Block Work

[UNCbigM]

Looking for some advice regarding my block.

Took my block and head to a machine shop after removal and dismantle. The number one and number three pistons were seized. The (first) assumption was that this occurred simply from non-use/storage over the last 29 years. I don't believe this was the reason the car was parked. The engine had plenty of oil in it when removed.

The second assumption was that after banging the hell out of the two seized pistons to remove them that I would need to have the cylinders bored and would purchase new rods and 20 over pistons.

The shop tells me that the cylinders look pretty good and they don't see the need to bore them out. I'm shocked. After the shock wore off my though process leads me to believe the shop since they're actually saving me money, rather than spending my money.

Does this sound nuts to anyone else?

Also, how do we feel about letting a local shop do the valve job for me rather than sending it out to a specialist shop out of state?

[UNCbigM]

And after speaking to the shop again, it sounds like to have it bored is not very expensive, so I may just do it anyway since I'm buying pistons, its not like I'm saving money by reusing the old ones.

[rgh0]

If the bores are round and straight and not worn then it may be possible to just hone them to clean up the surface and ensure new rings bed properly and fit new pistons of the same size. If you dont need to bore the block then dont do it and keep as much wall in the bores as possible.

cheers
Rohan

[elansprint71]

Rohan knows more than most on this forum about engines, I would do as he suggests re pistons, etc..
What, exactly, do you mean by "the valve job"?

[UNCbigM]

I'm leaning toward simply purchasing stock sized pistons and keeping the block stock since its a numbers matching car.


The proposed valve job, at least until they actually remove the valves and find more damage, is simply grinding them down as two of them are leaking.

[AHM]

I was in the same situation - a quick hone and new genuine Lotus pistons from Miles Wilkins will save you 700 dollars.

Get the shop to measure the bores and put on paper then you have a great selling point for a future buyer. Each rebore is a life

Spend your cash on balancing.

Get them to mark the flywheel to crank orientation.

If you have found a good shop great! Talk to them, spend your money with them - it is a passion not just a financial transaction

Simon

[rgh0]

A top end overhaul is not difficult unless specialist machining needed or you are trying to build a none standard head with big valves and high lift cam. Assuming your shop has the workshop manual information and measuring equipment needed they should be able to dismantle and check all the clearances and components and you should not need to send to a "specialist". If all is within tolerance then reseating the valves is a simple operation provided the valves are not sunk to far into the head already and the shims not to thin.

cheers
Rohan

[rviani]

Standard valve and seat grinding should be no problem for any competent shop. However if guide replacement is nesessary some caution is advisable. I had mine replaced by a "standard" shop who apparently (it was a long time ago) did not use the correct process of heating the head etc. and wouind up with an oil leak between the head and the guide (very unusual) which only occured when the engine was hot. Lots of smoke - and very difficult to diagnose since the guides seemed tight when the engine was cold and disassembled.

Not rocket science, but if the guides need replacement make sure the shop uses the corect technique.

[UNCbigM]

Lots of good information. Thank you all!

I'm leaning toward not boring the cylinders and staying as stock as possible. The head I would like to keep local if it a fairly routine job, if it looks to be more complicated then I would consider the specialist.

How important is an unbored block in a numbers matching car versus 20 over? I'm not building a show car, I'm building a nice driver, but with that being said, I know there is value to an original car.

Thoughts?

[garyeanderson]

Lots of good information. Thank you all!

I'm leaning toward not boring the cylinders and staying as stock as possible. The head I would like to keep local if it a fairly routine job, if it looks to be more complicated then I would consider the specialist.

How important is an unbored block in a numbers matching car versus 20 over? I'm not building a show car, I'm building a nice driver, but with that being said, I know there is value to an original car.

Thoughts?

If you give the cylinder-head to anyone to work on, DO NOT let them glass bead blast it. you will never get all of the glass beads out after and it will ruin the engine.

Gary

[UNCbigM]

Again, good to know, thank you.

Thoughts on my boring (no pun intended) question?

[garyeanderson]

Hi Morgan

I don't understand your question. If the block has all of the bores within spec and are parallel and square why would you want to bore it .020 oversize? A .020 pistons will give you 20 cc capacity increase in displacement or about 1.2 cubic inches or about 1 horsepower for ALL 4 cylinders. If you want to build a high performance, high Horsepower engine get another block and build that non-original block and put the original short block away for the future when you want to sell or restore to stock.

Gary

[holywood3645]

I would be concerned about the head. With it sitting for that number of years it came from a peroid that lead was used in gas. I think your valve seats may need to be replaced to accomodiate non-leaded fuel. Maybe some other parts may need changed also. I'm sure additional parts will be identified here.

James

[garyeanderson]

I would be concerned about the head. With it sitting for that number of years it came from a peroid that lead was used in gas. I think your valve seats may need to be replaced to accomodiate non-leaded fuel. Maybe some other parts mat need changed also. I'm sure additional parts will be identified here.

James

The seats will be fine. trust me

Gary

[ElanSeries2]

Gary is correct, the seats will not need replacing for unleaded unless there is damage to them. All aluminium heads run hardened valve seat inserts which will stand unleaded (actually not quite true - some modern engines have suface coatings). Looks like (if you want a standard rebuild) you can keep this local, as you are wanting. Replacing valve guides isn't difficult, but as rviani says, your shop needs to follow the instructions...

As others have said, IF the bores are good, then honing to bring back the hatching on the wall is perfectly acceptable. With standard pistons and new, properly gapped rings, there will be no difference in quality/longevity over a +20 overbore. Don't bore it out if you don't have to - save that for when you CAN'T hone.

Are you going to do the reassembly yourself? It's good fun!