engine rebuild what would you do and why ?

[stagmuffin]

hi folks I am soon to start the build on another tv8 and would like advice on your preferred recommendations for piston suppliers and your thoughts on manufacturers to as which may be the best option . im probably only going to need +20 oversize . my plan is to have all the rotating mass balanced when machining is complete and the block decked to maintain balance . what recommendations for work would you say are advantageous to the block while in the machine shop other than fitting a bronze bearing for the front jack-shaft and locating with a screw to prevent rotation and misalignment of oil ways .maybe changing out all old big end and mains bolts etc I think T.hart did some work on the mains caps ( beef up bracket ) to stop issues at high revs on his racing stag ,I want to try and cover as much ground as i can here with this engine and no rush as mine is still very good its a back up and will most likely be used to fit up my fuel injection project as well so I have a straight swap out . all ideas and advice welcomed as i want it to be the best I can make it .
regards
Steve

[flying farmer]

I am also going to be starting another rebuild in the not too distant future, I want to see if I can crack the 250bhp level this time.

I will be using County pistons, previous experience with the JP pistons suggests they are rather too heavy and rather too prone to seizing for my liking.

The County pistons do have a lower deck height than the original mk2 pistons, so decking the block is useful to get the compression back. One of these days I am going to peer down the plug holes of my 246bhp Stag to see the amount of carbon (or not) exists on top of the pistons with only 15 thou of piston to head clearance.

If your jackshaft bore is ok I would leave it alone, I am lucky in that the block I am going to be using is ok in this respect.

I enquired what Tony Hart did with his racing Stag engine regards bracing the bottom end. He machined the main caps flat and fitted spacer blocks to bring the top of the caps level with the sump mounting, and used a 10mm alloy plate to tie the main bearing caps to the sump bolts. I am considering this, as the engine will be for the TR which sees several track days per year (got another one next Wednesday) I think it is only really necessary for long periods over 6500rpm.

I will also be getting the rotating assembly balanced. The balanced Stag engine is noticeably smoother than the un balanced one in the TR
Neil

[new to this]

what valve guides would you use standard or bronze and why ?

Dave

[flying farmer]

what valve guides would you use standard or bronze and why ?

Dave

The standard valve guides seem to be adequate, they don't suffer side loading like an engine fitted with rockers. Rockers impart a side loading as they wipe across the valve tip which is why some high performance pushrod engines use roller tipped rockers.

Some years ago I was told by EJ Ward that the bronze guides they used were a fractionally bigger diameter than the original items which could be useful if the guides were loose in the head. I have actually used some for just this reason on an engine I built some years ago as I thought the standard guides went in a bit too easily.
However, on the last engine I built I used some guides bought from Paddocks. These were very tight to fit. In fact I had to buy some extra ones as I damaged a few trying to knock them in, but I am certain they are never going to come loose!
Neil

[jusm]

I am also going to be starting another rebuild in the not too distant future, I want to see if I can crack the 250bhp level this time.

I will be using County pistons, previous experience with the JP pistons suggests they are rather too heavy and rather too prone to seizing for my liking.

The County pistons do have a lower deck height than the original mk2 pistons, so decking the block is useful to get the compression back. One of these days I am going to peer down the plug holes of my 246bhp Stag to see the amount of carbon (or not) exists on top of the pistons with only 15 thou of piston to head clearance.

If your jackshaft bore is ok I would leave it alone, I am lucky in that the block I am going to be using is ok in this respect.

I enquired what Tony Hart did with his racing Stag engine regards bracing the bottom end. He machined the main caps flat and fitted spacer blocks to bring the top of the caps level with the sump mounting, and used a 10mm alloy plate to tie the main bearing caps to the sump bolts. I am considering this, as the engine will be for the TR which sees several track days per year (got another one next Wednesday) I think it is only really necessary for long periods over 6500rpm.

I will also be getting the rotating assembly balanced. The balanced Stag engine is noticeably smoother than the un balanced one in the TR
Neil

Will eagerly await the thread. What bore will you be looking at?

[flying farmer]

Will eagerly await the thread. What bore will you be looking at?

I have 2 blocks, one standard size and one plus 20 thou, and two sets of new county pistons, one set plus 20 and one set plus 40.

The +20 set were left over from an ebay purchased short engine that I only wanted for the rebored block as the one I had needed liners replacing but had new domed pistons. That formed the basis of the engine now in the TR.
The plus 40 thou pistons were a recent ebay purchase, to suit the corroded +20 thou block I got off a mate recently.

I will probably use the +40 pistons for the extra capacity (gives about 3060 cc).

What I am really after now is a standard size crank as I am hoping to get one offset ground to give a fractionally longer stroke. This will mean I don't have to skim the block so much to raise the compression, and will give a total capacity of about 3.1 litres.
I got really lucky when I built the 246bhp engine, I got a standard journal crank off ebay for £6 plus postage! Can't see that happening again!

I think I have 5 cranks in the shed, one of which is good enough to use as is, but they are all ground at least 30 thou on the big ends and don't have enough meat on them for an offset grind.
Neil

[mjheathcote]

I will probably use the +40 pistons for the extra capacity (gives about 3060 cc).

Silly question....could you overbore and fit TR7 pistons, being 90.3mm the capacity would then be 3305cc

T&M Garages offered a big bore Stag engine in the 90's...couldn't have been so simple could it?!