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Engine Rebuild by DaveSupTT


DaveSupTT

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I have a drapher set that comes in a steel box with tork bits and allen key sets simular to this (spelling crap on all of what ive wrote) ;)

http://cgi.ebay.co.uk/PRO-15pc-METRIC-HEX-ALLEN-KEY-1-2-SOCKETS-BITS-CRV-SET_W0QQitemZ120299879992QQcmdZViewItem?hash=item120299879992&_trkparms=72%3A985%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

Edited by johnd-mkiv (see edit history)
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Halfords are indeed a help, since their professional sockets are all bi-hex! In any case the head bolts have a female bi-hex in them, so you don't use a socket, you use an allen key. You can't use a normal hex socket on a bihex bolt, but a normal hex allen key will fit in a female bihex as found on the head bolts.

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Okay wel im looking for a fiar bit of advise here and I have got some technical questions I need asnwering as as well! So, Mr Wilson :D if your about and got a free minute or too........

Anyone else for that matter as well!! ;)

 

Questions!

 

1) Having removed pistons and found rings broke on 1,2 & 3 I checked the bore of each piston using a calibrated optical bore gauge.

The results shown below:

Results.jpg

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The manual states that the max diam allowable is 86.02 and as you can see @ 10mm from top in thrust direction all pistons are above tolerance. Having said that 0.03mm (amount oustide tolerance) equals 0.00118 ie just over one thousanth of an inch!

To me that doesnt seem to be much and certainly apart from piston 3 all the others measured near 180p.s.i. when I did the compression test and number 3 bore doesnt seem to be any worse than the others.

 

I really need an experienced opinion to give me a view whether I need a re-bore or not. Just to add, there doesnt seem to be any scratches or gouges. And if I do, who would you send it to?

 

 

Question 2 I would like a view on the following;

 

1) Should I replace big end bearing shells?

2) Should I remove crank and replace main bearing shells?

3) Should I replace pistons with better than standard?

4) I asked in a previous thread what things would you replace while the engine is out of the car? The results were

aux belt tensioner

alternator

water pump

cam belt

Oil pump

Re shell it ie New bearing shells. Main bearings, con rod bearings and thrust washers

New rod bolts

All new seals and gaskets and O rings

 

Is there anything else I should consider?

 

5) Does anyone know where I can get various bolts to replace either missing or damaged ones. They are all metric fine (1mm, 1.25mm or 1.5mm pitch) and I cannot find anywhere that stocks them.

 

6) The engine sump was sealed with flange sealant rather than a gasket. I have some Loctite 5920 premium Gasket Silicone, will this be okay?

 

Thanks guys.

Edited by DaveSupTT (see edit history)
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REBORE definitely

 

Remove crank, have checked for straightness, wear et cetera. have micro polished if OK

 

New main, big end and thrust bearings, new oil pump, new crank cambelt sprocket. All new seals. That should do the bottom end. Your choice for pistons, stock are fine for mild power, forged much preferable for modded engines. I like JUN (Cosworth) pistons, but they cost. Wiseco are a good cheaper alternative. I don't like CP.

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Dave what is an optical bore gauge? Have you got a picture of one.

 

I don't know much about boring engines, but those holes at work would not be aloud due to the ovality. And generally there is a bush either freeze fitted into our bores or loctited.

 

Sorry mate, I cant take a pic as my dad borrowed it from work and its gone back now.

 

REBORE definitely

 

Remove crank, have checked for straightness, wear et cetera. have micro polished if OK

 

New main, big end and thrust bearings, new oil pump, new crank cambelt sprocket. All new seals. That should do the bottom end. Your choice for pistons, stock are fine for mild power, forged much preferable for modded engines. I like JUN (Cosworth) pistons, but they cost. Wiseco are a good cheaper alternative. I don't like CP.

 

 

Cheers Chris,

Okay im going to get it rebored. Can you do this Chris, or if not do you know where I am best sending it to?

 

Thanks

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REBORE definitely

Your choice for pistons, stock are fine for mild power, forged much preferable for modded engines. I like JUN (Cosworth) pistons, but they cost. Wiseco are a good cheaper alternative. I don't like CP.

 

Unfortunately you can only get stock pistons in the stock size. So if you bore it out 0.5mm you have to go aftermarket.

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CP are good price wise and some package deals can be found with rods also. You're basically going to find that you get what you pay for. A good auto engineering place should be able to get the work done for you. I'd recommend giving them the crank, connecting rods and head and they can check, clean and work on them accordingly. As Chris said, new shells, gaskets, oil pump etc to give you a bit more peace of mind. If you're having a rebore I'd give the machine shop the pistons/rings so they can work with them whilst boring.

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Sorry mate, I cant take a pic as my dad borrowed it from work and its gone back now.

 

No I was just wondering what the "optical" bit was about. We use digital bore micrometers at work. The optical ones we have are old hat, but they're not digital, you hold them upto the light and it shows up a vernier scale to measure. Just wondering if there was a newer optical style gauge with digital readout.

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