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Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Wilitrun
Date: August 12, 2022 10:59AM

Hi all,
Hoping I could get a few questions in one go here as I've been working away at getting my engine and transmission mated together with some difficulties.
As you probably know: 300 marine engine with stock flywheel going in a '78 Roadster.
'96 GM WC T5 inclined transmission from Camaro/Firebird with Ford Pattern case flange and wedge mount at rear.
The bellhousing I have is a '77 H-body with Saginaw pattern, it's too thin to drill for Ford pattern holes so an adaptor plate will be needed.
The difficulty I'm having the most trouble with is the adaptor plate. I'm getting a set of headers from TSI, and Ted says the company that supplied him with this adaptor hardware is no longer producing them, and he has no alternate suggestions. I'll need at the very least an adaptor plate that mates the Ford Pattern T5 to the Saginaw pattern bellhousing. I'd rather not start over with either the trans or the bellhousing as both pieces just aren't coming up in my area and it's not for lack of looking.
I've been in contact with Glenn Towery, and he's sending me the transmission mount pieces and an engine mount set as soon as he can. I think we've agreed to use the set that mounts the engine 1.5" further back for AC, as that would give me the most room for the radiator. I'm not particularly concerned with the tunnel hole cutout, but if I don't have to trim it, right on. I'm more concerned about the harder points like fit of the engine and alignment of the mount to the crossmember.
I'm also sending a photo of the flywheel the engine came with. It's got several holes for a pressure plate and the friction surface is painted, so it looks like I should be able to go with it. If it's on the heavy side I'm not bothered - a smoother take-off from a standing start would be a plus to me, and as we all know these engines have good low end torque to start with. To this end I'm wondering if there's a consensus on a clutch, pilot bushing and pressure plate that will work well for this combo.
20220812_103901.jpg


roverman
Art Gertz
Winchester, CA.
(3174 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: roverman
Date: August 19, 2022 05:51PM

Hi Dave, What are questions ? Flywheel looks "heavy". Suggest lightening on back side,( budget permitting). I suspect a 10"
diaphram clutch in this light package, should suffice. You need transmission to BH. adapter ? Kennedy Engineering make
engine adapters. Good Luck, Art.


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 19, 2022 07:37PM

David, Easy way is to find a 80-83 CJJeep bellhousing for 2.5 four cylinder that had the T4/T5 in Ford pattern. It has the same pattern as SBC on the engine side. The Chevy bellhousing uses the same dowel location and shares the 4 of the same bolt holes. There is a thin adapter to add the additional bolts on the Ebay link below. You may have to clearance the bellhousing a little bit, Jeep/Chevy used a 153 tooth flywheel, your Buick has 160 tooth.

jeep.jpg

[www.ebay.com]



Edited 3 time(s). Last edit at 08/19/2022 08:16PM by mgb260.


joe_padavano
Joseph Padavano
Northern Virginia
(154 posts)

Registered:
02/15/2010 03:49PM

Main British Car:
1962 F-85 Deluxe wagon 215 Olds

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: joe_padavano
Date: August 20, 2022 08:54AM

The even easier way is to get a 1965-72 BOP bellhousing. These cars used the Ford, er... DEARBORN three speed toploader trans and the bellhousing has both GM/Muncie (blue arrows) and Ford (red arrows) bolt patterns. The Camaro T5 has the same input shaft length as a Muncie, so no adapters needed.
BOP Bellhousing sm.png


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 20, 2022 10:55AM

Joe, The Dearborn 3 speed isn't the same pattern as the Ford T5. It does look like lots of room to drill for it though. Ford top bolt holes would be just under GM. Bottom right looks close. Look at the beginning of this thread:

[www.mgexp.com]



Edited 1 time(s). Last edit at 08/20/2022 11:07AM by mgb260.


Airwreckc
Eric Cumming
RTP, North Carolina
(137 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Airwreckc
Date: August 21, 2022 04:43PM

Do you already have the transmission? I'm planning on using a Tremec 3650 with my 300. I had one built with an adapter for the BOP bellhousing. Yes, I know it's a big trans and I'll have to modify the tunnel, but it will easily handle the HP this engine can put out.


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Wilitrun
Date: August 21, 2022 06:09PM

Thanks to everyone for the replies.
Art, I looked into Kennedy as I'm already familiar as an air-cooled VW owner, but they only make engine to bellhousing adaptors, not the bellhousing to transmission adaptor I'd need if I want to use my existing bellhousing and transmission.
I'm really not keen to re-sell my bellhousing as I paid a premium to ship it up here from the US and I'll never recover that, but all the same I have been eyeing the local classifieds to see if a suitable BOP bellhousing comes up. The only one I've seen in 8 months is a dual pattern BOP in Thunder Bay for $75 but local pickup only (it's 14 hrs each way for me). Knowing the Ford T5 and Dearborn 3-speed patterns are close but not identical (thanks again Jim) makes that and any other dual pattern BH a risk of not improving my situation, so I might as well accept it for what it is and get an adaptor. While the CJ BH and engine adaptor is a very good thought, it doesn't look like it'd put me ahead of an adaptor for what I already have.
I did find thanks to Glenn T. an adaptor from Hotrodworks, which seems to be priced a bit high at $175USD plus shipping to Canada, but would in theory solve my problem. I'm told it's .550" thick, which would space out the trans quite a bit, but might help alignment of the shifter to my existing tunnel hole. My input shaft comes out about 7-1/4" from the trans mounting surface, so I already know I'll need an extended pilot bushing for the crank (or another input shaft if my splines are spaced back too far for the clutch face).
The other option is to get a local machine shop to make one out of 5/8" plate aluminum, in which case I just need to work out the measurements. The only thing that seems unclear to me is what's going on in the input hub area. It appears to be meant to be piloted to the trans case and there's additional clearancing on the BH side for the HTOB, which doesn't seem to be dimensionally critical. Am I missing anything?
[www.hotrodworks.com]
Finally: Eric, I did take a hard look at the Tremec line of transmissions but decided to go this route simply because if I break something, I'm only risking a few hundred dollars for a late V6 T5 if I set the car up for it from the start. Tremec transmissions really are a LOT of money and while I won't argue that they're not worthwhile in the right car, I'm simply not building that kind of car. This is a wrenches-on-the-fenders, smoke the tires, have some fun for junkyard money kind of car and if I sunk $35-3800 US into a transmission I'd just be too scared to beat on it - if I break this transmission I can get another fairly quickly and learn where its limits are without losing the rest of the summer to save up for another one whereas a Tremec T5X is a holy-smokes $4508CAD:
[performanceunlimited.ca]
This V6 T5 I have is specifically a 1352-247, which is a "Z" code 1996 Camaro/Firebird unit.
1st: 3.75, 2nd: 2.19, 3rd: 1.41, 4th: 1.00, 5th: 0.72 and 3.53 reverse. With a 3.07 LSD rear and the broader/flatter torque curve of the marine cam I don't think driveability will be too terrible to tweak a little with the tire diameter, but am I wrong? I'm open to feedback on this but again, making a big change here means a big jump in total spend so it would have to be worth it.



mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 21, 2022 06:33PM

David, .550 adapter is too thick. Here is an idea for NO adapter. The center hole is already the right diameter. Put your T5 on the bellhousing standing tailshaft up. Use a transfer punch to mark the 4 mounting holes. Drill out and use fender washers and bolts going out through the bellhousing with Nyloc nuts on the transmission side.



Edited 1 time(s). Last edit at 08/21/2022 06:38PM by mgb260.


Airwreckc
Eric Cumming
RTP, North Carolina
(137 posts)

Registered:
05/28/2020 10:10AM

Main British Car:
1972 MGB-GT (working on a Sebring project) Buick 300-4 V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Airwreckc
Date: August 21, 2022 08:44PM

Got it, I understand. Just so you know, my transmission with the adapter was about $2,500. And it is built to stronger standards than a standard 3650. I'm guessing the T5 will handle the torque of the 300, but it made me a little nervous. Good luck with your project. Love to see these 300 projects.


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Wilitrun
Date: August 21, 2022 09:19PM

Jim, you are correct the centre hole is perfect fit, and it even appears to have blank bosses that are close to the ford pattern lower bolt holes. But I considered this option carefully when I got the T5 home, and I don't see an option out of the adaptor plate. Consider the upper hole locations: to fit Ford pattern the right side (car side) lands about halfway into the hole for the original fork ballstud, and the other side lands in the middle of a sloped reinforcing rib. To make matters worse the unreinforced area is extremely thin, .158" by my micrometer read. So I would really rather take advantage of the strength of the existing bolt holes. I even considered using your steel adaptor bracket idea but the alloy H-body bellhousing goes very low int he bottom and covers that area completely unlike the steel Truck ones.
20220821_210049.jpg
20220821_210100.jpg
20220821_210055.jpg
Also Thanks Eric, we'll see how strong this one is given the cost for literally anything else being several times what I paid for this one, the V8 T5 units with Saginaw pattern are a pretty narrow and hard to come by set of choices if I want something for the $1500 or less range.


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 21, 2022 09:53PM

David, Would the 18 degree tilt the Camaro uses help? Try to position it with the trans mount level.


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Wilitrun
Date: August 22, 2022 10:10AM

Hi Jim, yes I've tried that orientation and it puts most of the bolt holes into a rib. Nothing really seems to line up in a practical way without going beyond where the trans will fit into the car.
What are the consequences of spacing the case 5/8" or .550" back from the bellhousing? And what input shaft length given the above would work with available Speedway bushings, or would a custom one have to be made?
If it's just the trans tunnel hole honestly I don't mind hacking into it a bit so long as I can cover it with a gaiter.


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 22, 2022 10:57AM

David, You already have the right input shaft length. I'd make a dual pattern template out of poster board and make your own adapter out of 1/4" steel. The top two bolts will be close so probably use Allen heads there.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6261 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: BlownMGB-V8
Date: August 22, 2022 11:25AM

Know anybody that does heliarc welding? You can add metal where you need it for ribs or bosses. Shouldn't cost all that much.

I got one of the interrim Tremecs built for John Forte by Tremec with the GM main case and input and the rest Ford parts, everything off the shelf. It's beefy. Has a larger input and main shaft than the T5, shifts nicely and has a perfect gear spread. Don't know if any of those are still around, I got mine as NOS from Jim Willenbrink after he went to an automatic and have been very pleased with it.

I know new Tremecs are expensive. I feel your pain. But considering that it's something that will last the lifetime of your car and give trouble free service, as well as allowing you to get the perfect steps between the gears, and that it is about the same cost as any other new transmission is it really that bad? I mean if you'd consider going out and buying a new crate engine a new transmission does seem appropriate.

OTOH we MG enthusiasts are notoriously tight with the purse strings and it's a difficult balance between inadequate gear and excessive spending. All I'm saying is that the transmission is often given short shift in the balance and we tend to pay for it later on. A transmission with good ratios is a joy to drive.

Jim


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: Wilitrun
Date: August 22, 2022 06:58PM

Hey Jim,
I don't know anyone that I'd trust with a job like this that's sufficiently motivated to take it on - I used to, but he strictly does big jobs now.
While I may learn your lesson once the car is on the road (and trust me, I am listening to your feedback) I have so many problems to solve on that car that I need that same money for. If the gearing is tolerable on this transmission, it can save me close to two years getting this car built and I know my dad does not have that much time left.
One thing I don't get much chance to talk about is the mathematics of living in Canada. EVERYTHING is so much harder up here when you have an antique car. Consider that although we are within 2% of the same total landmass of the USA, our population is less than the state of California alone - and over 90% of that population inhabits a narrow strip along the St. Lawrence Seaway - our Rust Belt. The only climate temperate enough to really enjoy a car more than 6 months of the year is on the West Coast - over 5000 miles away from here!... And about the only place here where dry project shells can still be found in a field is central Alberta - and the population density over there has always been low. So there's very little in the way of used parts trading locally. Shipping anything up here is more expensive due to the lower population density and long distances. And there's just not enough people here to support much manufacturing so almost everything has to be imported from out of the country, and that adds a lot to the price of things. A lot of this y'all just don't have to deal with!
(I know, there's a rust belt in the US too, and we don't have the corner on cold weather either - but when you add the cost of garage-storing the car half the year to the cost of everything it makes a bit more sense to stretch build money out a bit.)
The other thing is that this car has had all the body and paint work done by the PO - but on hobbyhorses - so the car is not straight and never will be. It's just not nice enough of a car for new major components. If I simply can't live with the gearing I'll start looking seriously for a used V8 T5 with close ratio gears - but now that my rear-end ratio is locked-in my choices are narrower still if I want to keep it under $1750 or so (I've seen one or two come up in the last year somewhere around this number).
Or I can get the TKX and a whole bunch of other things with my inheritance in a few years, but I know myself - once Dad and I go out on a few rips I'll want to keep it the same way forever. I just want to make it work well enough so we can go out and have fun with it without worrying too much about what it'll cost if we break it. It's the way he built his Jeep and he's had it out every season for the last 12 years with the upkeep more than comfortable on his fixed retirement income.
Let me see how thin I can get that plate - yes, if it's steel I can go thinner than Alloy and that's a good thought. Alloy is a bit easier to machine though and I would only trust my machinist with the centre hole and relief area so how much trouble am I getting in by going 1/2 or 5/8"?
Appreciate all the input so far.
dad.jpg



mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 22, 2022 07:40PM

3/8" steel is as thick as I'd go. I don't think there is a longer input shaft for that transmission. Using the center hole as reference it would be easy to make a dual pattern template and copy to steel.


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 22, 2022 08:28PM

David, this pilot bushing will take up 3/8" extra length.

[www.speedwaymotors.com]{match_type}&msclkid=2f9a0c96010c1735a41c6f921f11e843&utm_source=bing&utm_medium=cpc&utm_campaign=SMI%20-%20Shopping%20(CSE)%20(Bing)&utm_term=4577404348890847&utm_content=All%20Products%20(Feb28_2020)


DiDueColpi
Fred Key
West coast - Canada
(1336 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: DiDueColpi
Date: August 22, 2022 08:37PM

David, a company called DSP (Deep South Auto Parts) makes the adapter that you need.
[dsapinc.com]
No affiliation but I have used their stuff before and have been very happy with it.

Cheers
Fred


mgb260
Jim Nichols
Sequim,WA
(2270 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Transmission Adaptor Plate/Mount options? And Clutch/PP
Posted by: mgb260
Date: August 22, 2022 08:38PM

David 4 of these countersunk into the plate will stick out like studs for the T5.


[www.fastener-warehouse.com]


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