1974 TVR 2500M driver restoration

The paint damage is frustrating, but it's going to happen at some point.  During the very first drive in my first restoration, I had driven straight about two miles and come to an intersection with a two-lane road at a light.  There were two cars crossing through it in front of me.  The trailing one decided that the guy in front of him wasn't going fast enough, so passed on the shoulder through the middle of the intersection by flooring it.  He of course kicked up a ton of gravel, chipping the paint in two places. All I could do was shrug.

Wanted to come by and update my page here. I've enjoyed a good amount of time driving my M. For the most part it's been great! Been getting more familiar with the car and getting things more dialed in. Had to adjust the suspension for ride height a few times to strike a balance between comfort and striking the exhaust on the ground too often. I got the carbs mostly dialed in; could use a bit of fine tuning in certain places.

One of the bigger issues I was battling was a misfire the came and went entirely and when it was present was barely noticeable at times and almost undriveable at others. I always felt it was an ignition issue, and it would mostly be at WOT high RPM (+4000). Then it would settle into slight part throttle misfires that made it difficult accelerating from a light or maintaining speed. I never figured out an exact culprit but I am currently running a Pertonix distributor replacement and Pertronix ignition coil. I specifically had to make sure that the + side of the ignition module saw a full 12V while the coil (3 ohm) was ballasted. With that setup it's been running flawlessly for a few hundred miles.

The other issue is oil loss or usage. Even after getting a solid 1,200 break-in miles on it I'm losing about a quart of oil every 150-200 miles. The puzzling things are that my plugs are white with no oil on them at all so I don't believe I'm burning it off.With that in mind I'm trying to address any oil leaks I am seeing, even though it doesn't appear (to me) that any of them appear to be that serious from looking at the residue. There's a lot of oil on the underside of the car, don't get me wrong, but it didn't seem like it would drain the sump in 1,000 miles. 

Things I've done so far:

-replaced timing cover gasket,

-replaced crankshaft seal within the timing cover with a double lip seal and specifically installed the crank snout collar after the timing cover per the TR6 brown book.

-used "The Right Stuff" for all gasket dressing this time rather than orange RTV.

-tightened the oil filter spin on adapter, as I noticed a trickle coming from between the housing and the block.

-replaced the oil pan gasket, again using The Right Stuff.

All of these things stopped the leaks from their respective areas, but I am losing a bunch of oil very quickly. This week I pulled the transmission and was going to replace the rear main seal expecting this to be a major contributor to my oil loss, but actually the bellhousing was bone dry. I replaced the gasket for the rear main housing plate and resealed the bolt threads because I used oranges stuff the first time there as well, but left the seal alone. Still in the process of putting things back together but not sure what I'll try to fix next. I made an effort to re-reseal the transmission which I'll detail in the next post.

Per my exceedingly long post above I have the transmission out so I could get to the rear main seal. The tranny itself was leaking at least to some degree so I am attempting to do a better job sealing it so I can better tell what oil traces I'm seeing  on the underside of the car are engine oil vs MTF.

I had two main objectives here:

-replacing the shifter rod o-rings which I did not do on my first time through

-replacing the gaskets I had put in originally because I had used just general RTV orange gasket maker which has generally proved not up to the task for sealing oil.

Regarding the shift rod o-rings, I elected not to replace anything in this particular assembly when I cleaned up the transmission and replaced all the other seals the first time simply because it seemed pretty complicated. That, and I figured "Hey, it's at the very top of the transmission, how badly could it leak?" However from the "first" drive there's been an oily coating on these shafts and below, so I had to address them this time through.

I'm not going to cover the whole procedure here. The "Buckeye manual" does a pretty good job here, as does this video. Jump to 39:40- https://www.youtube.com/watch?v=30F4P0Vtfow  

What I found on some TR6 forums is that instead of the standard o-rings, others were using x-rings in their place. Specifically McMaster-Carr 90025K226: https://www.mcmaster.com/90025K226/. If anyone else wants to go this route I had to order a pack of 100, so just let me know and I can drop some in an envelope for you.

I found a few other things to address along the way. The o-rings are held in place by a plate that sandwiches them between it and the transmission cover. My plate was a bit dinged up and warped, probably not keeping things sealing tight.

Since these are NLA some quick time in the bench vice seemed to get things straightened up pretty well.

The rods themselves had at a minimum some discoloration on them, so I touched them up with some 1500 grit paper to knock down any high spots that have come up.

Down to the nitty gritty. New X-rings in place.

Reassembly is not overly complicated, at least in theory. The shift rods have indentation in them which catch a ball to give a positive location for N/1st/2nd/3rd/4th and R. A spring keeps tension on the balls. One has to compress the spring and send the ball down into the hole which houses it in order to slide the particular shaft past the ball. For the life of me I could not get the ball down far enough, so we went the route described in the Buckeye manual. 

The plugs drilled out, and tapped for hardware.

Set screws acquired but even the shortest examples the hardware store had were too long. If I wanted to take more time I likely could've ordered the proper pieces from McMaster as well, but I have a bench grinder so... The proper screw height ended up being about 1/4",

Two screws in the homes.

Shifter action felt proper, so I think we're all good to assemble the rest of the gearbox. I decided to forego the thin paper gaskets one can find for the transmission body sections, which I have to believe are about useless anyway. Instead I used Chrysler transmission/differential silicone sealer. This is applied with no gasket and then assembled to cure.

One other thing I came across on the TR6 forums in folks drilling out the vent holes in the trans case to lessen the likelihood of them getting clogged. I decided I could do better than that. I drilled out a 1/4 hole in the trans extension (prior to assembling extension & trans), fit some air line through it and shmutzed it up with some sealer, then secured the line to a pair of bolts for the extension and voilà, a breather tube.

On a more fun note, I pulled the trigger on a set of these yesterday. I went with 15x7 with 0 offset. Website says I should have them in about 3 weeks (built to order), so I'm not sure I'll bother ordering new rubber for them before I put the car in winter hibernation mode. But I'll have something to look forward to while it's sleeping.

Apparently in my first post above I said I installed a Pertronix alternator. That was incorrect, should have been distributor. 

I got about 100 miles on the car today after putting the transmission in yesterday and came across a cool derelict garage. Couldn't help myself from snapping some pics! 

Awesome wheels!

You'll love VTO's, but I have to admit that I think the stock TVR wheels are pretty awesome as is.

On your oil loss, take a pic of your ventilation plumbing from above the engine on the driver's side. I bet I know what your issue is and a possible fix. 
 

Edit, I did the same sealing job on my transmission. Documented it here.

http://coventrysfinest.blogspot.com/2017/07/resolving-leaks-in-tr6-od-transmission.html

oppositelocksmith said:

You'll love VTO's, but I have to admit that I think the stock TVR wheels are pretty awesome as is.

On your oil loss, take a pic of your ventilation plumbing from above the engine on the driver's side. I bet I know what your issue is and a possible fix. 
 

Edit, I did the same sealing job on my transmission. Documented it here.

 

http://coventrysfinest.blogspot.com/2017/07/resolving-leaks-in-tr6-od-transmission.html

I agree, I do like the T-slots as well. But the tire selection for 14" wheels isn't getting better, and some of the degreaser the body shop used when prepping for paint damaged finish on them and I really don't feel like going through that process a second time. All of those black tees where hand painted by yours truly! Ultimately I think there's no wrong answer here.

For crankcase ventilation I just have the valve cover vent connected to the Stromberg "evacuation ports." Can grab a picture tomorrow. The oil filter cap on the aftermarket valve cover is also vented. 

Here's how I have the valve cover plumbed. I think I know where you're going, and I did try running with the valve cover port open to the atmosphere. Only tried for about 50 miles but it didn't seem to make a difference. Maybe now that I have some leaks addressed going back to that will put me over the top 

Well shoot. That should work well. TR6's have bad blow by problems. This can get especially bad if the rings spin and line up a certain way. Venting the crankcase to atmosphere makes this much worse. They need definite vacuum pull to evacuate the crankcase. 
 

With 1200 miles, the rings should be bedded in well (not contributing much to blow by).

You don't have a top end oil line on it do you?

Interesting, I did not realize venting to atmosphere could have adverse effects on blow by. As I mentioned I was not running an "open" breather other than for a short time. As you can see this is the valve cover I'm using: https://mossmotors.com/223-340-cp-valve-covers?srsltid=AfmBOordm4h6Fk_UwOtUdOJJVVo2kxCcuwq0Sp2mZUVqNNRzOFVBYObW

It comes with a vented oil cap. It's possible this could be defeating the crank ventilation function of the carbs' evacuation ports? I'm not finding any similar non vented types. I could run it with some tape over it to test the theory at least.

Affirmative, no auxiliary oil feed to the rockers. I did a compression test not too long ago and all cylinders came back very healthy- between 167-170 psi. It did take at least 800 miles for my spark plugs to stop coming out absolutely covered in carbon, so maybe they were just taking longer to get fully seated. I just assumed it was fuel mixture related.

I know I made the comment several times to my wife that every time I take the car out it's running stronger and stronger. I just went with standard cast iron rings, maybe they're just getting fully bedded in now. My only other rebuild experience was with an aluminum block LS1 and it has had no issues with oil since the first start but we're talking different ball games. I definitely was successful in sealing up engine oil leaks as evidenced by the underside being significantly cleaner. Reducing crank case pressures could certainly have helped with that.

Pull the oil fill cap off while it's running and cover the hole off with your hand.  You should feel some pretty good suction.  If it's weak or non-existant, that may be your problem.  I have Richard Goods oil catch can that draws vacuum from the intake, and I had to add a restrictor to reduce crankcase vacuum.  It gave a strong tug at the valve cover oil fill.

In reply to JoeTR6 :

I couldn't feel so much with my bare hand so I might not describe it as a "strong" vacuum, but with a shop towel over the filler hole you can see there is active suction. I tried hooking up my vacuum gauge to one of the carb ports and it wouldn't read at all. I'm thinking that may be down to the small size of the port itself relative to the gauge? On the brake booster fitting in the manifold crossover I got a solid 16 inches of vacuum, which I believe to be in the standard range for a GP2 cam.

There is a fair amount of oil in the vent hoses to the carb ports so I did order a catch can to see if that's where it was all going. Just to for a sanity check I pulled the plugs again. Do these read like those of an engine burning 1/2qt of oil in 130 miles? Other than a few runs along the top of the oil pan I'm no longer leaking oil so I don't know where else it could be going if not into the cylinders. Starting to really pull my hair out on this one.

In reply to ViperT4 :

Yes those are ash deposits from the oil on the plugs. It is doing very complete combustion with said oil too. All 6 show ash on the outer electrode.  The insulator color says #2 might be a little worse as far as total bore seal, but if you give this engine 2"-7" of vacuum in the crank case you will probably fix it.

In reply to TurnerX19 :

Thanks for the notes. I'm unsure which direction you're suggesting I go- reduce vacuum @ the valve cover breather further?

Oy, I'm a bit thick headed. I was thinking the carb ports were in line with the throttle blades, but they are well ahead so of course that will affect the gauge reading. So, assuming I'm getting enough/too much vacuum I could try to reduce that further. I would mention that I am using the original reduces in those hoses which I understand are supposed to do precisely that. But I can continue to experiment.

The other thing I'm thinking is that aluminum valve cover I've been using does not have a baffle before the opening to the breather tube. The Triumph stamped steel cover has a pretty thorough baffle, so I'm thinking I'll put that back on and see how much that affects oil loss.

Seems like you're on track.  Keep at it.

Try the steel, baffled cover, but that will be a band-aid, not the problem. 
 

I'm not burning any measurable oil over 1k miles. Only the most minor weep from one gasket. 

I had similar issues and even a rudimentary baffle in my Triumphtune valve cover had a positive impact. I also had a remote breather/separator with a drain back to the sump, vented to atmosphere. 

oppositelocksmith said:

Try the steel, baffled cover, but that will be a band-aid, not the problem. 
 

I'm not burning any measurable oil over 1k miles. Only the most minor weep from one gasket. 

I take it my problem in your eyes is too much blow by from poor ring seal and not just the performance of the crankcase ventilation set-up? I suppose we'll see, but if the baffled valve cover does make a significant difference, with the strong compression numbers I recorded I'm not sure I would be inclined to investigate further. I may cross the bridge if/when I get there.

Edited for follow ups- Do you have a high compression head, no valve cover baffling and still not experiencing oil loss?

10/1 compression head. Alu valve cover with no baffle on my car. This is a build that I did on the engine first in 2020. I've owned the car since '90.
 

I had a serious blow by problem on my car several years ago. Resulted in pushing oil out every semi weak gasket and oil seal. Getting the vacuum right on my car helped immensely at the time. 
 

I saw your oil cap pic- I do have that hole sealed on my car. I had so much blow by that initially the cap whistled while driving. I fixed the vacuum evacuation and left that sealed. I think if not sealed, you're giving away vacuum.

The early TR's were designed to vent the crankcase to atmosphere. When they went to the 6cyl, and the 1500 4cyl, emissions regs required positive crankcase evacuation through the carbs.