Hone big end housings to true

[Witofthestaircase]

Having left crank rods etc at a well established shop for checking, crack testing and balancing, I've been presented with a bill featuring 'Hone big end housing to true' for all the rods. Can anyone tell me what is involved in honing the big end eye of a con rod to true? I'm curious because a) I think of honing as a size adjusting and surface refinishing process dependent on the pre-existing round/trueness of the subject (such as replaced bushes or cylinder bores) and b) I imagined that the the big end eye diameter tolerance would be minimal in order to control the bearing crush with any ovality or out of trueness requiring an equal amount off the rod and cap mating surfaces and a reboring of the eye to spec. The shop is being a little unforthcoming about details and dimensions, seemingly because of the nature of the communications between the counter staff and machinists. I'd like a little reassurance if possible!

Many thanks

[rgh0]

Like you say you would normally do this by taking a small amount off the mating face of the bigh end bearing cap and rod to close up the housing and make it fractionally undersize. Then you assemble and bore and hone it to return it to the correct dimension to achieve the design big end bearing crush. Not a commonly required operation and i would want to understand why it was required. Fitting and honing to size new small end bushes is normal and maybe it was this and it got lost in translation from workshop to bill?

If you have the measuring tools its always wise to measure parts and determine what machining is required before giving them to a machine shop with a specific list of what you want done. If you dont have the tools or knowledge then try to talk to the machine shop about what they measure and what they will do based on the measurements and get them to ring you and confirm the work required after they have completed the assessment.

cheers
Rohan

[Baggy2]

Hi,
Is your 'well established shop' in East London and known by three letters by any chance? If so I'll pm you with my experiences.
Regards
Baggy

[elansprint71]

Maybe we should establish a list of "rogue traders" in order to avoid forum members having bad experiences? This could easily be done in such a manner as to avoid litigation.

[nebogipfel]

Maybe we should establish a list of "rogue traders" in order to avoid forum members having bad experiences? This could easily be done in such a manner as to avoid litigation.

Not a good idea IMO.

We are all fallible. Things do go wrong from time to time and there may be misunderstanding between two parties.

It's a fact of life that folk usually only talk about bad experiences, all the good ones pass without comment.

The OP needs to go back to the workshop supervisor/foreman and establish the facts.

[Witofthestaircase]

Thanks Chaps I'll report more as it emerges Regards, Russell

[Jason1]

Burtons would be my first choice if I needed an TC rebuild in East London.

I used to use a 'well establish' firm in Dagenham with 2 letters who where very good and very well priced 15 years ago. I have heard reports more recently from people that they are not what they used to be. Very sad because they used to be very good.

Jason

[MickG]

Just to add confusion to the issue.
I enquired at Burtons about twin cam machining and they told me that they didn't do it themselves but send the engines to what may be the same three letter company in Dagenham
Mick G

[Chancer]

Its a standard line that is added to all invoices for appropriate engine work to pad out the bill, a bit like the garages do on servicing invoices, brake cleaner, recycling of old component, blah blah blah.

Something thought up by someone in accounts that gives a 100% margin.

[StressCraxx]

I respectfully disagree with the above opinions that this process is to simply pad the bill. Honing the big ends reestablishes the center to center distance between the big end and the wrist (gudgenon) pin bores. This dimension is important. So is removing any trace of ovality to the big end. If there is any ovality, the new bearings will quickly conform to the con rod bore.

If I do a major overhaul on any engine, I have the rods inspected, resized and honed back to original spec.

Regards,
Dan Wise

[rgh0]

Hi Dan

I agree it is important when required but it is rarely needed to do the big end bearing housing, normally only the small end bush needs work and its not trvial in time and cost to do when the big end also needs work.

I would expect a reputable machine shop to specifiy this up front with a cllent as a cost of $xxx if needed and to complete the inspection and quote the results of their measurements and whether the big end bearing housings needed work.

In the end you either measure it up yourself or trust the machine shop to measure and report fairly. But either way a big extra unexpected item should not appear on your bill after the jobs been done.

cheers
Rohan

[StressCraxx]

Thanks Rohan,

I have to trust my machine shop, because I do not have the tooling to accurately measure. The last time I rebuilt my Twink the shop said the rods were within spec and did not require resizing. I am fortunate I have access to a reputable shop with a very good engine builder/machinist.

I had the rods resized on my Formula Ford engine about 4 years ago. The cost was not unreasonable. I will likely do it again for the winter rebuild. We have to be careful when doing so, because the rods have a minimum weight spec under Formula Ford rules. I agree the small end needs attention too.

Regards,
Dan

[rgh0]

Generally when a shop quotes "resizing" they are just talking about doing work on the small end bush which is a relatively quick and simple job to replace and rebore to size at the correct pin to pin rod length.

if working the big end as well they will normally show this as a separate item to "resizing"

cheers
Rohan

[tcsoar]

Just to add confusion to the issue.
I enquired at Burtons about twin cam machining and they told me that they didn't do it themselves but send the engines to what may be the same three letter company in Dagenham
Mick G

Just to add even more confusion did you talk to Burton Power or Burton Engineering? Burton Power is where you will get your parts from, complete with on-line shop. Burton Engineering is a small engine shop with a very good reputation. Burton Powers address is 617-631 Eastern Ave, Burton Engineering is 621 Easten Ave, .

Have a look on google maps street view and you will see that the enginnering shop is actually placed between the shop and the engine shop of Buton Power.

From what I have heard they were the same place a long time ago but not anymore and Buton Power do not point people in the direction of Burton Engineering.

Chris.

[Jason1]

they were the same place a long time ago but not anymore

That's news to me but I left Dagenham and working in a garage over 12 years ago. I only go back when I have to.

I remember getting a Vauxhall Nova head skimmed, valves recut, new stem seals and lapped in for ?15!!!!