XJR5006
Could you explain to the ignorant what has been done please?
Thanks
Greg

 

yes, gonna be expensive,money wise!

i see engine has Forged pistons, not cast, and a short skirt, must be stroked .

 

I have heard, but not on this engine please do expound...
I know that taking a ford vulcan 3.0 v6 to 250 hp you can and will bolw the bottom end right out... there is a sort of bottom end plate and re-enforcement that can be added to that one... I am all Eyes and Ears! xjr5006 so I can learn and not make that mistake when going to 96 mm pistons and liners

 

.

jon ,quite simple bring money!!!

 

i;m guessing xjr5006 will put a steel strap across the large main bolts, for an easy fix!

what takes place when engine is really run hard, is combustion pressure is trying to push the head upwards(bad for gaskets etc), like lifting the head up, but equal and opposite reaction is piston and rod are trying to push the crankshaft out the bottom of block!

some engines have what we in states call a lower end girdle, some call it bottom end bed plate, lot of work, but holds the crank in place better.

usually holds the center 5 main caps in place better!

another fix is to make steel main caps, some mimic factory shape , i prefer a square rectangal shape , and all main studs larger,all 4 per cap same large size, along with GOOD quality stud material,(ARP), aircraft 12 point nuts!

being totally over kill is a form of side bolt affair, sometimes called cross bolted!

ALL of these fixes would require a complete align bore machining of the main bearing bores!

like said money,(cubic money).

 

I have taken some pics of a standard cap v a modded one and will post up in the next day or so , very very busy here atm 3 engines on the go and lots of pressure, Lead in time in the UK are unbelievable!
Check the pic of the cap, you need to look closely just inside the 2 tower nuts, usually this area is machined and leaves a ridge sticking up at the inner end of the machining (to give a flat to take the nut, ) on the modded caps the bit that sticks up is totally linished out, hence the shinny bit inside the nuts, This removes the stress raiser here and put off the point at which the cap gives up. It cracks from this point straight through to the crank center line.
OK off, back to work, got a lot to do today, bit surprised no one saw the difference, its also in some TWR prep literature I have but digging that out would take the kind of time I dont have atm.

 

That is wonderful! thanks... did a paper in college on the British Standard Whitworth thread being of superior strength due to the design not having the stress raisers of normal threads and how an un heat treated Whitworth was as strong as a heat treated common treaded fastener... and the world would save money if we switch to them...

 

.

of course we all believe everything the British say, i'm irish so you know how that goes!!

 

Thanks for the info, the photos were too blurry to see what was done.

 

100% true, even if the Irish do not believe it! Whitworth was the father of precision engineering techniques, the first to scientifically consider and codify thread design, and many other firsts. Sadly, one of the most unknown geniuses of the industrial revolution. he left his huge entirely self-made fortune to Manchester University, I understand.
Greg

 

English made a point of making sure some do not make it higher in life!

shame , and today the French developed METRIC system, and it made the most sense of all measuring systems!

anyway lets move on , who really gives a sh%y what holds things together,as long as you dont mix them up together!

 

You are talking utter nonsense. Stop it with the prejudice & borderline racist comment & keep the thread on topic - thanks.

 

'shame , and today the French developed METRIC system, and it made the most sense of all measuring systems!'

An English bishop, John wilkins, invented the metric system in 1668 in a book 'universal measure'. The French put it into widespread practice

 

In this case Ron, while he is unknown now, in his era he was a superb example of how someone from an ordinary family went right to the top professionally and socially. He got an hereditary knighthood and all sorts of other honours! https://en.wikipedia.org/wiki/Joseph_Whitworth It is a shame such people have almost disappeared from common knowledge. A bit as if the USA forgot about Thomas Edison or Henry Ford.
Greg

 

We did not forget... and Edison was a methodical hack... now tesla ... we forget gave us so many thing that we for get and Hedy Lamarr patented and gave us spread spectrum communications! with out which your cell phone would be just silly...


ok I was jus pointing out the removal of stress raisers... is a good thing and improves strength... I personally on the connecting rods prefer to grind away all stress raiser as the first part of lightening the connecting rods... a good polish job also does wonders in removing areas of stress and potential place for a crack to start...

 

Isn't polishing a reason why a while ago some propellor blades snapped on some older planes? I remember a series of crashs related to this issue...

 

steel shot peening is considered a better way to close potential stress risers after grind/cleaning the big stuff away!

but i have done both ways ,and nothing of interest ever happened anyway!

diam , i have heard about that propeller polishing, some of problem was Harmonic imbalance ,RPM related, but i cant say for sure!

if you are flying and you lost a blade,BET that will get your attention!!,LOL

 

HEY Warron ,sorry to hack your thread, sometimes i get carried away,with useless BS.

gotta stir the pot every so often!

 

I've been busy grinding intake ports, I posted a pic how bad they were a short while ago. It's taken me a LOT of hours as I have never done it before and I want to get it right.

Still have to tackle the exhaust ports, core shift is so bad there are steps in the exhaust ports about 0.040-0.050" where the outlet has been machined. So I still have a lot of work to do.

The pistons are ready to trial fit, and match the deck heights. When the pin bushes were done 2 rods were 0.010" sorter than the rest and these pistons will have 0.010" less off the top. Weights will be balanced by machining the pin boss.

 

about port matching , i usually try to open the exhaust manifold slightly larger than cyl. port sizes, like .020/.030 thou.

same with inlet but head port would be slightly larger than manifold, just a little, and of course have the gasket to size port.