Oil baffles and modern piston's

[jansens]

Spot on Steve,
  block boring to the correct size is must and the correct running in process making the car work to bed the rings in is most important.
 My reproduction Ulster returns 800 miles to the pint and like all my cars I give it the stick!

Oil baffles me too! Am just building up my engine now. No baffles, never had them and don't see the need to go looking for any and I am not sure they'd fit with Phoenix rods anyway.

What is the currently recommended oil to use and what is the recommended running in procedure.

Simon

[Charles P]

For running in cheap oil, changed frequently. I use B&Q's 20/50 for about a tenner a gallon.
No labouring the engine, no revving the nuts off. Don't leave it idling without some load. Warm it up by  running down the road gently, not sitting on the drive.
250 miles minimum.

Then put some decent oil in. I'm using Millers semi-synthetic 20/50

Charles

[jansens]

Thanks Charles, all sounds sensible. Is there a procedure for testing a brand new engine out of the car, to see that it will run? Or would doing so cause more harm than good?

The tricky thing for me will be the car is going to be registered as a new (period) one. Until it is registered you can't (legally) drive it on the roads.

But I am going to need to have the engine done, in the car and running enough to make sure it all works before I can get it road legal and drive-able on public roads. I am not sure that a running engine is even a requirement to get the car registered to be honest!

Sorry, this thread is going somewhat off topic.I might start another.

Simon

[Ruairidh Dunford]

I have a small test bed to run my engines up in Simon - has a radiator, fuel supply, exhaust and ignition switch connected to a battery etc. I usually start my engines in this to check for oil and water leaks, can also make adjustments to tappets, carbs etc. more easily. When running on this jig, and new, I constantly vary the revs. and rarely run it for more than a couple of minutes, if all is well here I then put it into the car and proceed as below. Worth noting that I run a new engine over on the starter with no ignition until oil pressure shows on the gauge before firing up (If you run a filter it would be sensible to do this each and every time, in my opinion). I also lance the oil jets a couple of times in this early stage to be absolutely certain they remain clear and fully operational.

My oil run-in procedure is as follows.

Cheap oil - 20 miles and dump.

Cheap oil - 50 miles and dump.

Remove sump and clean out all debris - you may be surprised how much has accumulated from the bores etc.

Cheap oil - 300 miles and dump.

Then every 1500 - 2000 miles or once a year - oil of your choice.

I use 7 Workshop pistons and rings, these are excellent in my experience but hard and do take about 1800-2500 miles of driving to bed in properly, the engine becomes very sweet at this point and I then consider it run-in.

My favoured driving style for engine run-in.

Start car and proceed immediately (no ticking-over on the drive while the tea is drunk...) - keep revs sensible using gears to ensure that it is free-revving at all times, do not labour the engine at all in the early stages but treating it too gently will result in the rings not bedding in properly - find that sweet spot and try to drive in it whatever gear you are in.

Every engine is different, makes it's own noise/s (my current one in the Pearl was described as sounding like a Racing Tractor by a so-say friend last night!). In the early miles stop regularly and check for water level, oil and water leaks etc. If using your electronic distributor you will find that it will require minuscule adjustment to get absolutely correct - they are much more sensitive to set-up than the conventional units in my experience.

Recently Gary Edwards and I fitted silicone tappet chest seals in an attempt to cure what we thought was a leak in the seal here. It turned out to be between the block and crankcase for both of us, tightening that down solved it for me - Gary has another issue before testing this! New oil is harder to spot leaking as it is clear. The Silicon gasket works very well and can be removed and reapplied for any tappet adjustments.

Throughout all of this torque down the head correctly a couple of time hot and the same when cold.

I am absolutely sure that you know much of this from your experience with the MG etc. and also that everyone's preferred method will differ.

Good luck.

[jansens]

Thanks R, printed out for future reference!


My main issue will be I need the engine in the car working so I can get the car registered and warranted (MOTed) but until you have done that you can't drive on the roads. So I need the minimal break in done in the shed to ensure it works enough but then need to wait to be on the road for the proper break in. 

See, this is why one Austin 7 isn't enough. With two I could swap engine around and break the new one in properly!

Simon

[Andy Bennett]

Following this slight diversion in the thread.
I am currently assembling bits for the new block I have.
As mentioned on previous thread my bores are 35 to 36 thou oversize (relatively rough vernier caliper measurement).
there is very light scoring in 1 bore and v small small steps at the top of the bores.
I have some second hand plus 30 pistons/rings etc but rather than hope that all is OK with them in the block, I am thinking that I should do the job properly and rebore.

So, my question (s), based on the comment from R above with A7 workshop pistons and the comment to rebore to the specific requirements of individual pistons, and previous comments re bore sizes at a tolerance of +0 to +5 thou.

What bore size do you specify to the machinist for +40 or +60 A7 workshop pistons?
And based on my current bores, what size would you go for, as it feels like plus 40 will likely be not enough material removal to ensure a clean bore and this is likely the only rebore I will ever need to do, so should I just go to +60?

Thanks for advice
Andy

[Charles P]

You cannot base rebore sizes on a digital calliper measurement. You need a decent Mercer type bore gauge. Taper & ovality needs to be assessed to know the minimum size that it'll clean up to.
Find your machinist (by recommendation ideally) and take them your block. Get them to measure and assess it and then buy the pistons. Bear in mind that some pistons (such as Tony Betts') are sized in metric which can be a useful size between standard 10 thou steps.

[Andy Bennett]

Thanks Charles
Appreciate the advice.
I have a meeting Saturday and was intending on canvassing local members for good workshops as I know a couple had rebores over last year or so.
Andy

[Tony Betts]

You cannot base rebore sizes on a digital calliper measurement. You need a decent Mercer type bore gauge. Taper & ovality needs to be assessed to know the minimum size that it'll clean up to.
Find your machinist (by recommendation ideally) and take them your block. Get them to measure and assess it and then buy the pistons. Bear in mind that some pistons (such as Tony Betts') are sized in metric which can be a useful size between standard 10 thou steps.

thanks charles, you mainly covered what i was about to say.

the reson you get a lip at the top of the cylinder is because thats were the rings stop, also the rings will not reach the bottom of the cylinders. this means useing a vernier is totally useless. as charles suggests you need to measure the used bore for wear and ovality, and what most people miss is if the last rebore was machined off centre, you may have to coorect it.

i would advise anyone looking to rebore, check with all supplier first for the sizes of pistons they have in stock? not being cheap to put on the shelf suppliers often run out of a couple of sizes before they restock. so no point in boreing to +60 if they are not available.

also as suggested by charles metric pistons work out at roughly +4 thou over metric. ie +80 imperial works as +84 or 58mm metric

also know what talerances the each piston type needs in the bore.

then you can get it machined to correct size, and burn less oil.

tony

[Bob Culver]

It is hard to imagine a reconditioner guessing bores more than .0015 out of size, and then only over. Split skirt pistons soon collapse to some degree anyway. And if c.i. rings do  not bed well initially (but not scuffed) they apparently  come right with use in reasonable time, even with current oils. Rings supplied here were generally pre gapped and had a coarse finish which soon disappeared so gaps were not absolutely minimal. Apart from that the big variations in oil use are a mystery. Some oil was lost under the block but would never amount to a pint in a long day trip! A little leak makes a big mess.
The situation with pressure fed engines is entirely different.
The advice from two ring manufacturers, based on plated rings, pressure fed engines, filters, is to warm up with brisk idle (possibly radiator masked) then accel and decel a few times at medium rpm with generous throttle. Change oil early, at not more than 200 miles. With a jet fed Seven the start up speed likely less important.
Costs seem not to matter nowadays but can pour oil through a filter and reuse.
I guess the total detritus after a rebore would approximate about 1/20 of one Dynamator tooth in 50 miles!
 
l looked up some old notes. Reconditioners and others were caught with a lot of Seven parts in the 1960s. Set of pistons with rings L2.10s! Rebore work L4.10. ( I produced the block out of a business briefcase which amused the staff) New b.es. L6. Seems cheap but a tradesmans  wage at the time was well under L20. (And a now $1.5m house was L5,000!)
 
Whereas now buy oil in packages, it was then usually bought from service stations by the pint in own container. So top ups usually also done at service stations pint at a time as no price saving doing at home. Hence owners became aware of consumption in terms of miles per pint. Topping oil was very much part of the attendants job. Basic grades about 1/9 pint. However as my car used a pint per 50 miles and worse at one stage it about matched the petrol ! Despite oil use, with the early head it never faltered, although following motorists often did, until they could see.
 
It is a pity to bore a Seven block more than necessary. It was common to centre the machine on the wear. The consequent slight shift in crank degrees is nothing.