> Hi Mike
>
> Here are the symtoms. If you can get this on the web it would be great,
>
> Problem
>
> Overheating and Fouling of No 4 Culinder
>
> The cars 1966 TR4A
> 1967 TR4A
>
> Both have recently had their engines completly rebuilt to identical
> specs,
> Oversized pistons (87mm)
> Cam, mild race
> Hardned valves and seats
> seals, bearings etc.
>
> The differences
>
> The 66 has Strombergs and the 67 SUs
> The 66 has a cast exhaust manifold the 67 a header
>
> The 66 has aprox 1000 miles while the 67 has aprox. 1500 miles since the
> rebuild. Both were rebuilt by the same shop and expert in Brit cars
> especially TRs. Both were properly broken in, keeping to less than 3000
> rpm during the first 500 miles and a gradual build up thereafter.
> Neither car has been pushed or mistreated during its life.
>
> The problem:
>
> The 66.
> First noticed on this TR. Valve sticking in cylinder No 4 which was
> diagnosed to a faulty valve spring then a hundred or so miles later a
> broken valve spring. These two problems appear to be incendental and not
> related to the real issue just mentioned for background info. During the
> diagnosis for the above it was noticed that the No. 4 cylinder was
> runnning hotter than the other three. This turned out to be a faulty
> seal at the PCU fitting at the intake and thereby running too lean anr
> too hot in cylinder No 4. After much soul searching and suggestions from
> many experts (?) it was further discovered that (once the motor reached
> operating temperature) removing the oil filler cap caused the rpm to jump
> rise aprox 300 rpm. This was cured by streaching the PCV valve spring.
> As far as we can detirmine this should cause an increase of 150 rpm
> (more or less)
>
> The 67
> No apparant problems since the rebuild other than one carb running a
> little rich, this was corrected. However, given the 66s problems it was
> also discovered that No 4 was burning oil and fouling the spark plug.
>
> The PCV solution (above) was discussed. With the retainer spring clip
> removed from the PCV the cap rose to be aprox. 1/2 inch proud of the
> housing. The PCV was disassembled and we noted that the top of the
> diaphram was dry but there was oil in the bottom of the PCV valve
> housing. The spring was streached and this clearance increased to 3/4
> inch. Now, when removing the oil filller cap the rpm increases from 800
> (idle) to 1000. Whether this was the case with the 66 is unknown. Other
> than that the car is running great. Solid engine performance, power etc.
>
> Questions
>
> Considering the PCU vacuum leak affected the No 4 cylinder only (on the
> 66) would a faulty PCU on the 67 create the oil burning situtation? The
> diaphram seems OK
> What is the relationship between the PCV and No 4 heating up
> Is there any spec that covers the PCV spring. Tension, length,
> adjustment
>
> Let me know if you get any responses
>
> Regards
>
> Tom
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