TR 3 engine strangness cam???

[Hydroglen]

Hello,

Earlier this year whilst attempting to adjust the valves I ran into a strangness with the pushrods.

Long story........eventually I removed the head, blocked the liners, replaced a couple of sad valves and basically cleaned everything up. Liner to block clearence as per the book. The head is a TR4 511695 and the height is now 3.231".

The fun was that most of the pushrods were bent! Why???

Ordered new ones with lifters and carefully started to set my valves....no go. Push-rods too long....compared them with my spare engine and they were the same lenght.

Head is within limits. Posted this question some time ago on a US forum and I got an answer that there were special "short" push-rods available, but no further explanation.

I made up spacers to fit under the rocker shaft towers and set it all up...pressed the starter and all went well.

Engine is smooth and comp is at 150 lbs EVEN on all cylinders.

 

So do I have a special cam or ??

 

Dorien

 

 

 

[Guest ntc]

Re profiled cam?

[LGFromage]

Hello,

Earlier this year whilst attempting to adjust the valves I ran into a strangness with the pushrods.

Long story........eventually I removed the head, blocked the liners, replaced a couple of sad valves and basically cleaned everything up. Liner to block clearence as per the book. The head is a TR4 511695 and the height is now 3.231".

The fun was that most of the pushrods were bent! Why???

Ordered new ones with lifters and carefully started to set my valves....no go. Push-rods too long....compared them with my spare engine and they were the same lenght.

Head is within limits. Posted this question some time ago on a US forum and I got an answer that there were special "short" push-rods available, but no further explanation.

I made up spacers to fit under the rocker shaft towers and set it all up...pressed the starter and all went well.

Engine is smooth and comp is at 150 lbs EVEN on all cylinders.

 

So do I have a special cam or ??

 

Dorien

 

 

 

Part of the problem may be "shortened" pushrods as supplied by Mr M. I bought a set and they were shorter when comparing overall length to the original rods but the working length (contact surfaces between cup and ball) were longer.

 

As for bent pushrods it could be that the valve springs are boxing ie the coils are touching before the cam has reached full lift. If this is the case a check on the condition of the cam lobes and followers would be a good idea.

 

Tim

[Ashley James]

Dorien

 

If you haven't already it's worth getting a Moss catalogue for the TR because it contains so much useful information including how much lift the various Camshafts have.

 

Standard is 0.290" and the hottest racing ones 0.340"

 

Check it will a dial gauge on the top of a push rod. Some fast street ones use wider tappet clearance, 22 and 34 thou.

 

Ash

[Hydroglen]

Thanks.....but tried that.

Moss was no help. Explained the problem but they do not show a different length pushrod to be put with the one "special" cam they list. No cam specs either, just talk about "grunt", and that is not good enough.

When I ordered them I expected to receive "shorter" rods, but it turned out they were the same.

Re coil binding....sure they would bind because the rocker would be pushing the spring down when the cam lobe was at the bottom.

I can try a dial indicator when I bring the car back from it's body adjustments, but not sure what that would prove other than I have a high lift cam.

Assuming a high lift, the question would remain....why have the same pushrods if they are not going to work? I can think of a number of engines that I have owned with high lift cams and stock pushrod/lifters.

We shall see....

 

Dorien