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push rod lengths............

1660bob

Well Known and Active Forum Website User
VOC Member
Hi All, this weeks question for the wise....... Put the pushrods into the motor today and followed them with their respective adjusters.When all are set at nil clearence, only one of the four adjusters(rear inlet) protrutes from the bottom of the rocker significantly( about 1mm).The other three are: one just emerging,one roughly flush, one a thread or two from emerging at the bottom of the rocker forging. I appreciate there are myriad reasons for the variation, but I wonder whether,with quite a lot of the adjuster exposed above the locknut, would I be better with shorter pushrods??? (they are standard at present )Some piccies to illustrate: vin valve adj 001.jpgvin valve adj 004.jpgvin valve adj 002.jpgvin valve adj 003.jpg

I should add that barrels/heads have all had a skim, albeit tiny,and valve seats are original re-cut so this could explain why the original pushrods are looking (to me at least ) a bit long........ What do you think? Regards, Bob.
 

petermb998

Well Known and Active Forum Website User
VOC Member
From the look of the length of the adjusters sticking out of your rockers, i would suggest that you VERY carefully fit you inspection caps one at a time and turn the engine over.
You may find that the adjusters will fowl the inside of the cap.
I have just found I have the same problem with the rear cylinder on my rapide.This will have to be turned out for clearance.
peter
 

Albervin

Well Known and Active Forum Website User
VOC Member
Either shorter pushrods or a set of Neal Videan's nifty socket head adjusters (or both) should do the job. At the moment they look like they may try to bash a hole in the rocker covers.
 

chankly bore

Well Known and Active Forum Website User
Non-VOC Member
I might be teaching Granny to suck eggs, but---- are the cams standard as to base circle?What cams are they? In any case, the pushrods look like they could go 1/16" shorter. Check tappet pads are all fully home as well on the shoulders of the valves.
 
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greg brillus

Well Known and Active Forum Website User
VOC Member
Hi there Bob, not sure exactly what you have/ have not changed in your engine. But one item i have found several times is the ball ends on the pushrods hanging up in the socket of the cam follower.....that is that the ball is larger than the opening of the follower, and these then often jam their way into the hole causing the tappets to need resetting regularly, this only if any replacement items have been installed. This may be a reason as to your odd tappet heights. Just remove the adjuster completely from each rocker and check that the pushrod rotates nice and freely in each cam follower socket, if they feel a bit tight or not smooth on rotation then this could be your trouble. To fix, just linnish the diameter of the ball end down a little until you are sure that they feel ok. Make doubley sure that the ball ends locate back in each follower, before you turn it over......Cheers for now....Greg.
 

bmetcalf

Well Known and Active Forum Website User
VOC Member
A good (not too loose) fit in the follower is a benefit when you are installing the pushrods with the timing cover on. If the follower cup has oil, you can feel the suction as you try to lift the pushrod and make sure it is really in the cup and not ready to mangle the timing chest when the motor runs.
 

1660bob

Well Known and Active Forum Website User
VOC Member
Thanks for the replies All,another step up the Vincent Learning Curve completed, I await shiny new shorter pushrods, Bob.
 

Big Sid

Guest
Question for Bob . Do the adjustors contact the inside of the rocker caps when the motor is revolved , the caps screwed fully down ? If not all is well . They WILL hang up if one rotates the the motor with the caps backed off a couple of turns and this is TO BE AVOIDED as the rocker will lock up and damage things . If removing a cap and it stops unscrewing , run it back down and revolve the motor a ways when that rocker will drop eliminating that situation . All these bits come very close to each other only clearing when the caps are fully down .
Of course if the pushrods are too long there WILL be problems . Also it the adjustors ride too high . The top hex can be removed or and the stub end slotted for use of a screwdriver . Or simply thinned . I did this on the Rattler to reduce weight for higher revs . Sid .


Sent from my iPad using Tapatalk
 

stumpy lord

Well Known and Active Forum Website User
VOC Member
I can if you wish, loan you a valve cap that has been modified to allow you to see the clearance or lack off clearance of the tappet adjuster in your motor.
stumpy lord
 
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