Skybrid

Summer 2023 update

• Late summer 2020 the 2nd Oldsmobile engine had a failure. In Early 2021, the Pontiac 400 engine, removed from the old Reserve winch, was installed. (At the same time as the winch was rewired) The Pontiac engine worked OK, a new water pump, divider plate and rubber seals were installed in April 2021.
• May 2022 - The rebuilt TH400 transmission failed again. JH made up a flexplate spacer plate which allowed a converter plate to link the Pontiac bell housing pattern with the Chevy Pattern of the spare TH400 transmission. The spare transmission was installed, and the winch worked OK.
• September 2022 - The Pontiac 400 engine was found to be down on power and a compression check showed no compression on one cylinder. Removing a rocker cover showed 1 loose rocker and one with a pushrod pushed through it. The cylinder heads were removed and the bores found to be in great condition. The engine was taken out of the winch and the sump removed - the bottom end was found to be in good condition too.
• The broken rockers were replaced (and a few others showing signs of wear) and all pushrods replaced. A new timing chain was installed and a new valley pan. (This later was found to leak badly, so BC got the original pressed steel valley pan repaired and installed that.

Background

A Tost model ?? converted and delivered by Skylaunch in March 2008. Cost of essential maintenance was similar to the cost of conversion: mounted on a twin-axle trailer with large, narrow drums, no paying on gear, new roller boxes and the Skylaunch panel. The winch is powered by an Oldsmobile V8 455 cubic inch (7.5l) capacity engine fueled with Propane gas. More details about the engine here:Oldsmobile 455 data. The power from the engine is transferred to the drive axle via a GM TH400 automatic transmission unit.

In early April 2019 the engine and automatic gearbox wore out simultaneously. The engine was replaced with an Oldsmobile 455 which had been rebuilt for, but never used, in a drag racing boat. The failed gearbox was taken for a complete rebuild and to reduce down time a replacement gearbox was purchased from Skylaunch and used temporarily until the original box was returned from the repairer. At the same time an external transmission oil filter and oil cooler were fitted. The repaired gearbox was installed shortly afterwards with a new flex plate and the temporary one placed in storage.

Work Required

• Fit missing rear axle bolts
• Check tyre pressures / determine 'correct' tyre pressures. Weight distribution always makes one pair of tyres look flat.
• Replace or repair stop lights.

NB: re torque half shaft nuts (300 lb/ft) every six months - remember to remove grub screws locking axle nuts before torquing. Failure to do this risks breaking half shafts.

• re torque exhaust manifold bolts as required (else gaskets blow)
• change auto trans oil every six months and filter every year - no auto trans failures have occurred since doing this.

General Maintenance Notes

Roller box maintenance

• How to change a roller: Media:Roller_replacement.pdf

Disc brakes

• Parts from Hyundai Coupe Reg.no: BP51 TMO

Winch brake drum removal procedure

If necessary a cable drum can be removed without removing the cable, however, note that if this is done the guard rail on the Skybrid drum must be protected.

• Position the winch under the crane with the centreline of the axle under the gantry.
• If air tools are to be used position the gantry crane on level ground within 20 metres of the compressor.
• Loosen the drum retaining bolts, the axle nut and the half shaft end plate retaining nuts.
• Use a suitable rope sling to prepare to lift the drum, take care to avoid damaging guard rails.
• Take the strain and and remove the drum nuts
• Use a pair suitable 10mm bolts to jack off the drum.
• Lift off the drum and tie it to the gantry stanchion. Do not allow full weight of drum to rest on guard rails.
• Remove the half shaft nut
• Removed the half shaft flange retaining nuts.
• Place an oil tray under the flange to catch oil.
• Break the seal between the half shaft flange and the brake drum and slide it outwards.
• Mark the angular position of the flange relative to the half shaft
• Use a sledgehammer and protective aluminium plate to 'break' half shaft taper
• Use a large screwdriver to lift the flange on the bearing retainer, then using a suitable drift unscrew the locking ring
• Remove the bearing retaining ring and keeper plate
• Remove the brake drum
• Note that if the brake back plate is removed that the retaining bolts are drilled straight into an oil reservoir. Be prepared to catch any lost oil.

NB: The recommended oil level in the differential and dog clutch boxes comes half way up the half shaft tube and floods back into the axle bearings. Consequently the only things that prevents the axle oil from leaking out into the brake drums are the brake drum oil seals (type 125 95 13 TC from Simply Bearings). It is recommended these are replaced whenever a drum is removed. See notes in para below on finding/monitoring ideal oil level.

The differential oil must be replenished to the dip stick level with 80W/90 gear oil.

Parts replaced / work done

• September 2022 - The Pontiac 400 engine was found to be down on power and a compression check showed no compression on one cylinder. Removing a rocker cover showed 1 loose rocker and one with a pushrod pushed through it. The cylinder heads were removed and the bores found to be in great condition. The engine was taken out of the winch and the sump removed - the bottom end was found to be in good condition too.
• The broken rockers were replaced (and a few others showing signs of wear) and all pushrods replaced. A new timing chain was installed and a new valley pan. (This later was found to leak badly, so BC got the original pressed steel valley pan repaired and installed that.

• May 2022 - The rebuilt TH400 transmission failed again. JH made up a flexplate spacer plate which allowed a converter plate to link the Pontiac bell housing pattern with the Chevy Pattern of the spare TH400 transmission. The spare transmission was installed, and the winch worked OK.

September 2021

• Annual maintenance completed. Engine coolant changed from blue to red 30%. The crankshaft damper had collapsed causing damage to the fan belt. Radiator removed and damper replaced. Alternator fitted with correct pulley to match fan belt profile. Axle oil drained and found to contain grey sludge - needs changing every two years (axle takes 3 litres of EP80-90). CB/RP/JH NB:Engine & transmission oil and filters were not changed as they were reported to have been done in the Spring.

• Late summer 2020 the 2nd Oldsmobile engine had a failure. In Early 2021, the Pontiac 400 engine, removed from the old Reserve winch, was installed. (At the same time as the winch was rewired) The Pontiac engine worked OK, a new water pump, divider plate and rubber seals were installed in April 2021.

26th Feb 2020

• Righthand cable drum brake master cylinder replaced due to old one seized. RP

15th Oct 2019

• Dismantled, cleaned and reassembled guillotines. Cable cutting test satisfactory with two strands per Skylaunch recommendation. Engine and transmission oil still clean after recent rebuild - change all oils and filters in Spring 2020. Air filter OK. Oil leak on transmission drain plug fixed with PTFE tape. Axle nuts re-torqued. Emergency bolt cutters hung on cab door. CB & RP
• Cab recently part lined with anti-drum foam. MS

Sept/Oct 2019

• New 4-branch exhaust manifolds fitted and pipes reworked to suit. Wiring to starter rejigged. JH

May 2019

• Expired OLDS 455 engine stripped. Hole in inlet manifold. New valve seats required. Valves serviceable. Bores and bottom end to be inspected. Possibly able to build a short engine?

20th May 2019

• New gas vaporiser fitted (old one had damaged internal seal and leaking water)

8th May 2019

• 1500m new cable fitted to LH drum. 1200m new cable fitted to RH drum. SH plus various helpers.
• Monthly guillotine check done. RP, MS

Period 17th - 30th April

• JH obtained reconditioned TH400 transmission from Skylaunch and fitted it with various help. Opportunity arose to fit transmission oil pressure gauge for diagnostic purposes (oil pressure relates to carburettor vacuum and controlled by adjustable vacuum operated spool valve. Flex plate found to be cracked, so to keep operational a non-matching replacement was fitted with incorrect crankshaft hole pattern. Later discovered insufficient flex plate clearance due to different bell housing dimensions. Original trans to be refitted with correct flex plate asap.

May 2019

• Engine stripped. Valves serviceable, seats need replacing. Inlet manifold needs repair to leak. Bores not checked. Bottom end needs inspection. Possibly rebuild as short engine?

17th Apr 2019

• Gearbox removed to be taken to Newbury Transmissions. JH,CB,WC,RP Later found to require replacement casing and total rebuild.

16th Apr 2019

• Oil change and filter. New air filter. Small bits of metal found in transmission sump pan. Gearbox declared unfit for launching. CB & RP

2nd/3rd April 2019

• Engine expired over the previous weekend due to a hole in the inlet manifold. Recently purchased conditioned engine fitted. JH,WC. Test launching successful on 7th April.

17th November 2018

• Auto engagement lever wrenched back beyond gate displacing ignition inhibitor reed switch. Mechanism stripped, repaired and readjusted. CB,JW & WC

31st October 2018

• Removed and sharpened blades on RHS guillotine. LHS done since 5th Oct. Both guillotines now fully serviceable. CB & RP
• Transmission oil changed. RP

5th October 2018

• Engine/transmission area cleaned and de-greased.
• Engine oil and filter changed.
• Transmission oil changed - (filter only three months old)
• Annual guillotine service/check. On reassembling, unable to get perfect cut. CB to sharpen/reset blades and obtain spare ones.
• Main half shaft nuts checked for tightness. RP & CB

3rd August 2018

• Replaced worn brake pads on RH cable drum. Sealed/bodged blowing RH exhaust manifold gasket. RP

Late July?

• Variable fan controller fitted by JW - see Media:0444_fan_switch1.pdf‎‎

18th July 2018

• 10A fan circuit breaker keeps tripping - replaced with 15A breaker.

4th July 2018

• New transmission radiator fitted. Transmission oil and filter changed. JH, RP

19th June 2018

• Battery stolen. Replaced with new one. CB & RP.

12th June 2018

• Replaced RH exhaust manifold gasket. Found that small sealing plate on top of intake manifold (under the air filter) was blowing again through some small holes which were than covered with sealant. This turned out to be main source of noise. RP

10th May 2018

• Following brief failure of starter, this was replaced with a reconditioned unit. RP & JH.

14th April 2018

• Changed engine oil and filter. RP
• Changed transmission oil only. RP
• Fitted new transmission oil cooler thermostat. RP & MS

11th Oct '17

• Changed engine oil and filter. New air filter.
• Changed transmission oil and new filter fitted.
• Carried out annual guillotine checks. Full strip down. RP, CB and SO.
• Some coolant drained and topped up with neat antifreeze.
• Main halfshaft nuts tightened.

Sept 2017

• Both cables replaced. 1500m each. RP plus various willing helpers.
• Transmission engagement problem solved by adjustment of detent.

9th Sept 2017

Transmission was jumping to 'Drive' uncommanded due to engine vibration. Push rod shortened but requires further adjustment. N.B. Ineffective transmission-end 'detent' requires freeing and adjustment. Alan S

7th Sept 2017

• Replaced blown exhaust manifold gasket (LHS) with white and metal lined gaskets plus small amount of gungum. Filled eroded parts on block and manifold with liquid steel. RP

1st Sept 3017

• Problem with replacement starter as below with solenoid jamming. Replaced by James H temporarily with starter from reserve winch.

25th Aug 2017

• Replaced faulty starter motor with recon motor supplied by James H. RP, KH & CB

13th April 2017

• Changed engine oil and filter
• Changed transmission oil only
• Replaced spark plugs
• Identified fairly severe air or exhaust leak from under small eroded blanking plate just to RHS of carburettor. Liberal amount of Gungum applied which has sealed it for the timebeing. Engine runs considerably quieter.
• Checked tightness of cable drum nuts - OK. CB & RP

17th March 2017

• Annual guillotine check - LHS failed initially but passed following second strip-down and reassembling. CB, PB, M SELBY, RP

22 Feb 2017

• Leaking radiator beyond Repair. Completely refurbished by Berkshire Radiators, 266 Gosbrook Road, Caversham, RG4 8EA 0118 947 3501, with 2 X larger core and 1 year guarantee. Fitted with new fan switch and leak tested by CB, KH, AS & DG.
• Intermittant starting problem solved by fitting additional engine earth connection.

25 Jan2017

• Further attempt to improve joint between RHS exhaust manifold and pipe by packing with piece of bean can and more gungum.

11 Jan 2017

• Replace RHS exhaust manifold. This did not seal fully against the head - rear port on head found to be corroded so GunGum used to seal as best as possible. Different connection to exhaust pipe. Liberal use of GunGum to facilitate a connection.

4th Oct 2016

• Remove RHS exhaust manifold. Surfaces found to be extensively pitted. Resorted to cleaning up as best as possible then applying exhaust cement and refitting with new gasket. RP

30 Sept 2016

• Transmission oil and filter changed. RP & M selby

16 Sept 2016

• Engine oil and filter changed. RP & M Selby

5 Sept 2016

• Tightened half shaft nuts - LHS little or no movement. RHS v slightly slack taking approx 1/8th of a turn. RP

June 2016 - New Cables Fitted

• 1200m each side plus extensions using existing (~100m) barely worn cable on LHS and approx 50m unused cable on RHS. RP & A Saunders

2015? - Disk Brakes

• Rod Harris converted both drums to disk brake operation, using parts from Hyundai Coupe BP51TMO

August 2015

• Changed engine oil and filter, changed transmission oil and filter, changed air filter, repaired exhaust leak from blanked off port, diff oil level OK, tightened half shaft nuts to spec.

July 2015

• Rear right hand vertical roller in right hand roller box cut half way through to retaining bolt during launch. Roller, compression tube, M12 bolt and bearings replaced. NB: roller was not seized, so no evident cause.

• New cables fitted.

• Leak from radiator filler re-soldered.

• Radiator fan switch inoperative and shorting to earth, replaced with thermistor bonded to header tank (80deg on 65 deg off +-5deg). Temporary manual switch fitted, 10A circuit breaker replaced, fan rewired.

• Plastic container fitted to catch overflow from selector boxes.

Jan/Feb 2015

• Following a catastrophic failure of the differential on the Reserve Winch it was found that the Skybrid winch differential had run dry and had sustained serious damage to the pinion teeth its bearing. A rebuilt differential was purchased from Skylaunch and all 'inaccessible' bearings replaced. New half shaft bearings and dog clutch cap screws were also fitted. New hub oil seals were fitted and the differential was refilled with EP80W/90 gear oil.
• NB: On fitting the new differential it was found that the half shaft splines of the damaged axle did not match those in the replacement differential. However, by good fortune the half shafts from the Reserve Winch were found to be the correct type, so these were cannibalised.

• On reassembly it was found that the left hand selector lever detent did not work, meaning that the dog clutch could accidentally become disengaged. This was fixed using a pair of adapted cap headed screws.

• Skylaunch advised that the hub bearings should be lubricated with axle oil at the same level as the differential. However, when new hub seals were fitted it could not be ascertained that they were making a very effective seal. Following a discussion with the Skylaunch engineer who rebuilt the differential it was agreed to set the oil level below the lip of the diff half shaft tunnel and top up the selector boxes to the level of the filler holes. Consequently a lower oil level marker was set on the dip stick.

• NB: as at 1/3/15 oil is still spilling into the selector boxes, so the oil level is indeterminate and we are using an adjustable dip stick. The plan is to keep draining oil from the selector box filler holes until the oil level stabilises (if it ever does). If it doesn't then we'll have to keep draining the selector boxes and topping up the diff.

• If all goes well it is recommended that the differential oil level be checked at the same time as monthly guillotine checks.
• Engine oil was changed, but not auto transmission oil and filter.

December 2014

• Replaced worn out right hand brake shoe and adjusted mechanism.

November 2014

• Replaced worn out left hand brake shoe and adjusted mechanism
• Re welded broken cable deflector
• Topped up dog clutch gearboxes and greased u/js

October 2014

• Changed oil and filter
• Changed transmission oil
• Torqued axle nuts
• Fitted new air filter

March 2014

• Flushed engine and changed oil and filter
• Changed auto trans oil and filter
• Torqued axle nuts

• Annual guillotine check found assister springs out of balance and causing blade to bind. Adjusted spring tensions to 'twang' equally. Guillotines stripped, cleaned and lubricated.

• Replaced exhaust blanking stub with fabricated part

• Fitted new floor to winch cab
• Fitted chains to release brake levers

February 2014

• Fixed exhaust leak from LH exhaust manifold. Casting eroded, so new gasket fitted with sealant. Also made temporary repair to leaking exhaust stub. Needs new part.

January 2014

• Fitted aluminium cable deflection plates over damaged cage under drums.
• Moved tow out brake tensioning mounting points, fitted new springs and rope ratchets.

October 2013

• Changed engine oil and filter
• Changed trans oil and filter
• Torqued axle nuts

March 2013

• Fitted cable buffers to protect paying-in gear

• Failed guillotine test

both mechanisms found to be clogged with debris:

Fitted assister springs and re-set guillotine blades on LH mechanism.

POSSIBILITY OF FAILURE DUE TO CONTAMINATION MANDATES FULL STRIP DOWN AT FUTURE ANNUAL GUILLOTINE CHECKS

June 2013

Changed engine oil and filter.

• Tightened exhaust manifolds.
• Changed transmission oil and filter.
• Torqued half shaft nuts.
• Changed air filter.
• Oil leak from base of dip stick tube contaminating starter motor. Resealed with RTV sealant.

September 2012

• Reconditioned starter motor. Contaminated with engine oil. Later found to be due to oil leaking from base of dipstick.

August 2012

• Replaced both exhaust manifold gaskets

June 2012

• Changed engine oil and filter
• Changed auto trans fluid and filter
• Half shaft nuts re torqued

Feb 2012

• Replaced sheared dog clutch cap head bolts (right hand drum)

one bolt missing as could not remove broken screw.

• Replaced right hand exhaust gasket
• Changed engine oil and filter
• Changed auto trans fluid
• Half shaft nuts torqued

Summer 2011

• Changed engine oil and filter
• Changed auto trans fluid
• Half shaft nuts torqued
• Compression checked

Feb/Mar 2011:

• Replaced exhaust manifolds gaskets (ones previously fitted eroded due erosion of manifold face – used cement when fitting)
• Removed broken exhaust manifold stud.
• Winch taken to Lee on Solent for catch rail repair.
• Repaired winch drivers chair.
• Right hand brake tension adjusted to balance pull out tension
• Electrics moved to main control panel and rev counter temporarily secured with cable tie.
• Exhaust manifold bolts re-torqued.
• Failed annual guillotine test. Removed both guillotine assemblies. Cleaned, lubricated and refitted. Both passed annual test.
• Sludge in oil. Checked breather - OK.

Oct/Nov 2010:

• Replacement (second hand) exhaust manifolds fitted.
• Engine oil and filter changed.
• Transmission oil and filter changed.
• Rocker cover gaskets changed.
• Leaking oil pressure switch replaced.
• Transmission cooler fan switch moved away from exhaust manifold.
• Compressions checked.
• Half shaft nuts re torqued.
• Exhaust system braced to prevent silencers swinging on manifolds.