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 64 Posts Member #: 6668 Advanced Member |
6th Feb, 2011 at 03:56:03pm
The race engine is apart and i am thinking of redoing another block for this season. Redoing another block will require boring to 73.5 mm. First let's assume the engine is an inline engine for reference. I can see the engine bores moved front to rear or longitudinally to just clear the oil pressure relief gallery and i realize a bit of luck is involved to get there. But in vizards book (yellow book P415) he says to move each of the bores outward .015. Also he say's to move them to the right .010 to clear the lower oil gallery on the left side of the block. Is this really necessary ? It would seem that unless absolutely required. moving the bore left to right would be a bad thing. Has anyone only partially offset bored an engine and what were the results? Thanks Aaron Racecar spelled backwards is Racecar |
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 11046 Posts Member #: 965 Post Whore Preston On The Brook |
6th Feb, 2011 at 04:37:16pm
This is an A+ block and a little more consistent than some of the old 'A' blocks I am led to believe. Look at the pictures and make your own mind up. I never moved the cylinders towards the push rods on my 74mm bore, but I did offset 1/2 and 3/4 cylinders 0.010" away from those pairs thus increasing the center distances between 1/2 and 3/4 by 0.020" I did this as obviously the 74mm bore is a bit larger and more likely to come closer to the oil galleries.
On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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64 Posts Member #: 6668 Advanced Member |
7th Feb, 2011 at 02:23:36am
Sprocket, So Just to be clear this block in the photo has a 74 mm bore? if so i think i will take a chance of not moving the bores side to side. And i like the idea of just moving the center bores. your a good thinker. Aaron P.S. If you can email me. I have a project you may like to see... Racecar spelled backwards is Racecar |
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11046 Posts Member #: 965 Post Whore Preston On The Brook |
7th Feb, 2011 at 11:17:08pm
On 7th Feb, 2011 hydrolastic said:
Sprocket, So Just to be clear this block in the photo has a 74 mm bore? No mate, that's a standard block. offset boring for 1380 is more to do with keeping the bore wall thickness between 2/3 a little more sensible, and even its thickness up when compraed to 1/2 and 3/4, since the middle is usually thinner than the others. Aslo just to be sure you have it correct. Offset bore cylinders 1/2 0.010 or 0.015" away from cylinder 3, AND, offset bore cylinders 3/4 0.010 or 0.015" away from cylinder 2, thus increaseing all cylinder centers by 0.020 to 0.030" Personally I would measure the wall thickness between 1/2 and 3/4 then see how much different there is when you measure the wall thickness between 2/3. This will then give you an idea how much you need to move cylinders by to achive an even wall thickness. Edited by Sprocket on 7th Feb, 2011. On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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