The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: TT John on 04.12. 2019 09:48

Title: Rebuilding top end
Post by: TT John on 04.12. 2019 09:48
I was so upset yesterday, I put another head on my A7 and it took me all of three minutes to get the push rods in place, that was because one of my copper gaskets moved stopping the stud going through the hole at the front, once I realised it was soon sorted but then fitting the head steadying links I dropped one, I heard it hit the floor but could find no sign of it, moved the bike out completely, still could not find it, after a nights sleep I thought just maybe it may have caught up in the engine somewhere so this morning went to have a search round again and low and behold it had wedged between the exhaust pipe and frame, that set me back a little but no worries, it's done now.

Regards TTJohn
Title: Re: Rebuilding top end
Post by: AdrianJ on 04.12. 2019 09:55
I wish I could get my push rods in place in 3 minutes.
I haven't got the knack yet (if there is one).
Takes me ages.
Adrian
Title: Re: Rebuilding top end
Post by: Swarfcut on 04.12. 2019 10:13
You and me both, Adrian. Talk of copper gaskets and head steady links make me think this is an earlier, Longstroke type, with two rocker boxes. Still, 3 minutes is a bit quick.

 Once dropped a piston circlip into the crankcase of a Lambretta LD. Got my mates round, turned it upside down and it fell out. No one thought of a dab of grease on a stick, or pushing a bit of rag around the crank. Youthful exuberance...Nah idiocy.

Swarfy.
Title: Re: Rebuilding top end
Post by: Sluggo on 04.12. 2019 10:47
Once dropped a piston circlip into the crankcase of a Lambretta LD. Got my mates round, turned it upside down and it fell out. No one thought of a dab of grease on a stick, or pushing a bit of rag around the crank. Youthful exuberance...Nah idiocy.

Swarfy.

Hah!  Yes, I know that feeling.  Always reminding people, especially when I worked in the military or govt service that we can solve problems and tasks with manpower or by working smarter and more efficiently.  You would think as stewards of the taxpayers money it would resonate that being smart and efficient were admirable traits to emulate but alas....... no.

Here is an account of a US Special forces guy who always has great insights and experience in a discussion about the different mindsets in their community.  Relatable but off topic a bit.

" One more, the definitive difference between SF and Rangers. TRUE STORY

I was a BNCOC instructor at Ft McCoy, WI. I (long tab) and two short tabbers were walking through a H shaped classroom building and noticed the door to a classroom which office had a class 'A' phone slightly ajar. We went into the classroom then it's office and made calls all over the US. Finished we walked out the classroom closing the door behind us. One of the Rangers said, "damn I left my car keys on the desk.

The classroom door locked when it was closed. It had a strike plate. We went outside and found the back door locked and also a strike plate. The windows had locked cages.

One of the Rangers shouted that he had his tools in his truck and they could take the hall door off the frame. They took off running. A Ranger Mission!

I walked to building 1435 (admin) and signed out the master key. I returned to the classroom, unlocked the back door, grabbed the keys and walked through the classroom. When I got to the classroom door the two Rangers were lifting the door off the frame. I tossed the keys and said, yea, Rangers Lead the Way. True story."
Title: Re: Rebuilding top end
Post by: TT John on 04.12. 2019 11:15
Hello all,

The method I use is pretty easy to get the push rods in, especially using my soft copper gaskets, firstly put the gaskets in place no need for any sealant, clamp the large gasket to the head using the comb & welding mole grips, that's the ones with the flat jaws, make sure that the two holes match up, put the push rods in place, turn the engine over so that the rods are almost equal, gently slide the rocker box over making sure you get the central web in the middle from the front, lower onto the head, checking you have captured the rockers on the way down insert the first bolt, middle, then put the others in, remove comb, job done.
See attachment.
Title: Re: Rebuilding top end
Post by: duTch on 04.12. 2019 12:06
 
Quote
.... No one thought of a dab of grease on a stick, or pushing a bit of rag around the crank. ...

 (I think I've figured a 'dab' is like a blob, but a 'daub' is the blob smeared on).....but that's not why I'm here......

 I have a magnet on a length of soft wire that I found somewhere a few years ago without realising what it was, has been *very* handy on many an occasion-  just used it an hour ago, but occasionally I lose it and go in a sweat, but usually find it stuck to something random...magnet is about 8mm diameter x 3/4" long- pic pending

 There's been at least one diagram with measurements of how to make a comb- might have to chase it up sometime......
Maybe this'll work;

A scan and measurements of a comb.
Cheers


https://www.a7a10.net/forum/index.php?action=dlattach;topic=1787.0;attach=12461;image
Title: Re: Rebuilding top end
Post by: berger on 04.12. 2019 12:18
i can't use a comb dutch, have to use a brush hairs to long *whistle* *bash*
Title: Re: Rebuilding top end
Post by: duTch on 04.12. 2019 12:34

 
Quote
i can't use a comb dutch, have to use a brush hairs to long *whistle* *bash*

 bluddy 'ippie  *ex*......me too.... *eek*

 I'm surprised how well that executed ^^^
Title: Re: Rebuilding top end
Post by: Swarfcut on 04.12. 2019 12:40
Well that's me banged to rights. That TT 's a very clever fella, and I got the wrong end of the spanner (again).

Nice one, TT.  Good story from Sluggo, Yup, lateral thinking usually wins the day with far less effort.

Swarfy
Title: Re: Rebuilding top end
Post by: RDfella on 04.12. 2019 16:40
Dutch, those small cylindrical magnets are ideal for the purpose in question. I usually poke one into a length of small bore rubber fuel hose - gets round corners a treat.
Title: Re: Rebuilding top end
Post by: muskrat on 04.12. 2019 19:07
G'day fellas.
I use a method very similar to TT.
At least if something drops from the rocker box it only goes as far as the lifters.
The old drop the pin clip in the case can be a nightmare. Good job our motors have a sump plate.
The worst thing about a top end is getting the valve spring cotters in. Think their in and release the compressor. Ping, one fly's across the shed. Wish I had a $ for every hour spent hunting. Good excuse to clean out the shed.
Cheers
Title: Re: Rebuilding top end
Post by: bikerboy on 05.12. 2019 00:41
TT

I have bent my comb exactly like yours and sometimes use the same method :)

I will add, because I like being smug, is that I can do them just as quick without a comb but then that leads to the question of just how many times have I done that damned job :(

I will admit on the plunger with the alloy head on it then it becomes a bit more tricky as those rear studs are a lot longer on the alloy head :(
Title: Re: Rebuilding top end
Post by: muskrat on 05.12. 2019 10:33
Another reason I luv my A7 plunger. !/2" more room for the alloy head!
Cheers
Title: Re: Rebuilding top end
Post by: duTch on 05.12. 2019 12:00

 
Quote
...........I will admit on the plunger with the alloy head on it then it becomes a bit more tricky as those rear studs are a lot longer on the alloy head :(.....

 I think there's some of those studs that have two flats carved below the WW threads for a small spanner so they can be easily screwed out and in to make that easier....if I'm wrong it's something I intend to do

 In the thread where I found that comb pic there's an explaination of the process I used to install my rockerbox last time, but can't find it easily now (thought it'd be in my search history)
Title: Re: Rebuilding top end
Post by: TT John on 05.12. 2019 15:21
Hopefully, the explanation & picture of how to do it easily will help someone out there who is struggling every time they come to doing this job, at least it takes the fear out of it.
For anyone interested, I do have the solid copper gaskets for sale at £16 per set plus p+p and I will be taking some to the BSA awards weekend at Scarborough this weekend. also M20/21 solid copper head gaskets both sets are made from C101 soft copper, so there is no need to anneal them.

Kind regards TTJohn
Title: Re: Rebuilding top end
Post by: Billybream on 05.12. 2019 16:59
I,ve always used the a bent comb, but struggled to secure it, tried clamps etc but the welding mole grip could have been designed for the job, just treated myself via Amazon
Title: Re: Rebuilding top end
Post by: TT John on 05.12. 2019 20:06
That's the one Billy, now you can do t with ease.

All the best TTJohn