Clamp Screw Importatance?

[EricB]

Whoops, forgot to bolt in the "clamp screw" (1/4 UNC x 3/4") which holds the inner chest casting against the block when we were putting the chest back together. It is located just below the water pump opening.I hope that is a blind hole? Any worries? Hate to take the castings apart.

[rgh0]

Its hard to say but it does not appear to me to be absolutely criticial to holding and sealing the chain cover back plate. The hole is a blind hole and the bolt is relatively close to the 3 water pump bolts that go through into the block so my guess is that the back plate would seal to the block OK without it.

Why did Lotus use that bolt if its not needed then becomes the question? My guess is that the hole was there in the block already and it provided a convenient location to hold the back plate while assembling the chain cover and water pump. In addition the bolting pattern for the whole assembly is not great as it used the existing block bolt locations which originally had totally different purposes and the extra bolt would not hurt.

I have never left one out or stripped an engine and found one missing, maybe someone else has and they have direct experience of any negative outcome. Personally I would pull off the chain cover again and replace the bolt in the back plate.

cheers
Rohan

[2cams70]

In that vicinity on the backplate is the oil channel that diverts oil from the location where it exits on the block for the pushrod application timing chain to where it is needed for the twin cam application timing chain. If you don't fit the bolt you may not get enough clamping pressure to ensure a good seal against oil leakage from this channel.

[alan.barker]

Is it possible to drop the Sump and fit it from the bottom.
I think Rohan you tighten that Screw from bottom before fitting the Sump.
Alan

[rgh0]

Is it possible to drop the Sump and fit it from the bottom.
I think Rohan you tighten that Screw from bottom before fitting the Sump.
Alan

Yes you can access it with the sump off and easiest with the timing chain loose. I am not sure if there is enough space to fit a screw though, but its work a try.

cheers
Rohan