retitled TR7 land speed record eng rebuild

[tony chiles]

What is the TR7 rod big end bore dia? having rods sized today and cant find this info anywhere.

Thanks in advance
Tony Chiles

[Beans]

Diameter 44.450 - 44.463 mm
minimum 43.434 - 43.447 mm
(according to the official workshop manual)

<center>
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>

[Marsu]

Interesting. The Repair Operation Manual, 1978 that I have (Part No AKM3079A) states:

Connecting rods
- Big end diameter less shells 48.146 to 48.158 mm

[Marsu]

Forgot to mention:

Tony, welcome to the forum.

[:)]

[tony chiles]

OK now I am confused- these dimensions are not even close to the same. Which one is right? 44.450=1.750 or 1.896

Hello Tony,

On the TR7 the big end hone would be 1.896â€￾ and the big end thickness would .958â€￾. If there are any other dimensions that you require or if you have any other questions please feel free to contact me at anytime.

[Marsu]

Hi Tony,

I think the dimensions Beans has given is the crank big end journal size (perhaps plus clearance) where the dimensions I have cited is the rod big end bore size. The discrepancy is the size of the shell bearings (perhaps plus clearance). My copy of the ROM also states:

Connecting rods
- Big end diameter less shells 1.8955 to 1.8960 in

Crankshaft
- Main journal diameter 2.1260 to 2.1265 in (54.000 to 54.013 mm)
- Minimum regrind diameter 2.0860 to 2.0865 in (52.984 to 52.997 mm)

Big end bearings
- Diametrical clearance 0.0008 to 0.9380 in (23.818 to 23.825 mm)

You can download a scanned copy of the [url="http://nk11r10-homepage.mac.com/WebObjects/FileSharing.woa/wo/jHTvLadVC3aEztAI.1/0.2.1.2.26.31.97.0.35.0.1.1.1?user=jclaythompson&fpath=Triumph_Articles&templatefn=FileSharing4.html"]ROM from jclay's site[/url].

[Beans]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Marsu</i>

... I think the dimensions Beans has given is the crank big end journal size (perhaps plus clearance) ...<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
... you're absolutely right [:I]
Sorry ... Johnny Foreigner etc. [:D]

<center>
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="2"><font color="red">My Weblog</font id="red"></font id="size2"></b></u>[/url]</b></i></center>

[tony chiles]

thanks guys got the information to the machine shop by noon and was able to pickup the rotating assemply at 4pm

[bmcecosse]

Why on earth would you be having the rods 'sized' ?? This is not something that is normally done - they are invariably correct. I've heard of rods being straightened - and check for centre lengths when Blueprinting an engine - but would be VERY surprised to hear of rods with anything wrong with the big-end bore.

[tony chiles]

well here is the deal, I have built a crazy tr7 motor for craig and it spun a rod bearing. So when we got the new crank I started cleaning up a new rod and found that the small end of the old rod was sloppy, after checking all of the small ends and being satisfied that they were junk.I started getting another set of rods ready. I fitted the piston pin to the rods and took the rotating assembly to the machine shop to get balanced. Since we had an issue with a rod bearing I wanted to make sure that the rods were correct. they were a little tight when checked. so all is well and we will be rebuilding again tomorrow. you can see the ECTA land speed record holding TR7 here
http://flashbackracing.com/

[PeterTR7V8]

Groovy. We were wondering about this car. Being so aero & lightened we expected a bit more speed than 111MPH. Can you tell us more about how the test is done please? Was the car able to redline in top gear etc? Cheers.



The map: http://tinyurl.com/wedgemap . The blog: http://www.forum.triumphtr7.com/topic.asp?TOPIC_ID=8548

[bmcecosse]

Ahh - I see! Nice carbs - what cam is it running ?

[tony chiles]

111 was with a stock engine and carbs. With the new motor we are just under 120(May-10 119.892 ). We only got 1 and a half runs before the rod bearing started playing around. The Maxton mile is where we run the car it is a decommisioned run way. more info here
http://www.ecta-lsr.com/
the engine:The engine boasts 12 to 1 compression. full race 7800 rpm cam, extensive valve trane upgrades, and MSD and crank trigger ignition.

[Marsu]

Superb Tony. [:D]

Do keep us updated [:p]