Did they skimp on skimming?

[robert.self@me.com]

Just had to remove the head as I suspected cross fire and low and behold it is! Trying to figure out what I need to do but only issue is that I had the engine rebuilt 3 years ago by a shop and it looks like the engine block and cylinders have been done by hand. Is this a thing? or did they rip me off? The engine number tag hasn't been moved so I know they haven't had the whole surface down at once though they assured me it was all machined.

Thanks in advance and thanks to everyone on here fyi, kept it running for 10 years thanks to y'all.

Bob

[les]

Bob, If by cross fire you mean a blown head gasket, then check the block and head with a straight edge to make sure it's perfectly flat. It's possible to removed and replace the tag after a skim, as to being ripped off, who knows? You can't skim by hand, only clean up on a surface plate with a sheet of emery paper. I'm not too sure if I understood your wording of the issue, apologies if I've got it wrong.

[robert.self@me.com]

Hi there, thanks so much for the reply and yes sorry for the wording writing is not my strong suit. Basically I can see that the tag hasn't been removed and the scoring on the block doesn't look like machining so yes was wondering if there was a effective process that would flatten the block and make these marks. Maybe your right potentially someone has just run over it to make it look clean and done the same with the cylinders but I was assured they had been skimmed. The car is burning a bit of oil now where it didn't before and I'm also worried that they have not done a proper job on the inner workings either. Just weighting up doing it again myself but properly. I've attached some photos of the surface of the block. Again many thanks!!

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[philthehill]

The marks on the top of the block are confusing as some of the marks indicate that a fly cutter has had a machining pass over the top of the block and the other irregular marks indicate that coarse emery paper has been used.
Looking at the top of another machined 'A' Series block the top surface on your block is nowhere as good a finish.
The Number 2 (with BMC the number would be inside a diamond) stamped into the top of the block I would suggest is the engine reconditioning company's bore to piston grade indicator. A re-bore is usually sized/made to suit the new pistons unless a good selection of graded pistons are available.
I note that the pistons are 0.020" oversize so a re-bore has been carried out which usually but not always entails removing the engine tag.
The engine tag can be removed and refitted as stated above.
It is usual for a head to be skimmed when overhauling the engine but unless there are serious concerns about the top of the block it is left as is.
What does it state on your itemised bill/receipt for the work carried out on your engine?

[NOEL]

Hi,I would agree with a previous comment, that has a rough skim with a cutter, probably one that is a little worn and also rubbed over as well with emery or something similar, suppose it depends on what equipment the machine shop had but I would expect a better finish than that.

[oliver90owner]

I somehow doubt that it was machined. Maybe someone can enlighten on the number 2s imprinted on the block face.

Blocks don’t often need decking - well, not as often as cylinder heads. Questions arising are:

Whether these ‘cleaning marks’ were made and then they found it was flat. Is it flat now?

Whether they charged for work not done, and not needed.

What does the head look like? Is it flat, what machining marks are visible?

Even if the head is marginally thinner than original, it does not mean a lot, unless you know the previos history.

What other ‘rebuild work’ was included? What do you call a rebuild - it may be different to what I might be thinking?

Do pistons protrude more than normal? Are direction marks on the pistons still there?

How many miles since the rebuild?

Is oil passing the rings or going down the valve guides?

I would say that if you are going to dismantle further, you may find other things which have been omitted in a proper rebuild, or you may find everything in order. I note 20 thous over-sized pistons which would not appear to have had anything taken off. But cylinder ovality, honing marks, ring wear, etc might add to the story.

[robert.self@me.com]

Thanks for all your replies! Basically the garage was a strong recommendation from an old school mechanic I know who works on Morris and the like, the machine shop had all the bells and whistles, he gave me the tour and listed all that would be done in a rebuild which was basically everything. I trusted this way too much, didn't get an itemised bill like a plum and just went with it, later found out the machine shop had changed hands prior to my going and seems like the guy might have taken me for a ride.

Skimming of head + block
rebore/hone
new pistons + rings
new big end bearings
main bearing
seals
crank grind
cam grind or new if needed
cam bearings
new timing chain

Think there was more but basically everything that could be replaced honed or machined he promised. The head is a decent machined finish and seems flat also, I have a day off tomorrow so will be properly cleaning the block and check the cylinders and piston protrusion properly, get the gunk off and doubly check were flat. Its very disconcerting by your feedback that the block surface is not good and does make me question whats underneath. I guess I can do a proper clean new gasket and do a compression test, its done around 3000 miles on this engine so if the rings are dodgy then maybe I should suspect cylinders/pistons weren't looked after and further suspect foul play down bellow?

[philthehill]

Robert
Thank you for the additional information.

Whilst the top of the block is not perfect I have seen worse.

I would advise that you check the top of the block for flatness. 0.003" max is the limit for any hollows/unevenness regards the top of the block. Check with straight edge and a feeler gauge.

If the top of the block is within the tolerance quoted I would suggest that you clean up the head and top of the block and fit a very good quality copper head gasket and carefully torque down the head and re-torque after the first heat cycle.

If the top of the block is outside the tolerance quoted above the block will need to be re-skimmed.

If you need any additional information please come back to this forum.

Phil

[les]

Don't get too despondent by the replies, the block could well have had a shallow skim, simply to remove high spots, the finish may then be barely discernible. You can check the bores by feeling how much, if any, of a ridge there is at the top. None or slight should indicate ok in that area. Unles you want to strip further, the rest you will have to accept. Any rumbling when running could indicate bearing problems otherwise you will have to take it that the work has been done.