Jump to content

Recommended Posts

Team, 

This is my first posting although I've used the forum many times in the past for technical searches so appreciate all the information provided.  I'm based in Aberdeen and have a 1972 TVR 2500M (UDB 744K) which I've had since 1989.  As you will be aware, the car is based on a TR6.  It's a long story but based on work and family commitments, its been garaged for more than 20 years with a seized engine.  I've now retired and started a restoration.  I'm not a mechanic but have a electromechanical background so I'm OK at using the forums and TR manuals.

I've rebuilt the engine (number MM24HE), serviced the carbs (twin strombergs), starter motor, fuel pump, alternator etc. and replaced the battery, HT leads, coil, plugs and points.  I'm 99% sure everything is back together correctly and static timing is set. I've gone over this a couple of times and can see the rotor arm in the correct position at TDC. I've checked and rechecked the HT wiring order.  The LT wiring in the car is a mess as it looks like one of the previous owners has bodged with a lot of splices so I'm slowly fixing this.  A new loom wasn't really an option as the early TVR's were all a little different so I prefer to build this myself.  I've done enough gf the wiring to get the ignition working but  the issue I have is that I can't get the car started after the rebuild.  It was a good runner before it was garaged (although tricky to start after a few days idle) but it had a stuck piston after local garage left outside with the head off so needed rebuilt.  Rebuild went well, new piston rings installed, relapped valves and everything in spec. The car turns over well and getting decent spark at the plugs. It has a ballast resistor but getting about 10v at the coil when cranking.  Oil pressure seems reasonable after a few cranks (I circulated the oil with an air-drill and an attachment to the distributor) .  Fuel tank is currently disconnected but I have a small fuel reservoir attached and petrol is getting to the carbs.  Exhaust, manifold and air filter currently disconnected.  Compression seems OK (between 150 and 180 psi on each piston). I've even tried a squirt of easy start but doesn't even attempt to catch.  Cooling system is also a mess so not connected at present. Using unleaded petrol which I know will be an issue with current valves but my understanding is that it will be ok for a quick run until I get the tank back and put in some lead additive. 

My gut feeling is that it may be related to the carb overhaul although this went fairly well and I see no immediate issues with the rebuild.  But the spark is good so if it's not timing, I'm not really sure what to try next. I'm pretty sure having the air filter,  exhaust and cooling system disconnected is not the problem but hopefully one of you good people can advise me if I'm correct.  I realise this is a bit of an ask and probably need to just re-check all the obvious things mentioned in the forum but any tips would be greatly appreciated (especially regarding the carbs because all the settings will likely be off after the rebuild).  Nightmare scenario is that the engine hasn't been degreed properly but I'm 99% sure its good as I spent a long time checking and re-checking. Thanks in advance too anyone who can help.  

Link to post
Share on other sites

Love the 2500M but couldn't afford one back in the 80's, so bought a 5. Funny old world.

You've probably checked all these, but first thoughts:

Petrol - needs to be fresh

Ignition leads - some of the BL workshop manuals listed the firing order incorrectly, it should be 1 5 3 6 2 4 anti-clock.

Exhaust flange gasket - if it has the standard TR manifold with twin pipes the gasket will fit 90deg out thus blocking off the exhaust.

Cam timing / distributor 180 deg out - check the valves are roughly doing what you expect and the rotor arm pointing to the right place when at TDC.

Plugs - are they getting wet - are the carbs actually flowing ?

Jerry

 

Link to post
Share on other sites

David, if you remove the dizzy cap and set cyl 1 on ign point alis the rotor in line with the position of the terminal in the cap? Also note the rotor advances, this is why the copper bit on the rotor is extended.

Waldi

Link to post
Share on other sites

Jerry, Waldi

Thanks for the quick replies.

I got excited for a while about the manifold idea but unfortunately, I think mine was on correctly.  I took it apart but pretty sure it was correct based on some on-line photos. Also tried the new fuel after flushing the system. The engine still doesn't even offer to start. 

Hopefully you can check my photo's re-timing. The 1 and 2 valves are rocking at TDC with rotor arm in position 1 so I'm pretty sure this means the cam-shaft is not 180 deg out. 

My thoughts from the start are that it is carb related and I actually don't think they ARE flowing.  They underwent a full refurb with new gaskets etc. However, I don't think the plugs are getting wet and no obvious smell of fuel (although I think my sense of smell is pretty much ruined after petrol fumes all day). I checked basic operation when I took them off the car today.  I figured they would be way out of setting because they were fully dismantled but I thought it would be possible to tune properly with engine running.  If only.  

With the carb manifold off, I checked the suction on the inlet ports.  There was plenty.  However, I expected to feel some suction on the carb inlet (air filter is disconnected) but couldn't really feel any.  Is this normal?  The carbs have a hose outlet which is connected to the rocker cover and the manifold has a hose connection to the servo (presumably creating a vacuum for the brake assist). The exhaust manifold is currently off.  I've seen some posts on issues with vacuum and tbh, I don't have a perfect seal as the gasket isn't yet fitted but I think there should be sufficient to get the car started. 

Any further ideas welcomed. 

BTW, a TVR was pretty much all I could afford back in 89. Cost me £4.5k from David Gerald in Worcester and was my daily driver for a few years before my kids arrived.  For a couple of £k more at the time, I could have had an E-type but couldn't afford the insurance. Funny old world right enough!  I think the TVR's are creeping up a bit in value now though, or so I keep telling my wife when another package arrives from Rimmer Brothers :)

IMG_0360.jpeg

IMG_0361.jpeg

IMG_0362.jpeg

IMG_0363.jpeg

IMG_0364.jpeg

IMG_0365.jpeg

IMG_0366.jpeg

IMG_0367.jpeg

IMG_0368.jpeg

Link to post
Share on other sites

Dave,

Is your rotor really in Cyl. Number 1 Firing position? If so, your rotor looks 180 degrees out to me. Am on a phone, on which I struggle with the views.
Waldi

Link to post
Share on other sites

"Hopefully you can check my photo's re-timing. The 1 and 2 valves are rocking at TDC with rotor arm in position 1 so I'm pretty sure this means the cam-shaft is not 180 deg out. "

That says it all, if 1 & 2 valves are rocking, then it is not on the firing stroke, so rotor arm should point at 6 not 1.

Bob. 

Link to post
Share on other sites

That’s the one I have. It is stamped DD, so I assumed it is from the Dizzy Doctor. Saved me additional shipping costs.
Waldi

Link to post
Share on other sites
On 7/22/2020 at 8:51 PM, John L said:

David

What model of distributor is fitted, the rotor arm doesn't look right for a 22D.  If it is a 22D it should have much more of beaked brass contact like this. https://www.moss-europe.co.uk/rotor-arm-25d6-high-quality-gra102hq.html?assoc=126157

John

Looks like a 45D distributor which was fitted to later 2000-2500 saloon cars without the mechanical tacho drive.

My understanding of the info so far says the distributor drive gear has been refitted 180 degrees out after engine rebuild. (We played this game yesterday on a TR2 engine fitting the distributor drive gear)  Simple solution (if a bit untidy) is to reposition all the ignition leads coming out the distributor cap 180 degrees further round.

So swap 1 with 6.  5 with 2.  3 with 4.

REM Ignition timing is 153624 and the rotor arm goes round anti clockwise when viewed from above with the cap removed.

Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

Thanks Peter, does that mean that all 22d6 distributors have the tacho drive, just for future reference, always willing to learn.

Do I also notice that #1 inlet has the exhaust valve top rotating caps?

John

Link to post
Share on other sites

Hi Dave,

 

It might be nothing but those look like emission control carbs due to the red label on the side of the top of the left carb and flat plug in the float chamber not an issue if done right, also the tops don't look to be in the right configuration (see photo) just thought.

Regards Mark.

20200614_123912.jpg

Link to post
Share on other sites

Carb tops are probably correct. I recently re-built a pair of CD150's, & the tops would only go on one way as I recall.

Stomburg.jpg.5cc8b05cf461e6f8c0b13050aed381ca.jpg

Bob.

Link to post
Share on other sites

Hi Bob,  Maybe but my 175's have tab on the top casting that lines up with the body you can see them on the left hand carb in Dave's photo.

 

Mark.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.