[Fot] Doug Still Guides Me...

Tue Mar 24 06:32:03 MDT 2020

Hi Marcel;
Line boring should not materially affect the chain itself, as the crank centerline is raised usually less than .005".  Might affect cam timing a bit, but in the worst case scenario that can be fixed with a Vernier sprocket.
However, I agree with your assessment of the tensioner.  Would like to know if there is a better solution.
Phil

-----Original Message-----
From: van.mulders.marcel <van.mulders.marcel at telenet.be>
To: Phil Gott <vfracing at aol.com>
Cc: fot <fot at autox.team.net>
Sent: Tue, Mar 24, 2020 8:26 am
Subject: Re: [Fot] Doug Still Guides Me...

What about the chain? Is there noticeably more slach of it?The chain tensioners do almost nothing . Sometimes there are deep grooves in a short time, sometimes there is almost no scoring. Probably this is because of the chain running smoothly or with severe oscillations. Oscillations of the chain will have an influence on the ignition timing too.Has anyone tried an alternative solution for the tensioner to keep the chain quiet?Marcel
Van: "fot" <fot at autox.team.net>
Aan: "Bob Kramer" <rkramer56 at gmail.com>
Cc: "fot" <fot at autox.team.net>
Verzonden: Dinsdag 24 maart 2020 12:47:41
Onderwerp: Re: [Fot] Doug Still Guides Me...

Yes, Bob, as far as I know you are correct, the bearing notches in the caps and saddles are always on the same side. In the TR wet sleeve engine, each cap is unique as to its position, so it should be really hard to mix them up.Kas is right, however, in that in many engines it is good practice to mark each cap as to position and orientation, just to be sure.I have had a wet sleeve block line bored just to true it up at ABT machine in Holliston, Mass. This creates two issues that must be addressed, both due to the slight raising of the crank center line:1) the clearance space of the top of the pistons needs to be checked to be sure there is no interference at TDC. Usually not a problem.2) more of a problem is that the aluminum insert for the rear main seal may interfere with the block. This will become apparent when using the centering tool, and can be addressed by filing down the area of the seal where it interferes. Do not file or alter any other surface, as this will compromise the ability of the seal to function and/or to hold correctly one of the aftermarket rubber seals.  Be careful also not to gouge the face of the aluminum seal where it mates with the flat surface of the block. Go slow and be careful. It should all work as intended.Phil Gott

Sent from my iPhone

On Mar 23, 2020, at 10:36 PM, Bob Kramer via Fot <fot at autox.team.net> wrote:

Don’t all the main bearing caps go in with bearing notches on the same side as the notches in the saddles in the block? Or is that just a TR4 thing?

Sent from my iPhone

On Mar 23, 2020, at 6:59 PM, Enquiries Road & Track via Fot <fot at autox.team.net> wrote:

firstly, are you 100% sure the caps are correctly fitted both round the right way and in number order?
you need to decide if the caps are misaligned across the block or if the tunnel is simply oval because the hole in in cap is too far up or down. this will need a combination of feel and measurement

if the alternative caps have a significant step to 1 side, so you will clearly feel a ledge at the mating faces when they are tightened up

if the stap is very minor, like a few thousandths of an inch, then the faces of the cap are machined down to create an oval hole, then it it is align honed
if it is really bad, like many tens of thou, then you have to firstly move the cap sideways by machining the register on 1 side and peening it on the other, and effectively moving it sideways, followed by boring/honing
sometimes, the bolts are too neat a fit to allow this and if thats the case, its usually easier to find some other caps or make them
if the tunnel is simply an oval because the cap is too far up or down, this is usually easily fixed by facing the cap mating surfaces and reboring the tunnels
not all engine machine shop have a line borer...mine did not, so subcontracting the job is not uncommon
the end result should be a perfectly round hole with a super fine hone (cross-hatch) mark on the bearing faces, to ensure perfect bearing shell contact
 TerryAustralia

On Tue, Mar 24, 2020 at 1:32 AM Bud Rolofson via Fot <fot at autox.team.net> wrote:

Speaking of main caps I bought a block that turned out to not have the original main caps. The caps on there did not match up with the block but I’ve been unable to find a machine shop that can machine them so there’s a round hole for the crank. The shop I had do my last block (and they do 427 race engines among others and are well respected) told me that the result would be ovaled out holes (not round) which obviously is not good.Certainly there’s a way to make this work but I haven’t found it. I checked out another block shop but said they subcontract line-boring to the the shop that said they couldn’t do it. 
Has anyone else encountered this problem? I’ve heard that steel mains might be an answer but they’d still have to be line-bored to make them match. I hate to ship a block to get this done before I have reassurances that they can make it work but does anyone know of that has successfully made main caps match the block? Given I’m spending a lot of time these days staying home and catching up on car projects in the shop I figured it would be a good time to start building the next engine.
Solutions or recommendations?
ThanksBud

On Mar 22, 2020, at 9:33 PM, Brad Eells via Fot <fot at autox.team.net> wrote:
Amici,
In typically rookie race engine builder mode with the block I selected for rebuild, I pulled the main bearing caps (with my new fancy DeWalt 20V Impact Wrench) and then couldn't remember which way around they went. 
This led to visions of catastrophic failure somewhere down the road. Yet, I had several other blocks I could flip over and make a determination if need be.
I was examining one of the caps when I discovered the faintest engraving on the surface of each cap:

Eng #2 Front FwdEng #2 Mid FwdEng #2 Rr Fwd
Doug Brown, my original owner/builder/driver extraordinaire had engraved each cap for me to make sure a mistake didn't occur. He rotated 3 engines during each season in a quest for Divisional and National Championships.
I guess that is the way a aeronautical/mechanical engineer and very successful racer thinks.
Thanks again Doug!
<IMG_8745.jpg>

Cheers,

Brad EellsChino CA#72 FP 1969 Triumph Spitfire Mk3#35 DP 1962 Triumph TR41965 Triumph TR4A IRS...for the road!

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