Main cap bolts. Help?

[r1ot]

I'm rebuilding a Ford Puma engine and have replaced all the main bearing shells (Ford say you can't, but you can) but I am having difficulty finding some replacement stretch bolts. Ford don't/won't supply them for that particular engine but I was wondering if anybody knows a equivalent bolt within the Ford range using the criteria below.

From bearing cap machined face to bottom of hole = 105mm

Bolt length from underside of hex head to end of bolt = 100mm

Total threaded portion = 75mm

Unthreaded portion = 25mm

Bolt is M10x1.5 thread/pitch

[steve_d]

Have you tried contacting ARP. As the leading manufacturer of aftermarket performance bolts and studs they may be able to help.
www.arp-bolts.com/Images/ARP_EU_Distributors.pdf

Steve

[r1ot]

I've tried arrow precision, who have been investigating arp stocks in the country and drawn a blank, for the time being. The guy there nick is going to have another crack tomorrow. I was trying to find something at this end

[that daddy]

Why dont you ring up Ford Uk and complain that is a ludicrous situation, we cant supply the bolts who do they think they are,you may find you have to buy a minimum amount 20 or 50 or something silly,thats what they did years ago when i was playing with X FLOWS and ESSEX engines,try another dealer.

[r1ot]

that daddy said:

Why dont you ring up Ford Uk and complain that is a ludicrous situation, we cant supply the bolts who do they think they are,you may find you have to buy a minimum amount 20 or 50 or something silly,thats what they did years ago when i was playing with X FLOWS and ESSEX engines,try another dealer.

Thanks, but that doesn't help. What I want to know if anybody has used similar bolts on another engine not necessarily in the ford range that I could use in my application. Any ideas?

[knightly]

if the bolts have not reduced in diameter (necked) you can re-use them.....just get a digital vernier caliper and measure all the way along the threads......you will soon see if they have "necked"......I can pretty much assure you they wont have........to be honest with you replacing head/main/big-end bolts is a big con to generate big aftersales for Ford.......I design diesel engines for a living and the cylinder pressures are much higher than gasoline stuff, and our drawings clearly state that you can re-use the bolts, and yes, they are a 10.9 grade, torqued PAST the yield point.

as a rule the non-engaged thread must not be less than 0.1mm less than the diameter of the engaged thread......any more than that and they will need to be replaced........ to be honest when a bolt "necks" you dont need a vernier - its blatantly obvious to the naked eye. measure em up and let us know.

Edited by knightly on Tuesday 30th January 11:45

[motorwise]

find out from your local engineering shop who supplies their hardware for these applications and either contact them or get them to supply them for you

[motorwise]

the reason ford don't supply is because they regard this as a throw away engine - obviously you and I know they can be overhauled succesfully but ford don't supply the bits

[GavinPearson]

In the absence of anything else buy M10x100 cap head bolts (allen bolts), grade 12.9.

Strength will not be an issue.

[knightly]

to add some more food for thought - I previously worked at Mountune as an engine designer and worked heavily on the puma and fiest super 1600 rally engines, and the 1700 was obviously the basis for the 1600 rally engine in de-stroked form for the puma - they produced about 225bhp at over 9000 rpm, and I dont seem to remember running special main cap bolts.......I think we used standard........I would advise you steer well clear of 12.9 grade bolts - they will be too brittle for this sort of application and may well fail, whereby the head will crack off.......stick to a 10.9 grade, or whatever is standard...... I have never seen 12.9 grade bolts used in an engine for this very reason......now I dont have my Zeus book to hand but I think M10 x 1.5 pitch is a non standard size, and you will just not find anything off the shelf.......as I said above - just measure them up for signs of knecking, if OK dont be afraid to re-use them.......oh yeah - the 1.7 is a Yamaha designed engine.

[r1ot]

I checked all the bolts with my digital verynear and thete was no sign of necking all the threads appeared to be parallel. The bolts do have markings on the top "KX 1020" also since the tightening torque is unknown what would be a good figure to start with.

[knightly]

I have never heard of that grade - I have googled it to hell and back and it appears to be a low carbon steel fastner that is heat treated to ASTM A108 spec......so its nothing special......if I had to put money on it its just a plain old 10.9......ford would never fit anything exotic - as exotic stuff gets an exotic price tag - ford just do cheap.

as for the torque - god knows......as a guide - if you can find the equivalent torque for the ford 1.6 sigma/duratec motor used in the current fiesta that will be your best bet - because the two engines were both designed by Yamaha, and the architecture / layout is near identical - some parts are actually interchangable......surely a service manual is available for the fiesta!

[wheeljack]

OK, the part number 96MM-6345-B1A or 96MM-6345-B2A.

It is a Ford special and the tightening torque for assembly is:

17.6 to 19.6Nm snug-fit

then

55 to 65 degs

There is a sequence to tightening but I'm afraid I can't find it, and the ETIS seems only to cater for those who buy the whole short-block. Usually they use a rundown machine which does the outer caps simultaneously and then the inner ones. I don't know how this should be done individually.

Sorry I couldn't be more help!

Phil

PS Knightly do you (or have you) work at DDC?


ETA: The bolt has a UTS of 1020-1170 MNm-2 and yield of 860 MNm-2 pretty close to a 10.9

Edited by wheeljack on Wednesday 31st January 15:34

[r1ot]

I love pistonheads how do you people find this stuff out?

Thank you for solving a mystery.

The ladder frame which is all the bearing caps locates quite tightly into the block so as long as it's lined up should hold itself in place whilst the bolts are being tightened up. As to doing them up simultaneously could be a problem but if I tightened them up in increments of 2Nm to the intial setting torque on the outers and then the inners I might be able to replicate what Ford do, probably easier than finding 4 torque wrenches!

one final query should anything be put on the bolts when assembly is being made, something moblyeum(?) grease?

[knightly]

wheeljack - yup I used to work in DDC in 2003 for Alan Towey - who are you?.......are you that nutter with a cozzy V6 supercharged taxi ;-)

[wheeljack]

knightly said:

wheeljack - yup I used to work in DDC in 2003 for Alan Towey - who are you?.......are you that nutter with a cozzy V6 supercharged taxi ;-)

I think I know who your talking about.....not me! YHM

[wheeljack]

r1ot said:

I love pistonheads how do you people find this stuff out?

Thank you for solving a mystery.

The ladder frame which is all the bearing caps locates quite tightly into the block so as long as it's lined up should hold itself in place whilst the bolts are being tightened up. As to doing them up simultaneously could be a problem but if I tightened them up in increments of 2Nm to the intial setting torque on the outers and then the inners I might be able to replicate what Ford do, probably easier than finding 4 torque wrenches!

one final query should anything be put on the bolts when assembly is being made, something moblyeum(?) grease?

Cut me in half and you'll find a blue oval!

Being torque and angle will take some of the variation out of the bolt clamping force (versus just torquing alone), but I guess cleaning the threads and a spot of grease won't hurt to even out the friction and hence clamping.

[GavinPearson]

wheeljack, you have mail.

[grahambell]

r1ot said:

I'm rebuilding a Ford Puma engine and have replaced all the main bearing shells (Ford say you can't, but you can) but I am having difficulty finding some replacement stretch bolts.

Hi r1ot,

Bit late with this, but could be worth you asking Power Torque Engineering in Coventry who do all the specialist Ford Powertrain stuff and might be more help than your local Ford dealers.

[r1ot]

just to let you all know that the bearing shells turned up from Impulse Developments and I refitted the crankshaft. I had to scrounge around a bit to find a torque wrench that went down to 17Nm but mangaged to sucessfully torque all the bolts back up to the required settings. I was absolutely cacking it when I was doing it as I didn't want to over do it and lock the crankshaft but now I have a crankshaft that turns evenly with no points in which it locks.

I have one gripe though, bloody Ford I ordered about £400 worth of bits to rebuild the engine on monday and was told it will be in on thursday. Got there and only half the stuff was in and I've got to go back tomorrow to pick the rest of it up. I mean, come on how hard is it to find 16 valve stem seals and to only send me 8, jeez. Also to supply one conrod bolt and then have to go back and pick up the other 7, arrrgghhh.

Thanks to everybody for your help.

Richard

Edited by r1ot on Thursday 1st February 17:50