L,F head to odd fire swap questions |
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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Posted: 04 Jan. 2021 at 4:31pm |
When doing a L or F head to odd fire swap what are some of the issues that people run up against? I hear about the steering bell crank, what about length and firewall issues?
Thanks Jay
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64CJ5
Member Sponsor Member Joined: 15 Nov. 2013 Location: NE Wyoming Status: Offline Points: 942 |
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Novak has most answers and adapters. Advance adapters also has info and parts. The original engines are really good if tuned and running right. The engineers at the time that put them together worked out the bugs and fitment problems.
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64CJ5 "Eeyore"
01TJ "Tigger" 52 M38 Severely demilitarized, "Popeye" The Coast Guard Jeep. 14 JK "Jake" To Trust Government Defys Both History and Reason. PUBLIC LAND Owner/User |
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Oldpappy
Member Joined: 09 Apr. 2018 Location: Tennessee Status: Offline Points: 4903 |
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I had a M38 with a Buick V6 installed when I got it. I liked the way the swap had been done.
There was no "adaptor" but instead whoever did the swap used some sort of GM bell housing, with a couple of extra holes drilled for the T90. The bell housing was deeper than the Jeep bell housing, and to accommodate for that the input shaft on the transmission was replaced with the longer one which I believe is for a Willys truck or wagon, but not sure. I installed a L134 when I rebuilt the M38, so had to replace that input shaft. I traded the V6 and related parts to a guy building a Jeep he wanted the V6 in, so don't have it anymore to look closer at what was there.
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If you can't get there in a Jeep you don't need to be there!
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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I feel the biggest mistake is not repositioning the engines centerline. I covered the Dauntless to flatfender jeep issues in depth along with many other flatfender modifications. You can read it here as long as tapatalk maintains the old 3B Bulletin Board. I don’t mind clarifying any of the details if needed. I oft need to refresh my own thinking. |
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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THanks Ken, That is a great wright up and a must read before I get too far in to this. Jay
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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Yeah Jay, hope you get something of value from that.
I just reread a big part of it. Have lately been considering other strange and very radical suspension modifications for jeeps. I see in that article that I had already determined the standard suspension seems to be near optimum with a Dauntless. Not sure what more if anything will work on the front axle other than standard leafs because front stuff is already at max for the Dauntless. |
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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Ken
It's very useful!!! My issue is I'm not sure what to do. I have 2 t98 CJ5's both as projects and an early 70's CJ5 frame and running gear with a odd fire and t14 (?). I would like a M38 with the t98 and a V6, I think. Was thinking of using the tranny and mounts out of one of the t98 5's with the odd fire and putting it in one of my m38 rollers that I have. First I have to finish my Kobota project!! Jay
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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The F-134 CJ-5 version was known as the T98-A.
Due to their unique front bearing retainer, the 15/16” shaft main drive gear and adapter plate they are ideal for use with any of the 134 engines. It will require extensive and perhaps expensive changes plus custom adapting to mate a T98-A to a Dauntless. One is “far” better off using one of the somewhat superior T18’s mated to any engine excepting the 134’s. On any flatty you must eliminate the bellhousing adapter plate if you hope to leave transfer case in standard location and use engine fan for cooling. Using a bell housing adapter plate of any sort will make the power train too long for standard transfer case placement. Without engine relocation; one is forced to relocate transfer case 5-12” aft when using a T98-A behind the 134 engine and that makes things “very” much harder to fit. On my T98-A CJ-3B I had to change propellor shaft lengths, reform the floor tunnel, raise the fuel tank, modify the driver seat frame etc. |
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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Yes the t18 was the plan if I go with the odd fire. One of my t98-a is set up with the M715 5/4 ton truck input adapted to SBC. Jay
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duffer
Member Joined: 02 Feb. 2012 Location: Bozeman, MT Status: Offline Points: 1086 |
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Does not the 225 weigh less than an L134? I've never found what I believe is a reliable weight number for the L head, certainly it is a little lighter than the 470 lbs often cited for the F head but probably not 45 lbs lighter. I did invest in a set of pretty accurate wheel scales a while back and will hopefully get some Willys engines set on them in the not too distant future. My aluminum 441 small block Chevy weighs 428 lbs complete with everything except the headers. The engine/flywheel/clutch/bellhousing is 472 lbs.
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1955 3B: 441sbc,AGE 4 speed transmission, Teralow D18w/Warn OD, 4.11:1 D44's/ARB's, glass tub & fenders, aluminum hood/grill, 8274, York OBA, Premier Power Welder; 67 CJ5: 225,T86AA, D18, 4.88's, OD
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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Yes Jay the M715 / T98 maindrive is the closest factory fit one can get for a T98 to GM bell.
If I’m not mistaken the M715 / T98 stickout length is 7-3/4”. Can you verify that ? To fit a T18/98 to GM bell without an adapter plate one ideally needs 6-3/4” stick out. The wide ratio T18 jeeps having 7-3/8” stickout can readily be shortened to ideal length because the pilot tip is extra long. The 6-1/2” Ford main drive stick out is actually a full 1/4” short without an extended pilot bushing.
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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Was there a bellhops made that will bolt a odd fire to a Jeep t98/18 with out an adaptor?
Thanks Jay
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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No. Not really, except you may be able to locate an AA aftermarket bell that is drilled and tapped to fit.
The M715 input is an inch too long to fit direct into a GM bell. To mate T18 to GM without a bell adapter plate you must modify the transmission bolt pattern and use 6–1/2” Ford or 7-3/8” Jeep main drive. Unlike most I much prefer to adapt to a Jeep T18 by welding on front of the Jeep T18 to form the required GM pattern. |
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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Joe Friday
Moderator Group Sponsor Member x 2 Joined: 26 Dec. 2010 Location: Jeep Central Status: Offline Points: 3654 |
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There was a Jeep shop in Pomona California that used to advertise surplus M715 transmissions with the input shaft shortened for the GM bellhousing... but that was 20 years ago.
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chasendeer
Member Joined: 24 Feb. 2012 Location: Napa,CA Status: Offline Points: 1086 |
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Did the M715 use a different case than a CJ t98? Thanks Jay
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Joe Friday
Moderator Group Sponsor Member x 2 Joined: 26 Dec. 2010 Location: Jeep Central Status: Offline Points: 3654 |
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I sold my M715 a long time ago. but since the 715 had a divorced transfer case I assume it was different.
I believe the attraction was GM v8's to replace the Tornado.
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4183 |
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Yes as Friday alluded to: the rear of the cases were drilled differently. Otherwise identical.
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Currently building my final F-134 powered 3B .
T98-A Rock Crawler using exclusive factory parts and Approved Special Equipment from the Willys Motors era (1953-1963) Zero aftermarket parts |
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