How to make an old motor new again?

neevo

neevo

Over 1,000 Posts
So I'm going down the rabbit hole quicker than Alice on my custom 400F project but I'm having fun and the rule is "to do it right" so that I can ride it for a while if I keep it, or know its done right if I sell it down the track.

I'm keen to make sure the motor runs for another 30,000 miles so what do I need to think about to make sure it's mechanically, structurally and performanc-ly sound?

I have already done:

1. New 466 pistons and rings
2. Bored out to individual pistons
3. New cam chain
4. New seals and gaskets throughout
5. Valve seats cut
6. Vapour blasted whole motor (soon)

I was thinking of doing the following too:

1. Machine the barrels (top/bottom) flat
2. Deck the head (to make sure it's flat too)
3. New primary chain
4. New main and crank bearings (where old ones show any signs of use)
5. SS bolt kit
6. New clutch

Anything else I should consider? Minor port and polish?

Cheers.
 
The stainless steel bolt kit is not necessarily a god thing for the motor as the bolts are harder than originally intended and may wear out softer aluminum parts faster than normal.
 
lurkmaster2000 said:
The stainless steel bolt kit is not necessarily a god thing for the motor as the bolts are harder than originally intended and may wear out softer aluminum parts faster than normal.
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I will bear that in mind. Seems like a pretty common mod as long as you use antisieze to stop the bolts fusing to the alloy cases.
 
i don't think the primary chain needs replacing, it's a hyvo and in one of the best designed sohc motors honda made, it'll go 100k. I'd be wary of machining the head or barrels, check if they're flat first, if you want a good seal, a surface plate and some sandpaper is the best way
 
No problem re the primary chain, they are beefy enough so I can understand how they can go forever.

For flattening the head, what grit is best? Do you do the barrels too? If so can you pop the sleeves out by popping them in an oven and letting them drop out or is this not worth the hassle?
 
I was told by the mechanic that the block(barrels) are not really prone to warping, since it is mostly steel covered in AL. The head is what warps from the head. I had my lightly resurfaced on a mill. But using a large piece of glass and some compound would work too, thats old school though. I wouldn't heat anything up to get the sleeves out, that sounds like a terrible box to open in my mind. I'd replace what needs to be replaced, surface the head and go with it.

I changed all of my main/rod bearings but I probably didn't need to.. But its an expensive path my friend. I probably wouldn't do it again. I have the bolt kit as well, not really worried about seizing too much, I'm using anti-seize. I did buy some new clutch plates, I believe from DCC. They are a modern take on the old ones. They were relatively cheap, $40 or something, so that's pretty worth it.
 
ronnie said:
I changed all of my main/rod bearings but I probably didn't need to.. But its an expensive path my friend. I probably wouldn't do it again.
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I was initially costing up replacing all the mains and cranks from David Silver Spares but you're right, the cost mounts up fast (£7 each I think). With 18 in total that's a fair chunk of change so I'm a little stuck with the decision. I have some good ones so was thinking of reusing what I had and replacing anything that was suspect.

Need to find someone to help me measure up the bearings with some plastigauge though to check what's in/out of spec.
 
To be honest, if your engine has less than 20k miles on it they are probably still fairly new. My engine had 17k and the bearings were barely used. My dad wanted to reuse them as they were hardly even polished, still had a machine finish on them. And it was a lot more than 7 for a bearing I believe. I'm pretty sure it was close to 200 for all the bearings. I'll have to look.

Sent from my Galaxy Nexus using Tapatalk 2
 
ronnie it's £7 each which your right is about $200 total. The reason I'm thinking of replacing all mine is my motor has unknown miles on it and the condition was appalling when I got it. Oil pump was buggered, it had a damaged cam, metal was pumping around the whole system and some of the crank bearings have some scuffing.

I would hate to put all new parts in the motor and skimp on bearings for the sake of $200 which is a small price vs the total build price.
 
No I hear what your saying, that's why I changed mine haha.. But I could have used mine again. Take some pictures of the bad ones and let some of these guys take a look at them. As long as they aren't scared they are still good. Unless the whole thing is polished all around then they are probably worn a bit.
 
Roc City is a pro, but I'd not have anyone, even a pro, take sandpaper of any grit to my heads or jugs surfaces.
He can do it to his own builds, but I would never suggest it to anyone. It's a good way to turn your top end into paperweights.

There's nothing wrong with having them resurfaced flat by a machinest at a machine shop. That's what they do. Make things fit other things correctly.
 
A surface plate is much flatter than any fly cutter will do, the sanding if done right, improved the surface finish, which the gasket needs to seal, decking the head will leave a much coarser finish, even if done well
 
I'll be sure to tell my machinest that I can make flatter and more precise surfaces by hand than his machines that do .0001" tolerance ;)

As I said, Roc, you know what you are doing. Look around you.
 
If you put that head on a surface grinder, then yes, you could get a very very flat and smooth surface, generally though, they'll toss it on a Bridgeport with a big insert cutter and have at it, which isn't all that precise. Also, the ways on the best machines in the world are often hand scraped, you can get exceptional accuracy by hand
 
Leave the liners in place. When they are heated and replaced, they are never perfectly round and they tend to slide up the bore as they cool. If you machine them at that point, they will work back down in use and leak. I usually get my machinist to lightly skim the top of the block after a rebore or run the block across his head finishing machine which is a special surface grinder.

Heads can be flycut by a good engine machinist who understand that the head must not be "bent" when he bolts it down to the table. Wet and dry on a surface plate is prefectly adequate to clean up any matching surface including heads and barrels , but you need to be careful. You can even draw file a head to remove any small high spots if you have a good clean file and have the touch. That is not a good technique if it's warped though. Likewise it is not acceptable to use sandpaper or emery or wet and dry held in your fingers or on a sanding block to do any work except cosmetic on external surfaces.

For mains and big end shells. They are color coded and matched to the crank and rods to get the correct clearances. Use Pastigage to test the clearances in each bearing. It's available from your local auto parts place - Try Supercheap but more likely from the good place that I forget the name of..
 
Roc City Cafe said:
If you put that head on a surface grinder, then yes, you could get a very very flat and smooth surface, generally though, they'll toss it on a Bridgeport with a big insert cutter and have at it, which isn't all that precise. Also, the ways on the best machines in the world are often hand scraped, you can get exceptional accuracy by hand
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We use very fine sandpaper and a surface plate to get carbon seals flat to within 2 angstroms. As with any machine work, the skill of the machinists and condition of his tools is what determines the accuracy of the work.

Even if your machine is good to 0.000001", set up wrong the accuracy means nothing.

A good surface plate and proper technique can yield VERY flat surfaces.
 
Of course you can.
You can royally fk something up too, if you don't know what you are doing.
 
teazer said:
For mains and big end shells. They are color coded and matched to the crank and rods to get the correct clearances. Use Pastigage to test the clearances in each bearing. It's available from your local auto parts place - Try Supercheap but more likely from the good place that I forget the name of..
Click to expand...

Yeah I've watched a few YouTube videos of plastigauging, I think I get it but am not sure what bearings you use to begin with. Do you use good second hand ones and measure and order to close or open the clearance or are you supposed to plastigauge with new bearings?
 
plastigage measures plain bearings, like the cam of big end of the conrod, the bag they come in has a gauge that shows what the clearance is based on how wide the plastigage is squished, the specs on clearance should be in the manual
 
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