Removal and rebuilding of a Twincam

[rgh0]

My head machinist will check both sleeve bore and alignment and integrity of the support around it as well as hardness test the removed sleeve. Talking to a few engine builders locally and overseas the one opinion appears to be inadequate lubrication due to to tight a fit - but I struggle with this as once it wears a little the fit would be OK and it would stop wearing and this sleeve had worn 100 times more than expected .. or .. a faulty sleeve material in some way. . I have another head to build also that needs re-sleeving of the followers and maybe I will try brass or alloy sleeves that some people are now using rather than the standard cast iron, but it should not be necessary as hard steel followers on a cast iron sleeve should be a good wearing combination.

cheers
Rohan

[2cams70]

I concur with the opinion that it's most likely a lubrication problem of some sort. My bet is that it's something to do with the oil pressure feed to or through the inlet cam. The oil flows through the cam from front to back. If there was some sort of restriction at the front of the cam it could be that although there may have been enough flow at the front of the cam to keep things lubricated by the time there was leakage through successive cam bearing journals from the front of the cam to the end where the number 4 tappet is located the amount of oil was insufficient to keep things properly lubricated. Wear may not have necessarily shown up on the bearing journal there itself depending on the exact alignment of the individual cam journals - some of the 5 may have been sharing more of the valve spring load than others.
I'd also be interested to know whether the end float clearance for the connecting rod on the crankshaft journal that was damaged is still within specification. Judging by the way the bearing shell extruded out the sides of the connecting rod it could have caused damage to the crankshaft here.
It's an interesting story so far!

[rgh0]

Got my parcel of parts on Friday from Tony Ingram - 2 days by DHL door to door California to Melbourne. I got a set of his new black nitrided stainless race valves which I will try in the next engine I build that I am collecting bits for in addition to the current rebuild.

Spent the day measuring valve springs to decide whether I need fit the new ones - the old ones measured up OK with no change since new in length versus load and as they have only done three years in the engine I will probably not change them.

The parts from QED are on their way and the Carrillo rods are a few weeks way still but I have plenty to keep me busy on the rest of the engine while waiting for parts and for the head and crank machine work.

cheers
Rohan

[Davidb]

Just like Christmas!

Rohan: I like the look of that valve spring pressure tester-is that a commercially available unit?

This guy has a good video-for a BMC A series pushrod engine but still interesting to watch:

youtube.com/watch?v=M0ktwq4ICYY

[rgh0]

Just like Christmas!

Rohan: I like the look of that valve spring pressure tester-is that a commercially available unit?

This guy has a good video-for a BMC A series pushrod engine but still interesting to watch:

youtube.com/watch?v=M0ktwq4ICYY

Yes - i think I got it from one of the US racing supply places, I cant remember which, it was around A$100 and its here on Amazon

https://www.amazon.com/ProForm-66835-Va ... lp_pl_dp_2

Simple 1 square inch piston with a pressure gauge that reads in PSI thus direct reading of spring load in lbs. I measure the spring compression with a vernier

cheers
Rohan

[rgh0]

Still collecting parts

Picked up the cylinder head today - nice new follower sleeve in No.4 inlet. Unfortunately could not get a hardness test done as the guy had to fully machine it to get it out cleanly but he said it machined like normal cast iron. He has done many twink heads and said he had never seen a sleeve wear like that before so he could not explain the wear.

Also got the parts I have been waiting for from QED.

So just need the crank back in a couple of weeks following ist grinding and new heat treatment and I can start reassembly as hopefully I have everything needed for both this engine and for the rebuild and modification of my other spare race engine to run on 98 Unleaded rather than Avgas also thats next on my list. Then I need to decide what I am going to build after that, maybe I will actually get around to that big capacity road engine I have been promising myself for my Plus 2 for years

[rgh0]

My new rods arrived Monday . Sent from Tony Ingram in California on Friday his time ( Saturday my time) and arrived first thing Monday morning my time at my work, cant complain about his service or DHL delivery. The maintenance store person who accepts all my deliveries is a bit of a car nut and is always interested in the bits being delivered to me, so he gets an update on my rebuilds as well as all of you

You can tell the rods are made in the USA . I needed 5 , as 4 for a new build and 1 to replace the damaged rod in the engine I am currently working on. But they came in a box for 8 rods - I don't think they know about engines less than 8 cylinders there

Personally I think they are engine "porn" and the most beautiful piece of metal sculpture I have ever seen, strong and light with all the curves in all the right places and almost unbreakable as long as the rod bolts don't fail ( been there, done that see my avatar) they make all other rods I have seen crude in comparison. A twincam at 9000 rpm needs the lightest pistons and rods possible for smoothness and reliability and these certainly fit the need.

cheers
Rohan

[HCA]

Still collecting parts

Then I need to decide what I am going to build after that, maybe I will actually get around to that big capacity road engine I have been promising myself for my Plus 2 for years

Come over here and you can rebuild my engine..

[rgh0]

Working on my next Holiday in Europe for some skiing and to visit my wife's relatives in Germany but given Covid 19 it may be a few years away unfortunately as international holiday travel appears to be shutdown for some time.

cheers
Rohan

[661]

Working on my next Holiday in Europe for some skiing and to visit my wife's relatives in Germany but given Covid 19 it may be a few years away unfortunately as international holiday travel appears to be shutdown for some time.

cheers
Rohan

Blue Cow it is then?

[alan.barker]

The blue Cow is Swiss.
Imho the best Skiing is Austria and Schapps mit Fruck. My best Skiing was always in the Tyrol after a Schapps.
Alan

[661]

The blue Cow is Swiss.
Imho the best Skiing is Austria and Schapps mit Fruck. My best Skiing was always in the Tyrol after a Schapps.
Alan

Snowy Mountains, NSW.
Weren't we building an engine...…………...

[StressCraxx]

My new rods arrived Monday . Sent from Tony Ingram in California on Friday his time ( Saturday my time) and arrived first thing Monday morning my time at my work, cant complain about his service or DHL delivery. The maintenance store person who accepts all my deliveries is a bit of a car nut and is always interested in the bits being delivered to me, so he gets an update on my rebuilds as well as all of you

You can tell the rods are made in the USA . I needed 5 , as 4 for a new build and 1 to replace the damaged rod in the engine I am currently working on. But they came in a box for 8 rods - I don't think they know about engines less than 8 cylinders there

Personally I think they are engine "porn" and the most beautiful piece of metal sculpture I have ever seen, strong and light with all the curves in all the right places and almost unbreakable as long as the rod bolts don't fail ( been there, done that see my avatar) they make all other rods I have seen crude in comparison. A twincam at 9000 rpm needs the lightest pistons and rods possible for smoothness and reliability and these certainly fit the need.

rods.jpg

You have great taste in engine porn, Rohan.

Regards,
Dan

cheers
Rohan

[h20hamelan]

Rohan, knowing your a devout cyclist.
Most of these teams use pedal power

https://r2ak.com

I had a year around the world sailing. In my late teens. Built a kite powered sea kayak, some of the first water relaunchable kites. Had a mast for a windsurf type sail for going upwind, and a fanning rudder for if the kite dropped out of the sky. Also a reel on the deck, to pull the kite in...There was just barely enough room to sleep inside, with the mast as an outrigger.
Not enough time, or sponsors. Wanted to be the first to do the northwest passage in a season. No problem nowadays.
I worked in Canada’s high arctic (Baffin) for a few summers when i was 17-18 between long canoe trips.
If your looking for a canoe adventure, I can highly recommend some spectacular Canadian waterways.

[rgh0]

The blue Cow is Swiss.
Imho the best Skiing is Austria and Schapps mit Fruck. My best Skiing was always in the Tyrol after a Schapps.
Alan

Snowy Mountains, NSW.
Weren't we building an engine...…………...

Hotham is where I ski in Australia and even that is doubtful this year. In the USA I like the chutes at Jackson Hole and in Europe I like Austria, especially Solden. But more places to ski than I have time and money unfortunately but I keep working on it

Now back to engine building

cheers
Rohan