Race Engine Forum UK

Yes, you can use any semi I know of for break-in,

G

Great.

Was a little concerned of some semi's being a little too slippery.

Thanks again.

Brit01 wrote:Heads were put on with the block in the car. Didn't have any other option.

But many boxer owners have done this and it is possible, but only with the 8v version.

Bit fiddly but possible with some patience.

It's possible to swap heads and torque them up with the engine out or in the car, both for 16V and 8V boxers. Given the fact that you had the engine out, you would have made it easier for yourself if you just put the whole engine together and then put it in the car.

If you're wondering how to torque head bolts with the engine in the car, you undo the front engine mount and move the engine to the side enough for your wrench to fit. Use a suitable piece of wood if required to fixate the engine in that position.

If you're wondering how to torque head bolts with the engine in the car, you undo the front engine mount and move the engine to the side enough for your wrench to fit. Use a suitable piece of wood if required to fixate the engine in that position.

Thanks Whizzman - good tip for next time. But what about the mid engine mount or is there enough play in that?


I managed to find just the right connections to squeeze in the torque wrench but yes a little fiddly.

Few pics:

It's a pretty build in it's own right. Hoping for smiles when you start her up again.

regards
Tom

Thanks Tom.

Last night I installed 80% of the cooling system/pipes, inlet manifolds and carbs.

Hopefully will have it ready for it's first fire up tomorrow or Sunday after double checking all nuts/bolts/cables etc.

Brit01 wrote: Thanks Whizzman - good tip for next time. But what about the mid engine mount or is there enough play in that?

If it's giving you grief, put an hydraulic jack (the type with little wheels) under the engine and unbolt the mid engine mount as well. Just make sure you take safety measures so it won't fall on you or on the ground.

I hope you'll get her running this weekend, you're awfully close now.

Thanks whizzman.

yep very close now - not too keen on getting out to the garage today.
We've got South Pole winds blowing making it feel about -8 degrees.

Probably try and get the radiator in, oil sump on, coolant added (checking for leaks), and then oil and prime the engine.

Would like to start it up today and break in the cams for 15 mins.
So it can cool overnight enabling me to re-torque the head bolts tomorrow.

Alfa recommend running the engine upto working temp. let it cool and then re-torque.
Some say drive it for some hundred miles then re-torque, others have not re-torqued at all and had no issues.

Why is re-torquing necessary? Is it because the head gasket gets compressed slightly when the block and head expand?

The gasket often settles a little and bolts may not be tight anymore. When retorqued, they last tight forever. I've retoqued head bolts after 500 kilometres and never had an issue!

If the engine has torque twist headbolts, then retorquing is not even possible and not necessary.

No they are not TTY bolts. Very short strong re-usable bolts.

Didn't have time to prime the engine today. Had a water leak after filling with coolant. Took a little time to find it.

And the oil sump bolts were very fiddly on the boxer engine, especially the front ones. Took me longer than expected and temperature dropped after 4pm to a point where my fingers went numb!

Hi Brit01,

You need to re-torque head bolts because of friction. Head bolt to head, head bolt to washer - washer to head, head bolt thread to block thread are all sources of friction. When you torque the bolt you are reading the torque of the clamping force of the bolt plus the friction of turning the bolt against the different surfaces. Depending on the lube you put on the different surfaces, or don't, you might have to re-torque many times. You can assemble dry, with oil, Arp assemble lube, or the stuff Top fuel dragsters use. They all produce a different result in regard to how many times you need to re-torque. You should refrain from dry assembly.

The head gasket, after it is properly torqued, doesn't compress further because of heat cycling. Aluminum heads do tend to move around which causes wear to the sealing surface.

I appreciate the interesting things you include in your posts. I always assumed Uruguay was a tropical climate.

Tim

A re-torque is only required if the manufacturer of the gasket states so. On the hydraulic 8v boxers from Alfa I've only seen gaskets that have a polymer inside and that don't need a second round. When in doubt, follow the instructions that came with your head gasket, the service manual, or ask the factory that made the gasket.

Hi WhizzMan,

I respectfully have to disagree. My favorite example of my position is the late 1980's Toyota v-6. I believe they are now at the ninth different head gasket design. It is difficult to deal with absolutes. Perma-torque head gaskets imply something they really can't guarantee, but they relieve the end user (you) of the insecurity one feels in torqueing down the head. Also, re-torque can be anywhere from a bother to almost impossible in the vehicle. So if the manufacture says no re-torque required one can feel better about not doing work that one doesn't want to do in the first place.

I'm sure most of the people on this forum have torqued down plenty of heads. I know I have. If it is a low output stock engine with a cast iron block and head(s) maybe one can justify not re-torqueing. That just is not the type of engine I build or that this forum is about. I guess my question is why not at least check the torque. Why drive all the way to the racetrack, with all the cost involved, just to pop a head gasket because it was not fully torqued down?

After break-in, and after cool down to room temperature ( except in Brit01's case of numb fingers), I re-torque the head bolts. Sometimes they are at the proper torque . Usually one bolt or several bolts will turn slightly at the required torque setting. Before anyone questions it, I have three torque wrenches with recent certification. I record which bolts I adjusted and run the engine again. I repeat until all of the bolts are at desired torque. Most of the engines I build receive aftermarket fasteners and torque up at least by the second attempt. Stock head bolts can take several attempts. After the first race is completed I check the torque again. If the same bolts are not holding their torque more investigation is required. Sometimes the problem is the threads in the block are failing which is another reason why one needs to check the head bolt torque. This is a personal record for the use of the word torque in a post.

I look forward to other opinions.

Tim

Interesting information gentlemen.
I have to agree with you Tim, very good practice to follow.

I will be re-torquing after the initial 15 min break in (manufacturer recommendations regardless of gasket) of the cams, and possibly re-check them after the first 500 miles. (Especially as the steel block is almost 24 years old - and the heads are aluminium).

Almost ready to start her up.

Took a photo today. Still had a tiny leak overnight on a T section of the coolant system (couple of jubilee clips).

In my exp only thermosetting polymer* and MLS gaskets do not need retightening. And of course you cannot retighten head bolts whose tightening regime is torque + angle.

If in doubt - retighten.


G

* usually ID'd by via the maker's instructions - if they say no retorque the gasket will invariably be of that type - they harden.