Most liked posts in thread: 1275 Motor Overhaul from Atlanta

Next I popped the head off......no real damage showing here - it actually looks pretty good. The head has already had hardened seats put in so we'll do a simple 3 angle valve job and replace the guides if they're worn.



Now the pistons, I haven't measured it but I'm betting it 40 thou over bored. The cylinders look pretty good so far, but he said he had a lot of blow by and it had started smoking like an old Chevy, leaving a trail behind him - not enough to kill mosquitoes or look like he was rolling coal, but enough that he could see it in his mirror when he drove.



My bet is the rings are shot - they only have 30K on them so I'm a little surprised they would wear out that quickly. The bores look fine so we may be able to do a light hone and just go back with new rings.

Once I get it torn down completely we'll know what's up for sure.

 

Once the head was off I got busy with the rest of the stripdown today.

The front cover came off, revealing a single row timing chain with tensioner. Chain looks OK but we'll replace it as a consumable.



Then the back end - I noticed quite a bit of play in the pivot pin for the clutch arm and when I got the disc out the springs were loose - maybe the rattle? We'll see. He also indicated the clutch wasn't releasing correctly so we'll address the play and replace the disc. Everything inside the clutch housing was clean and dry.



Once I got the engine split from the gearbox I noticed that the center oil pickup tube had no screen on it? Hmmm....that's not right. I haven't found the screen or any parts of it, but there was some brass swarf around the oil pressure plunger. We'll replace those parts too, along with the oil pump, fuel pump and water pump, just for good measure.





I loaded the block up on the bench and marked the rod bearing caps, then pulled them and the mains and removed the crank. Crank looks very good, records indicate it's been turned 10 thou under on both rods and mains and the rotating assembly balanced.

The bores didn't look bad, there was no ridge at the top and I haven't yet determined if it's been bored oversize, but it looks like it might be 40 over right now based on the size of the land between the cylinders.

Edit : turns out it's been bored only 20 over

Once the crank came out I got a surprise......the mains and thrust washers had little wear on them, but the upper bearing in the rods were a real surprise for an engine with approx 30K use. I'll let the pictures do the explaining.



So, I'll mic the crank, pistons and mains and then take the crank, rods and block off to the machine shop Monday morning where we'll give them a more precise measurement and make plans accordingly. In the meantime I'll get parts ordered and hopefully everything will arrive back about the same time.

 

The cam looked good but a few of the lifters were worn, I'll leave it up to Willie B if we go with a new cam or just replace the lifters. This head also has the sintered rocker arms, I'll suggest we go with the 1.13 Cooper S rockers if I can find them and of course a new rocker shaft as those are definitely a consumable.

Here's a pic of the inside of the gearbox, the center oil pickup is the tube in the top of the pic - there should be a screen on it much like the second pic. If it got chewed up by the gears and sent thru the oil system it seems I would be finding bits of it, but maybe not.




The bores looked clean with no ridge at the tops - which is usually a good indication - but the engine was blowing oil smoke and making a bit of crankcase blowby.....so I anticipated worn rings - they didn't look bad but the ring gaps on the few I checked were pretty large, a good indication of worn rings. I'll have the machine shop check for taper and wear in the bores, and if it's in tolerance we'll just give it a light hone and put some new rings in.

We'll mic the crank carefully and see if we can figure out why the upper rod bearings are worn like this - I've never seen them wear only one of the shells like this, but it makes sense that they'll wear the tops more than the bottom shells as that's where all the thrust is taken. Mains and thrusts looked as new.

 

Got a little more done on WillieB's engine project today......I got the transmission cleaned out and all the old gaskets scraped off - I don't know what kind of gasket sealer he used before but it was some TOUGH stuff to scrape off!

I installed the rings on the pistons and but before I did I put the top ring in each respective bore and checked the ring gap. they were all in tolerance so I slid piston one into it's bore.




Then I installed the crank, and used plastigauge to check the clearance Clarance. Everything checked out fine. I also checked the crankshaft end play using my dial indicator.



With that all set I torqued the main caps and the cylinder one rod caps and checked to make sure it all turned smoothly, which it does.

Before I installed the front plate I put the oil gallery plugs in.

Next up I put the lifters and cam in, then filled the oil pump with oil and installed it to hold the cam in the right depth so I could do the front end.

Then it was time to figure out how to install that slick cam belt drive....I looked at it a while before I figured out I had it upside down - once turned around it fit perfectly!



I had to make some small modifications to the front plate - same as you do if you're going to run a dual chain - you have to chamfer the holes for the two bottom screws then you have to use allen head screws instead of bolts. With that done and all the parts cleaned up it was ready to go together.



Lastly I had to clean off the end of the crankshaft, they tend to get a raised edge that keeps the lower pulley from sliding on easily. A little bit of work with a file and some 1200 cleaned it up . I also had to rework the woodruff key so the new pulley would slide on. It was interesting to find that the cam had a 3* offset key in it.

That's where I stopped for tonight, I'll install the cam drive and set the cam timing next....

 

Agreed. This engine had a 3* offset key in the cam gear as it was.

The pistons are about 10 thou proud of the deck height, and I wasn't able to borrow my friends CC'ing kit, so I'm just going to buy one for myself. I want to calculate the compression ratio of this set up so I know where we're at. It won't be a problem if it's higher than the 10.3 I normally prefer, but it affects how far you can go with the timing among other things.

It also won't be a problem with the pistons hitting the head as the head gasket is much thicker than 10 thou.....

Edit: preliminary calculations make it look like this engine is running 11:1 compression - that's too high for a street motor on even top octane gas, it would need race gas at 100 octane or an octane improver to keep from detonating - now we know why it banged up the bearings so badly.

 

We've been discussing what to do about the compression - it's too high at 11:1, but I want to make sure so I have a burrette and plate coming so I can CC the heads, then we can get an accurate calculation.

In the meantime....

Making small progress on the engine build while I wait for the burette and cover plate to come in....

In cleaning up the thermostat housing I noticed that one of the bolts only had about three threads going into the head, rather than find another bolt with a different head I decided to put studs back in - they're stronger anyway.




I also put the new studs in the bottom of the exhaust manifold - one interesting point, those studs are metric! 8X1.25 for those counting.....



I'm also waiting for the gasket to put the trans cover on, one of the pot joints was leaking engine oil into the joint - it's a common problem on these - the easiest way to fix it is just put some JB Weld over the cap on the inside so I cleaned it up good, blew some carb cleaner into the joint and blew it out with air then sanded the surface a little to give it some tooth for the JB to stick to. I also replaced the axle seals and shift shaft seal and installed the new center oil pickup to replace the one that lost its screen. To do that I had to pull that end cover so I could remove the laygear.



That done I went ahead and mounted the engine onto the transmichigan....then I mocked up the exhaust and intake manifolds to make sure my intake would work with that exhaust - only to remember I'll be using my header in the test stand! Oh well....




Next up I'll mount the rear cover, flywheel and clutch and button up the back end as much as I can. Once the last bits come in either I'll be reworking the head to have larger combustion chambers to take the compression ratio down or waiting for a thicker head gasket or what ever the owner wants to do.

I was hoping to have it in the engine stand this coming weekend, but I don't know if we'll make that now.

 

After some discussion, we decided that I would go ahead and resize the combustion chambers to get the compression ratio more in line....our calculations indicate we need to go from the current approx 21.5CC to 24 to get compression down from 11-1 to 10.3-1.



I copied a pic out of Vizard's book to get an idea of the best place to remove metal, and decided if I could get enough off from the exhaust valve area that would work the best (Areas marked C and Din the pic) . In these pics, the green area is inside the fire ring, so at the edges I did not want to remove any metal if I could help it, just enough to blend in the new area (areas marked XXXXX).



I marked a small area off in red and took my burr in my die grinder to it - going really slow and carefully so it would blend at the bottom and not leave any sharp edges that could evolve into hot spots that could cause detonation or trap carbon. You don't want a polished surface, but rather a slightly imperfect one and smooth surfaces cause the fuel droplets to condense and you don't get as good and complete of a burn.


After the first go around I had only gained about 1 cc, so I marked off a larger area and went at it again. After blending and polishing I rechecked it and had my 24 cc. I did the second chamber in one go and measured it and bingo - right on the money!









I had to cut away and take the bride to dinner and do some other honey do's so I only got two cylinders done today, I won't get back to it till tomorrow.

Die grinders use a lot of air - especially my 35 year old and well used one - so it was nice to be able to have the new air compressor which not only could keep up but would shut off for quite a bit even when I was going at it pretty long and hard....not to mention the grindier stayed at full speed unlike with my old compressor where I'd get about 30 sec of full speed then it would begin to slow down.....then I'd have to stop and wait 5 min or so for it to catch back up.

 

Buttoned up a few more things, set the valve clearances and closed up the front of the motor, then I installed the radiator and got the engine loaded into the stand and mostly wired up.



Took quite a bit of fiddling to get the yellow fan blade not to hit, also the water pump pulley hit the cam belt cover, so I had to add a spacer inside the pulley between it and the pump. Then everything finally cleared ok.



Just a few more bits to hook up. Add oil, water and gasoline, then I'll crank up oil pressure and see if it will make some good noises.

I also need to weld the 02 bung into the muffler, then move a few things around and clean up a bit so I can get it to the back door for the exhaust to go out....

I have an exhaust hose but I don't think it's big enough to fit over the chrome end on the muffler - if I can get that sorted I can run with the back door mostly closed when it's really cold out.

 

Yes, I requested it.....same driver who brought me the last engine and picked it up to go to Boston - we're on a first name basis now!

 

So, further info....

I cleaned the head up and pulled the valves out - the guides look fine, valves will only need a slight touch up and they'll be good too so the head will need very little work to get it sorted. I will replace the rocker shaft and if the owner agrees replace the standard sintered rocker arms with Cooper S forged 1.13 rockers.

On closer inspection the cam has damage on three or four lobes too, so we'll be getting another cam and a new set of lifters.

I also found one of the pistons had a chunk of ring land broken out and being held in by the rings, so we'll be getting new piston(s) depending on whether it needs to be bored out or not.



Once the machine shop checks out the crank carefully, then we'll know what we're doing there too - I'll also have them check the rods for straightness - although it seems to me if the rods were bent it would wear on the cap end bearing too opposite the wear on the top bearing. So, not too sure what's going on there yet.

There was damage to the rear cam bearing too, tho not as bad as on some engines I've seen.



Lastly, tomorrow I'll remove the lay shaft and take out that oil pickup tube and see if I can find the remains of the screen that's supposed to be there.

 

One of the mysteries of this engine is what happened to the screen over the end of the oil pick up tube? You can see in these pics the imprint of the screen and where it might have been soldered on. I don't know if the screen got chewed up in the gears and run thru the engine or if maybe the tube didn't have one when it was assembled?




Either way - it's a puzzle.

Of course my assumption is it was there, came off and got chewed into tiny bits and sent thru the works......either way we'll put a new one in.

I've looked thru the sump and can't find any trace of it, and absent a brass magnet or a complete stripdown of the gearbox I don't know if I will. So. My plan is to set the gearbox on it's end and spray some clean clear solvent in the case and see if anything washes out - it not I'll call it good. I already stood it on it's end in a clean pan to drain every smidgen of oil out and found no pieces in the oil....I'm thinking it's either been digested or it's in the oil filter in a billion bits.

 

Heard back from the machine shop, the bores are good, we can simply give it a good hone and keep the same size pistons. We're going to put all new pistons in it as one of the pistons broke and we don't want to take a chance on the others - but we're having a hard time finding some. Everyone is out of stock right now.

The crank is straight and not bent or worn, so we'll just give it a good micro polish and call it good.

The rods are also straight and OK.

So, I'll drop off the new pistons (if we can source some) so they can balance the assembly then it all goes back together. With any luck, it'll be home for Xmas!

 

Consensus is detonation, that's what broke the ring land too.....

 

Pistons came in today, so I ran them over to the machine shop. The head and crank are already done so I brought them home with me.





The block still needs to be honed to size, but we wanted to have the pistons before we did that - and he'll also swap the pistons onto the rods for me - while the old pistons are off he'll double check the rods to make sure they're straight and the big ends are round.

He'll also match the weight of the new pistons to the old ones if they're close enough, otherwise I'll take the rotating assembly over and they'll balance the whole thing together....but they think just matching the pistons up will do it.

The block and pistons should be done by midweek......and I'll go pick it all up and get ready to build it up once the rest of the parts we've ordered come in.

 

What's the old Chinese curse? "May you live in interesting times"?

My machinist friend called me this morning to let me know he'll have the block done today, and that he was going back home cause he's had Covid for the last week and it's kicking his butt! Yet he's still going to work every day because he can't afford not to and the shop can't do without him as they're so backed up with work. I think the only reason our stuff got done so quickly is that it was fairly easy and he slid me in ahead of other work.

So, I'm going over tomorrow to pick it all up....I'll have plenty of hand sanitizer, latex gloves and mask on and just hope for the best. I dunno if I need to spray everything down with Lysol when I get it home or what? I sure can't afford to get it, what with my other health issues and upcoming surgery in early January! My daughter called and said both her oldest boy and she had it and the whole family is quarantined - fortunately they live on a small farm so they have room to get out of each other's hair so they all don't go nuts being cooped up together.

As for the block, he said it cleaned up with very little effort, he had to straighten and resize one of the rods slightly, and everything was close enough in spec that it took very little to balance it again. So, once it's all home I can start the cleanup and measuring.....

New parts should be here both today and tomorrow, then I can get started in earnest. With any luck it will be home in time for Willie B to have it in the car by Xmas!

My health issues are kicking my butt too, and really limiting what time I can spend in the shop - some days I can't even get off the couch! I have yet another Dr. appt Monday, we'll see if he can get me over this crap.....I'm still convinced it's a meds issue.

Edit: My buddy is going to loan me his surface plate and burette so I can CC the head, and calculate the compression ratio...I'm sure it's fine but I want to document everything.

 

So I went over to the plague infested shop today and picked up the block and pistons, I think I got out unscathed, they carried the stuff out and put it in the car for me, and they were wearing masks and latex gloves. I got it all in the shop but the block will need a lot of cleanup before it's ready to build....I wonder if safety solvent kills the 'Rona?





The box with the belt drive came in and it's a really nice bit of kit - he got a great deal on it IMHO. The cover and back plate are a lot heavier than I expected, but the whole setup is nicely made with great little touches like the TCD mark on the cover.

Other projects will have to take precedence over the next few days, but I plan to get started on the build up phase early next week with the goal of shipping it by the end of the month or very early Dec.

 

First up today, I installed the cam bearings using my special came bearing installerator....a piece of all thread with some specially sized bushings and washers....



Then, this afternoon I worked on the cylinder head and rockers.....

First up was to clean it, then set the valves in, install the stem seals, then the new double springs, caps and keepers. I don't know why the gasket sets only come with 4 stem seals as I and every other engine builder I know puts them on all the valves. I keep extras on hand so I'll always have a full set available.



Next I run a tap in every threaded hole to make sure there's no crud in there that will keep the studs from setting properly. Lastly I'll run my flat block over the head surface with some 1200 wet or dry to make sure the head surface has a good "tooth", then I'll give it one last clean up.



I also assembled the rocker arm assembly with a new heavy duty shaft and new forged Cooper S rockers. There's nothing wrong with the sintered rockers on here as they tend to wear the shaft more than the rockers, but I've read that they're not exactly real accurate for geometry or ratio - these Cooper S rockers are an honest 1.13% and well made, so I prefer to use them with the cam we're using.




The shaft wear doesn't photograph well, but there was definitely some wear on it - they're considered a consumable and I always change them.

So that should do it for the cylinder head, valves done, new stem seals, new double springs, new rockers and rocker shaft.

Next up some more work on the block.

 

I finished up the head and today I bolted it on and torqued it down.



I still need to set the valve lash and button up the front end - the gaskets came in late this afternoon, I'll do that tomorrow.

I also need to install the distributor drive and set the initial timing.

If things go well I'll get it loaded into the test stand tomorrow and by Wed with any luck it should be making some good noises!

I'll video the startup, but I know after about the first minute or so it doesn't make for compelling watching as I run the cam in.

 

OK, ready to leave the nest and head back home on Monday.....the owner has been working on his Moke, he'll have to shift back over to his Mini now so it will be running by Xmas, but it should be an easy install for him.

I'm sorry it took so long but between machine shop delays and other projects I had already promised it took about 2 weeks longer than I anticipated. still, given the pandemic and all its associated woes. not bad - 2 months and two weeks door to door.

Pulled it out of the stand...




Strapped it down and then screwed the top back on. Then I loaded the starter, distributor and a few other odds and ends into the crate and put the lids on top.

The truck has already been arranged and should be here tomorrow to load it up. I'll need to get up early and move my green classic, my small trailer and my blue MINI out of the drive so he can wheel it down to the truck.





In the meantime since my shop space is at a premium, I loaded the next engine into the test stand, it's actually supposed to be in good shape, so my plan is to fire it up and if it runs well, doesn't smoke and has good compression I will clean it up and put it in the green car as is. The engine and trans both in the green car need to be rebuilt - the engine is smoking pretty good on upshifts now, leaking oil and the trans grunches going into second when cold, and also has a noisy final drive bearing.

The only thing I might do to the newer engine is check to see what final drive it has - if it's not the 3:1 drive I have a spare I can install. My green car currently has a 3:44 and it makes 4500 rpm at 70 mph, the 3:1 will drop that to 3800 making it more comfortable on highway runs. It may already have a 3:1 tho as that was common on this later model engine.

 

And off it went a couple days ago - I forgot to post the pic, in fact he should have it tomorrow. The same guy came out - he and I are on a first name basis now since he's been to my shop 4 times now!