I usually have the rocker gear fitted pushrods in tubes etc

But then i know what im doing when it comes to sticking engines together from a pile of shrapnel at 4am

Well this isn't proving as easy as I'd hoped.

I removed the two old tubes with no problems and no damage to the head.

I put the first tube in the hole from the rocker side of the head and tapped it (quite firmly) into position with a smear of sealant on the final inch of tube or so.

So far all was going fine.

The second tube went in okay at first but got increasingly tight until I completely knackered it by having to hit it so hard trying to get it in any further that I spread the end of the tube.
(I was using a large bolt with a large washer on it in the end of the tube to avoid hitting the end of the actual tube with the hammer).
I spent another hour or so removing the remains of this new tube and tried again.

This time I spent some time with some cleaning up the hole with some wet and dry wrapped around a large screwdriver. I also used some spray grease to help ease it in. None of this made any difference. The tube went in so far until I finished up mushrooming the end of hit followed by an hour of swearing to remove the remains.

On the third attempt I had five minutes with a round file cleaning up the hole in the head and then rubbed at the new tube with some wet and dry followed by polishing it up on a wire wheel. I then put it in the freezer while I heated up the head with a blowtorch. Another dose of spray grease and it was time for another go.

This third tube went better and I thought I'd cracked it until the last inch or so refused to budge any further and I've now completely ruined the end of this one too.

I've given up now before I lost my temper and started throwing things.

Has anybody had this problem before? I know it's usually a case of replacing the heads and throwing the old one away but I'm obviously a glutton for punishment (and I gave my spare nearside head away a few months ago).

Hope the photos below are helpful. You need to insert the tubes from the cylinder side. Also not sure that the rawl bolt can do a proper job.

Lenny,
as Viking has already mentioned, the tubes should be inserted from the underside of the cylinder head, not the rocker side, so that'll be the reason for the problems you've had.

@ Viking,
if you've never used an expanding bolt to fit a replacement tube, how can you judge whether or not it works?
I've done plenty of them using an expanding bolt and none have failed.

ken

Ya but you're in a league of your own

The only reason I did them from the rocker side was that they were such a tight fit that I couldn't see them going in place without some persuasion. I didn't fancy tapping the thinner end of the tube with my trusty knocking stick.

I assume from this that they should be a simple push fit with no persuasion needed?

(And thanks for the digrams Viking. They'll be handy.)

Lenny,
could you drop a caliper onto the tubes you've still got?
The ones I've got here are 18.00mm or just slightly under, maybe 17.98mm OD.

Not an 'easy' slip fit, but no hammering should be required, iirc.

ken

These seem to be a shade over 18mm.
Sort of 18.1 to 18.2ish.
I've also measured the ones on the other head (that I haven't started butchering yet) and they were the same so it would appear that the new ones are correct and that my top quality (fiver off ebay) digital calipers are possibly a touch optimistic.
I reckon I'll try to lay my hands on an 18mm reamer tomorrow and run it down the hole to make sure it's all clear.
It seems so odd that the first one popped in place so easily but this second one has caused be such problems. It's got to be something to do with the hole in the head.

Despite having never changed pushrod tubes, I think I might wade into this debate with a half cocked thought that probably hasn't been suggested yet for a good reason, and suggest why not het the head hot and the tube cold? Stick the tube in a freezer overnight and get a propane torch on the head for a wee while, and the tube should slip right in, shouldn't it? Or am I twat as usual?

Russell,
from Lenny's log, if you'll pardon the expression...

"I then put it in the freezer while I heated up the head with a blowtorch. Another dose of spray grease and it was time for another go.
This third tube went better and I thought I'd cracked it until the last inch or so refused to budge any further and I've now completely ruined the end of this one too."

ken