Maybe its time for a new block....

[san_maru_zed]

I dont have a mic so I cant measure the bore accurately, but I have testing the ring end gap...and with new rings,the top ring has a gap of about 25 thou....

Im off to the wreckers to see what the measurements are with some other L28s....but from this measurement it looks like I might need a new block right ?

(PS...I guess its pretty obvious by now that I'm rebuilding my engine and its my first time :paranoid: )

Ray

[ChrisA]

Hi Ray, I'm not sure on an L28 but on an L24 the top ring gap in my FSM is 0.23 to 0.38. So its possible that your L28 is fine at the measurement your getting.

Can someone with an L28 FSM give us the ring gap specs?

Thanks,

Chris

[CoastGuardZ]

No FSM here, but I have a Haynes - not the authority by any means but, it doesn't list a seperate ring gap for the L28, the L24 & L26 both are .23 to .38mm.

Does that help any?

Nate

[webdawg1]

I'm showing the same thing as ChrisA. I'm looking in the 75 FSM on page EM-32.

Ring Gap...........Top.........0.23 to 0.38 mm (0.0091 to 0.0150 in)

Second....0.15 to 0.30 mm (0.0059 to 0.0118 in)

Oil...........0.15 to 0.30 mm (0.0059 to 0.0118 in)

webdawg1

[san_maru_zed]

Yeah I have the haynes manual as well...but I would like to get people's experiences.

i just bought a short block for about 30 USD....its better that the block i had, but still has a slight ridge on the 1st and last bore. I think I will be happy with this block, I figure that since I am going to all of this effort to rebuild the engine, I may as well do it properly

Ray

Edit: When I say 25 thou...I mean .025 in.....not .25mm

[Murph]

Hey Ray. Same deal here really. I'm rebuilding an L26 and have the same problem that there is a slight ridge in the top of one of the cylinders. Everything else on the car I pulled the motor from suggests that it's a low km car....but still just a little worried about this block.

Either way I'll be needing to get it honed, so I figure I'll get them to measure the bores and give me their opinion.

What have you heard so far regarding having a slight wear ring at the top of a cylinder?

[Z Kid]

As long as when you say do it properly you mean have the block either bored or honed to remove the ridge, because if you can feel a ridge its way too big, and there is nothing a new square edged ring loves less than belting a ridge at the top of the bore made by the old roudned ring.

[Murph]

Z Kid: With mine right, it's only the tiniest ridge. You can only just catch a finger nail on it. It's also only the one side of one cylinder. My thinking was that a hone should be enough to remove it. However, really I don't have any experience in this area so can't know for sure.

[Z Kid]

If I were you I'd have the local machine shop run their hone through and see if it disappears, they are able to get the exact crosshatch pattern required for seating rings, and they only charge about 10 dollars per cylinder if not less. They will also be able to run a micrometer through it and check that the bore is ok for standard pistons and rings as well as checking that its not oval. Its a small price to pay for somethign that could write off a rebuilt engine in quick time.

[Murph]

Thanks for the advice. That's pretty much my plan at a minimum. I'll be avoiding a rebore if I can as this is supposed to be a "quick freshen up".....so don't wanna pour in too many $. But like you said, there's no point if it's going to die in 6 months.

[san_maru_zed]

Oh by all means if it has a ridge get a ridge remover and get rid of the thing. That is what I will be doing tomorrow. Im not so worried that it has a ridge, but what it indicates (worn block, possibly generaly worn engine). Realistically though, the blocks are getting on almost 30 years old in some cases, if you are within the specs of the haynes manual without a re-bore, than your doing pretty well. My new N42 block will just be out of those specs, but the pistons seem 'tight' in the bore.

[san_maru_zed]

As long as when you say do it properly you mean have the block either bored or honed to remove the ridge, because if you can feel a ridge its way too big, and there is nothing a new square edged ring loves less than belting a ridge at the top of the bore made by the old roudned ring.

Wel, as properly as my budget allows I guess. I guess properly really means haivng the whole thing blueprinted.

As I said in my above post, my new block seems much better so all should be well.

EDIT: Forgive me, I've been out in the sun all day and didnt read your post properly. The bores are getting the ridge removed and honed tomorrow