Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Calvin, absolutely no rush at all. Please don't take time away from what you need to do for this.
Thanks! Scott |
74ls1tr6 Calvin Grannis Elk Grove,CA (1151 posts) Registered: 11/10/2007 10:05AM Main British Car: 74 TR6 / 71 MGB GT TR6/Ls1 71 MGB GT/Ls1 |
Re: LS4 Into an MGB
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Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Haven't been posting because there wasn't anything new to report. Still making steady progress.
The wiring harness is, for all intents and purposes, done. What remains is better done with the engine out of the car. As anyone who has done something like this before knows, there are a million details to deal with...all part of the fun in projects like this. I use the original gauges and I was planning on drilling out a head to accommodate the "B" temperature sender. Fortunately, I came to my senses before making that stupid move. What I did was chucked the sender in my drill press, turned it down to the correct diameter, and threaded it to fit into the existing hole at the back of the passenger side head. This picture shows the LS temperature sender along side the "B" unit. The thread is 12mm X 1.5, FYI. This one shows it in the head. I needed to make sure it was going to fit correctly before pulling the engine to put the firewall back together. So I'm making slow but steady progress on the firewall. I'm tackling the hard side first and expect the remainder is going to go more quickly. You can see my approach in the photo below. I spent a lot of time measuring and fitting the steering column before welding things together and I'm going to tweak what you see here a little more before finishing that side. I'm using 16 gauge steel if you're wondering. I'm working now to finish the engine compartment completely. That includes finishing the firewall, cross member, running new brake lines, finishing the motor mounts, and mounting the steering rack and steering shaft. Hopefully another few weeks will do it. One other bit of news is the car won't be ready for Colorado. I'm sure that isn't surprising to anyone, it was a long shot. So now I'll be shooting for the fall get together in Townsend. We will see. |
Re: LS4 Into an MGB
Scott it is looking good!!
On my TR6 I used the stock TR6 temp sender and mounted it into the aluminum thermostat housing on the 3400. My buddy that did the electrical work told me that it would have to be properly grounded. I told him is it not grounded to the engine via the aluminum housing. He replied that it is better to have a separate ground to the sender than have it ground through the aluminum body. So I made a washer with a tag on it out of copper and it is held in place by the sender. The ground wire then plugs onto the tag. Cheers Byron |
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Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Quote: Thanks for the feedback Byron. Interesting. I ran the same sender on the aluminum lower intake on my V6 and it seemed to work without issue. Was your buddy worried about gauge accuracy? Is there that much of a difference between an iron block and an aluminum block? Just curious. |
Re: LS4 Into an MGB
Scott I talked to my electrical buddy and he has 2 reasons:
1/ On the 3400 all sensors that attached to aluminum bodies came from GM with both a power lead and a ground lead. 2/ With dis-similar metals you get corrosion issues, oxides that build up and create resistance. Aluminum is bad for this. On your fuel lines will you have to go to larger lines for the bigger thirsty er er er engine? Cheers Byron |
Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Jim,
Thanks. Still have a little ways to go but progress is steady. Bryon, Sounds like a really good idea and I"m not trying to discount it but interestingly, the grounds from the sensors go to the grounds in the PCM which usually are grounded to the engine. Mine are all to a common point on the passenger side head. I'm already running 3/8" line for my supply (from my V6 swap) and that is what the LS4 needs so I should be good there. It's a returnless system so I'm going to run a Corvette fuel filter/regulator which has a single 3/8" outlet to the engine but allows you to run a pump that recirculates and it has a 3/8" supply and 5/16" return on the tank side. I'll go into more detail when I get to that point. I'm in the process of acquiring what I need for the fuel system now as a matter of fact. The AN fittings aren't cheap! Scott |
Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
One inch at a time! So I'm still putting the firewall back together. It's pretty tedious work but I'm pleased with the result. I'm doing the most complex stuff first and I believe I just about have that part complete. Hope to have the firewall done at the end of this coming weekend. I'm taking my time because this has to be done right. It's amazing how fast 8-10 hours can go by. Here's where it sits at the moment.
One thing I didn't realize about the MGB firewall before I started this is the heater plenum seems to be an important part the unit body in that area. It contains some of the thickest metal I've cut into. I've been wondering about the bellhousing alignment and thought it would be better to do the measuring now rather than wait and then find an issue at an inopportune time. Good thing I did. So both the bellhousing face and bore runout were measured. I got about .014" on the bellhousing face and a measured value of about .020" on the bore runout which means it is about .010" off center. Both are out of spec so something will need to be done. There are a couple of ways to handle this, another bellhousing, offset dowel pins, and/or shimming the bellhousing. I checked into getting the bellhousing machined but that will be a last resort. Most likely I'm going to have to go with another bellhousing but I'm going to try shimming it first to try to get the bellhousing face parallel and then see where the bore runout ends up. The spec is 0" to .005". Oh, I can't seem to find the right sized offset dowels pins. The small GM pattern uses dowels that are about .71" in diameter, I believe, and they are hollow too. The available pins I could find are a much smaller diameter so it appears they won't be an option in this case. Should be an interesting exercise. In other news my friend Artie, who I think most of you may know, will be coming out to Ohio during the week of the V8 meet and we're going to try to get some major stuff done on the car. For those of you who don't know him he's a British V8 wanna be and a Corvette guy. :-) My wife will be away so there shouldn't be a lot of distractions. Should be a lot of fun and I'm looking forward to it. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: LS4 Into an MGB
Scott, I ran into that exact problem with a D&D bell I used on my original 215 conversion, although I think your runout is a little more. I made offset dowel pins on the lathe and cut a large screwdriver slot in the end so I could turn them. They weren't very hard to make but without a lathe wouldn't be easy. For the angular misalignment I wouldn't hesitate to cut the block face of the bell, even with a coarse file.
Jim |
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Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Made some visible progress this weekend. The engine bay is done except for a small section near the starter, finishing the driver's side motor mount, some minor clean-up of the exhaust openings and preparation for paint. I'm very pleased with how it turned out. Here is where I am at the moment:
I also got the cross member buttoned up and the upper gussets welded to the passenger side motor mount: Next up is assembling the steering and getting the engine/transmission back in for a final check of clearances. Then getting the engine changes done and putting it into the car permanently. Got another bell housing but haven't had a chance to check it on the motor yet. Keeping my fingers crossed on that one. The original bell housing was too far off to use without spending a lot of money. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: LS4 Into an MGB
Scott, the only issue I can see there that you might want to think about has to deal with front/rear stiffness of the column mount where the original sat in a cup. Don't know if it is an issue or not, could be a factor in crashworthiness maybe. I'm sure functionwise it'll be fine.
Jim |
Scott68B Scott Costanzo Columbus, Ohio (562 posts) Registered: 10/25/2007 11:30AM Main British Car: 1968 MGB GM 5.3 LS4 V8 |
Re: LS4 Into an MGB
Jim,
Thanks for the feedback. It's pretty stiff, I used 16 gauge steel throughout. I haven't noticed any flexing at all to this point but I will double check and deal with it if I find anything. Take care Scott |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6470 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: LS4 Into an MGB
Should be fine.
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