Hi Dan,
I've rebuild two TR6 engines and one TR250 engine. The first, a '76 I thought
looked pretty good but an engine specialist told me I had to have it bored.
Turns out I could get a new block from TRF for $100. Went that route and kept
the old pistons, etc. and didn't give him the $500 plus (20 years ago when a
dollar was worth 25 cents) to bore, new pistons, rings, etc. The next two I
went to a different shop. They told me the only thing of concern was excessive
taper and wear that causes piston slap near the bottom. Both of these had some
taper (I think a couple thousands but don't recall exactly). They told me not
to worry about it. Don't know the exact mileage on these engines when rebuilt,
my guess is that the TR250 had 50K miles and the '73 TR6 had over 75K. The
250 still uses very little oil about 10k miles later. That one has a
compression well over 10 -- wanted to reduce the weight a bit so shaved the
head. The '73 TR6 was run another 125K miles as I recall, my daily driver for
a couple years and then my daughter's college car. At the end it burned about 1
qt per 1K miles or maybe a little (and was always a qt or two low since the
daughter wasn't too attentive). That block is still around and definitely
needs bored or trashed.
On the other side, bored block, new pistons, etc make a nice arrangement if one
wants to throw $$$ at it.
It's interesting that the expert says a rebuilt unbored block will not burn oil
for 6 months then start. That must mean that a bored cylinder will start in a
year or two.
My experience is that the worse oil consumption is right after the rebuild --
like 1 quart per every few hundred miles. The rings start to seat and oil
consumptions goes down to normal after 2k to 5 K miles. On that new block I
got, I didn't hone the cylinders --- figured the factor would have it all ready
to go. Wrong! That sucker took well over 10K miles till the smoke went away.
Great now at somewhere like 20K miles later. Compression is so high I think I
must have put a slightly shaved head on it ---- to old, too many cars, can't
remember.
Nelson Riedel
Granville, OH
76 TR6 (just painted, now repairing damage from fender bender)
68 TR250 (next project - new paint)
70 TR6 (all the parts in a pile ready to assemble)
----- Original Message -----
From: "Dan H. Detweiler" <dandet@alltel.net>
To: <6pack@autox.team.net>
Sent: Tuesday, July 17, 2001 10:02 AM
Subject: Engine Rebuild
> Hi folks,
>
> I was just told by a fairly well known engine man in the Atlanta area that all
> British engines need to have the cylinders bored out and oversized pistons
> made for them when they are rebuilt. He stated to me that the cylinder walls
> are a soft metal and that they almost always have worn almost as quickly as
> the piston rings. He said that if this is not done that the engine will start
> burning oil within 6 months. I can't tell the amount of wear on my engine
> because I STILL can not get the head removed. He suggested welding the
> remaining nuts to their studs and giving them a good rap to try to break the
> crud that he felt had probably gathered around the stud and then baked on by
> the heat of the manifold effectively sealing the studs to the head.
>
> Can anyone PLEASE shed some light on this for me. Having oversized pistons
> manufactured was not on my list for this rebuild if possible.
>
> Thanks in advance.
>
> Dan H. Detweiler
> "70 TR6 CC51639
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