Lotus Elan

Another Engine Spacer Question- How Short Is Too Short?

PostPost by: DreamsOfA26R » Fri Nov 17, 2023 4:58 am

Hello all,

I haven't posted an update in a while but I've been hard at work on my race car project since my last post. I've run into an interesting problem. I have a later production, 701M stamped, Big Valve engine that I've been working on getting into my (what I think is a) 1967 frame using QED heavy duty, stock type engine mounts. I did all the research that I could and it seems that depending on certain factors the spacers needed between the engine and the exhaust side engine mount are either 1.125" (1 1/8) or 7/8"

Here's the problem: no matter what I did with either of the supposed proper spacer sizes I could not get the mounts and holes to line up. With the intake side engine mount properly secured to the frame and block, the exhaust side mounts wouldn't line up with the holes in the frame. The engine mount was too far outboard compared to the holes in the frame. The only way I could make it all fit together was with 1/2" spacers between the engine and the mount. Something about that just doesn't seem right. Everything else in the drivetrain, from bell housing back to axles into the wheel hubs seems to be properly functional so I'm inclined to believe that the smaller than expected spacers shouldn't be a problem.

Does anyone have any thoughts on why the spacers may be so much shorter than expected and whether or not that'll be ok?
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PostPost by: GLB » Fri Nov 17, 2023 5:31 am

I had a similar problem with my Elan 1600. I just shortened the spacers until it all fit. I don't remember how much I had to shorten them but they were all the same. No problems in several thousand miles now. I felt like having the mounts in an unstressed position was a better way to fit them. Gary
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PostPost by: types26/36 » Fri Nov 17, 2023 4:25 pm

DreamsOfA26R wrote:Hello all,
I've run into an interesting problem. I have a later production, 701M stamped, Big Valve engine
Does anyone have any thoughts on why the spacers may be so much shorter


Are you sure you have a 701M block and not a 711M? The 711 (1600) is wider at the mounting points and neither blocks were stamped with their designation, they had the 701/711 cast into them on the exhaust side.
The engine sequence number was stamped on them with its engine number on a ledge above the engine mounting on the 701 and on a ledge at the top on the exhaust side of the 711 blocks.
Attachments
701m.JPG and
711.JPG and
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PostPost by: DreamsOfA26R » Fri Nov 17, 2023 6:48 pm

Well, Gary if it worked for you I guess I’ll just finish getting the car running and see how it all goes. If it’s been going well for you it’s probably worth giving it a shot!


Types, yes I’m certain that the block is stamped 701 not 711. I do recall seeing on here that the 711 block is notably wider at the mounting bosses but in this case that doesn’t apply. Even so from what I’ve been able to research the 711 spacers are something like 7/8” which is definitely a fair but larger than the 1/2 spacers I have on there now. I’m quite perplexed by this.
1967 Lotus Ean Racer project
1967 Lotus Type 46 Europa
1983 Mazda RX7
1982 Mazda RX7 Racer
Vintage Lotuses and Mazda rotary engines!
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PostPost by: vstibbard » Fri Nov 17, 2023 8:33 pm

+1 for sizing spacers to suit
Are the mounts oversized? Most non OEM part today require some fettling to fit is my experience.
I’ve used their group 4 style mounts and had terrible vibrations through the car at certain rev ranges. I think on steel monocoque shell the resonance is absorbed, on Elan way less so.
I’m going back to updated std mounts.
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PostPost by: GLB » Fri Nov 17, 2023 9:31 pm

I had not thought of that. In hindsight that was the variable that required shortening the spacers. Gary
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PostPost by: nomad » Mon Nov 20, 2023 1:32 pm

The available engine mounts are not the same spec as original.

The mounting holes make them about 1/4" wider per side.

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PostPost by: gjz30075 » Mon Nov 20, 2023 9:47 pm

^^^Agree! This is what I'm finding. I've ended up wallowing out the holes in the mounts.
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PostPost by: DreamsOfA26R » Mon Nov 20, 2023 11:24 pm

Well if the new production engine mounts are each a 1/4" wider per side that would explain pretty simply why i needed to cut about half an inch out of the spacers to make them fit! Thankfully none of y'all are telling me that something is catastrophically wrong so I guess that means I can run it the way that I have it. Thankfully nothing involved in the trial and error of fitting the mounts was terribly expensive! Now to get some properly sized grade 8 hardware and move on to the next part of the project.
1967 Lotus Ean Racer project
1967 Lotus Type 46 Europa
1983 Mazda RX7
1982 Mazda RX7 Racer
Vintage Lotuses and Mazda rotary engines!
DreamsOfA26R
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