TEA20 nuts and bolts

pcp20us · Mar 22, 2015

Hi guys.

At the stage of starting to reassemble my motor.

I need to buy some replacement nuts and bolts, some of these are the maifold bolts and valve cam bolts. Do bare co or sparex sell them, as i could not find any on the websites?

What type are these bolts: british standard thread? as i will probably go to a nut and bolt supplier if possible

Rule no, do not move a tractor when its half dismantled!!

Charles in Aus. · Mar 22, 2015

General rule , UNC threads when in cast iron , UNF threads when in steel .

Tony in Mass. · Mar 22, 2015

What did kiwis call it? Fractional? Old style? Not motorcycle Wentworth British, certainly not metric.
I think you are dealing with 7/16's and 1/2 inch at that part of the engine. If you can find brass/bronze nuts for the manifold studs, it will all come apart easier and with less damage the next time around.
As Charles said, you will/should find studs with Unified National Coarse on one end, that screws into the cast iron head, Unified National Fine that should have bronze washers and nuts to replace the old stuff on the other.
Don't rush this, take your time to shop and assemble....

Grandfatherjim · Mar 22, 2015

"Imperial", I believe

Bruce(OR) · Mar 22, 2015

I remember putting brass nuts on an exhaust manifold
once. Once. Engine got warm, they all backed off and
fell off. Steel was designed to stay in place and
resist the expansion effect.

Charles in Aus. · Mar 22, 2015

The studs that hold the cast iron upright exhaust bend onto the manifold are 3/8ths'' UNC . I have had to clean up a number of these in the past . The manifold studs may be the same , at least the end that screws into the head .
I have had similar problems with brass nuts working loose , I still use them though . It is a matter of checking their tightness every once in awhile , copper coat anti seize is also a must .

cdmn · Mar 25, 2015

I have some familiarity with how the French do this. They use a long nut, perhaps 25-30 mm. They then counterbore the end facing the manifold, and leave about 10-12 mm of thread at the outside end. This helps counteract the heat effect and is much less likely to loosen up or become seized tight.

TEA20 nuts and bolts

pcp20us

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Charles in Aus.

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Tony in Mass.

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Grandfatherjim

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Bruce(OR)

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Charles in Aus.

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cdmn

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