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Rookie pushrod question
https://www.ausmini.com/forums/viewtopic.php?f=5&t=88155		 Page 1 of 2
Author:  TimW [ Mon Dec 29, 2014 7:23 pm ]
Post subject:  Rookie pushrod question
Bolted the head on my cooper s engine, inserted the cam followers, push rods and rocker assembly and torqued it up.
Went to adjust the rockers and found there was a significant gap of about 5 to 6 mm between the rocker adjuster ball and the top of the push rod (pictured) even when the adjustment bolt was screwed all the way in.

Background
The head has been ported and shaved by GR, but looked like it had been ground at least once before.
The Cam has be ground.
I have used new cam followers, and had the faces ground with the slight radius.
The rocker posts have been shimmed with 2mm shims allowing for the thinner head and for optimal alignment of the valve stems and rocker pads.
Any ideas why there would be such a gap? Am I missing something?
Image
Author:  Kennomini [ Mon Dec 29, 2014 7:27 pm ]
Post subject:  Re: Rookie pushrod question
I do believe the small bore pushrods are shorter than 1275 pushrods. It may even be 1/4" if I remember correctly but lets wait for someone who knows for sure the confirm this or not.
Author:  justfanginaround [ Mon Dec 29, 2014 7:45 pm ]
Post subject:  Re: Rookie pushrod question
yes 850, 998, 1098 pushrods are shorter than 1275 ones because the 1275 block in { might get shot for getting this wrong } 3/8ths of an inch taller than the small bore block. on a side note when fitting holder grey follers there are 2 thicknesses which is why we run 7 1275 and 1 998 pushrods in our 1275 based toy.
Author:  TimW [ Mon Dec 29, 2014 10:32 pm ]
Post subject:  Re: Rookie pushrod question
The rods going in are the same that came out, so I assume they are the 1275 length, but I will measure them to be sure. Is there a chance the cam followers are deeper than the originals? I am using the isky style.
Author:  Fishyoil [ Tue Dec 30, 2014 4:52 am ]
Post subject:  Re: Rookie pushrod question
Are the shims the spacer I think I see in between the pedestal and head? Were they there before? They would account for the gap.
Author:  VulcanBB18 [ Tue Dec 30, 2014 7:29 am ]
Post subject:  Re: Rookie pushrod question
Has the valve seated properly? If it was caught slightly open for any reason this would give the gap too.

Yes small-bore rods are shorter, and there is a style that looks *exactly* the same as the big-bore rods, except it's shorter..

...this is assuming it's only this one valve with the problem, not all of them?

cheers,

Jacob
Author:  TimW [ Tue Dec 30, 2014 7:48 am ]
Post subject:  Re: Rookie pushrod question
Thanks Jacob
All valves are the same. Even when I take the spacers out there is still too much clearance.
If I take the spacers out the rocker is not aligned over the valve stem. I am going to measure the bed thickness of the lifter and see how this compares to the original.
Author:  justfanginaround [ Tue Dec 30, 2014 9:12 am ]
Post subject:  Re: Rookie pushrod question
Std 998 is 8 3/8ths inches
1275 is 8 7/16 ths inches.

Hope this helps
Author:  MiniVLT [ Tue Dec 30, 2014 9:30 am ]
Post subject:  Re: Rookie pushrod question
You say your cam has been reground. When a cam is reground for more lift....the back of the cam, when the valves are closed and you check your clearances, is where the cam is usually ground down. You don't put metal on top of the lobe, you take it away from lowest part to increase the difference between the bottom and the top, thus increasing the lift.
So now your cam followers sit lower down in the block.
This basically means you need either longer push rods, or for some reason I thought I saw some longer adjusters for sale somewhere?
You could also take out the 2mm shims you have under the rocker posts too!

Adding up the fact the cam is reground, the cam followers have also been refaced and the 2mm shims, it all adds up.
Do you know what specs you got the cam ground from and what it is now?
Also, did you get the bottom of the pushrods refaced as well?

Cheers Shane

Another thing, did you replace the valves? if the valves are slightly shorter, another "add" to the gap equation!
Author:  smac [ Tue Dec 30, 2014 2:58 pm ]
Post subject:  Re: Rookie pushrod question
TimW wrote:
If I take the spacers out the rocker is not aligned over the valve stem.


Me no comprende :roll:

You sure the followers are in there? (semi serious question!)
Author:  TimW [ Tue Dec 30, 2014 3:13 pm ]
Post subject:  Re: Rookie pushrod question
Yes absolutely.
Author:  kiwiinwgtn [ Tue Dec 30, 2014 5:44 pm ]
Post subject:  Re: Rookie pushrod question
Q. Is it just one tappet with the problem.
Author:  Ian_B [ Tue Dec 30, 2014 5:50 pm ]
Post subject:  Re: Rookie pushrod question
Machine the rocker pedestals down a bit or longer pushrods ???
Im thinking too that machining down the pedestals too much could get ugly too.
Author:  FNQ [ Thu Jan 01, 2015 8:30 pm ]
Post subject:  Re: Rookie pushrod question
It looks like there is still some thread on the adjuster/nut, but not 5-6mm.... another suggestion skinnier lock nuts - ? but before anything check that you are achieving full lift- back off all the adjusters ( probably done this three or four times already :)) and are you sure cam is timed correctly... i suppose it comes down to volume, but in a lot of HP builds, you set the geometry correctly tyo achieve lift etc then you measure pushrod and get the appropriate ones made, but in the mini, we make do, ... and even if you pay big bucks for rockers , you still need to fettle around to correct the geometry
Author:  drmini in aust [ Thu Jan 01, 2015 9:58 pm ]
Post subject:  Re: Rookie pushrod question
Are those 1.5 rockers or standard S ones? Hard to see from that angle.
If 1.5s, those std rocker posts are wrong offset. If buying 1.5 rockers you need their special posts too. Or, do serious mods to the stock posts, as I did for Corolla rockers.
You should not need that thick packing in there.
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