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2.5 petrol rebuild and conversion to EFI thread?


Gazzar

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Yes, I don't understand chemistry, too close to magic, but I know caustic and ally don't work well.

I'll need to look up the acid that doesn't eat ally and does eat steel when I get to the door tops, though. But that's another day.

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2 hours ago, Gazzar said:

Thanks! Is there a quick easy to decoke the combustion chamber? Mr muscle?

Carb cleaner and elbow grease is pretty good. Or send it out to an engine shop for a bath, it's not expensive and will come back nicely clean. 

Anything caustic on ali is a no-go. Dishwasher tabs eat it for breakfast! Ask me how I know... 

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The verdict is mostly good, and better than I feared, a lot better. My engineer builder expert thinks the engine is fine and hasn't done a whole lot.

New shells. New cam, new followers and a couple of the tappets. He's happy with the rockers, but the bushes on the rockers need to be checked after the new rocker shaft, so might need replacing anyway.

The head would benefit from a skim, and the exhaust valves might need a bit taken away, they have ever so slightly the shadow of the seat in them.

He's going to do bring the head to his regular guy to do all that.

I'm going to replace the oil pump, because of the oil issues on the cam, probably an abundance of caution, though.

The crank could do with a very very slight polish, which he's shown me how to do, and the pistons need new rings, but only just.

So, stick it back together time coming soon!

I'll compose the parts list and send it off.

Who knows, this might be turning over by Easter!

I'm chuffed!  

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It's supposedly a high compression head, Roland, from ACR, think it might be one of his, it's good a number stamped on it that ties in to one he did in the 1990's.

Although my mate didn't think much porting had been done to it.  

I'm getting it skimmed, and tested, that should do, along with the new cam and exhaust. Don't see the point to head work, it mostly favours the high RPMs.

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Porting a head is for high rpm power, yes.  Smoothing out the rough edges makes it breath better , wich will give you a more lowdown and midrange power.  Banking the edges in the combustion chamber helps as well.   

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Do you mean turning the step in the combustion chamber into more of a slope?

I think I'll leave be, unless it's one a couple of hours work with a die grinder, I'd rather not....

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Pretty certain I can see three angle valve job in there, and some flashing removed is clear, so I would be tempted to leave it be. 

Don't change the combustion chamber shape, unless you want to start grinding them to match volume down to <1cc....

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I know the theory, but I think I'll leave it be.  It's a series with styling inspired by a brick. 

A warm cam, spi, fancy exhaust, high compression head and an extra 10% capacity over standard should be enough to push the RRC diffs to near legal limits.

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The flywheel on this engine had seen better days. Or at least the starter ring gear had.

A new one arrived from a popular engine rebuild outfit today.

The "official" way of removing the old ring involves drills and chisels, by I thought I'd try the other way..... Heat!

And it worked.

 

I used a mapp torch and warmed the ring all the way around for about 5 minutes. Not glowing, or anything, just hot.

Tapping with a punch and hammer shifted it a few mm. Repeat until free.

 

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Thankfully the new gear is correct for the 17H engine.

 

I know, I could have moved the gear 135 degrees, but I'd rather start this engine with a new gear, and I can keep this as a spare.

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I've made a start on the flywheel itself, which is in good condition. I can't feel any imperfections with my finger nail, but there is some prominent marks visible. I'll cut the face back with wet and dry when I get a chance, clean the back, then I'll fit the new gear.

 

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