Pre-starting concerns - justified?

[bigtone]

Hi All,

Counting the days til we aim to start the newly rebuilt engine in the M - going for a Sunday afternoon wake the neighbours session!

Running through everything in my mind, there is one thing that I keep going over and over, trying to convince myself it's normal, and hoping i'm right.

A few weeks ago, when we picked the engine up from the builders, we put the rocker box covers and gaskets on ourselves. We noticed as we did so that the rockers themselves were looseish on the studs, not to the extent that you could swing them one way or the other off the push rods or anything, but there was vertical movement. The interference nuts seemed tight enough, wouldn't budge by hand anyway.

Can someone reassure me this is pretty normal, and to do with acceptable tollerances or something, before we try to fire her up on Sunday and realise that it's all gone horribly wrong!!

Thanks in advance folks,

Tony
www.tvr-3000m.co.uk

>>> Edited by bigtone on Wednesday 11th September 16:35

[GreenV8S]

quote:
the rockers themselves were looseish on the studs, not to the extent that you could swing them one way or the other off the push rods or anything, but there was vertical movement. The interference nuts seemed tight enough, wouldn't budge by hand anyway.

Not sure I get you, are you saying the pillars supporting the rocker shaft are moving relative to the head (surely not?) or there is play between the rockers and the shaft, or the shaft and the pillars?

[hansgerd]

Tony, why don't you post a picture of the delicate area ? Post it on your site and post a link on here. Then we can have a look and comment on it. Ehm, just saw it, the link is www.tvr-3000m.co.uk.

>> Edited by hansgerd on Wednesday 11th September 22:06

[philh]

You have to remeber this is a ford mass produced engine, if i remeber the rockers are just pressed steel with a lug to stop them from rotating, i think this movement is okay, if the engine builder is reputable and they put the rockers on i would say they were okay, i presume you got a warranty with the engine??

[SimonSparrow]

Hi,

I had the rocker cover off mine last week (attempt to find rattling noise before a Track day at Donnington...)and all the rockers that weren't actually opening valves were loose as you describe.

So it must be a feature of these engines. :-)

[bigtone]

I'm trying to dig out some pictures to show what I mean, but it sounds just like you describe Simon.

I guess the side to side movement (from above) is only because there is a little rocking movement when they're not acting against anything. The stud into the head doesn't move at all.

I'll see if I can find some relevant pictures anyway.

Thanks all,

Tony (feeling slightly easier about it now!)

[SimonSparrow]

I think the interference nuts which the rockers pivot on will have a spherical underside, hence all the movement.

[sprintmp]

quote:
I think the interference nuts which the rockers pivot on will have a spherical underside, hence all the movement.

...and the interference nuts can become loose. This happened to my M about 6 months ago. Fortunatly no damage was done to the engine (I was at 4,500 revs when the noise started, and I just turned the engine off and coasted to a stop). One nut was almost at the top of the piller, and I was able to lift the rocker off and turn it 90 degrees! I was really lucky!

John Wade (JW Engineering) sorted it out, and supplied his own pinch nuts (pinched on 3 sides not the normal 2 that are on the Ford nuts.) He replaced the studs (a press fit of around 20 tons I believe!) and just for safty's sake, pinned them in place - This was not really neccessary, but .......

All been OK since.

Pietro

[bigtone]

We've just got the two pinch nuts, that came with the heads from Adrian. Do you think these are sufficient then for the time being, just general running in, or is it advisable to change them as a matter of urgency?

We'd probably look at them before harder driving/track days anyway, but the car needs to be built first!!

Thanks,

Tony

[sprintmp]

Tony,

They will be OK - don't worry - get that car going!!!!!

[hansgerd]

...but take at least one step aside when turning the key for the first time. Oh gosh, you've been fast with your re-build. Well done so far, get it going... good luck.

[noahstvr]

If you look in your owners handbook under maitinance the valve clearance adjustment procedure and specification are there. When the valve is closed there is an intended clearance. this is necessary for the valve to seat completley on the "valve seat" if the clearance diden't exist the valve may not seat fully creating at least a poor performance condition and at worst burned exhaust valves.check with your builder if he "lashed the valves". also there is usually a cold spec. and a hot spec. After a good run in period (500 mi.) it is a good practice to re tourque the cylinder heads and re adjust the valves. If you error on the valve adjustment, error to the "loose" side. As the valves wear into the seat, the stem effectivley become longer taking up the intended clearance. Hope this helps relieve your concern.

[bigtone]

Thanks all for your comments and reassurance!!

Well, it's definitely on now, which is a better position that we were in this morning, with an exhaust manifold in Macclesfield! I'm off first thing to meet someone on the M5 to get it back, and then Sunday afternoon is D-Day. I'll let you all know how it goes, and hope to put video, or sound clips at the very least, on the site next week.

Roll on Sunday the 15th, can't cope with any more of this Friday 13th. Now, should I go anywhere near wiring tonight

Tony
www.tvr-3000m.co.uk