blown head gasket

[Costin Moga]

Following total rebuild, I've started the engine of the Sugga, and after just 3 km, the head gasket was blown.

We've torqued the engine to manual specifications (3 proggresive tightenings). Operation was done on cold engine.

Normally this operation has to be redone after 500 km, but... to get it blown after only 3, is curious (I mention haven't forced the

engine whatsoever).

Checking the internet, I've found some say flathead engines has to be (after the 3 proggresive tightenings) torqued again with engine hot.

Others say to repeat the job 4 times after warming the engine and then waiting to cool - warm, wait to coll, retorque - repeat 4 times (?!).

Any ideea ?

 

Efter totalt ombyggnaden har jag startat motorn för Sugga och efter bara 3 km, var topplockspackning blåst.

Vi har vridmoment motorn till manuella specifikationer (3 proggresive åtdragningar). Drift gjordes på kall motor.

Normalt denna operation måste göras om efter 500 km, men ... att få det blåst efter endast 3, är nyfiken (jag nämner inte har tvingat

motor som helst).

Kontroll av Internet, har jag hittat en del säger platthuvade motorer måste vara (efter 3 proggresive åtdragningar) åtdragna igen med motorn varm.

Andra säger att upprepa arbetet 4 gånger efter uppvärmning av motorn och sedan väntar på att svalna - varm, vänta till Coll, retorque - upprepa 4 gånger (?).

Någon ideea?

[KristianEriksson]

Mounted like 4 of them and never had problem. Never done the retorque things.. Thoose pictures looks weird for sure. Maybe bad threads took the torque? Bad torque wrench? Anyway nice to see that you have been out driving

[Johan Josefsson]

Are you sure that your cylinderhead is perfectly plain? To me, it seems like the head is the problem.

[Johan Josefsson]

Forgott one thing. Are you sure that the treads are deep enough? It can be some dirt in the bottom that makes the bolts does not tighten the cylinderhead correct.

[Costin Moga]

Thanks for the answers, but... I think have found the reason:

DEL2, page 43, paragraph 13

From what I understand it says: ,warm the engine at operating temperature, then retorque the head bolts' - interesting that no swedish-speaking forum member noticed this, or did not bother mentioning it.

I will also check again the bottom of threads and reclean the mounting hole.

On the other hand, the gasket (purchased from Altyco - selling remanufactured gaskets from specialised workshop) is somehow of poor quality having the core made of some weak, easy to rip material.

Probably all these reasons combined have made the gasket to get 'blown'.

[H.Hansen]

I think that the repaired head gasket, was that caused it.

Your three kilometers of driving, is probably not the cause.

 

There are probably as many manuals, as the author of them. In all, it is not written that you should run the engine warm and immediately tighten the bolt.

And repeat 4 times ? I never heard of it. Hope you find a new head gasket

I'm thinking also what Johan Josefsson wrote. Are you sure that your cylinderhead is perfectly plain.

 

Regards H.Hansen

[Costin Moga]

There is link to Plymouth and Dodge tech-adviser/manual:

http://www.merc583.addr.com/mopar/framesets/techtipframeset.html

 

Lower on page at 'Head Gasket Replacement' is written:

 

"Make sure you have an accurate torque wrench and follow the correct torque sequence. Start in the middle and move in an expanding circle outward (See the shop manual for details). Make at least three passes to bring the bolts up to torque, such as 25 foot/pounds, 45 foot/pounds, and then the final 65 foot/pounds. After everything is reassembled, refill the coolant and start the engine. Bring it up to normal operating temperature (160 degrees). After the engine is warmed up, shut it off and make one more pass with your torque wrench at the recommended 65 foot/pounds."

 

I think in DEL2 TP21 manual the meaning is to retorque when hot, although not very explicit, but it does make sense with 1.8mm thick gaskets. I forgot to mention when we disassembled the head (after gasket blown), the bolts seamed a bit loose.

 

I had a new gasket made locally, but using a more modern inner layer + the the 2 copper sheets. The middle material is a sandwitch itself having a steel core sheet and non-azbestos upeer and lower layers.

I purchased new 'Reinz' M11 x 1,5 thread cylinderhead bolts which I'll cut to size and replace the original ones (which are a bit worn - 10,75mm diameter instead of 10,85mm the new ones - rust took its toll on them as they're bottom sitting in coolant fluid).

Early next week I'll rebuild the engine and pray for the best.

My concern are the threads in the engine block which are very short - about 18mm, and this combined with ageing cast iron makes a frightening combination.

 

And yes, the engine and head are plain (were machined and checked prior rebuild).

 

I'll keep you updated.

[Glynn]

I think that looks like a problem with the gasket, it hasnt leaked as such but broken.

[Johan Josefsson]

If you had a gasket made locally, you need to use a manual made locally. You can not use a torque for another kind of gasket. Ask the company who helped you with the gasket what torque they recomend for you and your engine.

[Costin Moga]

I've mounted the (new) gasket today, torqued engine at 8 kgm, warmed it up mainly at idle, retorqued. Incredible, but considering the few minutes of use it was possible to tighten about 45'+ each bolt ! That's a lot ! At the same 8 kgm.

Had a short ride and all went well.

I'll retorque the bolts again after some use, I'm pretty sure it will work again then.