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1275 Engine Rebuild


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#31 Chris.Williams

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Posted 11 January 2019 - 04:58 PM

Update:
Well it turns out the engine block I've purchased is actually a 1380, complete with (What I believe are) Omega pistons. Upon inspection of the main bearings and big end bearings that came with everything, they were stamped as standards, which makes me think the crank hasn't been machined, which has impressed me as there are no causes for concern over the journals/bearing seats, and whilst the bearings are in poor condition from being out of the engine and not protected properly, they have no signs of scoring or sufficient damage, so thinking of continuing with standard bearings and not machining the crank where it isn't necessary. 
 
In terms of the parts I'm thinking of using to rebuild this engine, I'm still only after a fast road setup at relatively low cost, and I do plan on making upgrades in time as funds come available for elements which can be swapped out while the engine is in use. In terms of the components I'm thinking of upgrading now, I was considering an uprated oil pump and maybe a fast road cam, then beyond that I currently have a simplex timing assembly and have been researching on the benefits of upgrading to duplex, but I'm a little uncertain on whether to stick with simplex and tensioner, duplex and tensioner, or just duplex. If anyone has any recommendations for additional or alternative components then I'm welcome to suggestions  :proud:

Do you have any pictures of this new block?

#32 Cooperman

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Posted 11 January 2019 - 05:36 PM

Before you spend money on rebuilding a 1380 you need to be sure that the bores are not worn. If they are it can be very expensive or even impossible to bore further or to bore and install special sleeves.
Many consider 1380 to be the limit for over-boring because the cylinder walls are getting thin and no two blocks are identical. Some blocks will go bigger or take sleeves, but others will not.

#33 Will96

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Posted 11 January 2019 - 10:52 PM

Currently don't have any pictures as I'm out of town, but again the cylinders didn't seem all too bad, the apparently the engine hadn't been run for long after being bored before it was "taken out of action" when I get back I'll post some pics. I need to check that the cylinders are correctly offset, which I suppose is the make or break of the project and forgot to do up until now and now been added to my list.

#34 Fastorq

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Posted 12 January 2019 - 09:01 AM

Sounds like you have struck lucky with the second hand block you bought and got more for your money than just the crank.
Totally agree with Cooperman tho
I've bought parts at budget prices before thinking I had just got a windfall only to find the real reason they were being unloaded!
Be really careful with things that are not immediately obvious as mentioned above ... Particularly wear patterns , machining accuracy, cracks etc.

Hope everything is OK.
Regds
DavidR

#35 Will96

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Posted 12 January 2019 - 10:08 AM

Thanks David. Couldn't agree more the fact that it's different from what it was advertised has made me very cautious when going into this. Currently looking into machine shops that do chemical dipping but before that I might get them to accurately measure everything rather than my own judgment with a set of verniers.

#36 Cooperman

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Posted 12 January 2019 - 11:13 AM

The big problem with the 1380 is that when a further re-bore is needed it either means another block or expensive machining. You can't get a standard sleeve to fit a 1380, so special sleeves have to be made and fitted. You can usually get back to 1275 with special sleeves, but bear in mind that the cylinder walls are a bit thin at 1380 and a further bore to press-fit the sleeves can see the cutting tool break through the wall into the water jacket.

 

The best thing to do at this stage might be to try to find a 1275 block and re-bore it with new 21253 pistons. Only re-ring the 1380 if there is absolutely no measurable wear in the bores and the bore diameter is within tolerances. To do otherwise could be a waste of your hard-earned cash.



#37 Will96

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Posted 12 January 2019 - 02:54 PM

Funny you should say that, I originally set out with a 1275 block I already had and was thinking of machining, the purchase of this 1380 happened as it was advertised as a +60 (the fact it's not has made me rather cautious) but yeah, if this "new" block isn't all it's cracked up to be, it's still running a standard crank which is the main reason I bought it. So there are back up plans

#38 Cooperman

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Posted 12 January 2019 - 11:33 PM

If I had bought a block advertised as +0.060 (i.e. 1330 cc), I would be very p****d off if I found it was over-bored to 1380. In fact, I would want my money back.

A 1330 will take the original-type standard sleeves to take it back to 1275 and these are easy for a machine shop to fit and relatively low-cost.



#39 Will96

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Posted 30 January 2019 - 10:29 PM

Right. First order of parts have come (this might get slightly confusing but bare with me), in this order were a set of main bearing and once they've arrived I noticed that all 6 bearings are the grooved sort that go in the block as opposed to 3 grooved and 3 solid bearing faces that sit inside the main bearing cap. Suspicion raised. So question is, have mini spares made a mistake and I'm to send these back, or am I able to use this type of bearing throughout?

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#40 Will96

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Posted 30 January 2019 - 10:40 PM

Also, sorry for the delay Chris, but photo of the block, please ignore the bit of surface rust, had to sit for 3 days in the garage while the paint dried properly in the cold weather. Additionally, got myself a minispares evo001 cam, read a fair bit of praise people on here were giving it and thought I'd give it a shot

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#41 Retroman

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Posted 31 January 2019 - 01:59 PM

The shells with centre oil groove all the way round are A series type, tangs on both on side so will fit to block or cap

 

The shells with one plain [centre tang] and one grooved [side tang] are A plus. The centre tang is for the main caps

 

Both shell types are usable in either block or cap but you may have to cut/file a slot to allow the tang to fit, if its not the intended type.

 

The 'usual' modification is to fit the plain centre tang shell in A series caps by cutting the centre slots in the caps

 

The A plus plain shell bearing does survive better.



#42 Will96

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Posted 31 January 2019 - 03:05 PM

Excellent. Much easier fix than I thought then. Thank you

#43 Will96

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Posted 11 February 2019 - 06:54 PM

If anyone actually still pops into this topic. I'm also thinking of upgrading elements of my car between the work I'm doing to the engine to help stabilise the car on the road and put the additional power into the road. I'm already thinking of 165 tyres instead of my current 145's, and things like updated poly mounts for my subframe. For stabilising I'm thinking of widening the wheel base from standard but I'm wondering if anyone has any suggestions on thickness of spacers (or if theres another way to approach it) so that the outcome looks alright and actually makes a difference. As in it's current state I rather violently veer between wheel ruts in the roads. Also, does anyone have any experience with the cone to spring suspension conversions you can buy. Are they actually any good? Many thanks.

#44 KTS

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Posted 11 February 2019 - 07:32 PM

there's quite a few threads on the subject of poly bushes and spring conversions

 

from the threads i've looked at, poly bushes for the front subframe aren't advised as they can permanently deform with the loads exerted on them (OK for the rear subframe though as the loads aren't so high).



#45 Will96

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Posted 11 February 2019 - 07:38 PM

Oh okay. Thank you for the heads up, still in favour for the standard rubber mounts then? This is just a fast road as well. Don't know if I've said through this rebuild




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