stripped thread on engine

[DanS]

had this for a while but not got round to sorting it yet.

When I rebuilt my engine a while ago I managed to strip the thread on the pic below

its the right one of two that holds the top of the inlet mani on to the rocker cover.

What's the best fix without dismantling everything? Helicoil?

Will I be able to get a tap in there if I need to turn it with the arms sticking out?

 

[gogsie]

I'd say helicoil it.

 

[DanS]

Are they easy to fit, or should I say are they easy to balls up more like.

Is it simply drill down into the hole to clean, re-tap the thread then turn in the helicoil to fit?

Also how do you know what size helicoil to fit?

 

[oVerboost.]

Is the lack of a bolt causing any problems? Air leaks etc? As I had a similar problem on a friends 172 and his caused no problems so it was just left... It is not ideal, but you can use some plumbers tape wrapped around the original bolt thread to "thicken" it slightly as a temporary fix...

 

[Fred@BTM]

its 7 x 10mm bolts to remove the plenum (well 6 in your case!) you lazy sod!

 

[DanS]

its 7 x 10mm bolts to remove the plenum (well 6 in your case!) you lazy sod!

not sure what you mean? the thread is/was in the rocker cover (if I remember rightly) so I didn't want to remove that, just repair it, I dont mind taking the plenum off, thats easy!

Is the lack of a bolt causing any problems? Air leaks etc?

there is something that is a bit odd that I'm trying to get to the bottom of; the engine hesitates and splutters quite a bit when I rev it from idle, not sure if there is an airleak or something else!

 

[dave1980]

i have done the same to mine tonight, although its the bolt at the bottom right on mine. seems ok to run the engine at the minute but do fancy getting it redrilled soon.

only had 4 bolts on the front of mine, i can see the missing ones now

are they standard bolts or the usual renault special thread?

 

[crazycup_racer]

2 options,
1. Drill bigger and tap new thread, fit new bolt.
2. Drill through, use a small m6 or m8 bolt with matching lock nut

Done both before, both of which work fine!

 

[DanS]

what is the standard thread for that bolt and what corresponding helicoil size would I need.

also would this cause an air leak like I think I have, or could that be something else?

 

[T.Trophy]

yes it could cause an air leak.

The ph1 clio 172 have a breather system which feeds into the underside of the inlet manifold. On ph2 they have a blanking plate on the rocker cover.

Both have the hole in the lower side of the plenum so if it's not sealed against the blanking plate you will get some form of leak (probably air being sucked into the engine rather than escaping), you could try pressing down on the plenum while some blips the throttle to see if it disappears?

 

[DanS]

another thing is that it only does it when the engine is warmed up;

if its idling and I dump the throttle to the floor quickly (this isn't something I do often, its just to test it) the the engine seems to splutter & hesitate for a second and its almost as if the revs drop slightly before they pick up, it doesn't do it when cold! does this seem a symptom?

 

[sideways danny]

what is the standard thread for that bolt and what corresponding helicoil size would I need.

also would this cause an air leak like I think I have, or could that be something else?

m6x1

the thread isn't in the rocker cover, it's part of the breather box, so you could completely remove it from the car in about 5 minutes if you wanted

 

[DanS]

m6x1

the thread isn't in the rocker cover, it's part of the breather box, so you could completely remove it from the car in about 5 minutes if you wanted

nice one, thats what I was looking for, shouldn't be too much of a hassle tosort that then!