Sleipnir's very early original engine

rockdemon

Administrator
Staff member
#1
Hi guys,

I've finally started dismantling the original engine from the car from the point of view of getting it in tip top condition before the 50th anniversary celebration of the v8 in August.

I'm concerned that there seems to be some rust in the bores.
IMG_20170505_185727.jpg IMG_20170505_185723.jpg IMG_20170505_185719.jpg

Obviously I need to remove the sump and the crank/flywheel next...

Once i've dismantled is the next step to measure the bores to see if they're circular? Do i just try and get the rust off to start with or does that mean it does need boring out?

At the minimum we're doing the piston rings and cam. I'm guessing regrinding the crank is a no brainer to get good oil pressure...?

I'd like some help with general direction because I'm diving in having never done this before!

Thanks

Rich
 

mtb_tuli

Active Member
#2
There are a lot of guys who are more familiar with the RV8, but before you do anything, start with soaking all the bores with Caramba, WD40 etc, removing dirt with normal textile rags, soaking soaking soaking, waiting, waiting, waiting.
I would not turn the engine until the stuff had 1-2 full days for soaking between pistons and cylinder bores.
You can only measure when the bores are really clean and then you can see if the rust has made a better job.
 

chrisyork

Active Member
#3
Mmm. Rust in the bores...

Why did you sideline the engine in the first place?

Given rusty bores, the correct action is to pressure test the block to see if you have a loose/slipped liner...

If not, then start by trying the existing rings in the bores to see what their ring gaps are...

A re-bore is a big decision because of the cost of 8 pistons.... So if it is posible to get away with rings that would be great... Let's hear the ring gaps before going further. And have a very careful look see for scores in the bores... That would settle the discussion... Otherwise a hone and new rings is <usualy> sufficient...

On the crank, a polish might be sufficient unless it was actualy knocking before... Or has bad scores..

Have a look at the crank first. Then I think I would take the block for pressure testing, chemical dip cleaning and bore honing, posibly with the crank for a journal polish.

No point trying to clean the block yourself. All you'll do is loosen debris and allow it to get into oilways.

Then you have the pleasure of a nice clean reassemble with all the new bits..
 

rockdemon

Administrator
Staff member
#4
It was sidelined because it was pumping oil out under pressure out of every orifice.... I think the strong smell of off petrol when i started disassembling suggests it has to be the rings that were the initial problem. The problem now is going to be that i've left it standing for 6 years..... I havent turned it over for a year or two which is my bad. Shame i didnt have somewhere indoors to store it. It's been under a lean to - so not wet so not sure what would cause the rust.
 
#6
I have read somewhere that rust (oxidation of metal) starts with in a couple of hours if not sealed (indoors or out).
CRC soft seal is excellent if storing metal parts no painted.
 

ghce

Well-Known Member
#8
Dont worry about the rust it really has little no effect on the bores, once they are honed, measure the top and bottoms for out of round and taper. After that the only thing that really matters is ring gap and even with that there can be a wide margin of tolerance before you need to think of rebores.
Check for out of round on the crank big ends and mains and polish or grind as required.

There is no magic to engine rebuilds just how fussy or rich you are, a good rebuild can be done on the cheap or you can spend a vast sum doing every thing back to factory spec but cheap is just as servicable as expensive, the RV8 is a very tolerant engine, its not a Honda!


Graeme
 

harveyp6

Well-Known Member
#9
Buy a flexible hone from Machine Mart, hone the bores and then feel for a wear ridge, and if you're really keen measure the bores. I have it in my mind that Rolls Royce used to leave their new blocks outside to get a coating of the rust on the bores before honing and assembling, the reason being that the tiny rust pits hold tiny amounts of oil on the bore.

If it does want boring personally I wouldn't bother.
 

rockdemon

Administrator
Staff member
#10
Well this afternoon i've taken the sump off and turned it upside down. Seems water had definitely got in as there was half an inch of it in the sump. I've now put some oil down the bores from the bottom....

One one bore there is what looks like a amall gouge amongst the rust. Everywhere else it looks surface rust. Also cleaned it down a bit to make it less grubby to handle...

IMG_20170506_153008.jpg IMG_20170506_153003.jpg
 

rockdemon

Administrator
Staff member
#11
Dont worry about the rust it really has little no effect on the bores, once they are honed, measure the top and bottoms for out of round and taper. After that the only thing that really matters is ring gap and even with that there can be a wide margin of tolerance before you need to think of rebores.
Check for out of round on the crank big ends and mains and polish or grind as required.

There is no magic to engine rebuilds just how fussy or rich you are, a good rebuild can be done on the cheap or you can spend a vast sum doing every thing back to factory spec but cheap is just as servicable as expensive, the RV8 is a very tolerant engine, its not a Honda!
That's good to know :) I know i've not left it in the best of conditions....

Buy a flexible hone from Machine Mart, hone the bores and then feel for a wear ridge, and if you're really keen measure the bores. I have it in my mind that Rolls Royce used to leave their new blocks outside to get a coating of the rust on the bores before honing and assembling, the reason being that the tiny rust pits hold tiny amounts of oil on the bore.

If it does want boring personally I wouldn't bother.
I love that idea.... I was just copying Rolls Royce :D

I know what you mean about the boring - it's difficult to weigh up, With it being such an early engine I feel it matters a little more than usual.
 

ghce

Well-Known Member
#12
I always want to keep the original engine if only so that the numbers match, these days there is a tendency to just swap out with another second hand unit and that's fine if it's a boring modern future rot box that will be in the scrap yard in a few years time but for a classic to me that's a bit of a sin.

I must confess I have committed grave sins in the pursuit of the above and have not ever regretted it.
 

harveyp6

Well-Known Member
#13
With it being such an early engine I feel it matters a little more than usual.
I can understand that if it's the original from the factory, if not I don't see that it matters.

With six grades of piston for the standard bore from the factory, and only one oversize grade available for a rebore, throw in the vagaries of the competence of the person doing the boring, and you can end up with a whole lot of trouble, for a lot of expense.
 
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