Bob........
Did you fit new oil pump gears when you were building the engine? Did you
take the time to measure the end clearance between the new gears and the oil
pump cap?
The problem you describe has happened on several engines with which I'm
familiar (though, thankfully, not ones I built!) The gears are just a skosh
too long and, when they heat up, they bind in the housing. The weak link is
the gear on the shaft, so this shears off. In one instance, it then jammed
between one lobe of the camshaft and the inner wall of the block. Room was
made for it by a large piece of the block exploding outwards..............
When fitting new gears in an XPAG or XPEG oil pump, it is imperative to make
sure there is 3 thou clearance between the ends of the gears and the cover.
Just a possiblity..........
Lawrie
British Sportscar Center
-----Original Message-----
From: Bob and Carolyn Grunau <cgrunau@pathcom.com>
To: MG T List <mg-t@autox.team.net>
Date: Thursday, February 25, 1999 11:26 AM
Subject: Fw: TC race cam troubles
>I am forwarding this message in the hope some TD/TF owners can shed some
>light on my problem. Apologies to those that have already received this
>earlier.
>Thanks for any input, advise etc.
>Bob Grunau
>
>>
>> I built a TC race car out of spare parts and ran it at two events in 1998
>> with a stock TF 1500 engine. I then built an expensive 1500 XPEG race
>> engine for the car and hoped to run it at Watkins Glen. The race engine
>ran
>> fine initially, oil pressure 70 psi hot , water temperature 75 C., lots
>of
>> power for 45 minutes running on the highway ( the car is road licenced).
>> Then suddenly the cam gear driving the oil pump failed and I was left
>with
>> no oil pressure in the middle of nowhere. I shut off as the oil pressure
>> was falling.
>> So I re-installed the stock TF 1500 engine for the Glen.
>> Inspecting the race engine I find everything OK except for stripped oil
>> pump drive gear on the camshaft and the oil pump shaft gear
>> damaged/stripped.
>> I am trying to determine why I had this failure. I am using a new Phoenix
>> crank and rods. Rod side clearance on crank is 0.008", full floating rods
>> with an oil squirt hole on the side away from the cam to lubricate the
>> trust side of the piston bores, same as original rods.
>> The cam gears look like they may have been starved of oil. Discussions
>with
>> another TC racer at the Glen indicated this problem was not unique and an
>> additional oil supply was required to the cam oil pump gear to make sure
>it
>> was lubricated. It appears that the present main lubrication for the oil
>> pump drive gears ( and distributor drive ) comes from gravity oil flow
>down
>> the side cover from the rocker shaft.
>> Anybody else had this problem of failed oil pump drive gear? And how did
>> you solve it? I can buy a new cam, but am afraid I may have the same
>> failure.
>>
>> Speaking of a new race cam, any suggested magic grinds? I am considering
>a
>> new Crane T-4 cam. Any suggestions/help gratefully received.
>>
>> I don't want to bore the list with this trivia, so anyone with
>constructive
>> assistance please email me directly so we can talk.
>> Thanks for any help.
>> Bob Grunau
>
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