• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

TR6 Fixing a TR6 engine

Offline
A few months back I had a brother of a friend call me, he live a few hundreds miles away, and has a TR6, he had paid a local British car garage to rebuild the engine for him, and once the oil got hot, at idle it only had 15 pounds of oil pressure. So long story short he brought the engine to me to go back into and fiquire out why the oil pressure was low.

The first thing I did was purchase a new oil pressure regulator spring and rod and compare them to the ones in the engine, I compared the spring rates on both spring on my Rimac valve spring tester and saw no real differences there, thats was about the only thing I could do externally of the engine that might effect oil pressure so it was time to go inside and take a look. I removed the oil pan, took the oil pump out, took it apart and checked the clearences, it looked good and measure good, no problems there, it was new oil pump. Then I moved on to plastigaging a couple of rod journals and main journals, what I found was .0025"-.003" on the two rod journals I checked and .0035"-.004" on the two main journals I checked. This was enough to tell me that was too much clearence and for sure one of the culprits of the low hot oil idle pressure, I beleive they told me cold crank up oil presure was about 45 psi. The mechanic who built this engine, I don't beleive was very experienced in engine building, and from his notes and own amissions, basicly had the crank, which was standard polished, and never measured anything, not even plastigauged, the bores are still standard as well, even though this has nothing to do with oil presure, I needed to make measurments there as well to determine if the engine needed to be bored oversize, it has .003" piston to cylinder wall clearence and I think that is about the limit of what you can stay with and not over bore, so for now, no plans to overbore the engine.

I don't think the engine builder was neglegent, just a bit unexperiecned, I'd say that probably 90% of backyard rebuilds are done the way he did this one with little to no measuring, and probably 90% of the time it works out for the amatuer buider, but we pros can't take such chances with our customers, so that why we measure and blueprint these engines, to insure this sort of mis-step does not happen.


I would like to ask the group here with Triump 6 cylinders who have rebuilt them, what kind of cold oil pressure do you see, and also what sort of hot idle oil pressure do you see in your cars. Any other clearences you have would be appriceated as well, I paln on building the rods and main to .0015", and I am yet to check the connecting rod big end, and I fully expect to found them out of spec and part of the problem, I will resize them myself. Thanks
 

M_Pied_Lourd

Darth Vader
Country flag
Offline
Hap,

My 6 at cold idle is about 75 -80 and at warm idle about 30-35. Running VR1 20/50.

Cheers,
M. Pied Lourd
 

tomshobby

Yoda
Offline
Hi Hap,

I had mine built to the tolerance you are planning. It was bored and I had cam bearings installed. You might also inspect the cam bearing surfaces for wear. My engine was also balanced and blueprinted. The blueprinting was expensive but I am glad I did it.

My builder recommended 10w-30 but the idle psi was a little under 20 so I decided to run 15w-40 oil and when cold it is around 90+ psi. When thoroughly warm, including the oil in the pan, it is 70 to 75 psi at around 2,000 rpm and higher and 25 psi at idle. That holds from days when the temp is 40 to 95 degrees.

I have about 20,000 miles on the build and don't baby it at all. I also have taken longer trips running 3,500 and above for hours. Also worth noting, my engine temp runs where the needle lays on the first mark from the base on the gauge when the engine is warmed up.

I believe you will find my build specs, oil weight, running temp, and psi numbers a little different than most but it has been working for me.
Tom
 
V

vagt6

Guest
Guest
Offline
Hap, the Dave Vizard book on tuning these engines would tell you everything you need to know in about 15 minutes of reading.

The Triumph 2.0/2.5 lump is about a fully developed as an engine can get, and Vizard had it all figured out about 35 years ago.

Does anyone have a link or a .pdf copy of the Vizard book for Hap???
 

Brosky

Great Pumpkin
Offline
Hap,

My engine was machined and built by a local racing engine shop and everything is documented on my web site in great detail. I have new cam bearings and new bronze thrust washers/King tri metal main and rods, etc., etc., as well as an oil pump that was polished internally for a perfect fit.

My oil pressure cold is at 100psi on a newly calibrated gauge and the oil pressure warm is 45-50 at idle and 65-70 at 2,500rpms and up.

You can check my site as this is a small amount of detail as to what was actually done to the engine.
 

71MKIV

Jedi Warrior
Offline
I'm going to throw two pennies into the pot.

When I was spinning my oil pump prior to first start I was amazed at how much oil was pumping past the shaft.

don't forget to make sure that even if the oil pump is new, that it's bore in the block isn't worn out.

FWIW
 
Similar threads
Thread starter Title Forum Replies Date
Slider748 TR6 Need help on fixing TR6 odometer Triumph 5
steveg TR6 Fixing the intake manifold Triumph 8
steveg TR6 Fixing Twisted Sway Bar Bracket Triumph 2
B MGB 1972 MGB Project Blue First attempt and fixing no spark and other checks MG 67
Got_All_4 TR6 Is this head toast or worth fixing Triumph 3
S TR4/4A Fixing dash support Triumph 11
T 100 4 Seat Base Fixing Hole Centers? Austin Healey 0
BN6_2197 Fixing the Hood of my BN6 Austin Healey 5
M BJ7 back panel fixing method Austin Healey 5
Tinkerman TR2/3/3A Rear wing fixing clamp Stan Part # 602167 Triumph 5
Jeepster Seat belt fixing Austin Healey 4
P BJ8 wing and panel fixing help? Austin Healey 3
Jeepster Front wing flash fixing holes Austin Healey 5
JamesWilson Fixing Fiberglass Flaws?? Restoration & Tools 9
T ideas on fixing - one carb keeps "rusting" Triumph 4
T Tips for locating/fixing foam rings under gas tank Triumph 4
T Ideas on fixing this? Triumph 19
regularman Found one problem while fixing another Spridgets 9
B Fixing crack in rubber bumper MG 1
bcliff Fixing a bad spot in the paint MG 3
germanmichel Fixing outer tube in steering box Austin Healey 11
G I my engine fixing to blow........................ Triumph 9
glemon "Fixing" Zenith Stromberg Emission Control Carbs MG 4
beaulieu fixing a cut in half Temperature capillary gauge Restoration & Tools 13
roscoe I'm fixing my overdrive with a saws-all Austin Healey 10
jhorton3 Fixing Things Spridgets 27
drooartz Leaking hubs, parts for fixing Spridgets 11
T Fixing Rust Triumph 16
bluemiata90 Fixing turn signals at head Triumph 3
69MGC Any tips for fixing a bent boot lid MG 7
cjm lightened flywheel,best fixing? Triumph 3
sparkydave Fixing Zenith-Stromberg needle adjuster Spridgets 5
S Fixing Dime sized chip Triumph 3
M Wedge tr7 turn signal switch fixing? Triumph 1
B Will fixing Healey Shake negatively affect Resale? Austin Healey 6
BierRunner TR6 TR6 Gas Pedal Triumph 2
nichola TR6 Another TR6 back on the road Triumph 1
TR6Canuck TR6 Wire spoke rims to fit Michelin Red Line Tires on TR6 Triumph 12
E TR6 74 TR6 - ā€œ A Post Sealā€ Triumph 0
J Wanted TR6 seat vinyl Triumph Classifieds 1
E TR6 Temp Gauge - 74 TR6 Triumph 11
K TR6 tr6 not starting Triumph 8
E TR6 74 TR6 Renegade Dash Wire Triumph 7
BwanaJoe TR6 TR6 radiators Triumph 4
E TR6 ā€˜74 TR6 Starter & Trans Cover Triumph 13
M TR6 Fuse box wiring mystery Triumph 9
M TR6 Windshield Trim TR6 Triumph 14
J TR6 72 TR6 starter problem Triumph 10
nichola TR6 Procar Pro-90 Seats in the TR6 Triumph 0
E TR6 TR6 top dash trim paint Triumph 2

Similar threads

Top