MGExp

T-Series & Prewar Forum

What have I got?

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

What have I got?
#1
  This topic is about my 1954 MG TF
Ctwidle Chris Twidle
Reesville, Queensland, Australia   AUS
1954 MG TF
One year into my 54TF rebuild and today I bit the bullet and took the head off the engine for the first time. It came with matching numbers - HDE 23/2071 and XPAG - TF31921 but now I have more numbers that I need a hand to interpret:

Pistons don't move but they have no carbon on them and I can read the following: "RA 2098.030" followed by "TOP .0015. OL", I assume the .030 is 30 thou over standard, but the rest? Digital calipers tell me the bores are consistently 67.1mm with no wear ring at the top and no obvious scoring. I also find "16821" and "2608 M3" cast into opposite sides of the block.

The head has "282 4C 4" in the middle under the rocker shaft and "8842 5" on the edge, (I wouldn't have found the stamped 5 but for another thread which explains that number) Calipers give a reading of 73.48mm for the thickness. No7 push rod is slightly bent but not as much as No3. The valves are approximately 36.1 and 37.3 Dia.

I can reconcile the measurements easily enough when I get my hands on a more accurate measuring device but would appreciate any feedback on the rest.

Chris

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Buckdendave David Hill
St Neots, Cambridgeshire, UK   GBR
1954 MG TF
Chris. I'm no expert, but for what its worth, this is what I think.
Original bore size was 66.5mm, so +0.030" (0.762mm) = 67.26mm. Sounds like the bores are in good condition and require no work.
Original exhaust throat size was 29mm, and inlet size was 33mm.
The head has obviously been skimmed - originally 75.16mm.
The pushrods may or may not have been shortened, but its a good idea to do it with a skimmed head anyway. Easy to do yourself by pulling out the cup end, shortening the rod and glueing back in with cyano. Throw away any bent ones and replace then.
In addition you might want to grind out the ports, etc., and match them to the manifolds.
Dave H

plus4moggie Tom Lange
Bar Harbor, Maine, USA   USA
Bent pushrods don't just happen - you need to look for the reason, or face the same situation down the road (literally). In addition to what Dave notes above, the engine might have been over-revved, or there is a sticking problem with the valve stem/guide clearance. Your timing might be off, or a tappet is sticking in the bore. I have also seen an engine where a pushrod was not seated in the tappet cup, with a bent pushrod the result.

While you are right there, I would carefully check the cam and lifters, as you may well find wear. If the cam is OK you can just replace the lifters, but don't use old lifters with a new cam.

Tom Lange
MGT Repair

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Ctwidle Chris Twidle
Reesville, Queensland, Australia   AUS
1954 MG TF
Thank you gents for the early responses. All taken on board and will be looked into. I am sure there will be a lot more questions to come as this is just the beginning of this part of the continuing saga. I will probably have to wait till I can get some longer mad metric bolts to fix the block to a stand before I can do much more with it but I can get to work cleaning the grunge out of the head galleries. Just needed to share what seems like another milestone in the rebuild.
Chris

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Members Sign In   or   Create an Account

Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster