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pushrods and mini heads
https://www.ausmini.com/forums/viewtopic.php?f=2&t=92232		 Page 1 of 2
Author:  GR [ Mon Mar 28, 2016 8:05 pm ]
Post subject:  pushrods and mini heads
Hi All
Just a little technical note for those that don't know a lot about fitting bigger push rods to mini motors, there is a reason why BMC made little skinny pushrods and that is because the holes in the head do not line up with the holes in the block.
Next time you have your head sitting on the block have a look down the pushrod hole and you will see what I mean, not as bad with the Cooper 'S' block.
How ever when you try to fit bigger push rods to these engines you are going to get into trouble with the rods hitting the block and the head,and also when you have a bigger grind cam and high lift rockers it makes the problem worse, you must also remember that in fast road motors and race engines these pushrods flex so you have to give them more clearance.
When fitting an after market head (alloy) be it a arden, pinion elder you are going to fit longer push rods most people fit 5/16ins dia pushrods to these heads, and in doing this you will have to grind the block and head to get them to fit.
Now another problem that a lot of you may not be aware of is that the 1100"S" and the A+ block have smaller pushrod holes in the block than the Cooper"S" 1/2ins for the cooper and 3/8ins for the other 2 blocks, making the the problem a lot worse.
Most of the time on the later blocks the ball end on the 5/16 push rods will not even go down the block at all it will have to be ground away to get them down
At the moment I am trying to fix an Arden head for a guy, the pushrod have all but worn through in 2 places where they have been rubbing on the block and on the head, I will get some photos up to show you, AARON,where are you.
There is another problem when fitting an after market alloy head (Mini) to your engine and that is the head nuts and rocker posts are going to sink into the head,i do not know why this is, I do know that the Elder head is made from the right alloy and the heat treatment is to T6 hardness, as the other heads would be, this is not a problem with after market heads for other engines, Fords , Chevy, Chrysler,etc like Pauline said please explain.
One thing I have done to help this problem is to get a plate laser cut to fit (1mm to 1.5mm) under the nuts and post to try and give it some support and spread the load, I only pull these heads down to 35LB as when they get hot they will expand putting more tension on the items.
Just a side track some of the drag cars with alloy heads and blocks and no water start off with very little valve clearance .005ins, buy the time they do their burn outs and get some heat into their engines the tappet clearance will grow to.020 plus tho. :shock: cool hay.
Graham Russell

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Author:  gtogreen1969 [ Mon Mar 28, 2016 8:24 pm ]
Post subject:  Re: pushrods and mini heads
Thanks GR. Good info to know.
Author:  Ian_B [ Mon Mar 28, 2016 8:36 pm ]
Post subject:  Re: pushrods and mini heads
Appreciated Graham I also understand that VALVES WERE OFFSET and pushrodholes haven't been on mine.
I have no pushrods at all .I am s%%t scared of filing and yes ive confirmed the size of the block holes.
I was going to drill them but didn't have to
A bolt on or non bolt on shouldn't involve a 3500 buck filing risk I cant tig weld.
That's a manufacturing issue.
Someone said didn't you get them and the studs .Nope.
Less angry Ian
Author:  Ian_B [ Mon Mar 28, 2016 8:41 pm ]
Post subject:  Re: pushrods and mini heads
I had to respace all my roller tip rockers and move oilways to them . I didn't have a problem and accepted that
If I stuff the head :cry:
Author:  Ian_B [ Mon Mar 28, 2016 8:52 pm ]
Post subject:  Re: pushrods and mini heads
:lol: I wonder what alloy the japs Koreans used ????
Author:  Ian_B [ Mon Mar 28, 2016 9:00 pm ]
Post subject:  Re: pushrods and mini heads
Quote:
One thing I have done to help this problem is to get a plate laser cut to fit (1mm to 1.5mm) under the nuts and post to try and give it some support and spread the load, I only pull these heads down to 35LB as when they get hot they will expand putting more tension on the items.

You shouldn't be the one having to do that !!
As for the pushrod problem Its exacerbated by moving the valves .Tell the customer re cam and rocker ratio.
Professional manufacturers do recalls .
Im not an engineer in mechanics but would it be possible to bore the hole and sleeve it with Loctite??
Its the exhaust valves as im sure you know
http://www.mantonpushrods.com/Images/Manton_Catalog.pdf
Check these guys out 1/4 inch or 3/16 rods!!
Author:  TheMiniMan [ Mon Mar 28, 2016 9:45 pm ]
Post subject:  Re: pushrods and mini heads
something i should say here,,, --> this is "part-of" the reason i spent years developing my build guide
for the Bimmer Twinky cyl head conversion.

after a few years designing & hand-making all the bits for the first one
i spent literally years & years developing the build guide so that "All" the issues were nutted/sorted out for "ALL" the differing & various & miss-matching & small bore & big bore & 8v & 16v & K100 & K1 & K1000 & K1100 & K1200 & & & & & RS cams & LT cams & & & all the options with oil feeds & Oil drains & Oil fillers & & &

get my point???

i`ve done many alloy crossflow head swaps over the years & already know enough about most of them to get myself into trouble :-) :-) :-)

but "Homework" is the key to stay out of trouble. simple as that

ask question,,, "GET" the answers
get answers to the questions you havn`t asked,,, ask "Them" for questions & answers etc etc etc

"research" is your friend with any modification.

& "NEVER_EVER" expect things to just bolt on.
crickey look at all the simple replacement spare parts these days, almost "NOTHING" fits without having to stuff with it in some way.
how can anyone expect a cyl head was going to fit without any drama?

& ive been telling people about the small pushrod holes for years but seems no-one listens to me :-) :-) :-)

Oh & then they`re full of oil trying to get back down , all the while a little crank-case pressure is trying to hold it back up there, etc etc etc blah blah blah,,, literally years & years of babbling on about exactly this

sorry to here of your dramas Ian, be patient, GR will sort it, yes it`s painful but once it`s done you`ll be ok... don`t sweat the small stuff mate, it`s only an engine.

i`ve died a few times in recent years,,, & then even more curry hit the fan in soooo many other areas of my life,,, i`ve since learnt & realised that life really is too short to worry about a silly little mini thing... relax, chill out, have a beer, lifes pretty good here in Aust & we`re all living like kings & queens compared to other places in the world

there`s really no big drama ok?
cheers
Matt
Author:  Ian_B [ Mon Mar 28, 2016 9:55 pm ]
Post subject:  Re: pushrods and mini heads
Thanks mate That manton pushrod site is the best thing ive found for pushrods
Author:  TK [ Tue Mar 29, 2016 6:31 pm ]
Post subject:  Re: pushrods and mini heads
Vizard in his books has touched on this. He even has cut away photos of the pushrod holes in blocks.
Author:  MiniBrad [ Tue Mar 29, 2016 7:15 pm ]
Post subject:  Re: pushrods and mini heads
Interesting stuff GR & Matt.

Brad
Author:  Monaco [ Tue Mar 29, 2016 8:51 pm ]
Post subject:  Re: pushrods and mini heads
It really doesn't say much for these alloy heads.......
Author:  Ian_B [ Wed Mar 30, 2016 7:43 pm ]
Post subject:  Re: pushrods and mini heads
Question.If the pedestals and head stud nuts are sinking into the head .What stops the Valve seats from doing the same??
What is the right alloy??? I did some study.Once a motor has been overheated the head becomes soft and we can see this situation occur
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Author:  Besser [ Wed Mar 30, 2016 10:01 pm ]
Post subject:  Re: pushrods and mini heads
Alloy used in heads vary widely. Holden have differing mix in the eco tech v6 for gas and petrol versions due to the heat range. Had me chasing gremlins on a machine I supplied them once till I was informed of the fact. Maybach used Bellville washers to limit tension growth through expansion.

GR, any in car methods for rubbing pushrod diagnosis?

GR, given correct rocker geometry would a longer pushrods ( taller pillars, rods and valves) assist with clearance?
Author:  GR [ Thu Mar 31, 2016 7:36 pm ]
Post subject:  Re: pushrods and mini heads
Hi Besser
There's just no room in there for the bigger pushrods you just have to grind the block away and head away,or use std type push rods and lengthen them or cut down MGB pushrods, I can not find what BMC used in the day, I seem to recall seeing std type push rods in the day they may have got away with using the long tappet screw the used in the day.
Graham Russell
Author:  Ian_B [ Thu Mar 31, 2016 7:43 pm ]
Post subject:  Re: pushrods and mini heads
What head do you have Besser??
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