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Torque values for tightening the heads on SP250

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wadams
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Joined: Wed Feb 01, 2017 4:07 pm
Location: Pontypridd

Torque values for tightening the heads on SP250

Post by wadams »

Hi Guys
Can anyone advise me as to the torque values I need to use to tighten down the heads on my SP250 please? I have followed the instruction in the manual but this did not work!
Thanks

Wayne

Vortex O'Plinth
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Re: Torque values for tightening the heads on SP250

Post by Vortex O'Plinth »

wadams wrote: Fri Jun 16, 2017 11:48 am Can anyone advise me as to the torque values I need to use to tighten down the heads on my SP250 please? I have followed the instruction in the manual but this did not work!
In what way didn't it work - did the head gaskets not seal?
Nick

"Don't bother with the Air & Space Museum - there's nothing to see.......".

fireboss
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Joined: Wed Feb 24, 2016 10:20 pm
Location: Whitby, Ontario

Re: Torque values for tightening the heads on SP250

Post by fireboss »

Wayne:

I saved this email from BT:


All the listed torque settings for the SP 250 are as follows:-
Cylinder head where studs fitted with nuts - 40/45 lbs. ft.
or where Bolts are fitted – 50/55 lbs. ft.
Connecting rod nuts – 28/30 lbs. ft.
Main bearing nuts – 25/30 lbs. ft.
Oil Sump screws – 10/13 lbs. ft.
Flywheel bolts – 43/48 lbs. ft.
Clutch to flywheel bolts – 14/16 lbs. ft.
Pinion bearing nut – 95/105 lbs. ft.
Differential bearing nuts on caps – 35/40 lbs. ft.
Crown wheel bolts – 50/60 lbs. ft.
Road wheel nuts – 60/65 lbs. ft.

Hope this helps, Bruce

wadams
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Joined: Wed Feb 01, 2017 4:07 pm
Location: Pontypridd

Re: Torque values for tightening the heads on SP250

Post by wadams »

Many thanks Bruce this is a great help.
Wayne

tjt77
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Re: Torque values for tightening the heads on SP250

Post by tjt77 »

Factory manual states 55-60 lbs ft (660-720 lbs ins) for head BOLTS.. given the propensity for head gasket issues.. this is an area that requires great attention to detail.. a number of things to consider..for bolts and torquing:- (1) the bolts are coarse thread.. so getting correct torque is a little tricky.. (2) crud build up threads in block will effect torque setting significantly.. its best to blow them out with solvent and comperessed air.. then check for thread binding with std 7/16" coarse bolts to make sure it will go full length with no binding/resistance..its wise to clean the threads on actual bolt as well..use a 'thread chaser' if there are nay binding issues that are no solvable with normal clean ing..(rather then a 'tap' which will remove metal) a bench or stand mounted rotary wire brush is good for clueing stud threads.. test again with actual bolts before putting head in position.. they need to go in easily to full length with NO binding whatsoever. a small dab of 'anti seize' on the bolt threads is recommended.
Other issues to check are head face for both warping an corrosion of water passages..
IF there have been any past problems with head gasket issues replace ALL the bolts or studs.. if they have been overtightend ( common) at any point tensile strength will be comprimised.. do NOT go over 65 ft lbs of torque .. or it will compromise the bolts and they are likely to give problems.
i use 'coppercoat' sealant in aerosol form of both sides of the gasket.. hang the gasket by a wire in a position you can get to both sides of it with a thin but even coat .. and allow solvent to evaporate and the sealer dry before assy..
years ago when building rolls royce turbo prop engines the manufacturers recommendation was 'hylomar' ..stippled on with a brush which had its hairs clipped back to get a thin but even coat all over on both mating surfaces.. its still a good product.. If properly applied.

tjt77
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Re: Torque values for tightening the heads on SP250

Post by tjt77 »

someone asked where to get 'coppercoat' in Uk ( I'm unable to access the message ..it was forwarded to my email) the answer is i dont know.. I believe they make hylomar in aerosol form in Uk and likely stockists such as 'halfords' would keep it .. or try 'Moss Motors' online..
another issue i forgot with head bolts installation:- the washers are chamfered on one side.. this chamfer needs to go on top.. it is in place to avoid binding to underside of bolt head. thereby effecting torque settings ... if in doubt check EVERY head bolt and washer for possible binding issues.. the washer should spin freely under bolt head.. a dab of anti size is wise..

daimlersteve
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Re: Torque values for tightening the heads on SP250

Post by daimlersteve »

OR, use the sp studs.
steve

wadams
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Joined: Wed Feb 01, 2017 4:07 pm
Location: Pontypridd

Re: Torque values for tightening the heads on SP250

Post by wadams »

Many thanks indeed Steve!

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