fitting Tremec FORD T5 to RV8

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Allan Robinson
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fitting Tremec FORD T5 to RV8

Post by Allan Robinson »

I have a Dax Rush with a 3.9 RV8 and SD1 LT77 gearbox. I am in the early stages of fitting a new Ford Tremec T5 gearbox (Part N0 1352-000-251). I chose this box because of its slicker gear changing, close 1st to 4th gear ratio and very high 0.63 5th gear for economic cruising.

My plan was to marry it to the RV8 with a TVR / T5 bellhousing and to carry out the swap after the winter. As yet I do not have a TVR Bellhousing to view; however, understand that it is not just a bolt together job.

Quote below from Devonman:

"I will tell you what I know about the Ford T5 conversion. My Mate Devonrod Has done it.

The TVR bell housing will have a gearbox location hole too small for the Ford T5 gear box front bearing retainer. You will need to get a TVR T5 bearing retainer and clutch release bearing carrier which will accept the LT77 release arm and bearing. The preload on your new gearbox will need to be reset with a correct shim because you have fitted a different retainer.

A new prop with a 28 spline sliding yoke will be needed.

The rear mount will need to be fabricated.

If you have a cable driven speedo then you will need a Mustang cable with the correct cog and fitting into the box. The cable comes out the box on the left side.

The spigot bush in the end of the crank will need to be reamed out to suit the Ford T5 shaft.

Hopefully the gearshift will suit your tunnel opening into the car."

Question please. As stated I do not have a bellhousing to view so please forgive me if I ask a stupid question. With regards to the bellhousing gear shaft retainer hole, would it not just be a simple case of making the hole bigger? Job done?



DEVONMAN
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Post by DEVONMAN »

From my notes I see that the Ford T5 front retainer is 124.7mm dia and the TVR retainers are 118.9mm dia. Making the hole bigger will put the edge of the hole very close to the clutch arm pivot point. (The Ford cars don't have a similar pivot point as they tend to be cable operated which pulls forwards at the end of the arm.)

However, the T5 Ford Retainer on the 251 Box is in the main aluminium with a steel tube to carry the release bearing. The aluminium protrudes forwards much more than the TVR retainers and space for the clutch release mechanism movement gets very tight. You could do some careful measuring to see if it will work but another factor is that the O/D of the steel tube is 36.32mm (1.43" typical ford) and a suitable release bearing carrier/bearing would need to be sourced or made as your existing LT77 carrier has a smaller bore some 4mm less.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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Allan Robinson
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Post by Allan Robinson »

Devonman, could I please ask you to view a 'Rover V8 T5 Gearbox Conversion (competition)"kit on the V8 Tuner web site. Any thoughts?

The kit includes a Custom Machined Motor Sport Bellhousing and Hydraulic Throwout Bearing Assembly. Perhaps I should ditch the TVR / T5 bellhousing concept and go for this. I would only require part of the kit but it is probably not cheap.

I have emailed V8 Tuner and left a phone message but as yet no response. I wonder if anyone else would supply similar?

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Post by DEVONMAN »

The v8tuner kit would obviously work as a complete item. I vaguely remember someone saying they needed to machine the bellhousing to ensure correct clutch spline engagement but that may not have been a complete kit. I personally don't like concentric clutch release as when it leaks everything has to come out. It all depends on the car and how easy the gearbox come out.

Which way you go with this is really all down to money and what you have and want to spend.

For my approach the cost would be as follows:-

Gearbox £1800 delivered
TVR Bellhousing £350 secondhand
TVR Retainer £115
TVR Release bearing carrier £80
New release bearing if needed £18
New 10 spline Clutch centre plate £210
Ream spigot bush £10
Speedo cable from usa £40
No additional cost of clutch hydraulic pipes.

This is a lot less than the Kit at £4290

Propshaft needed in both cases
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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Allan Robinson
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Post by Allan Robinson »

Ok thanks for the very comprehensive reply. The gear box has literally just arrived and paid £1700 so happy with that.

The bit I am little concerned about is:
"You will need to get a TVR T5 bearing retainer and clutch release bearing carrier which will accept the LT77 release arm and bearing. The preload on your new gearbox will need to be reset with a correct shim because you have fitted a different retainer."

Could you please talk me through what is involved in reseting the preload with correct shim? I'm not bothered about the LT77 release arm and happy to replace with what ever is required that will do the job.

Is there a distributor outlet who will supply the parts you mentioned or am I reliant on second hand bits? I live in Weymouth and not aware or any local TVR scrap yards.

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Post by DEVONMAN »

First of all, the TVR Parts are available new form TVR Parts Ltd. and other TVR part stockists.

The front bearing retainer on the gearbox (held in place with four bolts) has a shim behind the bearing and the thickness of this shim sets the end float of the main shaft of the gearbox. The gearbox you have will have a tapered type pocket bearing and end float for the main shaft will be set at zero.

Before we removed the Ford front retainer we measured the torque need to turn the front shaft. This was done with a 12" long piece of timber with a hole in it at one end sized to be tight on the spline shaft. We then used a spring balance to find the load needed to turn the shaft with the spring balance 12" from the shaft. (If you do fishing you will have a spring balance).

Make a note of this load and then swap the front retainer for the TVR one. The shaft stays in place so push inwards on it as you pull the retainer off the box.
If you are lucky the load needed to turn the shaft will be the same or within 10%.
If the load is less the you need a thicker shim behind the bearing and visa versa.
Shim kits are available but I cut my own from shim sheet.
The shim is a ring about 75mm o/d and 70 I/d.

It's then a matter of swapping shims to get close to the load you measured.

Replace and Reseal the retainer with a gearbox flange sealer when you are happy with the torque value.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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Allan Robinson
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Post by Allan Robinson »

Brilliant. I'm happy with that and will now look for a V8 TVR/T5 bellhousing.

On the new gear box there is a speedometer sensor. Would you happen know if this is just a simple pulse switch triggered by a magnet or perhaps something more electronic?

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Post by DEVONMAN »

I don't know about the speedo trigger, but, If it has 2 wires then it's probably gives out pulses from a magnet and if it has 3 wires it may be electronic and need a 12v feed.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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DEVONMAN
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Post by DEVONMAN »

One more thing, you will need an oil seal for the TVR bearing retainer fitted before you compare the turning torque of the gearbox.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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DaveEFI
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Post by DaveEFI »

The SD1 drive is two wire - but active. It's more akin to a hall sensor than VR.
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Allan Robinson
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Post by Allan Robinson »

The sensor on the T5 is also two wire. From some pics I've seen it looks like it has a gear drive same as for the cable drive so will not be a magnet / pulse setup. I guess I will have to remove it to confirm.

Correction on above. The two sensors on the box were actually switches for reversing lights and Neutral related sensing. There is only a bung in the hole for the speedo drive or sensor. I can see a Yellow (7 tooth) worm gear inside to drive either a cable or sensor device.
Last edited by Allan Robinson on Fri May 12, 2017 7:04 pm, edited 2 times in total.

DEVONMAN
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Post by DEVONMAN »

Allan Robinson wrote:The sensor on the T5 is also two wire. From some pics I've seen it looks like it has a gear drive same as for the cable drive so will not be a magnet / pulse setup. I guess I will have to remove it to confirm.
Could be a multi segment magnet within the unit on a shaft triggering a reed switch.
Something like 8 pulses per rev.

I've used that type in the past attached to the end of a speedo cable.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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DEVONMAN
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Post by DEVONMAN »

Allan Robinson wrote:The sensor on the T5 is also two wire. From some pics I've seen it looks like it has a gear drive same as for the cable drive so will not be a magnet / pulse setup. I guess I will have to remove it to confirm.

Correction on above. The two sensors on the box were actually switches for reversing lights and Neutral related sensing. There is only a bung in the hole for the speedo drive or sensor. I can see a Yellow (7 tooth) worm gear inside to drive either a cable or sensor device.
Ok. You will need a Mustang cable fitted with the correct cog. Sets of cogs can be obtained from the States with the number of teeth ranging from 16-22.
You will need to establish the number of turns of your prop per mile and select the correct cog to rotate the speedo cable to match whatever TPM your speedo head needs. Ford Speedos are usually 1000TPM and others sometimes have the number marked on the dial.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


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Allan Robinson
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Post by Allan Robinson »

Thanks Devonman. I have a set of year 2000 EBT Instrument gauges that I wish to keep so need to establish an electronic speedo output.

My current thinking it to abandon the T5 Speedo source altogether and fit a speed disc to the propshaft with sensor. This speed disc is just a plate with a series of holes that the sensor detects. I'm not sure what type of sensor my EBT Speedo requires so have written to EBT Instruments and await an answer.

Regarding my Ford T5 installation, the starting point is a TVR V8/T5 bellhousing but tracking one down is proving to be quite difficult. I have one potential source and await a call back hopefully this weak. I am happy to buy new if I knew where to find one.

V8 Tuner have a RV8/T5 Motorspot Bellhousing advertised. I have tried phoning them but as yet they have not responded to my email or voicemail. If my other source comes up blank I guess I will just have to keep pestering them!

Greg55_99
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Post by Greg55_99 »

Measuring from the face of the transmission to the tip of the input shaft, what is that length (in inches).

Greg

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