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Engine rebuild or not

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bluemiata90

bluemiata90

Jedi Trainee
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Should I rebuild the engine or just clean it up and add new externals(waterpump, generator, hoses, etc). I just recently purchased this 61 TR3 and after cleaning the gas tank, changing the oil and cleaning the carbs, the engine started up. Very little smoke when first started and it cleared up almost immediately. Did a compression test, 120 psi across all 4 cylinders. The vehicle has 71000 on the odometer, supposedly original miles. My question is are 71000 miles alot of miles for a triumph TR3?. I never really drove this TR3 around and I already pulled the engine and trans. to clean up the engine bay and engine. A rebuilt engine will obviously be the most reliable way to go, but also much more expensive. If 71000 miles is high for these engines then I guess I'll have to do it. Feedback is needed in this situation. /ubbthreads/images/graemlins/driving.gif /ubbthreads/images/graemlins/confused.gif
 
Scott, this is a tough call. If the compression is good, which it is, and the smoke went away, I'd be tempted to let it go. A cylinder leakdown test would be nice, as it can tell you the condition of the rings and valves much more accurately than a simple compression test.
I would probably take a look at the clutch while everything is out, and replace it if it looks like it hasn't been done recently.
What the heck, they are no big deal to pull and rebuild, and if you get some fun motoring out of it the way it is, let it ride.
A friend of mine is showing 118,000 on his MGA, and the odometer quit a few years ago. It is all still original, and runs like a top.
Given the TR3 engines' roots, I don't think 71,000 would be cause for concern. Perhaps other TR3 owners will give a little better guidance, as I haven't had a 3 for years. My '59 had close to 100,000 on it when I wrecked it, and still ran strong. My TR4A went 125,000 before I pulled the head.
I'm fortunate in that I have fresh engines in storage for all of my stuff, so I don't lose much to down time if I have to yank one for any reason. Then I can rebuild as budget permits.
Jeff
 
Hi Scott -

Drive it like it is. Make sure you're going to keep it a long while, then when it really needs a rebuild, do it. I say this because the sidescreen TR's are a different breed, and not much fun in the rain for us who are spoiled by modern conveniences like power windows, air conditioning and heaters that actually work! A very important, albeit obvious, consideration is how much use the car is going to see.

Mickey
 
Scott, I knew one of the TR3 guys would be along, so there is more current experience than mine speaking.
Mickeys' car makes me green with envy. As does Sammys', Georges', yours,...........................
Jeff
 
Jeff -

There's a pretty nice one right next to the church that's for sale - I see it every day. I'd be glad to test drive it for ya. /ubbthreads/images/graemlins/wink.gif

It's got a little rust, but overall presentable, and I have seen them out driving it a time or two. They were "asking" 12K for it - don't know where they are now.

Mickey
 
Thanks, Mickey, but I've got too many irons in the fire right now as it is. I have to make finishing my GT6 a priority for this off season, or Racing Girl will never let me hear the end of it.
There was a '60 TR3A here for $4500, but I started adding up what it needed to meet my standards, and quit at the $20k mark. I hadn't even gotten to the driveline yet!
Jeff
 
If the oil pressure is good, and the compression test shows the cylinders are in pretty darn good shape, just drive it. In the day, that Standard four cylinder engine was good for about 150,000 miles. Take into consideration the improvements in oil, filter, gasket and fuel additive quality and technology, and I think you'll find that your engine has a lot of miles ahead of it.

I do agree that it's worth looking at the clutch while it's out.

And keep in mind that engine rebuilds aren't 100 percent foolproof. Good machine shops are getting increasingly difficult to find, although TR3 engines are a little simpler with the liner design.

When you get a chance, post a picture of your new baby!

Sam
 
You didn't say anything about the oil pressure reading (preferably, when hot).
If it's good, then you're probably OK.
I'm not sure I recall what "good" oil pressure is on one of these engines (been 30 years since my last TR-3)....but I imagine at least 15 lbs at idle and 40+ at cruise would be OK (some of you others may have a better idea).
For what it's worth, I'm a big fan of changing connecting rod bearings on a regular basis, especially on an engine with unknown history. It's a cheap way to add many miles to a used engine. Obviously, you'd need to "mike" the crankshaft rod journals (and using Plastigage to double-check clearances isn't a bad idea either).
I am also jealous and would love to have another one of these cars....then again, there's about 10 other cars and airplanes I'd like too! /ubbthreads/images/graemlins/thumbsup.gif
 
Drive it as is. The 120 psi is good compression, and if your oil pressure is decent there is no need to worry about doing any major work.
 
[ QUOTE ]
...but I imagine at least 15 lbs at idle and 40+ at cruise would be OK (some of you others may have a better idea). For what it's worth, I'm a big fan of changing connecting rod bearings on a regular basis, especially on an engine with unknown history...

[/ QUOTE ]

I agree those numbers would be okay -- hopefully you'll see something a bit higher. Both con rod and main bearings can be changed with the engine in the car so if not now then later would still be easily possible.

When I got my TR3A I did rings and bearings thinking I would be able to drive it awhile before I had to do a true rebuild... Ronald Reagan had just been elected and Disco was the scene. Someday I may do that rebuild.
 
at 15 at idle, you'd be a little too low...My TR-250 (albeit, a 6-cyl) had just north of 15psi at idle, and it blew smoke like Cheech and Chong before a Grateful Dead concert.

You hope for about 25-30psi at idle.
 
It seems the general thought here is I should just drive it. I'm glad everyone has confidence in TR3/4 engines. I think I will change the rod bearings and add a new waterpump,change to a alternater, etc. and drive it. I already planned on changing to a TR4 trans with a new clutch for the synchro in 1st gear. So thanks for all the input and wish me luck.
thanks
scott
 
Just remembered, as mentioned before the engine is already out of the car and I can't remember the exact oil pressure, but I do believe it was within the good range or I would have been concerned and changing the rod bearings will help anyways, so I think I'll be alright in that area.One more quick question, what would be an exceptable clearance when using plastigage for the rod bearings. I've used plastigage when rebuilding V-8s, but I would assume that the clearances would be different for a TR3. Everybody thanks again for your input.
scott
 
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