Merlin DOHC Progress (2018)

Bsamat said:
Another really interestingly pic Phil, thanks. Staring at this photo it looks like the top couple of fins of the barrel are trimmed, presumably to allow exhaust clearance. The barrel currently fitted to the Merlin doesn't have this, but we have another barrel in the pile of bits that has this trimming. I wonder if its the same set fitted originally to this grass tracker? The fins on the drive side are also cut square to allow the belt drive to the OHCs to fit. There is very little wear in the bores. Maybe it was a spare? Here are a couple of pics;

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Well spotted Mat the top couple of fins of the barrel are trimed not to allow exhaust clearance more like to reduce weight (or as Peter said to clean up damaged fins),I think the one you pictured is the same set fitted originally to the Wasp sidecar if you look verry closely the top fin has more off than the second,As Peter also said "then put a decent set of barrels on it for the Earls court show bike" also to help cooling as the road bike would be used for much longer runs than the sidecar
 
dobba99 said:
Alan and John (who were Merlin) probably used 'used' spares to modify into the merlin format (trimming the fins on the drive side for the cam belt) and boring out to 920. I bet they had spare barrels that had broken fins so cleaned the break up and used them as well. The Previous owner in Wales could have done this as well. I know he bought Merlins first engine (presumably with the timing side 'trimmed fins') and then put a decent set of barrels on it for the Earls court show bike? Its all a bit of a mystery as all this happened 40 years ago.
What is the bore size on this set of barrels? 77mm is standard 828cc. 81mm will be 920 using a 89mm stroke crank.
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Its 77mm, so I don't know where these barrels fit in the story. Do you know if they ever did an 828 version, maybe a prototype? Or maybe it was just a dummy set the guy down here did. I know the turbo was on display with no engine internals for a while, so maybe he did the same with the Merlin at some point.
 
Wasp Wasp said:
Well spotted Mat the top couple of fins of the barrel are trimed not to allow exhaust clearance more like to reduce weight (or as Peter said to clean up damaged fins),I think the one you pictured is the same set fitted originally to the Wasp sidecar if you look verry closely the top fin has more off than the second,As Peter also said "then put a decent set of barrels on it for the Earls court show bike" also to help cooling as the road bike would be used for much longer runs than the sidecar
Click to expand...
After talking with Pete Lovell (who got the Piper 8 valve head to work properly) To glean whatever info he had about the Merlin he told me that he didn't have much to do with it and that the one he did see (number two or three of the three engines Merlin made) went to Chris Wilshaw who raced it for a while, said he found it a bit top heavy. Also he had problems with the cylinder head being porous (I know what he means!) as the head i had cast, taken from the patterns I obtained from Merlin looks to be porous, So much so, I am using the porous head as the practice run for machining and will use a huge chunk of HE30 TF for the 'proper one' Pete also said they had problems with cooling, possibly not much of a problem in sidecar cross but in a fully faired roadrace bike it seemed to be. The fact that the engine used a total loss ignition (no alternator) possibly prompted the substitution with the turbo motor. With the previous owner passing away a lot of this is conjecture.
 
dobba99 said:
After talking with Pete Lovell (who got the Piper 8 valve head to work properly) To glean whatever info he had about the Merlin he told me that he didn't have much to do with it and that the one he did see (number two or three of the three engines Merlin made) went to Chris Wilshaw who raced it for a while, said he found it a bit top heavy. Also he had problems with the cylinder head being porous (I know what he means!) as the head i had cast, taken from the patterns I obtained from Merlin looks to be porous, So much so, I am using the porous head as the practice run for machining and will use a huge chunk of HE30 TF for the 'proper one' Pete also said they had problems with cooling, possibly not much of a problem in sidecar cross but in a fully faired roadrace bike it seemed to be. The fact that the engine used a total loss ignition (no alternator) possibly prompted the substitution with the turbo motor. With the previous owner passing away a lot of this is conjecture.
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I think the wasp sidecar whould have also had oil in the frame which helps the cooling,A thought about the barrels he my of had the liners swapped to keep the 920cc and have a spare 828cc set of barrels to use or get machined up to the size he required at a future time
 
Bsamat said:
Its 77mm, so I don't know where these barrels fit in the story. Do you know if they ever did an 828 version, maybe a prototype? Or maybe it was just a dummy set the guy down here did. I know the turbo was on display with no engine internals for a while, so maybe he did the same with the Merlin at some point.
Click to expand...
As this set of barrels is 77mm it could possibly be the 'development set' that Merlin used as they built the first one and then swapped over to the 81mm bore barrels when they had sorted out how much to trim off the fins to clear the cam drive etc. Makes sense that they could use a set of barrels with broken fins to do this
 
dobba99 said:
As this set of barrels is 77mm it could possibly be the 'development set' that Merlin used as they built the first one and then swapped over to the 81mm bore barrels when they had sorted out how much to trim off the fins to clear the cam drive etc. Makes sense that they could use a set of barrels with broken fins to do this
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I think you might be correct Peter I found this program from Petersfeild 22 7 1979 number 44 Alan Baker/Robert Marchant on Merlin Norton 850cc

www.dropbox.com

Merlin 850 1979 A.jpg

Shared with Dropbox
www.dropbox.com www.dropbox.com

www.dropbox.com

Merlin 850 1979 B.jpg

Shared with Dropbox
www.dropbox.com www.dropbox.com
 
Found this out
Terry Good & Barry Williams tried/tested the twin cam Merlin Wasp at Beenham Park 1980 on the Saturday 12/7/80 the chassis was older and Terry really needed it in his chassis.
Terry liked the motor it pulled well but it was in the old chassis needed much more work before it could go racing,
So he went back to his own Wasp for timed practice and Sunday The World Sidecar Grand Prix of Great Britian 13/7/80
 
Wasp Wasp said:
I think the wasp sidecar whould have also had oil in the frame which helps the cooling,A thought about the barrels he my of had the liners swapped to keep the 920cc and have a spare 828cc set of barrels to use or get machined up to the size he required at a future time
Click to expand...
I have a set o 920 barrels in my workshop that have had every other fin removed. I understand his was done for a sidecar cross outfit where the cooling demands allowed it, and it made it easier to get the mud out!

I bought them quite early in my project.

My Rickman has oil in the frame, which can get very hot and burn my thighs on occasion, so I would not be confident of using these barrels on a road racer.

However, my initial reason for not using them was based on the need to open out the Maney cases I had just bought! (and In the end I built a short stroke 750!)
 
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SteveA said:
I have a set o 920 barrels in my workshop that have had every other fin removed. I understand his was done for a sidecar cross outfit where the cooling demands allowed it, and it made it easier to get the mud out!

I bought them quite early in my project.

My Rickman has oil in the frame, which can get very hot and burn my thighs on occasion, so I would not be confident of using these barrels on a road racer.

However, my initial reason for not using them was based on the need to open out the Maney cases I had just bought! (and In the end I built a short stroke 750!)
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Funny you should say that about the 920 barrel
I also have a 920 barrel (Rgm conversion) this has every other fin removed too
The bloke I bought it from claimed he used it on his road bike with no problems at all!
I'll find out one day when I use it
Cheers
 
Have these been posted already.
I was looking for something on the PC and there was a Merlin folder with some content saved in 2014.

IMG_0001_NEW_zpsc91e1d5e.jpg IMG_0002_NEW_zps09070aa6.jpg IMG_0003_NEW_zpse52a33f0.jpg IMG_0004_NEW_zpse8deb75a.jpg

IMG_0005_NEW_zps5aa826e8.jpg RoyBaconText_zps81225eb9.jpeg
 
dobba99 said:
Yep, They have. I scanned and posted the paper cuttings back in 2014
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That would explain that then including the save date (and probably saved them from this very thread !)

Maybe it was due to the thought of making a DOHC cylinder head for my S7 Deluxe, I bought a AMR300 instead.
 
Progress of sorts. Managed to buy the Merlin engine from Dave (who along with Matt got the pile of Norton stuff from the family of the man who sadly passed away)
The engine was run on Castrol R, when it last ran was probably forty plus years ago. Also in the deal was a Nourish crank that has the extended drive side for a Mk3 electric start, carbs (Mk2 amals), one exhaust pipe (from the show bike) and a modified inner primary drive case. I think the welsh chap had the crank made as its has what i think are date stamps of 9 82 and N1
It is going to be a slow strip down as i have to measure the valve timing before i can take the head off. The cam sprockets (i know they are toothed belt wheels) are just held on tapers on the cams, no keys, dowels, pegs, or any positive location at all. I've just managed to free off the crank but the jockey shaft that has replaced the camshaft is still seized so can only just turn the crank within the slackness of the cam chain!
Even the wire lead to the points was seized in the case and took a hour of persuasion and a hot air gun to come out!
 
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