Helicoil thread insert in VP2003 engine head?

[Slowtack]

One of the fixing bolt holes in the engine head (for the exhaust outlet bend) has stripped threads. Has anybody tried helicoil type thread inserts for this repair? If so are there any issues about tapping into the casting? Grateful for any advice.

 

[Len Ingalls]

Suggest you replace stripped 8 or (10mm) factory bolt with next size up in SAE & re-tap hole accordingly. I have a VP2003,have had elbow off several times for cleaning,but haven't stripped one yet. I do have one bolt that is on the verge of stripping,because it it 1/4" too short in my opinion.I got a pair of longer original metric size & will be replacing the "short" ones in next few days. If that doesn't pan out,I will try SAE bolts next-easier than helicoils at this point.
Plan on a new gasket also.I have found re-using old gasket usually leads to weeping leak-not a big deal but messy over time.
A new rubber seal ring for the water pipe is a good idea too.
Cheers/Len

 

[cryan]

Some people swear by Helicoil some, myself included, are not so enamoured. If given the choice I would go for a drill out and conventional tap.

 

[Slowtack]

Thank you both. I managed to sort one by using a longer bolt and some washers to adjust the depth. The other must be re=threaded. The helicoil hopefully will last the season until I can redrill for a larger bolt diameter - trying to avoid that just now as it probably means drilling out the elbow bolthole also. The helicoil is available locally and looks fairly straightforward to remove if it gets damaged. Seems advisable to use non-stainless bolts. The Time-sert inserts look more robust and possibly better able to deal with casting imperfections but seem to be only available from USA. My main concerns are keeping the drill and tap straight operating in situ and any impurities in the casting. Gasket advice noted. I find the VP gasket rather hard and possibly contributed to overtightening on my part and hence my current problem. In the past I have cut out my own from sheet (dirty black fibrous material - dont recall name) which I found beds in and seals more easily.

 

[old_salt]

It is far better if you can fit Studs for manifolds and use silicon-bronz nuts or even brass nuts with graphite grease on them they should never seize up enough to brake the studs.

Quote from Slowtack :-
I have cut out my own from sheet (dirty black fibrous material - dont recall name) which I found beds in and seals more easily.

KLINGER Graphite PSM-AS is a pure exfoliated graphite with a tanged stainless steel 316 reinforcement for improved resistance to blow outs.

 

[Slowtack]

Makes sense!

 

[chewbacca]

Helicoil is probably the preferred repair method if you want to retain the same thread diameter and they certainly do the job they are designed for.There are several different varieties on the market all of the same ilk.Slow and steady is the game good lubrication and removal of swarf and follow the manufacturers instructions closely.Assuming there is room to get your tap in the hole there's no reason not to use one.If it's continual removal that's stripping the thread or just overtightening,why not insert a stud instead,assuming you have the room to fit the exhaust over the top of it.
Regards

 

[old_salt]

Quote from chewbacca
why not insert a stud instead,assuming you have the room to fit the exhaust over the top of it.

To prevent any Lakering
I have already suggested that one. :encouragement:

 

[Slowtack]

Second opinion always welcome!

 

[savageseadog]

Helicoil every time. I would resist fitting non standard sizes

 

[Slowtack]

Thanks all. Advice much appreciated. For now I seem to have got a seal - achieved by a light bang on slightly longer bolt head and then retightening. Probably wont last so I have the drill and helicoil on board for installing on some calm evening.