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7/27/2018 9:24 am  #1


chevy distributor height

Did someone find a way to find the right height when final assemble a performance small block for the distributor with a slip collar or not, i read lot of theory but did someone have a measure to look before everything is finish...

 

7/29/2018 9:45 pm  #2


Re: chevy distributor height

I set the height by checking the gear mesh like you do any gear set.
As long as the oil pump drive is correct length you can use cam lube to check the mesh or gear marking compound get the height correct and lock the collar.
Since no 2 engines use the same height measurement you need to confirm the mesh is correct. There is too many other issues like manifold mounting height etc hell I have had to machine intakes and dist. bodies for 30+ years to get them right way before the slip collars became available.


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

8/21/2018 10:45 am  #3


Re: chevy distributor height

I understand the slip collar, but it s only set the end play of the oïl pump shaft in a lot of time, try to set the gear mesh if you have an issue with the oïl pump  will be impossible, what i finally try is with a straight edge on front and rear of the block ( where we put sealer ) the highest poit of the oïl pump shaft, if you are below 6 inch , you will have issue setting the gear , you need 6 inch and more, so Moroso and other made different lenght shaft.. When everything is finish and the pump is prime it s a nightmare to find a too much long oïl pump shaft. I have that issue with the new sharkteeth coming with too long shaft....

     Thread Starter
 

9/10/2018 11:36 pm  #4


Re: chevy distributor height

Can you not install the pump then confirm the shaft length needed and adjust that as needed.

I find the bast way is to get the cam and dist. gear mess correct 1st without the pump installed then correct the shaft length as needed.
The easiest shaft is a hex type to shorten. and it allows for a small amount of misalignment as well without a binding issue a stock type shaft has as it rotates.


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

9/11/2018 5:18 am  #5


Re: chevy distributor height

Sure, but when you receive an engine with a distributor gear issue...An other thing, the aftermarket distributor, have a bigger , long radius on their shaft and the race pump do not have a bevel on the end of the shaft, like the factory, so you end up with an other height issue, yes , now i have to do the pre-assembly with out the pump, but when someone call for a distributor that wear gear on a rebuil motor....it may come out with an expensive repair.... Thank Dave..

     Thread Starter
 

9/15/2018 12:15 am  #6


Re: chevy distributor height

I know where your going with that but what it comes down to is checking all the bases during the 1st assembly like we always do. That way there is no issues when the customer gets and uses the engine. Like BBC cams most limes I fine need about .020-.040 machined off the front or gear end to get the lobes aligned correctly with the stock lifter bores. Now if someone has an issue with the cam gear location that may need to be changed fore and aft as well as the dist. gear may need relocating vertically to get everything to mesh right

What it really comes down to is correcting an issue in a old production block so it can be reused for another purpose.
You will see the issue the engine will never know the difference. Just don't be afraid to do what is needed to fix the issue. Thats what a true machinist lives for. To fix other guys errors and may it run smooth and sweet for a long happy life
 


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

9/17/2018 5:13 am  #7


Re: chevy distributor height

It s more than 8 years, in a rebuilders meeting i ve told peoples that the chevy b.block the cam set too deep, in fact , the exhaust lobe on number 6 set .100 thou. too far back, the reason , the old cam have the lobe cast .065 to .070 wider, but peoples claim the lifters bore ???

     Thread Starter
 

9/18/2018 10:59 pm  #8


Re: chevy distributor height

Yes any current aftermarket cam is not the same from 1 ,aker to the other.
They have been wrong since day 1 and the stock cams differ some what but I have found that Isky makes the closest correct lobe configurations for the GM BBC engine.

Thats why most times the cam nose must be machined to move the cam forward in the block. The lifter bores are bas as well so combine both issues and you have to wonder how GM kept cams in the engines as long as they did. I believe its because they used minimum spring pressures and better materials and lots of high pressure additives in the oil used made them live long lives.
 


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

9/19/2018 2:31 pm  #9


Re: chevy distributor height

If you machine front of cam to move the lobes, what do you do about the distributor/oil pump and fuel pump position also needing to move forward?
Graig in Wyo

 

9/29/2018 12:29 am  #10


Re: chevy distributor height

competi-tech wrote:

It s more than 8 years, in a rebuilders meeting i ve told peoples that the chevy b.block the cam set too deep, in fact , the exhaust lobe on number 6 set .100 thou. too far back, the reason , the old cam have the lobe cast .065 to .070 wider, but peoples claim the lifters bore ???

I had never had a NOS GM BBC cam till the other day and found the same thing that some measured+.050 wider up to .074 on others on the factory replacement cam.

I have needed to take about .040 to .050 off the nose on some cams to get the bore to lobe alignment acceptable but I have not had any issues with the gear or pump drive during mock up to worry about it since the manifold hole for the dist. is always larger then the dist. when checking it seem to have been OK to lean the dist. body slightly in the block and check the drive pattern for correct mess. I have had a few blocks that the dist. support/ locating  bore was way off thus making the block scrap and on  rare 348 and 396 blocks I had to get them sleeved to correct the hole size on a rusted block that was a numbers matching deal. But regardless the BBC engines of the 60's 70's and 80's and 90's that were FT cams all need special attention to get the FT cam to live without  reducing spring pressures to the point of valve float issues to do so.

And thanks for the tip on the factory can lobe width issue.


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 
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