MFH 1:12 Lotus 77 query

[Paul_OFarrell]

Hi all,

As the 1:12 MFH kit for the Lotus 77 is a trans-kit to convert the Tamiya Lotus 78 into a 77, I had hoped that working out the plumbing for oil lines etc would be fairly simple to decipher.

All my plumbing planning is going well so far, except for one problem:

MFH supplies a small radiator for cooling of the transmission oil, which mounts onto the left side of the rear wing upright. This radiator doesn't appear on the 78, only the 77. Unfortunately, there is no other info available to indicate the correct routing of the transmission oil lines, both to and from this cooler.

If there is any pictorial info available could I please ask for a copy to be posted here?

Thanks in advance...

Cheers, Paul
Sydney, Oz.

[jordan]

Yep..not much info in the MFH sheet, nor in ref pictures.I routed de lines as it was done on other F1 cars from that era (P43 is an example )

Alex.

[smbrm1]

Hi Paul

I would say that this P34 schematic is unfortunately not totally helpful in understanding the gearbox lubrication plumbing. It does not do a good job of outlining the engine oil schematic either.

The standard FG 400 always had an oil pump, but it was internal to the gearbox off the tail of one of the gearbox shafts.

The big issue is that 1974ish began the era of non standard Hewland FG type gearboxes when teams made modifications to the standard FG type gearboxes - casings and lubrication system. In particular some teams added external dry sump oil pump and filter arrangements. The many variants may also have been mixed and matched in restorations, so that is often not a help. Both Tamiya and MFH often do not help to clarify either.

However, if I look at the MFH instruction for the Lotus 76 and the references for the Lotus 77,78 & 79, it appears that there is evidence of a common FG gearbox variant between them.

The 1/12 scale Tamiya Lotus 78 instructions appear to use a similar variant(see Instruction 26). It is identifiable by the two small canisters on the very rear of the shift mechanism cover. When looking at the gearbox from the rear, the lower canister(part D3) is usually an external oil pump and the upper one is an oil filter(part H20). Normally an oil line comes from the bottom of the CWP part of the gearbox. It can be situated on either the lower left or right side rear corner of the CWP portion. The CWP part of the gearbox is of course the front part where the drive shafts exit left/right. This oil line will be the feed from the gearbox to the oil pump(D3). Oil then goes from D3 to the oil cooler(part G7&G8 instruction 23), then from the oil cooler into one side of the oil filter(H20). From the oil filter it then goes into one of the bungs on the top of the CWP. There is also evidence that some gearboxes had a cast in channel that allowed the line out of the oil filter to go into the top centre of the gearbox casing(the piece between the rear shift cover and the CWP portion). This channel was integral to the gear case and CWP case and ran longitudinally directly into the rearmost bung on the top back of the CWP case.

If my description above requires more clarity, I would suggest that you consult the MFH instructions for the Lotus 76 (1974 Belgium)as instruction 35 gives an example, however, it misses the oil out from the oil filter to the CWP(probably because this is under the large engine oil tank assembly of this version of the Lotus 76 and not visible in "assembled car" photos).
The only other oil line of consequence that you may find is a looped pig tail clear(dark amber) breather line coming from the top right side of the rear shift case just to the left of the shift rod entry point.

Hope that helps.

cheers

Stephen

[AJP01]

That is an excellent analysis and explanation Stephen. My compliments.

AJ

[jordan]

Hi Paul

I would say that this P34 schematic is unfortunately not totally helpful in understanding the gearbox lubrication plumbing. It does not do a good job of outlining the engine oil schematic either.

The standard FG 400 always had an oil pump, but it was internal to the gearbox off the tail of one of the gearbox shafts.

The big issue is that 1974ish began the era of non standard Hewland FG type gearboxes when teams made modifications to the standard FG type gearboxes - casings and lubrication system. In particular some teams added external dry sump oil pump and filter arrangements. The many variants may also have been mixed and matched in restorations, so that is often not a help. Both Tamiya and MFH often do not help to clarify either.

However, if I look at the MFH instruction for the Lotus 76 and the references for the Lotus 77,78 & 79, it appears that there is evidence of a common FG gearbox variant between them.

The 1/12 scale Tamiya Lotus 78 instructions appear to use a similar variant(see Instruction 26). It is identifiable by the two small canisters on the very rear of the shift mechanism cover. When looking at the gearbox from the rear, the lower canister(part D3) is usually an external oil pump and the upper one is an oil filter(part H20). Normally an oil line comes from the bottom of the CWP part of the gearbox. It can be situated on either the lower left or right side rear corner of the CWP portion. The CWP part of the gearbox is of course the front part where the drive shafts exit left/right. This oil line will be the feed from the gearbox to the oil pump(D3). Oil then goes from D3 to the oil cooler(part G7&G8 instruction 23), then from the oil cooler into one side of the oil filter(H20). From the oil filter it then goes into one of the bungs on the top of the CWP. There is also evidence that some gearboxes had a cast in channel that allowed the line out of the oil filter to go into the top centre of the gearbox casing(the piece between the rear shift cover and the CWP portion). This channel was integral to the gear case and CWP case and ran longitudinally directly into the rearmost bung on the top back of the CWP case.

If my description above requires more clarity, I would suggest that you consult the MFH instructions for the Lotus 76 (1974 Belgium)as instruction 35 gives an example, however, it misses the oil out from the oil filter to the CWP(probably because this is under the large engine oil tank assembly of this version of the Lotus 76 and not visible in "assembled car" photos).
The only other oil line of consequence that you may find is a looped pig tail clear(dark amber) breather line coming from the top right side of the rear shift case just to the left of the shift rod entry point.

Hope that helps.

cheers

Stephen

Very technical..WAY to complicated to me because I am a modeler ..makes me feel very small.Anyway,thanks for a perfect analysis.

Alex.

[Paul_OFarrell]

An excellent description Steve, thank you very much for sharing your wealth of knowledge.

Cheers, Paul
Sydney, Oz