Cylinder head differences

The 3 1/2 forum

Cylinder head differences

Postby Steve Brown » 09 Oct 2018 17:41

Hi all, I've always thought that all the 350 cylinder heads were the same. Eg, is a Kanguro head in any way different to a Sport or Strada head?
I'm asking as I see mentions of cylinder heads from one model or another as if they were in some way different.
Also, I'm currently trying to complete an engine for a mates Kanguro and it would be convenient to use cylinder heads I have here, that are in better shape.
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 487
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Cylinder head differences

Postby 72degrees » 09 Oct 2018 20:25

It so happens I have boxes next to me with 77? Strada heads and ?? Kanguro heads. Bad photo attached.
The only difference I can see is an extra casting 'lump' on the kanguro head (on the left) and a 'flat' on the top of the exhaust port. The rocker stud threads also seem longer (though the studs are the same length) - but they might be replacements.

The Forgotten Error has one 'old' head and one Kanguro head. So far as I can tell they are interchangeable - but perhaps the 'flat' on the port is vital for clearance if in a Kanguro frame?

Heads.jpg
Heads.jpg (191.05 KiB) Viewed 877 times
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby 72degrees » 09 Oct 2018 20:34

Ah. There is also more 'meat' round the exhaust port on the Kanguro head (left). Not sure why. Perhaps makes for a better thread, or better cooling.?

Ports.jpg
Ports.jpg (165.4 KiB) Viewed 875 times
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby norbert » 09 Oct 2018 21:08

The size of the valves of some Kanguro heads are diferent (guess the ones with Gilardoni barrels) don´t have the dates "a mano" but at least one of them is bigger.

norbert
norbert
 
Posts: 332
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: Cylinder head differences

Postby 72degrees » 09 Oct 2018 21:53

Ah, it looks as if the exhaust valves could be a bit bigger in the Kanguro head, but hard to say without getting the vernier gauge out. If they are, then the 'nice' pair I have will be going on the Forgotten error for next season!
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby Steve Brown » 10 Oct 2018 17:41

Thank you both for that, I'll look a bit more closely at the ports then too. He may end up with two Strada/Sport heads on it then! The X1 engine (I bought two Kanguros in bits) had an E type cam shaft in it and both had Sport pistons too. I was trying to persuade Ned the buyer of the X1 to go for Strada pistons-mainly so I could stock up on Sport items with rings to suit plated bores... 8) I think he's twigged that one though. :roll:
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 487
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Cylinder head differences

Postby Tommy542 » 17 Oct 2018 14:07

Steve Brown wrote:Thank you both for that, I'll look a bit more closely at the ports then too. He may end up with two Strada/Sport heads on it then! The X1 engine (I bought two Kanguros in bits) had an E type cam shaft in it and both had Sport pistons too. I was trying to persuade Ned the buyer of the X1 to go for Strada pistons-mainly so I could stock up on Sport items with rings to suit plated bores... 8) I think he's twigged that one though. :roll:


Just make sure you do the exhaust up tight on this one Steve :lol: :lol: :lol:
Tommy542
 
Posts: 2
Joined: 09 Oct 2018 11:19

Re: Cylinder head differences

Postby 72degrees » 25 Oct 2018 12:57

Well after dismantling one of the Kanguro heads as the start of this years winter project, it appears to have exactly the same sized valves as the earlier heads I have. Inlet 30mm and exhaust 22mm. The exhaust port seems the same size (25mm or so), just more meat round it. The valves and guides are in nice condition though and no trace of a crack between the seats. The exhaust port threads are perfect on both, so these are definitely going on the Forgotten error for next year.
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby norbert » 25 Oct 2018 16:45

As I said some heads of the Canguro motors have bigger valves, some have nikasil cilinders and some have the M camshaft. Not all of them, this depends of the year of production an what they had in stock :wink:
norbert
 
Posts: 332
Joined: 15 May 2007 15:15
Location: Lübeck/Germany

Re: Cylinder head differences

Postby 72degrees » 25 Oct 2018 18:17

norbert wrote:As I said some heads of the Canguro motors have bigger valves, some have nikasil cilinders and some have the M camshaft. Not all of them, this depends of the year of production an what they had in stock :wink:


I have no idea what year machine these came from but I'm glad I snapped them up. They will be going on an engine with genuine L5 cam though. Evguru has been tempting me to try rebuilding without base gaskets for a bit more CR. Anyone happen to know the 'Piston to Deck clearance' and 'Piston dish' cc for Sport 11:1 pistons? To put in this calculator:
https://goodcalculators.com/compression ... alculator/
Looks like leaving out a 1mm gasket might be a step too far?
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby harrymuffin » 25 Oct 2018 19:16

Determining the piston chamber volume is pretty straight forward. Simply install the piston you want to measure onto the connecting rod with rings, put the barrel on , you will see that the strada piston crown will be about a milimetre lower than the sport piston, place a piece of perspex on the top of the cylinder with two holes and sealed to the cylinder with some grease and then pipette using an oil such as hydraulic or transmission fluid. That will them give you the combustion volume. CR = CV + SV /SCV. Don't forget that this is theoretical compression as compression does not start until the inlet is closed, so with late closing inlet timing gives you a lower actual compression ration which in turn pushes the power band higher up the rev range. Try riding a works Manx round W'ton in the evening rush hour. If you do leave the base gasket out, ideally you will need a clearance between piston and head of about 1/4millimetre to allow for the expansion and connecting rod stretch. You can check this clearance by putting a lump of plastecene on the top of the piston and clamping the head up and rotating the crank. Lift the head and the plastercene now squashed can be miced up and tell you the clearance. I have run the 507 without the base gasket in without any problems and compression worked out at about 12.5:1 with no pinking even on 2* petrol, which is why Major Heron developed the set up in the first place, when aero engines were struggling to run with compression ratios above 4-5: 1 on crap petrol. I put the base gasket back in and compression is now about 11.5:1 because the starter struggles with the higher compression. If you do leave the base gasket out, to stop leaks where the oil drains back down through the pushrod tubes cut and fit a paper gasket and assemble with a smear of Wellseal on both sides.
If you are 'gas flowing' the heads, the inlet valve seats ideally need to be radiuses so that when you lap them in you will have line contact. The exhausts can be teated similarly, but the seat wants to be about a 1/32" wide. The inlet valve will flow at it's maximum when the valve seat area equals the actual valve opening area so maximum flow will occur with a lower valve lift than seats that are 1/2" wide as standard. The radiusing will also stop turbulence through the seat and encourage laminar flow of the gases through the valve. narrowing the valve seat has through empirical research shown to give 1-2 bhp on each cylinder over standard.
Just a word about the similarities of the Morini head. Remember, this engine was designed to be modular, same crankcases for all the engines including the sloping singles. The heads came from the same molds like the crankcases and over time development the castings were devoted and improved by adding metal where reliability was required i.e. beefing up the exhaust port, so that some heads (350) look different (500) but it is only because of the thread is smaller. The brand spanking new 507 heads I have are different from my SEI used heads, but the castings are the same. On the 507 heads the rocker studs break through into the inlet ports, the ports are larger and there are casting bumps where there are none on the SEI heads development.
harrymuffin
 
Posts: 149
Joined: 07 Apr 2014 16:06

Re: Cylinder head differences

Postby 72degrees » 25 Oct 2018 22:10

harrymuffin wrote: If you do leave the base gasket out, ideally you will need a clearance between piston and head of about 1/4millimetre to allow for the expansion and connecting rod stretch. You can check this clearance by putting a lump of plastecene on the top of the piston and clamping the head up and rotating the crank. Lift the head and the plastercene now squashed can be miced up and tell you the clearance. I have run the 507 without the base gasket in without any problems and compression worked out at about 12.5:1 with no pinking even on 2* petrol, which is why Major Heron developed the set up in the first place, when aero engines were struggling to run with compression ratios above 4-5: 1 on crap petrol. I put the base gasket back in and compression is now about 11.5:1 because the starter struggles with the higher compression. If you do leave the base gasket out, to stop leaks where the oil drains back down through the pushrod tubes cut and fit a paper gasket and assemble with a smear of Wellseal on both sides.


OK. Nothing like practical experience. Worth a try then. The only starter on the hill climb engine is my right leg and quite a few hill climbs are, well, hills - so bump starting is often an option if required. My workshop facilities aren't up to radiusing valves but I can at least address any 'step' in the inlet port/adapter interface.
User avatar
72degrees
 
Posts: 1117
Joined: 31 Aug 2007 21:24
Location: West Midlands

Re: Cylinder head differences

Postby Steve Brown » 26 Oct 2018 20:39

Thanks again for all the replies. I'm quite happy now that there aren't any differences in the important details of the 350 heads.

In reply to the idea of leaving the base gasket out, that was what I did back in the 1980's as a cheap way of raising compression when I raced my 350 in the Forgotten Era series. Measuring the clearance is easy to do without a lot of faffing about. Assemble the cylinder and head with a strip of soft solder wire on top of the piston. Gently turn the engine over TDC and the solder gets compressed to the size of the clearance left. Then measure it with a Vernier or micrometer.


I can't remember the clearance I ended up with but I can say that I never had any problems with pinking, oil leaks or anything else. There you go, it's race proven championship winning practice! :)
All donations to the rest home for old Camels, Leicestershire.
Steve Brown
 
Posts: 487
Joined: 12 Nov 2007 23:44
Location: Leicestershire


Return to Tre e mezzo

Who is online

Users browsing this forum: No registered users and 5 guests

cron