Running in Twink

[tdafforn]

Now have rebuilt engine installed and running and car has an MOT..
So I need to run in the engine..
Anyone have any suggested protocols?
(First drives the car seems a lot more responsive, i guess the old engine really was on its last legs!)
Tim

[steveww]

Once the engine has been round a couple of heat cycles, re-torque the head bolts. Back them off 1/4 of a turn then tighten up to the required torque.

Keep the rpm low for the first 500 miles.

[garyeanderson]

Once the engine has been round a couple of heat cycles, re-torque the head bolts. Back them off 1/4 of a turn then tighten up to the required torque.

Keep the rpm low for the first 500 miles.

This should read
"Back them off ONE AT A TIME a 1/4 of a turn then tighten up to the required torque"

Gary

[steveww]

Sure. I just assumed that the normal sequence would be followed.

[Robbie693]

Back them off ONE AT A TIME a 1/4 of a turn then tighten up to the required torque

Does this apply whenever one takes the head off, or just on a rebuilt engine?

[denicholls2]

Back them off ONE AT A TIME a 1/4 of a turn then tighten up to the required torque

Does this apply whenever one takes the head off, or just on a rebuilt engine?

A retorquing procedure should be applied whenever the head is off, plus at regular intervals even when it stays on. You should always back off the bolt first when retorquing as noted earlier.

Given the Twink's short head life in typical service, I would think that it's not unreasonable to retorque every 20k miles if you think of it. The only consequence (besides evening out pressure on the head gasket and potentially saving yourself from a failure) is that you then might want to replace the head bolts at major rebuilds instead of reusing them (as they've seen more cycling stress, which is what will most likely cause them to fail.)

Those of us with Renault Europas know already that failure to retorque soon after head-off can quickly lead to a major rebuild. That engine design is very sensitive to correct torque to keep the water where it belongs.

[Robbie693]

Ok, thanks.

I'll do that when I get chance to replace the head gasket, which is weeping water from the back of the head at the moment...

[rgh0]

Tim

My engine running in procedure is similar to Keiths answer in another forum to you.

1. Ensure you use a properly formulated running in oil during this procedureand that a good quantity of assembly lube is on the cams and tappets and that oil pressure has been established
2. Start and run the engine for a maximum of 10 to 20 minutes from idle to around 2000 to 3000 rpm while checking for leaks noices etc and doing carbs and timing checks. This time does the initial bed in of the cams and tappets so they will be OK for the next step. Dont spend excessive time on this step as excessive no load running can glaze the boers and prevent the rings bedding in. Dont spend excessive time at idle durng this step as you need a little speed of cams to buckets to help lubrication during initial bed in.
3. Take car on road and do a sereis of full throttle accelerations from 3000 to 5000 rpm in a suitable gear. I normally do it in third gear on a 100kmh speed limit road near home. Accelerate to 5000 lift off and allow revs to drop revs to approx 3000 then full throttle accelerate again. Dont run at constant speed or light throttle loading any longer than you have to. I do this for about 100 km on the road for about an hour. This beds in the rings in the bore. The aim is maximum gas pressures in the cylinders and changing revs to ensure the rings properly seat without glazing the bore. You dont need to take to 6000 rpm as aim is to run it through the torque peak area where you have maximum gas pressures.

After the above change to a top quality synthetic oil and replace filter and the engine is fine for anything provided it has been built right with correct tolerances. Applies to a standard road engine build or a race engine build

regards
Rohan

[tdafforn]

Rohan, what you are saying sort of equates to going for a normal drive on twisty roads without hammering it totally!
Looks like a fun trip this weekend
Tim