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MG MGA - Rebuild Assembly Tips

I have some questions here guys:

I know that the cam installation calls for liberal amounts of grease, however I'm wondering about the appropriate means of prelubing all the bearings. Do you grease them or smear oil on the bearing surfaces?

Anti-seize, can you/should you use anti seize on studs and bolts that call for a torque'd installation?

Gasket seating any suggestions here? Presoaking in oil? What about the paper gaskets?

Thanks
T McCarthy

Here is a link to the Anti seize info. http://www.saftlok.com/safteze/antiseiz/index.htm
Anti Seize is very slippery so you will end up with two much torque.
I have had very good results from the Blue RTV from Permatex on gaskets.

Gary
Gary Krukoski

A good point from Gary, often contrary to popular belief, if there is reduced friction (i.e. greased and/or oiled threads) clamping force (same amount of torque) will be significantly higher. This can lead to sheared bolts/studs or stripped threads.

On the other hand prevailing torque nuts (e.g. nyloc) require a higher torque to achieve the same clamping force as plain nuts.

Another important aspect of torque is that the longer the free length of the fastener (bolt or stud) the more angular movement for a set torque range (known as a soft joint). One significant aspect of this becomes apparent when the mechanic has the habit of tightening (by feel or meter/gauge) and then adding 1/8th of a turn or whatever for security/luck. While this might have little adverse affect on soft joints it can cause shearing/thread stripping on a hard joint (short bolt/stud).

One last thing regarding torque is the joint relaxing with time. This is particularly important if there is paint, gasket, washers or multiple surfaces in a joint. It is good practice to overcheck all fixings, the time will depend on surfaces and materials, but 24 hours would be sufficient for most (cylinder head will need additional of course). The correct torque is reapplied and if the joint has relaxed the fastener will tighten up, however, if star or split washers are used the fastener should be turned slightly in the slackening direction before reapplying the torque. These can otherwise have "stiction" (high friction caused by the washer edge biting into the surface resulting in lower clamping force).

Bored yet?
Neil McGurk

Tyson,
Some gaskets call for a presoak, especially paper gaskets. On water pumps and valve cover gaskets, I use Indian Head Gasket Shellac, and am very happy with the results. I only use it on one side of the valve cover gaskets, but both sides of water pump gaskets. When assembling cam bearings, I use Lithium white greae, and not too much, but a nice coating on the journals. For torque-ing bolts and studs, I use anti-seize on the studs, i.e. when installing them in the head, but only a light oil coating on the nut and washer surface when installing the stud nut.
Here is the word from Loctite:
http://www.loctite.com/int_henkel/loctite_mx/binarydata/pdf/LT3355v4_MROantiseize.pdf

Torque guide
Proper clamp load is an essential part of any bolted assembly for trouble-free operations. Torquing either nut
or bolt creates the clamp load. An anti-seize lubricant used on a bolt helps to develop greater clamp load for the same torque compared to an unlubricated bolt. An additional benefit is greater uniformity in clamp load among a series of bolts. The relationship between torque and
clamp load is expressed in the following equation:
Where:
T = KFD
T = Torque (in-lb, ft-lb, N-m)
F = Clamp Load (lb, N)
D = Nominal diameter of bolt
(in, ft, m)
K = Torque coefficient or nut factor, determined experimentally
K Factors: K factors are obtained on Grade 8, 1⁄2" steel bolts and grade 5 nuts by a test procedure which measures torque tension properties. Lubricant was applied to the bolt threads and both faces of the washer. See the Properties Chart for the torque coefficient or K value for the anti-seize compounds.
Henkel Corporation believes that this data fairly represents performance to be expected. However, Henkel makes no warranty of specific performance on any individual fastener. In critical applications, it is necessary to determine K values independently.
Note: There are two “coefficients” used to express the relationship between torque and tension: torque coefficient (also called “nut factor”) is the most commonly used. A different concept is the “friction
coefficient,” which has value 2/3 (or 67%) of the torque coefficient.
mike parker

Bored?? This is what this site is all about! More More! I have a dedicated bookmark folder for just this kind of information.
Fuzz
Russ Carnes

T, I'll throw my two cents in from recent experience. With my recent rebuild of my 1600, I paid particular attention to torque settings. I installed and ran the engine for a couple days and the started chasing minor oil leaks. I was amazed at how "Loose" the pan bolts, timing chain cover, and tappet cover bolts had become after experiencing the heat cycle of a running engine. Almost every external bolt on the engine required snuging up. Solved all the problems with oil leaks except for the dreaded notorious rear scroll quarter size leak.


WMR Bill

This thread was discussed on 06/09/2008

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.