12 replies to this topic

[babsbrown]

Hi guys,

I have a feeling I'm going to open a can of worms here. But I want to get the general consensus. I have just started my 1130 engine I've rebuilt on the engine testing stand

Momentarily for about 30 seconds. To ensure it actually fired up. I primed the oil pressure before.

Now.... there's no leaks and everything seemed fine. I want to get the rings and cam bedded properly.
Hence under load ASAP.

Is it worth the effort putting the motor in the car and getting it under load or better doing it on the stand?

I can't really see any benefits of the stand.


Cheers,

Edited by babsbrown, 21 March 2025 - 02:11 PM.

[Steve220]

The engine requires load to bed in the rings. Don't ever let it idle. If its a new cam, you'll need to keep the revs above 2.5k for about 20 minutes too.

 

If you're out on the open road, do 5 pulls between 2-4k, then let it cruise for a minute to let the bores cool, then repeat. You only really need to do about 50 miles of that and the engine is ready for an oil and filter change.

 

Where people get this 'drive normally for 500 miles' nonsence from, is beyond me - You're only bedding the rings in and 80% of that is done in about 10 minutes of driving.

[ACDodd]

Load!

You need load to do this properly and use proper break in lube.

Ac

[babsbrown]

Thanks gents,

I'll start putting it in tonight, makes complete sense to me.
I might be thinking too much into this but running it for 20 mins at 2500 is very do able on the stand but normal driving a bit more difficult on the roads near me. Would you just increase the idle adjustment so it still maintains the rpm when coming to a stop or crawling in traffic?

Cheers

[Ethel]

No. Load means pressure above the pistons & that requires something for them to push against. Wind resistance, driving uphill, accelerating the car.

[Lplus]

There's a contradiction between running it continuously at 2500 for 20 mins from start up and having to drive it on the road to put load on the rings.

[Steve220]

There's a contradiction between running it continuously at 2500 for 20 mins from start up and having to drive it on the road to put load on the rings.

Yep. Welcome to the flat tappet cam conundrum.

[sonscar]

I thought the 2000rpm was to ensure oil was splashed on the cam and followers.you will be doing this whilst driving.Steve..

[Shooter63]

The problem with the static rpm method is that it's been taken out of context, its the method used by a dyno operator, set the rpm, induce load on the engine to make it work, I think Keith Calvers method is best, start the car up and drive it, that way you always have some load on the engine. You can set the initial timing while building oil pressure, and obviously use running in oil, probably the best £40.00 you will spend.

Shooter

[Lplus]

I thought the 2000rpm was to ensure oil was splashed on the cam and followers.you will be doing this whilst driving.Steve..

Well that's the supposed reason for holding 2500 rpm for so long,  I'm sure you'll achieve those revs for part of the time it's being driven but it can't be guaranteed.

[babsbrown]

Thanks for the input gents, I have just checked back in. I've put the engine back in and I'm just sorting the wiring to my wideband gauge. Last thing I want is bore wash.

To be honest it made more sense just to install the engine and wire everything in properly. It didn't actually take that long and I installed it complete apart from manifold and carb.

It might take a while to run in mind, I probably do less that 200 miles a year.

[Spider]

There's a contradiction between running it continuously at 2500 for 20 mins from start up and having to drive it on the road to put load on the rings.

 

Actually, it's not less than 2500 (or more usually 2000) RPMs, not necessarily 'hold it steady' and certainly not a good idea with fresh rings and bore.

[cal844]

It's supposed to be 2500 rpm MINIMUM for 20 minutes, get load on it and drive it keeping above the 2500 rpm. When I have built engines previously I took a week off work and drove the car, 250 miles a day is achievable but tiring 😂

Edited by cal844, 29 March 2025 - 12:00 PM.