• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR2/3/3A TR3 engine building tips needed

59Rob

Senior Member
Country flag
Offline
Hi guys, just cobbling together parts to rebuild the TR3 motor and was looking for any tips and suggestions for the build. I've never done anything major with a Brit motor. I have the 87mm piston/liner kit, new cam and cam bearings. Not sure what all else I'll need until we tear it right down other than a gasket set.

Cheers
 

TR3driver

Great Pumpkin - R.I.P
Offline
Sounds like a good start. I would plan on replacing the timing chain & tensioner as a matter of course; if the old chain is badly worn then replace the sprockets as well. There is a new 'Viton' rear main seal conversion available that seems very worthwhile to me; but even if you don't do the conversion be sure to get (or machine) a proper mandrel for setting the seal in place. The dimensions given in the factory workshop manual appear to be a misprint, the largest diameter should be 2.818 instead of 2.822.

When you install the rear cam bearing, make sure it is turned the right way so the passage to the cylinder head is open. Also be careful to position all 3 inserts so the locating hole is centered and the tip of the special bolt can't grab the edge of the insert.

I hear that some gasket sets don't include enough felt for the rear main cap, so you may need to source additional felt. Soak the felt in your favorite sealant (I use Permatex #3) and tamp it into the hole until you can see the sealant fill the seam.

Valve springs are almost certainly tired. Probably the guides as well. And might as well install the hardened exhaust seats while you have it apart.

Be sure to carefully check the piston ring end gap in the cylinders. They should be fine since it is a set; but mistakes happen and some ring sets are supplied slightly oversize. Also check the liner protrusion on both sides. I've found two TR3 motors in a row now where the liner bores are not perfectly perpendicular to the block surface, resulting in the protrusion being different from side to side. And if it is less than the book value on either side, you're going to have a head gasket leak eventually.

Last gasket set I bought didn't have the fiber washer for the timing cover support, so I cut one from an unused air filter gasket.

Best to reuse the old oil pump, if it isn't too badly worn or broken. If you do replace it, check the new one for the cross pin holding the lobes to the shaft. Some of the aftermarket pumps don't have the pin, and the lobes tend to work loose with disastrous results. Also best to rebuild the original fuel pump, IMO. If you replace it, check that the pivot pin is positively located in the housing (eg clips on each side) rather than just staked in place. The staked version sometimes works loose and can break the camshaft when the lever jams.

Get the lifters refaced. If you do use new ones, be sure they are 100% tested for hardness. Be sure to use plenty of good assembly lube. On initial startup, run the engine at fast idle (1500-2000 rpm) for 15 or 20 minutes. According to Kas Kastner, this helps work harden the faces of the lifters & cam, to let them live longer. Use an oil that has plenty of ZDDP (like Valvoline VR1).

That's all that occurs to me offhand, tho I'm sure there is more.
 

bobhustead

Senior Member
Gold
Country flag
Offline
Have the cam bearings placed by a machine shop. Invest in having the machine shop balance the engine. Makes it last much longer. Be sure to confirm all assembly tolerances, like plastigaging the main and rod bearings, filing the compression rings for end gap. If your pistons are not brand new, be careful that the ring lands are absolutely free of carbon or the rings will never fit. All this is detailed in the manuals. Have the machinist install hard valve seats and modern valves, as promoted in the Moss catalog. Use STP when assembling the rod and main bearings, engine oil on the rings/cylinders. Turn the engine thru a full revolution after each bearing is torqued. This will alert you to tightness problems immediately. I used a new original aluminum rear main seal; couldn't bring myself to drill the two extas holes in the rear main cap that the Viton kit called for.
More, of course, but I can't think of it now.
Bob
 
Last edited:

martx-5

Yoda
Country flag
Offline
Not much to add, but I can confirm what Randall says about the mandrel dimensions being wrong in the workshop manual. I made my own mandrel to the dimension suggested above (2.818") and so far, (knock on wood) no leaks from the rear main. I firmly believe that if set up correctly, the TRactor rear main "seal"...it's really not a seal per se, will keep the oil where it's supposed to be. One of the guys in the club with a TR4 used a mandrel he got from Moss, which was even larger then the workshop manual shows. I warned him about it BEFORE he stuffed the engine in the car, but I guess it fell on deaf ears. He's now suffering the consequences.
 
Similar threads
Thread starter Title Forum Replies Date
J TR2/3/3A TR3 engine cylinder top clearance Triumph 22
Pool Dad 1960 TR3 engine serial number Triumph 14
Joel Lester TR2/3/3A "TR3" painted on the engine block Triumph 13
K For Sale TR3 Engine Lift Bracket...hard to find! Triumph Classifieds 0
HalLucy Standard Vanguard Sportsman engine and the TR3 Other British Cars 7
Got_All_4 TR2/3/3A TR3 engine hand crank Triumph 14
Moosca TR2/3/3A "56 TR3 Engine Verification Triumph 17
D TR2/3/3A TR3 Engine dumping Coolant out its rear end - HELP Triumph 5
W TR2/3/3A Novice TR3 Engine Rebuild Triumph 47
J TR2/3/3A TR3 engine build Triumph 12
doc50 TR2/3/3A How to verify TR3 engine numbers Triumph 20
6 TR2/3/3A Engine in my TR3 Triumph 15
M TR2/3/3A TR3 engine hood wanted Triumph 7
T TR2/3/3A TR3 Engine Noise trouble. New to Triumphs. Granfather's Car. Need Help. Triumph 43
Kleykamp TR2/3/3A TR3 lower engine parts?? Triumph 2
Got_All_4 TR2/3/3A Tr3 engine trany pull Triumph 6
Brinkerhoff TR2/3/3A TR3 free engine parts to forum members Triumph 6
K TR2/3/3A Putting an XKE engine in a TR3? Triumph 10
Kleykamp TR2/3/3A TR4 engine into TR3 crankcase vent tube? Triumph 16
RedTR3 TR2/3/3A Tips for Breaking in a Rebuilt TR3 Engine Triumph 6
charleyf TR2/3/3A tr6 OD tranny on a TR3 engine Triumph 7
DornTRoriginal TR2/3/3A Timing Chain Installation Procedures [TR3 engine TS 36161E] Triumph 5
mt10flyer TR2/3/3A 1959 TR3 engine rebuild problems Triumph 14
PatGalvin TR2/3/3A TR3 Engine Front Sealing Block, Oil Pan Screw Size and Thread Pitch? Triumph 11
T TR2/3/3A having no shame I ask another question about a TR3 engine that is giving me fits Triumph 10
DornTRoriginal TR2/3/3A TR3 Engine Painting Triumph 8
AEW TR2/3/3A TR3 engine front cover repair Triumph 10
D TR2/3/3A tr3 engine Triumph 6
H TR2/3/3A Cant get my Tr3 engine to start. any advice? Triumph 29
V TR2/3/3A TR3 Engine Noise Triumph 33
NutmegCT TR2/3/3A TR3 engine question Triumph 6
MGTF1250Dave TR2/3/3A Questions about Breaking in a refreshed TR3 Engine Triumph 13
MGTF1250Dave TR2/3/3A TR3 Engine Rebuilt & Installed Triumph 7
O TR2/3/3A TR3 Engine Miss Part 2 Triumph 11
O TR2/3/3A TR3 Engine Miss Triumph 5
K TR2/3/3A TR3 Engine block marking? Triumph 4
G TR2/3/3A TR3 Rear engine seal issue Triumph 13
T TR2/3/3A TR3 engine ground Triumph 9
O TR2/3/3A TR3 engine removal Triumph 5
Bremer TR2/3/3A Hypothetical: Big bore TR3/4 engine Triumph 13
MGTF1250Dave TR2/3/3A TR3 Engine Noise Identified Triumph 11
PatGalvin TR2/3/3A Engine Harness and/or Attachment Points for TR3 Triumph 10
MGTF1250Dave TR2/3/3A TR3 Engine Noise Up-date Triumph 11
C TR2/3/3A tr3 engine numbers Triumph 23
MGTF1250Dave TR2/3/3A TR3 Engine Hoisting Fittings Triumph 5
MGTF1250Dave TR2/3/3A TR3 Engine Noise Triumph 26
T TR2/3/3A TR3 floor replacement. Engine in or out? Triumph 3
K TR2/3/3A TR3@70mph engine seemed to "flatten out" or..... Triumph 10
A TR2/3/3A TR3 engine removal Triumph 9
GBRandy TR2/3/3A TR3 Engine Bay Color Triumph 5

Similar threads

Top