• Welcome to the website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Hon. Editor and Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this website.

    If you have previously registered to use this forum, you should log in now. CLICK HERE.

    If you have never registered to use this website before, please CLICK HERE.

E: Engine Lapping head into barrel video

craig

Well Known and Active Website User
VOC Member
20210513_HeadLapToday1.jpg
Is there a video of some competent Vincent mechanic lapping the heads in to the barrels.
Description of the exact brand name and grade of compound used , application technique, etc.

Then a show of how you hold the barrel and head and apply pressure and twist.

Then a clean up and inspection and possibly reapplication.

I realize these bikes are quite new and maybe we haven't had the time or need for this.

Thanks
Craig

The machine work was done 7, 8 years ago , i didnt like my current measurements on fit up altho they seemed close, so this is a follow up by me .

Should i just chuck these heads up in a lathe and make sure i have couple thou clearance head to muff?
 
Last edited:

Cyborg

Well Known and Active Website User
VOC Member
I
I always put them in a lathe, skim and make 0.03 mm interference fit.

So far no problems.

The grinding has one big disadvantage: the head is not kept concentric to the muff, i.e. the liner rim is far to small to the head reces diameter
This might sound like a dumb question, but what ( if anything) do you use to support the end of the cylinder when it’s chucked in the lathe?

What sort of setup do you use for attaching/truing the head to the face plate? I have the bolts to hold the head and its simple enough to make the spacers, but wondering if you have any tricks for truing it up... or do you just use shims?
 

timetraveller

Well Known and Active Website User
VOC Member
Top- hat bushes with centres. The top hats are made to be a good fit in whatever bore size you are using. The tail stock in the lathe has a centre. The chuck is fitted with a centre and the kind of device that will drive it, like for grinding but is not able to impart any side loads. Then you can skim both the top and the bottom. The bottom is particularly important if low clearance pistons are to be used.
 

vibrac

Well Known and Active Website User
VOC Member
Old farts in Vincenteering may know better but I cannot see a need for much more than one thou / 0.03 mm gap between head and cylinder liner flange. You just want a tad more load on the flange than on the large face of head. Get that gap much more and don´t be surprised about warped cylinderhead and muff. I prefer to have a wide contact head-muff sitting firmly bolted up , don´t think you get a better seal with three thou but only deformation in components.

Vic
I stand to be corrected as I dont have a copy of Richardsons to hand But I think three thou was his recommendation, if so I am happy to join the management of Vincent factory Stevenage as being classed as an old fart :)
 

Cyborg

Well Known and Active Website User
VOC Member
Top- hat bushes with centres. The top hats are made to be a good fit in whatever bore size you are using. The tail stock in the lathe has a centre. The chuck is fitted with a centre and the kind of device that will drive it, like for grinding but is not able to impart any side loads. Then you can skim both the top and the bottom. The bottom is particularly important if low clearance pistons are to be used.

I was wondering about skimming the top of the liner as well. I have a rig that holds the cylinder in the chuck (without distorting the bottom of the liner) for boring, but it requires a top plate which would double as a torque plate. Assuming that a torque plate would be of any benefit if one ended up using that 0.03 mm number. I don’t have an expanding mandrel big enough.
 

Vincent Brake

Well Known and Active Website User
VOC Member
Somewhere in an very ol ol old picture here it shows...
We ol farts are getting bit to ol to find a link...

Sorry its wine o clock.

Yes mr Ernie L. i have opened up an other bottle.

Beter...
 

clevtrev

Well Known and Active Website User
VOC Member
Old farts in Vincenteering may know better but I cannot see a need for much more than one thou / 0.03 mm gap between head and cylinder liner flange. You just want a tad more load on the flange than on the large face of head. Get that gap much more and don´t be surprised about warped cylinderhead and muff. I prefer to have a wide contact head-muff sitting firmly bolted up , don´t think you get a better seal with three thou but only deformation in components.

Vic
That will depend on the quality of the muff you are using, use a series D one and have fun.
 

chark_mandler

Website User
VOC Member
Top- hat bushes with centres. The top hats are made to be a good fit in whatever bore size you are using. The tail stock in the lathe has a centre. The chuck is fitted with a centre and the kind of device that will drive it, like for grinding but is not able to impart any side loads. Then you can skim both the top and the bottom. The bottom is particularly important if low clearance pistons are to be used.
So long as the top of the crankcase is also square to the main bearings as well.
 

Can't Find What You Need?

Buyer Beware: Fake or Real?

The Mighty Garage Videos

List of Forum Categories

Top