Adjustable pushrods

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Simeon
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Adjustable pushrods

Post by Simeon »

Could someone please tell me the correct procedure for setting adjustable pushrods with hydraulc lifters. I don't think i've got it quite right as they rattle a bit.


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ChrisJC
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Post by ChrisJC »

There should be between 20 & 60thou clearance between the plunger and retaining clip in the top of the lifter.

Assuming standard lifters anyway.

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Post by turbodave »

I've often wondered this too - so I assume this is when the lifter is completely drained down? How can you be sure the lifter is completely drained down - is there a dimension (height) to aim for?

Are stock engines (a discovery 4.6 for my example) often running poor pre-load (or geometry) to warrant adjustable pushrods and/or machined rocker pedastals, or is it only when running re-profiled cams?

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Post by sidecar »

turbodave wrote:I've often wondered this too - so I assume this is when the lifter is completely drained down? How can you be sure the lifter is completely drained down - is there a dimension (height) to aim for?

Are stock engines (a discovery 4.6 for my example) often running poor pre-load (or geometry) to warrant adjustable pushrods and/or machined rocker pedastals, or is it only when running re-profiled cams?
The way to do the job is either with new lifters or remove each lifter in turn, flick out the spring clip then tip out enough oil so that the central cup and be pushed down once the lifter is back in once piece. You don't need all of the oil out, just enough so that the cup can be pressed down a few mm. Once you have done a few of the pushrods you can work out a method...

1. Make sure the lifter is on the base of the cam
2.Turn the pushrod adjuster so that there is no play in the system BUT no pre-load has been added either.
3. Turn the adjuster 'an amount' more. From memory 3 flats of the adjuster bolt was 20 thou pre-load.

I spent a fair amount of time checking the geometry of a standard engine, it wasn't very good! Having said that there must be loads of engines running around with poor geometry without there seeming to be a problem. It just depends how fussy you are! Shims will make the geometry worse and in my opinion are ATPITA!
Last edited by sidecar on Fri Sep 10, 2010 5:08 am, edited 1 time in total.

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topcatcustom
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Post by topcatcustom »

They are "ideal", meaning not necessary but beneficial. And you don't have to check they are drained, when the cam lobe to the valve you are checking is "off" you can check the pre-load with some small feeler gauge type wires, just like with adjustable rockers on old engines.
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Post by bigaldart »

its well worth setting it up properly, keeping preload to 20 thou increases the rev range before pump up. gives you a bit more scope on gearchanges and max rpm. Like Tom says, I made up some feelers from welding wire, hammered it flat, trial and error and a good micrometer, made go and no go gauges, 20 to fit and 25 to not fit then call it done.

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Post by TVRleigh »

Anyone Found the RS adjustable rods to be too long.
I fitted a set to a 4.2 that had a lot of block skimmed.
it was running 120 thou of Shims, and this was causing the rockers to wear/break up on the tips.
So decided to fit new rockers and adjustable rods, but the rods with ends fitted was 8920 thou (IIRC) only 100 thou shorter than standard, so not much room for adjustment.
In the end I had to take another 100 thou off the nut end of the rod, to be able to get 60 thou pre-load.

But seeing as the thread is at least 1000 thou I would have though they would have made them more than 100 Thou shorter than standard ones, a 90% of the time your going to want to go shorter not longer.
Current V8 car TVR 400SE 240 BHP
Current Project TVR Tasmin Race, with 3.9 running at 230 BHP
Currently building a 4.6 300 BHP Xbolted Engine for it. Solid Lifters and Group A rockers, Stange 4 heads, Pocketed piston, fully balanced.

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Post by mgbv8 »

Yep they do come out longer than required.

I had mine trimmed at a machine shop to be the same length as standard rods with the adjustable ends fitted adjusted out by 1/4 inch.

This left me with rods that I could adjust each way quite a bit.

The end that gets trimmed also had to be slight bored to take the ball end as the trimming removed some of the end that was already bored out.

hope this helps?

Perry

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TVRleigh
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Post by TVRleigh »

mgbv8 wrote:Yep they do come out longer than required.

I had mine trimmed at a machine shop to be the same length as standard rods with the adjustable ends fitted adjusted out by 1/4 inch.

This left me with rods that I could adjust each way quite a bit.

The end that gets trimmed also had to be slight bored to take the ball end as the trimming removed some of the end that was already bored out.

hope this helps?

Perry
Thanks at least I'm not the only one who has found this, wish I knew before fitting the ends though, as would have been easier to remove for the ball end as you did.

Does seem a bit daft seeing as they are a lot of thread of the adjustable end.
Current V8 car TVR 400SE 240 BHP
Current Project TVR Tasmin Race, with 3.9 running at 230 BHP
Currently building a 4.6 300 BHP Xbolted Engine for it. Solid Lifters and Group A rockers, Stange 4 heads, Pocketed piston, fully balanced.

mgbv8
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Post by mgbv8 »

I bet the rod ends are a bugger to get out eh?

I was just looking at the bits and laid a rod next to a normal one when I saw the problem luckily. Good job I wasnt in "ooh I've got to get my new bits in asap" mode or I would have done the same as you.

Regards
Perry

Perry Stephenson

MGB GT + Rover V8

9.62 @ 137.37mph

Now looking for 8 seconds with a SBC engine

http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw



https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw

TVRleigh
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Post by TVRleigh »

mgbv8 wrote:I bet the rod ends are a bugger to get out eh?

I was just looking at the bits and laid a rod next to a normal one when I saw the problem luckily. Good job I wasnt in "ooh I've got to get my new bits in asap" mode or I would have done the same as you.

Regards
Perry
We did try and could not easily, so reduced the size of the nut end, so it's half the size.
Current V8 car TVR 400SE 240 BHP
Current Project TVR Tasmin Race, with 3.9 running at 230 BHP
Currently building a 4.6 300 BHP Xbolted Engine for it. Solid Lifters and Group A rockers, Stange 4 heads, Pocketed piston, fully balanced.

sidecar
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Post by sidecar »

mgbv8 wrote:I bet the rod ends are a bugger to get out eh?

I was just looking at the bits and laid a rod next to a normal one when I saw the problem luckily. Good job I wasnt in "ooh I've got to get my new bits in asap" mode or I would have done the same as you.

Regards
Perry

I got the ends of mine out and they were a bit tough but a managed it, they are quite tough to get in!

I got them out by clamping the whole length of the pushrod in my vice between two bits of softish wood, the pushrod was horizontal in the vice running in parallel with the length of the jaws. I then used a piece of silver steel rod that fitted inside the push rod and whacked it with a hammer. This worked very well!

My pushrods also needed to be shortened and the internal step drilled a little deeper. You don't want to make them too short as you want a good amount of thread engaugement.

BTW I've just rebuilt the top end of my 4.6 lump after blowing a head gasket, I set the rods up by draining the lifters, I got each piston in turn on TDC with both the valves closed I then carefully extened the pushrod via the adjuster until there was no more play. After that I turned it another 5 flats of the hex nut. I had already measured what one turn of the ajuster worked out to be...30 thou. (After the lock nut was done up). 5 flats is therefore 25 thou. This method is quite quick, much quicker then messing about with bits of wire!

Personally I would not go thinning down the nuts, they are pretty small anyway which means that there is not much actual thread in them. And if you make them thin with will be hard to hold just the lock nut with a spanner without it also getting in the way of the other spanners.

All just my humble!

TVRleigh
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Post by TVRleigh »

sidecar wrote:
mgbv8 wrote:I bet the rod ends are a bugger to get out eh?

I was just looking at the bits and laid a rod next to a normal one when I saw the problem luckily. Good job I wasnt in "ooh I've got to get my new bits in asap" mode or I would have done the same as you.

Regards
Perry

I got the ends of mine out and they were a bit tough but a managed it, they are quite tough to get in!

I got them out by clamping the whole length of the pushrod in my vice between two bits of softish wood, the pushrod was horizontal in the vice running in parallel with the length of the jaws. I then used a piece of silver steel rod that fitted inside the push rod and whacked it with a hammer. This worked very well!

My pushrods also needed to be shortened and the internal step drilled a little deeper. You don't want to make them too short as you want a good amount of thread engaugement.

BTW I've just rebuilt the top end of my 4.6 lump after blowing a head gasket, I set the rods up by draining the lifters, I got each piston in turn on TDC with both the valves closed I then carefully extened the pushrod via the adjuster until there was no more play. After that I turned it another 5 flats of the hex nut. I had already measured what one turn of the ajuster worked out to be...30 thou. (After the lock nut was done up). 5 flats is therefore 25 thou. This method is quite quick, much quicker then messing about with bits of wire!

Personally I would not go thinning down the nuts, they are pretty small anyway which means that there is not much actual thread in them. And if you make them thin with will be hard to hold just the lock nut with a spanner without it also getting in the way of the other spanners.

All just my humble!
Well its done now. there is loads of thread of the adjuster end, and the tube is threaded also, so a doubt I'd pull the thread out. I took as little as possible off though due to wanted to still be able to get a spanner on, but this meant I could do have 0 pre-load and measure by the number if flat method.

and it's actually 5.5 thou per flat, as the thread is 30 TPI so a complete turn is 33.3 thou, so 5.5 thou per flat, but 27.5 is still is tolerance.
I set this engine to 50 thou as did not want it to over rev.

On the racer I set pre-load to 20 thou and that will rev past 7k
Current V8 car TVR 400SE 240 BHP
Current Project TVR Tasmin Race, with 3.9 running at 230 BHP
Currently building a 4.6 300 BHP Xbolted Engine for it. Solid Lifters and Group A rockers, Stange 4 heads, Pocketed piston, fully balanced.

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Re: Adjustable pushrods

Post by reedreed »

Hi there,
Could anybody explain is it possible to use adjustable pushrods from TURNER or RIMMERBROS along with steel rockers (TURNER) installed? Don't now why but onTURNER website these pushrods specified like "not to be used with steel rockers". Any experience ???

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