Should these be touching? (Pushrod tube and manifold) Options

[mcswiggs]

Hi guys - this is my first proper post and I’d welcome your advice.

I bought my ex-Colorado ‘74 2-litre about 18 months ago and have concentrated so far on a total rebuild of the engine.

The engine is back in and I’ve just completed the cam burn (scary). I’m now left with a couple of oil leaks from the pushrod tubes at the case end, both on cylinder no4. The heat exchanger was a complete pig to fit, and the manifold is actually touching the pushrod tube on No 4. Is this normal?

The tubes are new but are exactly the same diameter as the old ones. I’m thinking of putting a bit of a dent in the tube to give it some clearance passed the manifold. Any suggestions welcomed!

[JFG]

no they should not touch. iwouldn't dent the pushrod tube as you'll risk rubbing or distortion of the tube.

Something id not right with the fitting of the exhaust. is is properly seated in the head?

[Olympic 914]

Sometimes the copper gaskets fall out of place when installing the heat exchangers. That would also cause an exhaust leak.

Others here have suggested putting a drop of super glue on the copper gaskets to hold them in place during the install. I tried this the last time I had mine off and it worked perfectly.

[mcswiggs]

It was a real wrestle to get the exhaust/HX on - it basically banged up against the first tube and wouldn't go over the studs on the head. It need some brute force persuasion.

I believe it is properly seated on the copper seal; it would be really loud if it was leaking badly there and the seal was lovely and snug when i popped it in. The exhaust/HX was tight against the tube all way down as i screwed it in, and even if there was another 10mm of travel left they would still be touching.

At a bit of a loss... (IMG:style_emoticons/default/confused24.gif)

[Mike D.]

I have had this problem when a broken exhaust stud is replaced/repaired. With drilling and tapping and perhaps a helicoil, the new stud is not in the exact location as the original. I'll probably get flamed for this but I drilled out the mounting hole on the heat exchanger flange a bit to give it more wiggle room. Also leave exhaust flange nuts a little loose, then fit the muffler, again leaving nuts loose. Then go back and torque everything to spec.

[dr914@autoatlanta.com]

of course they should not be touching as previously stated, but years in the past, some of these cars have been hit in the rear, causing the heat exchangers to bend and very impossible to fit. Cannot see the bend until trying to fit then a real bear. Thing to do (you probably did anyway) is to install one heat exchanger at a time, and snug the four metal locking nuts in an x pattern a bit a a time shaking the exchanger a bit for a uniform and tight seal. If it immediately starts to rub the tube, something is wrong with the exchanger.

[SirAndy]

If it immediately starts to rub the tube, something is wrong with the exchanger.

(IMG:style_emoticons/default/agree.gif)

[rhodyguy]

Did you do the grinding at the closest point to the HE?

[914sgofast2]

I have had this problem when a broken exhaust stud is replaced/repaired. With drilling and tapping and perhaps a helicoil, the new stud is not in the exact location as the original. I'll probably get flamed for this but I drilled out the mounting hole on the heat exchanger flange a bit to give it more wiggle room. Also leave exhaust flange nuts a little loose, then fit the muffler, again leaving nuts loose. Then go back and torque everything to spec.

I have done the same thing. Drilled out the holes in the mounting flange one drill bit larger. Works perfectly!

[porschetub]

It was a real wrestle to get the exhaust/HX on - it basically banged up against the first tube and wouldn't go over the studs on the head. It need some brute force persuasion.

I believe it is properly seated on the copper seal; it would be really loud if it was leaking badly there and the seal was lovely and snug when i popped it in. The exhaust/HX was tight against the tube all way down as i screwed it in, and even if there was another 10mm of travel left they would still be touching.

At a bit of a loss... (IMG:style_emoticons/default/confused24.gif)

You can't have this contact,you will also cause excess exhaust heat to that tube and limit it moving as the engine expands.
Dimple the exhaust pipe or get that pipe moved and rewelded away from contact,don't mess with the tube.

[mcswiggs]

Thanks everyone who responded- really good insights there.
Hadn’t occurred to me that it could be caused by a shunt - I think it’s a got a new passenger side rear wing (fender) so perhaps the silencer took a push too. Next job is to dismantle the hx and leaky tubes and do some fettling.