The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Duncan R on 06.11. 2010 17:53

Title: Average cost of bottom end rebuild
Post by: Duncan R on 06.11. 2010 17:53
Had some engine trouble today,tried to restart and it only fired up on one cylinder. The right hand plug gap was closed right up and there was a nasty metallic sound on the top end. I guess the plug is coming into contact with the piston (broken rod?) engine turns freely and compression is good

This has now bought forward my planned engine overhaul, I was wondering what the approx cost of a bottom end rebuild is  - crank regrind,sludge traps cleaned,bushes, big end bearings, balance and line bore plus reassembly. This asuming no other parts need replacing. Also can anyone reccomend and engineer in the Kent area who can carry out this type of work?

Many thanks

Duncan
Title: Re: Average cost of bottom end rebuild
Post by: Goldy on 06.11. 2010 18:15
Sorry to hear that Duncan. If you look on the SRM website they list prices for all the work involved. This will give you some idea, and you will possible find you local Engineer is a bit cheaper.                                                                                                http://www.srmclassicbikes.com/engine-and-gearbox-reconditioning-service/crankshafts
Title: Re: Average cost of bottom end rebuild
Post by: alanp on 06.11. 2010 18:26
It's tricky to work out the prices for SRM to sort out your engine since they will need the engine at their works to enable them to take a detailed look at it and then quote you a detailed list of work to be done and prices. My bottom end cost me £1284.14. Seems a lot but they do a good job.
Alan
Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 06.11. 2010 19:16
Thanks for your replies - I know that SRM do a top quality job, but I can't lay out that sort of money. I will prob have to do the re-assembly myself(I have rebuilt BMW and Japanese engines before) I Just need some one to do the engineering works.
Title: Re: Average cost of bottom end rebuild
Post by: chaz on 06.11. 2010 19:19
very difficult to price that sort of job up, so many plus or minuses.
man bearing £30 but then yours  may be ok.
shells possibly the same a pair., depends on strip down you may need other bearings.
regrinds £15 a diameter, yet again may or may not be needed.
rods, anything up to £80 a pair but Ive rebuilt wth used rods a fraction.
gasket set around £30
sludge traps cleaned as a matter so no charge, labour £40-50 per hour.
but then the question to ask is how about as you have brought forward the overhall you might as well look at the full deal as hone or rebore yet again a big price difference, valve guides, recut seats or even add on vapour blasting of cases etc.
Title: Re: Average cost of bottom end rebuild
Post by: andy2565 on 06.11. 2010 19:24
i just had mine done by rob wardle,who does JB restorations engines,more than half the price of srm,that was with needle roller convertion,shells,pump rebuild etc,wouldnt go to srm,just on principle of price,
Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 06.11. 2010 20:15
The problem with my engine is that I don't know what parts have been used in the last "rebuild" I bought the bike in India and the timing side bush was redone in Delhi about 1000 miles ago. I know that  the bush was made to fit the crank as the max undersize bush I gave them was miles to big for the crank. I have a good secondhand crank now so I will need a set of bottom end bearings. Also looking at the pistons when the engine was down I was not convinced they were even BSA pistons. I know also have a decent secondhand camshaft and conrods and a set of standard pistons (so need a resleeve as well)

As you say Chaz, I might as well go for the whole works

Andy - could I ask where Rob is located?
Title: Re: Average cost of bottom end rebuild
Post by: andy2565 on 06.11. 2010 21:29
 if its come from india,take it as a total rebuilt ,all parts suspect,i have shipped loads of bikes back from india and sent along time there to,may i ask who you bought it from,just out of interest,robs in newcastle,but i'm in wolves,i bilt myself a box and sent it by courier.
Title: Re: Average cost of bottom end rebuild
Post by: Stu55Flash on 07.11. 2010 00:32
Rob did a great job on my A10 Plunger. End feed. Big ends, small ends reassembly about £400. Go's like a train and sounds like   a sowing machine. He does a oversize rebore with datson pistons! top bloke and highly recommended.

Stu

Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 07.11. 2010 09:56
Hi Andy,

I got the bike from Vinod Sharma in Delhi. I ran it for about 3 years in India without any major issues until my last year in India. I knew full well that the engine was a time bomb, so have been expecting problems. I have slowly been collecting parts to try and get a decent engine together.

Hi Stu,

The rebore sounds interesting,what is the capacity? Price sounds good for all that work.Any contact details for Rob?

Thanks

Duncan
Title: Re: Average cost of bottom end rebuild
Post by: andy2565 on 07.11. 2010 17:47
 i know vinod really well,i lived in his yard for a year,but i would say you'll  still need a good check over,rob wardle and i'll pm you his number.
Title: Re: Average cost of bottom end rebuild
Post by: BSA_54A10 on 07.11. 2010 23:31
Pull the head and have a quick look.
It might be something really stupid like a bit of crud ( washer, bit of gravel , that missing ball bearing ) sitting on top of the piston.
Could also be a worn plug thread allowing the plug to go a bit lower in the head.
OTOH it could also be a loose rod.
So it would also be a good idea to pull the sump and see what is in there.
Then you can decide what to do
Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 08.11. 2010 08:58
Thanks for the number Andy. I used to spend a lot of time at Vinod's just hanging around and drinking chai,lovley guy.

I am going to start on the engine today and see what is going on. As you say Trevor must be some debris floating around in the combustion chamber. Engine was running prety smooth with no excessive vibration, I shone a torch down the plug hole and you can see the pock marks on the piston crown.
Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 08.11. 2010 17:18
Well I got the head off eventually - some numpty had replaced a rocker box bolt with a stud so there wasn't enough clearence to lift the rocker box off to get access to the cylinder head bolts *problem*,after some keyhole surgery I managed to get all the bolts out and slide the head and rockerbox off together.

I found sitting on top of the piston (RH) a small chrome plated nut in 4 pieces *dunno*, where this came from and how it got in there is beyond me. There are a few pock marks in the combustion chamber and piston crown, there appears to be no damage to the bores or the valve heads. It must have got in via the carb/inlet manifold, I do have an airfilter fitted. Tomorrow I will drop the sump and also have a look inside the timing cover
Title: Re: Average cost of bottom end rebuild
Post by: wilko on 08.11. 2010 21:56
She'll be right, just shove it back together and ride it! The nut was probably sitting inside the airfilter for years and decided to commit suicide!
Title: Re: Average cost of bottom end rebuild
Post by: Duncan R on 09.11. 2010 08:53
Hi Wilko,

I think I might just do that - the 4 pieces of the nut fit together like a jigsaw so as far as I can tell there is no other debris, motor was running v.good prior to this.