with exclamation mark.

Matt?

Regards,

Brian
Click to expand...

Brian,

I am sure in a stock set up the disclaimer is true. The performance head and cam box from Midwest have both been shaved, this means that if I used a 1500 tensioner bearing and bracket I would not be able to get the belt tight enough. So Matt's solution is to use the larger 1300 bearing to take up the slack.

So maybe the difference in the brackets relates to the size of the inner diameter of the race for the 1300 vs 1500 tensioner bearing? I must have one of each around here somewhere. Maybe I can figure this out?
 
Pics

Jim,

Here is a 1300 bearing, 1500 bearing and 1300 mount...

IMG_4345.jpg


Inside diamter of both bearings is 25mm.
Outside diameter of 1300 bearing is 60mm.
Outside diameter of 1500 bearing is 56mm.

Interestingly, the 1500 bearing is about 2mm wider...

IMG_4346.jpg


I wonder if that's significant.

So the question remains - am I asking for trouble by combining a 1500 bearing, 1300 mount, 1500 block?

(here's where I'm up to at the moment...
IMG_4343.jpg

)

Regards,

Brian
 
Same issue

Brian,

I've been building an engine similar to yours. I had it up and running & it started acting horrible & very difficult to start. The belt is very loose, so I assume it jumped. Yep, you guessed it. I wasn't paying attention and I put the 1500 bearing on instead of the 1300 bearing.

This is Memorial weekend, so I'm going to do the swap.

-- Mike
 
I will try to find my 1500 mount

Brian,

I know I took a 1500 mount off the engine when I was tearing it down, but I can't find it. :( It is out there lurking in the garage somewhere. There must be a subtle difference in the mounts as well as the bearings.
 
Brian,

I am using 1500 block, 1500 belt tensioner mount, 1300 head and 1300 tensioner.

BTW your block looks clean.
 
Ha! - Good one, Lawso!

Actually, it hasn't been too bad so far.

Having said that...
  1. This project has been going for so long, I think I have forgotten a lot of the cost
  2. SteveC is yet to furnish his final bill - though I know he'll do the right thing and sharpen his pencil
  3. Most costs to date have been able to fly under the radar of the Minister for Finance at home

A few more pics here, if interested...

http://www.turbo124.com/forum/viewtopic.php?f=10&t=9261

Regards,

Brian
 
Brian, beware..............!!

bmck said:
[*]Most costs to date have been able to fly under the radar of the Minister for Finance at home
Click to expand...

.........she who has eyes in the back, side, top, underneath, every direction you think you have got hidden from her!
Remember that old saying - "I seek them here, I seek them there, I seek them $$$$$ EVERYWHERE"
(Apologies to Winston Churchill, I think?)

The repower job is lookin' good, mate - will be nice to hear it running!!

cheers, Ian - NZ
 
I used the 1300 bearing only, with my shaved head & cam/cam box from Bayless.

I believe the tensioner mount is the same, I had no trouble pressing the 1300 bearing onto the 1500 mount.
 
Found my 1500 bearing mount

JimD said:
Brian,

I know I took a 1500 mount off the engine when I was tearing it down, but I can't find it. :( It is out there lurking in the garage somewhere. There must be a subtle difference in the mounts as well as the bearings.
Click to expand...

Visually and dimensionally they "seem" pretty much the same but do have different part numbers:

1300 = 4320894

1500 = 4462672

The 1500 seems to be fractionally taller. I will add a couple pics later.
 
Jim,

Thanks for the research.

How about this theory?

Remember above I discovered the 1500 bearing is a little wider than 1300?

When the 1500 bearing is mounted on the 1300 mount, there is bugger-all clearance between the rear of the bearing and the mount. Less than 0.25mm...

IMG_4347.jpg


It spins OK - doesn't touch the mount, but it's bloody close.

The 1300 bearing on 1300 mount has more than 0.9mm clearance...

IMG_4348.jpg


I wonder if that's the difference?

I'd like to know the clearance between a 1500 bearing on a 1500 mount.

Regards,

Brian
 
My measuring wasn't very scientific

Hi Brian,

I tried using my HF micrometer, but I didn't find any way to get an accurate measurement from the centers of the holes. I measured the distance between the holes as best I could and did not find any real difference. Here is the pic that shows that the 1500 bearing (on the left) is a bit "taller" when both are laid on the ground.
13-15-tensioner_3.jpg


Here are the side by sides:
13-15-tensioner_2.jpg

13-15-tensioner_1.jpg
 
Jim,

What's with the glove?

Thanks for the pictures.

Can you see any height difference here between the two mounts...

13-15-tensioner_3.jpg


Perhaps the 1500 mount has a higher 'shoulder' on it keeping the wider 1500 bearing away from the back plate.

Can I ask you to throw a 1500 bearing on your 1500 mount and measure the clearance at the rear - like in my feeler guage photo above?

Regards,

Brian
 
No 1500 bearing

Hi Brian,

Unfortunately I don't have a good 1500 bearing. The bearing on this mount came apart when I was removing it from the mount a few months ago.

I agree that the 1500's base/shoulder looks a little thicker, so it could be related to the bearing width difference that you pointed out. Maybe we can get Matt to weigh in and explain the differences?

I wasn't playing doctor, I had the rubber glove on because I was working on reassembling a 1500 that will be going in my 78. :)
 
JimD said:
Unfortunately I don't have a good 1500 bearing.
Click to expand...

Well, could you bung the 1300 bearing on both mounts and check if the clearance at the rear is identical or otherwise?

We're getting closer...

Regards,

Brian
 
The bearing is pressed onto the tensioner - it isn't so easy to remove without damaging the bearing in the process. Not important when the one you're removing is worn anyway, but if it's a new/good one, I wouldn't be doing it unless it was staying on the tensioner.
 
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