20 replies to this topic

[pete l]

Hi all,

 

How do I go about my first engine start after a rebuild ? 

 

Rebore, new pistons and rings, new camshaft, cam bearings and followers, new crank main and big end bearings.

 

Apparently I have to keep the engine revs up to at least 2000 rpm, at the same time I need to load the engine up to push the rings into the bores to get them to bed and and not glaze up the bores.

 

How do I do all that at the same time ?

 

Pete.

[Icey]

https://www.calverst...in-new-engines/

Mr Calver has (an) answer, but there are many opinions.

[pete l]

Thanks for that. 

[mab01uk]

Also remove plugs, disconnect the coil and crank up oil pressure on starter motor before first starting the engine. If you don't get oil pressure doing this you will need to prime the oil pump. 

(Remove the block to filter head oil transfer pipe where it leaves the cylinder block and insert a pipe/funnel into the hole in the block, then fill it slowly with oil. Put car in gear and push it backwards which will turn the engine backwards, so drawing the oil in and filling the oil pump. Then reconnect the oil transfer pipe and turn the engine over on the starter with spark plugs out, which should now give oil pressure on the gauge...if the pump was primed ok with with the oil you added).

 

 

[Spider]

If the engine has been sitting for a few weeks since doing the build, I'll do the manual prime that mab01uk has referred to soon-ish after getting the engine in and even before doing all the bolt ups. That give the oil some time to drain back through the pump .

 

When it comes to that first start,I'll screw in the idle screw about 1-1/2 - 2 turns and I like to have everything for the car to be ready to drive right away, literally withing it doing those first 30 turns, then I'll go for a short drive (about 400 - 500 metres and bring it back to top up the water and check things over before going a few more similar short drives, but going out further. I have found it quite important to get some load on the engine right away to avoid glazing of the cylinders. You'll also probably need to pick your time of day when to do this so you can best avoid traffic.

 

This is a sheet I would give to owners following an engine rebuild;-

 

 Engine Initial Start & Running In_Page_1.jpg   40K   11 downloads

 

 Engine Initial Start & Running In_Page_2.jpg   34K   13 downloads

[sonscar]

Start it and drive it straight away,use it fairly vigorously with lots of snapping throttle shut to bed rings.Give it twenty miles or so and check vitals.Enjoy.Others will have their own views.Steve..

[pete l]

Didn't realise it was so complicated !

 

How did every new owner of an A series car run theirs in ? Did Rover pre run in their engines ?

Edited by pete l, 25 August 2026 - 09:17 AM.

[Spider]

Didn't realise it was so complicated !

 

How did every new owner of an A series car run theirs in ? Did Rover pre run in their engines ?

 

I am not sure about very late years, but yes, in the BMC and Leyland days they did a 1 hour test run in the factory - every engine, later when the 73 fuel crisis hit, that was reduced to 20 minutes, but they still did them and really, 20 minutes is well enough for the initial start and early running in.

 Hot Run Tested - BMC.jpg   20.68K   1 downloads

 

 Hot Run Test 03WM.jpg   42.4K   1 downloads

 

As well as this, there was the following info in the owner's manuals

 Pages from GT 1100 & Van Cover & Running In 01.jpg   110.01K   4 downloads

[stuart bowes]

factories have the benefit of rolling roads, don't they, which makes things somewhat easier

 

I remember going to the ford factory with school as a kid (dagenham, back in the day when the ford plant still existed!) and one of the stages there was having the cars run for a set period on rollers, amongst various other quite interesting insights

Edited by stuart bowes, 25 August 2026 - 11:20 AM.

[Steve220]

Don't be sucked in by the 500 miles gently BS. The rings need load to bed in. Spider has put a good methodology. If yours is an MPi (I think it is) your fuelling and timing will be ok. 20 minutes at 2-2.5k to bed the cam in (it also means you can check for leaks and fluid levels) then go drive it!

[mab01uk]

factories have the benefit of rolling roads, don't they, which makes things somewhat easier

 

I remember going to the ford factory with school as a kid (dagenham, back in the day when the ford plant still existed!) and one of the stages there was having the cars run for a set period on rollers, amongst various other quite interesting insights

 

If anyone wants an insight into how a modern car factory builds cars today, I highly recommend booking a tour of the MINI Plant in Oxford (Cowley) :-

https://www.visit-bm...nt-oxford-tour/

 

(Some of the Oxford MINI Factory Tours I have been on have had retired workers BMC/BL/Rover workers as tour guides who also had some great stories to tell of classic Mini production back in the day).

Edited by mab01uk, 25 August 2026 - 11:32 AM.

[stuart bowes]

If the engine has been sitting for a few weeks since doing the build, I'll do the manual prime that mab01uk has referred to soon-ish after getting the engine in and even before doing all the bolt ups. That give the oil some time to drain back through the pump .

 

When it comes to that first start,I'll screw in the idle screw about 1-1/2 - 2 turns and I like to have everything for the car to be ready to drive right away, literally withing it doing those first 30 turns, then I'll go for a short drive (about 400 - 500 metres and bring it back to top up the water and check things over before going a few more similar short drives, but going out further. I have found it quite important to get some load on the engine right away to avoid glazing of the cylinders. You'll also probably need to pick your time of day when to do this so you can best avoid traffic.

 

This is a sheet I would give to owners following an engine rebuild;-

 

Engine Initial Start & Running In_Page_1.jpg

 

Engine Initial Start & Running In_Page_2.jpg

 

is this a sticky?  can we have it added if not, really useful reference guide and I'll be trying to hunt it down at some point in the near future hopefully!

[pete l]

Spider, will I be OK running the cam in for 20 minutes before taking it for a drive ? or will I risk glazing up the bores ?

[Spider]

 

If the engine has been sitting for a few weeks since doing the build, I'll do the manual prime that mab01uk has referred to soon-ish after getting the engine in and even before doing all the bolt ups. That give the oil some time to drain back through the pump .

 

When it comes to that first start,I'll screw in the idle screw about 1-1/2 - 2 turns and I like to have everything for the car to be ready to drive right away, literally withing it doing those first 30 turns, then I'll go for a short drive (about 400 - 500 metres and bring it back to top up the water and check things over before going a few more similar short drives, but going out further. I have found it quite important to get some load on the engine right away to avoid glazing of the cylinders. You'll also probably need to pick your time of day when to do this so you can best avoid traffic.

 

This is a sheet I would give to owners following an engine rebuild;-

 

Engine Initial Start & Running In_Page_1.jpg

 

Engine Initial Start & Running In_Page_2.jpg

 

is this a sticky?  can we have it added if not, really useful reference guide and I'll be trying to hunt it down at some point in the near future hopefully!

 

 

 

If the members feel it's of value, I'll add it in to FAQ.

 

 

Spider, will I be OK running the cam in for 20 minutes before taking it for a drive ? or will I risk glazing up the bores ?

 

I drive them right away, set the idle up so it's at 2000 RPM (or what ever you cam supplier recommends but don't let it drop below that for any length of time at all) and drive them. The 20 minutes they need seems an eternity, but it goes quick.After this cam break in period, set the idle back to to 1000 for the rest of the break in period, then set it down to the normal idle speed after that.

 

Fresh ground steels don't readily absorb oil. The cam lobes are lubricated from oil that's flung off the Big End Bearings, at low engine speeds, the crank is spinning
slow and the volume of oil being pumped is quite low, this is why we set the idle speed up for this early period. After this first 20 minutes the cam lobes and followers have been bathed in warm oil long enough that they hold some oil and have also been coated with the ZDDP ('Zinc') that they are 'broken in' holding lubrication.

 

This also raises another problem I have observed with the late engines that run these cray tall final drives that the engine never seems to run long enough at medium (or higher) revs to keep the cam properly lubricated, hence why they seem to wear the lobes so much quicker than the earlier cars.

From my experience, how you do this running in process dictates the life of the engine, of course, there will be many other factors along the way, but this to me is critical.
 

[pete l]

OK, I understand it all, the only hick is that mine is an MPI and I can't adjust the idle speed. It's all done by the ECU.