Block Work

[UNCbigM]

Yes, we will be assembling the full engine ourselves. Looking forward to it.

I've decided to go with the block as is. It's been honed and that's all she'll get. New pistons and rods will be on order soon. The shop is going to check the valves for thickness soon to make sure they're good to go. They said that it is possible that it could simply be carbon buildup from sitting for so long. They'll know more once they get into it. I gave them all the measurements etc from the shop manual.

Looking forward to having the pieces back so I can start putting it back together!

[ardee_selby]

Yes, we will be assembling the full engine ourselves. Looking forward to it.

I've decided to go with the block as is. It's been honed and that's all she'll get. New pistons and rods will be on order soon. The shop is going to check the valves for thickness soon to make sure they're good to go. They said that it is possible that it could simply be carbon buildup from sitting for so long. They'll know more once they get into it. I gave them all the measurements etc from the shop manual.

Looking forward to having the pieces back so I can start putting it back together!

Does it need new (con?) rods? Were they damaged?

Good Luck - Richard

[UNCbigM]

Was mulling simply getting a set of later, sturdier rods as mine are the thinner early rods.

[garyeanderson]

Here are both rod types for folks to see what the differences are.

I would replace them seeing you have the opportunity to do so. An original twin cam is not so original with a con rod peeking through the block. I didn't ever blow one up and I am sure that lots of folks still are using them but Lotus changed them for a reason. Put the ones you have in a plastic bag and keep them for a future owner to look at.

Gary

[StressCraxx]

Gary,

Do you use the Ford rod bolts or the Cosworth/ARP 12 point rod bolts?

I was told by my engine builder years ago the original Ford bolts were good for one use only and were more expensive than the Cosworth 12pt bolts. He advised I could reuse the 12 pt bolts if I was not racing.

I use the same bolts in my FF and they held together despite the crank breaking in 4 pieces @5500 rpm last month.

Regards,
Dan

[garyeanderson]

Hi Dan

I did re-use those early bolts in 1976 and the engine lived. When I took it apart last summer to re-use it I was able to salvage the head and the front cover. The head is on the engine installed in the "Sows Ear Chassis" The block had been sleeved on two cylinders and one of the sleeves had moved up so it was set aside, the crank had been cut .010 on the rods and .020 on the mains so it was left in the block. The pistons had one or two broken rings and one had the impression of a weber trumpet nut that was embedded in January 1978 so those were also "set aside". I have more and better parts to work with today, the money is just about as tight as it was then but parts are more available and the cost is reasonable. I hate to admit it but the engine that went into the Sows Ear chassis had valve guides installed in the head and surfaced, the short block was from another Elan I had bought and was "untouched" by me, that includes the water-pump and it may well bite my ass, but today I have less money than I did 10 or 20 years ago and a lot more time. The old saying of if you don't have time (or money) to do it right, than you must have time to do it twice may ring true. The thing is I have the time now to do it again, I won't like it but if these Elans don't get put back together they won't ever be driven by anyone, and lost to everyone! This probably didn't answer your question, If I had the money there are lots of parts I would buy and the first on the list would be new 12 point rod bolts like these

Gary

[StressCraxx]

Gary,

There are lower cost alternatives. Grade 12 socket head cap screws, 1-3/4" long by 3/8" UNF from a reputable supplier such as A/C Spruce or Wicks? Robinshaw and Ross recommend them as an alternative to the 12 point bolts.

[UNCbigM]

Interesting stuff. Looking forward to seeing what you think of that last question too, Gary.

I'll probably go ahead and get the 125E set from a later engine. I'll keep my original around though, so they're available if a later owner wants them!

[George4th]

Gary,

There are lower cost alternatives. Grade 12 socket head cap screws, 1-3/4" long by 3/8" UNF from a reputable supplier such as A/C Spruce or Wicks? Robinshaw and Ross recommend them as an alternative to the 12 point bolts.

Like these? http://www.aseriesspares.co.uk/imperial ... d_597.html

Would these be OK?

Thanks
George 4th

[CBUEB1771]

Gary,

There are lower cost alternatives. Grade 12 socket head cap screws, 1-3/4" long by 3/8" UNF from a reputable supplier such as A/C Spruce or Wicks? Robinshaw and Ross recommend them as an alternative to the 12 point bolts.

I would only use a bolt specifically design for use in connecting rods. You need the right alloy, heat treatment and geometry (no stress risers) to give the appropriate strength and toughness. ARP or equivalent rod bolts are very cheap compared to a broken rod bolt.

[StressCraxx]

Gary,

There are lower cost alternatives. Grade 12 socket head cap screws, 1-3/4" long by 3/8" UNF from a reputable supplier such as A/C Spruce or Wicks? Robinshaw and Ross recommend them as an alternative to the 12 point bolts.

I would only use a bolt specifically design for use in connecting rods. You need the right alloy, heat treatment and geometry (no stress risers) to give the appropriate strength and toughness. ARP or equivalent rod bolts are very cheap compared to a broken rod bolt.

Russ,
I agree with you. SHCS bolts are a limited use (at best) item on con rods.

[George4th]

Ha anyone had or known about a failure due to the cheaper bolts?

Thanks
George

[BillGavin]

Back when I was racing Minis and Sprites, parts availability was a constant headache. At one point, the rod bolts were not available from the manufacturer, and the quality of aftermarket parts was spotty at best. Some of the racers did the sums and decided that industrial cap screws were strong enough for the job and started using them in their engines, torqued to the specified value. They were cheap enough to buy by the box and toss after each use, although, inevitably, some did get reused.

All went well for a time, but then there were some expensive failures - fortunately, not in my engines. The bolts all snapped at the parting face between the rod and the cap; it was decided that the cap screws were a bit more flexible than the OEM bolts, and would require more tightening torque. Everyone used the new, higher, torque spec, and there were no more bolt failures. The radius under the head was bigger than the OEM bolts, so we chamfered the holes in the rod caps rather than using washers, and the rods were resized at the higher torque spec.

The engines in my 1098cc G-Production Sprites would pull as much as 8500 rpm in the dip at Road Atlanta, so the bolts got a good stress test! To the best of my recollection, I never reused cap screws, as I had a friend in the hardware business who would supply a box as needed. The engines usually came apart, for one reason or another, after three or four races, so the cost of the best bolts would have been significant.

Today, I'd probably go with the best available bolts, as it's a one-time expense.

- Bill