Rebuild U20 with SU

[sevenmilebridge]

I am rebuilding a U20 and some suggestions please. What parts should be replaced engine has 66k. Would a new oil pump be needed or harmonic balancer? I am planning on replacing timing chains new tensioners what about rod and engine bearings? I am also rebuilding the head with new valves and springs and new head bolts. Is there anything I am missing some important issues ect. All suggestions are welcome

[spl310]

Many will tell you that you need to replace everything. Others can be more pragmatic. My question is why are you rebuilding an engine with that low mileage? Seems like a lot of expense for no gain.

[theunz]

Now that’s a way to stir the pot! You’re likely to get a wide variety of opinions on this one. Some will advocate for only replacing what is worn out, while others feel that everything that shows even minimal wear should be replaced. How fat is your wallet I would at a minimum…. Assuming all parts are within wear tolerances

Replace rod and main bearings
Hone cylinders and get new rings
Grind or lap valves
New valve seals
New valve guides
New timing gears
New timing chains
New front and rear crank seals
Of course all new gaskets

I recommend all of the above plus
Polish crank if it doesn’t need turning
Resize rod big end
New pilot bearing
New pistons (will probably need an over bore at 66,000)
New timing tensioners
New Jackshaft bearings
New freeze plugs
New clutch (pressure plate, disc, and throw out bearing)
New water pump and starter if still on originals
Probably neglected something here…it’s early

There is even more to be done for a 1st class rebuild, but the above is, I feel usually adequate.

[unklpat]

I agree with mike, but would defer to a machine shop on the head work, and need to bore. Basically, take everything in, and let them tell you what to replace. You can expect up to $1500 in machine work if everything is done, including surfacing the head and decking the block. My cam bearings were fine, but are a minor expense. Pat

[unklpat]

Also, find the busiest machine shop you can find, and get recommendations. There is a reason they are busy. Pat

[spl310]

I would add - DO NOT LET THEM CUT THE HEAD UNLESS IT IS ABSOLUTELY NECESSARY!!!! Many machine shops want to skim the head just because they have it. This isn't like a chevy small block head - they aren't making them anymore. Keep it as thick as possible.

[sevenmilebridge]

Wow thanks for the reply. The money doesn"t seem to be an issue just want a perfect motor.

[Solex68]

I would add - DO NOT LET THEM CUT THE HEAD UNLESS IT IS ABSOLUTELY NECESSARY!!!! Many machine shops want to skim the head just because they have it. This isn't like a chevy small block head - they aren't making them anymore. Keep it as thick as possible.

I agree with this !

[Pschram68]

MIKE / PAT: Really do appreciate the feedback here. Sold my 1970 1600 about 25 years ago and regretting ever since. Working with Rick (he asked original question) to get this engine perfect. MIKE M. - ?…what else would you recommend? Going to replace water pump, oil pump, alternator, and starter since engine will be out of car. Your list is pretty extensive. Guidance is 100000% appreciated. Rick is solid on engine work. Obviously….have machine shop do the dirty work. 1969 Datsun 2000. Many thanks! - PETE. (Thanks, Rick!)

[theunz]

Well, if your going all out then I would use all new valves and valve springs along with new keepers. New or reground rocker arms, and would consider a new cam based on condition with possibly an upgrade to a B cam or equivalent. If the engine is to be bored and run hard you might want to go to forged pistons ( Datsun restoration parts LLC) (just took one apart with stock cast pistons with a broken skirt). Now would be a good time to replace the motor mounts. Either upgrade to an electronic distributor (East cost roadsters) or be sure stock has been converted to pre smog cam and springs and has good bushings. Check the quick links tab for access to vendors. Carbs and exhaust have not been mentioned, but carbs in particular can cause headaches if throttle shaft bushings leak which is a common problem. A ceramic coated header, while you won’t necessarily see any noticeable improvement would be a good idea for longevity.
Now, if you want High Performance and have $$$$$ + more $$$$$….check with Rebello, Jim Tyler, or Lou Mondello if you can add even more $$$$$

[Gregs672000]

As an FYI, my oil pump has seen over 300K miles and still works fine. If money is not a concern then go ahead and replace everything. Alternatively, as Pat said let the machine shop inspect the engine and determine what's what. The cam and rockers (especially the two piece) can be reground no problem for little cash. Timing gears can be inspected and reused depending on wear. I'm glad Mike mentioned the need to address other items like throttle shafts and ignition timing (EI dizzy or equivalent) as that will make the whole engine much better and make a good engine terrible if worn out. Anybody mention a lighter flywheel? These are pretty basic engines to a machine shop compared to what they have to deal with today. We are fortunate in that we have several vendors who have spent a lot of time and money investing in upgraded parts or providing good NOS ones. They also offer other parts that have nothing to do with the engine per se but make the whole Roadster experience better. Spend some time searching the site and don't be afraid to ask questions!
Good luck in your build!

[redroadster]

This car going to be a daily driver of sorts ?
it sounded like it was ....Id refrain from it for safety reasons

[spyder]

Looky here........Nissan 1970 Datsun Fairlady 2000 Cylinder Head, Gasket, Timing, Valve, Parts

https://www.ebay.com/itm/334260718823?h ... SwZe5hvlJg

[Pschram68]

Mike M//Pat // Greg: really do appreciate the guidance. Let me get back to my parts spreadsheet for Rick! Thanks again. - PETE

1969 Datsun 2000
1949 Rolls Royce Silver Wraith
1954 Ford F100…3” Chop // 454 CID bored .060 Over.

[jhayden]

Looky here........Nissan 1970 Datsun Fairlady 2000 Cylinder Head, Gasket, Timing, Valve, Parts

https://www.ebay.com/itm/334260718823?h ... SwZe5hvlJg

Really nice find there, Spyder. An apparently NOS head (though smogged) with line-bored towers intact, plus ancillaries. If there is a future for U20s, likely a safer investment than any crypto.

Jon