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1098 v. 1275 engine transplant ??

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George Zeck

George Zeck

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I'd like to get some thoughts from the wise and experienced. In short -- my 1098 Sprite needs a rebuild due to sitting for 18 years unused.

I am torn if I should dump the 1098 and purchase a 1275 engine and put in it's place (after a rebuild). The cost for this would be an addt'l $300 - $600 plus rebuild parts cost (roughly the same for either engine)..

At first I thought this was a great idea -- mainly until I read that the 1098 had 56 horsepower and the 1275 had 65 hp. Hardly worth the extra money. I figured that I could do "tweak" things to the 1098 (for example: racing flywheel, slight bore out of the pistons, better exhaust & / or manifold, etc...) to get the same increase of 9 horsepower.

Since I've seen so many cars for sale on ebay with this upgrade, and relatively new to LBC's -- I was wondering if there were other issues unknown to me about benefits of the 1275 over the 1098 engines ???

Any thoughts would be appreciated. (Also -- if I rebuilt the 1275, I'm not exactly sure where I would store the "spare" engine or toss it out ??).

Thanks all-

Geo Zeck
 
I've got a hotrodded 1275 in my Bugeye. It's got a mild cam, performance headers and exhaust, the 1 1/4 SUs, electronic ignition and a host of other go fast goodies. I bet it puts out at least 80 hp. It really moves. You're better off putting in the 1275 with upgrades, rather than sticking with the 1098.Just MHO.
 
The 1098 has a relatively long stroke compared to it's bore. Therefore, it is slightly more difficult to get as much hp. However, it is possible to have a steeper power curve. that means you'll feel the power at lower rpm's. Personally, I'd build up a 1275. Also, in these cars 9hp is nothing to sneeze at. It can make a big difference when you consider the weight of the car.
 
There are many more go fast goodies for the 1275 than the 1098. Since you are rebuilding an engine, I would go for the 1275. Street cam, not too radical (Kent 266) aluminum flywheel, slight bore .020-.040 max, Weber side draft carb.
Roller rockers and rim flow valves may be nice but personally I didn't see much (if any) bang for those bucks.
Adjustable timing belt makes a nice improbment too.

I recently rebuilt a 1098 to replace an aging stock 1275 in my wife's Sprite. The longer stroke sure sounds sweet on the road but the power lose is very noticable. I am rebuilding the ole 1275 this winter and switching it back.

Frank
 
Do forgive if my facts are weak. But didn't the 1098 have weak bearing journals? Too small, if I remember correctly, and they wore quickly. If I am right, then the 1275 would not only respond better to the upgrades, but stand up to them better as well.

So I guess that driving style would figure in as well.

If I am confusing engines here or something, feel free to ignore me at will. /ubbthreads/images/graemlins/grin.gif
 
"There's no replacement for displacement", even 177 ccs is a good thing. 9hp is a 16% increase in power, this is stock engine for stock engine. Hang some of those other goodies you mentioned; exhaust system, the "big valve" 12g940 or 12g1306 head and the right size single or twin SU and you'll know the difference. You'll have a 0-60 in 10 second shoe box rather than 17 seconds.

Whatever you do will cost more than you think, so choose the path that'll provide the most fun.
 
Matt, there were two versions of the 1098. The 10CG models had 1 7/8" main bearing journals, the same as the 948. They have been known to rip the center main right out of the block, if you over-build them, or really run them hard. The later 10CC models shared the 2" journals with the 1275.
I have a "big crank" 1098 in a '65 street car, that puts out a reliable 92 hp. But it wasn't cheap to do. Five grand or so, about 8 years ago.
I've got a new A+ 1275 sitting there, so when the 1098 goes poof, that will take its place. With suitable cam and head upgrades, of course. /ubbthreads/images/graemlins/grin.gif
Like the man said, the only replacement for cubic inches, is cubic dollars.
Jeff
 
George, which 1098 do you have? 10CG or 10CC?
The 1275 route will give you more bang for the buck, and presents greater options than the 1098. For instance, if you want good performance pistons for the 1098, I can just about guarantee you are going to have to have them made. About $400.00 a set, including pins.
If you have a 10CC 1098, I may be interested in it, if you decide to go to the 1275. 1098's are the only engine I am allowed to run if I want to change my race car from "H" to "G" production.
Jeff
 
If you have a choice and the cost difference is reasonable, go big.
It's torque that turns the crank, and you generally get an increase proportionate to the displacement increase, about 16% in this case. ( Almost as much as the difference between an MGA 1500 and an MGB).
Just my opinion! Simon.
 
Jeff --

I have the "10CG" model. Sorry that's not the one you'd be interested in. From the sounds of it; "bite the bulet" and I'll be happier, quicker, and more reliable with the 1275.

I just am trying to watch the costs -- I like the cubic displacement equals cubic dollars comment. IF I had driven the car this summer (> 20 miles and more than 3X); it wouldn't be so darn hard to spend the money on it.

At least with either upgrade I would be getting: "new" engine (verified no cracks, etc), new bearings, clutch (while I'm at it), timing chain (ditto), new / recond. head, upg to unleaded gasoline.

Since 2 of the 4 cylinders have slight to severe rust on the walls -- I am assuming they must be bored out. Cost to do machine work (I assume) would be same for either, but parts are much cheaper and more available on the 1275 vs. 1098. (Thus equalizing the overall cost towards upgrading.

Please holler at he if any of the assumptions are "off base".

Tx-

Geo
 
Then the solution is simple: Drive the car more to justify spending more money. ;-)
 
15 - 25 miles is all that I could drive it before leaving me stranded !!! I'd love to drive it 10k per year (summer miles) and am hopeful once I get past the rebuild (which frankly intimidates the @&*#$@ out of me) that I will do as such.

(but I did look good sitting on the side of the road).

- Geo
 
George, from both a total cost, and cost vs performance aspect, the 1275 swap is the only way to go. You should be able to pick up a running 1275 for $250 to $500, far less than the cost of a total rebuild of the 1098.
Have you called Rob or Dave at The Winners Circle, to see if maybe they had a lead on an engine? They are the "go to" guys for Spridgets, and are in Cleveland.
I don't have a disposable spare 1275 right now, but I'll keep my eyes open.
Thanks for letting me know that your 1098 is a 10CG. I've got two or three of them lying around. Paperweights! /ubbthreads/images/graemlins/grin.gif
Jeff
 
[ QUOTE ]
Matt, there were two versions of the 1098. The 10CG models had 1 7/8" main bearing journals, the same as the 948. They have been known to rip the center main right out of the block, if you over-build them, or really run them hard. The later 10CC models shared the 2" journals with the 1275.
Jeff

[/ QUOTE ]

Thanks for the clarification. I knew there was something like that, I just couldn't remember the exact situation.
 
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