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1928 Series 128/129 Fast Four engine rebuild


RichBad

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Finally got my engine parts back from the machine shop - after a year!  Getting everything cleaned up and ready for re-assembly and wanted to check a few things.  Bob, I know you told me some of the correct clearances - I should have written them down:)

 

Mains are 0.0022”

Big ends are 0.0018”

Cap-shim interference - 0.004”

crank end float 0.005”

Piston clearance 0.0025”

Ring gap - 0.008”

 

Main bearing torque - 60lbs? (This is what they used when the shop linebored the bearings and they stamped on the case by no.1 bearing).

 

Big end torque??

 

The main bearing oil grooves look pretty good but the big ends grooves look a little dodgy.  I think that should be ok as they have the correct ‘x’ pattern.  Bob, you mentioned that they should have a chamfer running into the split line on both sides?  Mine doesn’t have this, is it something I should add?  Any photos?

 

Big Ends

DA715A27-D5D1-4AF6-A4AE-97236C0B289B.thumb.jpeg.6fb294ac80a5bf3044cc6dd985fc3164.jpeg

D7A3C2A7-215F-465C-A9FC-37B6F5D1FFD7.thumb.jpeg.228c93e9f6136082e8206978e6603e89.jpeg

 

Rear main

77B5E6A8-CA62-4E2A-9059-629A5A159B90.thumb.jpeg.c4c5607bf4458574e3d74d0d7a59b799.jpeg

 

Centre main

207F23C5-FB80-4183-BD61-6D35C56E244E.thumb.jpeg.ee73b93ed6b71d2ff5a1beff9ff80a9d.jpeg

 

AEEAD70E-F7FF-47B2-9ED2-B1B160BF1735.thumb.jpeg.9ed10a546a36a6d93d295376d36f2223.jpeg

 

 

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Every thing looks good  , groves are good and yes there should be a chamfer on both sides of the metaled bearing begining and endind  1/8 inch from the the outer edges on all bearings , see if i can find a pic . The main caps to what they had and big ends about 40 to 45 foot pounds .

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Perfect, thanks Bob - time for the dremel:)

 

Next Q :)  I’m putting the oil gallery plugs back in the block before painting and the rear one has a step.  I’m guessing it’s just to locate the oil tube in place but it had quite a long threaded section so I thought maybe it is supposed to be a flow adjuster for the rear bearing in which case I probably don’t want to screw it all the way in?  

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8B3648B7-DE07-4EA5-B1D2-FFB57862C8EF.thumb.jpeg.562060df043981e8e731053602b1e73b.jpeg

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Thanks Bob - I’m pretty sure it’s to retain the tube and stop it rotating when you put the plugs in each end otherwise there doesn’t appear to be anything stopping tube rotation which would probably shorten the engine life (as it would cut all the feed to the bearings).  Just odd that it’s so long - perhaps to cover the tolerances you get in the block?

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Next question - do the head studs need to be sealed into the block?  I see that they go through to the water jacket and the old ones that were removed had Teflon thread sealer on them.  I guess a stud lock is probably a good idea and that would probably seal the threads?

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Block up on the stand and cleaned again.  It’s been decreased, power washed, hot tanked, wire brushed, decreased again, power washed again and still getting dirt out of the oil galleries!  Bob, your notes came in handy as I made up a ‘U’ shaped tube for my airline which helps get in to the cavities.  Also got a great bottle brush kit from Moroso which has some long ones which do the full length of the oil tube.

 

first step, engine bolted to rear mount and oil gallery blanking plugs fitted.

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Crankshaft in, felt a little tight to start with but as I gradually increased the torque on the bolts it became very smooth to turn.  Torqued to 60lb (some a tiny bit more to get the split pin holes lined up).  Don’t forget to fit the oil slinger upper trough to the block before fitting the crank:)B9FE0A0E-BA54-45B6-A225-6D9564E98D7A.thumb.jpeg.9f6608320e0b58e8bd8910af9ec9a55b.jpeg

 

Camshaft and oil pump fitted (camshaft needs to go in first).

B65EB64C-5088-40C8-A372-C0505E036F40.thumb.jpeg.8f8668d43e88ba153814c44c8be663fd.jpeg

 

Cam followers and valves fitted.

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Fitted manifold and water pump studs (used thread lock to seal as they all go into the water jacket).  Tappet covers fitted to keep the dust out - still need to set the gaps.E3D0E5A2-F5D8-4195-BF15-05B7C0AAF7DE.thumb.jpeg.e2adfddaf083df58cd73c500a7a7a1f2.jpeg

 

Pistons fitted and caps torqued to 45lbs, still feels nice and smooth to turn by hand.

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1 hour ago, Spinneyhill said:

Looking beautiful. Sounds like a good build going on.

 

How was the engine painted in the factory? Assembled or as parts? If assembled, which seems more likely coz there is a lot less masking, the valve covers would be engine colour?

Probably all as one but I’m not too worried about that - as soon as you remove anything for repair it breaks that anyway and can result in paint chipping/peeing at joints.  I did the covers black as I prefer the look, it’s powder coat so probably a little more harder wearing (as they’ll be on and off for adjustments) and also won’t show fingerprints soo much:)

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Anyone know where this cork gasket goes?  My gasket set had this and a felt strip.  The felt strip looks like it fits on the rear bearing cap to seal against the sump but not sure about the cork.  It looks like there should be something that goes on the rear cover to seal the cover to the sump but I would have thought that would be felt not cork?image.thumb.jpg.d21dd044cbfeaa7212c0f2335a1edbb6.jpg

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OHH SHT, I think I’m done - was just about finished on the engine rebuild, torquing the head bolts and it was all looking good...

 

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Was going up in gradual steps and was at 35lbs, heard a slightly strange crack when tightening one nut but it tightened ok so I thought it must have just been something settling, finished torquing all the bolts and then while looking around the engine saw this

AB4CD51C-839F-4885-AE72-0C198ADB1E84.thumb.jpeg.a01e652ed91cd02e24518434b56dd128.jpeg

 

its two cracks between cylinders 1&2 on the starter side.  I’m guessing I’m stuffed and its start again from scratch with a new block (if I can find one). I can’t believe it, having spent so much $ on the block work (resleeving, bearings, guides etc) and a year waiting it’s all gone:(

im going to bed to cry!

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What would cause something like that?  I wonder if there was already a small crack around a stud that let loose when you torqued it?  If there was something between the head and the block, I would think the head would have gone first.  Man, I really feel for you, that motor was looking great.

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Oh Boy, I feel the pain. That dreadful sinking feeling.

 

The vertical crack is open at the top, meaning the metal is stretched laterally. The sub-horizontal crack below indicates stretching vertically. It is like the metal has pulled upwards as a bulge, perhaps due to an opening above, such as a depression in the block deck or head surface, or a too-compressible gasket?

 

You were at 35 lb.ft; what size and thread are the studs? If they are 7/16-14, 32 lb.ft is max for Grade 2 bolts; for 7/16-20 threads, 36 lb.ft is max recommended for Grade 2 bolts.

 

I see you have you have removed and replaced the studs (post #15). Is it possible the stud turned rather than the nut and you have bottomed the stud in the hole, pushing up the block metal?

 

Edited by Spinneyhill (see edit history)
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Has me baffled.  Head and block were both skimmed.  Studs were new and tightened first with stud lock so I don’t think they would have turned, I’m pretty sure all the stud holes are open into the water jacket. The studs are 7/16 unf and I was tightening progressively (with some wait time inbetween to let the gasket settle).  Maybe it was a bad gasket, I’ll pull that and have a look.  There could have been a crack initiated, the engine builder removed the old studs and said they were seriously hard to remove - perhaps that stressed it? But they did crack test and pressure test the block (but not sure if they did that before or after remiving the studs).

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7/16 UNF = 7/16-14? If so, you would have exceeded the suggest torque for that thread in Grade 2 bolts. You can put Grade 8 bolts in, but you are still in old cast iron so should stick to the Grade 2 recommendations.

 

Another possibility is that the cooling jacket is thinner than it originally was. I see there are holes beside most of the head studs. This would leave less metal to resist the torque. Remember, they only did them up "tight enough", by hand with no measurement, in 1928.

Edited by Spinneyhill (see edit history)
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Spinney, just checked - 7/16 x 20 tpi.  I was told 45lbs for these, my plan was to go to 35 then leave until i was ready for the first start.

 

Matt, you may be right, it’s quite thin there and easy to overheat.

 

i just pulled the head off and it is quite thin in that area which probably didn’t help.  The stud holes are all open ended but I did notice the stud was slightly lower than the others (only 0.020 - 0.040) but perhaps the stud wound in more and the non threaded section of the stud ‘forced’ the hole open?

 

I also noticed that one on the front had cracked too, again it’s pretty thin there too.

 

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Black day today, my wife found my bill from the engine shop for my ‘paperweight’ and I’d promised my son it would be ready for his end of school year:(. Oh well, how does that monty python song go...

 

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2 minutes ago, Tinindian said:

Is this a case where it would be possible to stitch the block?

I don’t know what’s possible, I’m guessing not in that area but I don’t have any experience with what can be done with block repairs.

 

would be good if it could!

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Geez, what a tough story, I'm planning to button up the head on my '31 Straight 8 Chrysler and was told everything from 65 ft lbs down to 50 ft lbs, and now thinking I may go to Gorilla Glue!! No fun when this happens. I'd rather blow a head gasket than ruin a block or head. My studs are also 7/16" x 20TPI, 27 nuts on a 30" long head. Some of the studs are drilled into solid part of block, some pass into water jacket area. Those are the ones I would think are most likely to crack if any. I guess "fingers crossed" you start with a careful consistent tightening sequence and head toward 40 ft/lbs and go from there. At 40 ft/lbs, what is worst that can happen when engine is running at moderate speeds. When I took the head off 6-7 weeks ago, the head nuts seemed to come off pretty easily, perhaps 40 lbs torque, and looked to have been original , engine had 60,000 miles, and no sign head had ever been removed. Was initially concerned if the 7/16"x20 acorn head nuts would be suitable for 50lbs+ torque, and now it appears that is the least of my concerns.

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Yea, cracking was the last thing on my mind - I was more worried that I was going to pull the threads, apparently that can happen quite often on these.  I would have thought that the threads would give before something cracks but not the case for me:(. My engine was up and running 18 months ago and the only thing different since then is all the engine machining - I can’t help but think perhaps a crack was started when the old studs were removed. I didn’t pull them out as I was scared I may damage something (they were in very tight) the engine shop said they would machine them out to avoid any damage.  when I picked up the engine, the studs were in a bag with the other engine parts and hadn’t been machined (but did have some pretty large marks from some monkey grips or mole wrench).

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Took the block back to the machine shop today as I felt the way they removed the old seized studs may have contributed to the cracking (they clearly used a lot of forces as the studs were bent and had large wrench marks in them).  First thing they said was that they had seen some cracking around some of the studs before they started but they didn’t think it would be a problem because they were already there.  So why do the crack test and charge me $100 for it if they aren’t going to use it!  Interestingly, when they did do the original crack test they did say that there was a crack in the tappet area so they did a pressure test.  But that was before they removed the studs.  Anyway, they thought that they may be able to repair with threaded plugs, I’m less confident.  Will find out tomorrow.

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That’s a bit of a worry Richard I would think with the cracks going to the outer edges that would not work in my opinion. I don’t know if you could ever be  confident running around with that engine. 

For your sake I hope they can repair it successfully.  

 

 

 

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