Rod bearing size

[Rob1]

well im on a strick budget and really dont want to put alot into this thing cuz i might just sell it any way. but its still in the air, another thing is my block mating surface.

there was about a quarter inch chip only going very very shallow into the block, almost like someone tightened up the head bolt with a peice of debris in the threads and it just popped a very thin layer of metal off, its not affecting any of the commpression seals but its very close to a water jacket seal, but not on it just close.

I cant afford anothe block so i set up some JB weld to fill in the low spot and sanded it down to the surface of block.

Now i know thats not the best way to fix it but since its just around the rear intake side head blot and not affecting any crucial mating surfaces, that should be ok right?

SO that being said i cant have the block decked cuz the bad spot looks a little to deep to take off enough metal to compinsate, and with the JB weld on it it obviously cant be decked, im wanting to use a metal head gasket so i need a very smooth finish on block.

If i used like 800 grit, then 1200 grit, then about 1400 grit wet sand on a flat sanding block could i get the finish on th block im looking for?

The head has already been decked and looks like glass.

[cre]

Originally Posted by Rob1

If i used like 800 grit, then 1200 grit, then about 1400 grit wet sand on a flat sanding block could i get the finish on th block im looking for?

NO... or, I'll put it another way... NO.

JB Weld is not made (specifically) for repairing block decks... if it needs to be filled (which it sounds like it does) you need to use the right materials, especially if it's that close to a coolant passage. The name of the stuff I've seen used escapes me now... If I think on it I'll post back. You should be able to find it via Google; It's made specifically for repairing blocks and heads and is made to handle the constant heat cycling and the expansion and contraction that comes with it.

A MHG? Forget it... I hope you give any buyer a disclaimer and list of all the corners you've cut and skimped on... they're liable to sue you in a month otherwise.


EDIT: Belzona Super Metal (No. 1111) is the favorite that I know of. It's not cheap though, but there do appear to be other products which are less expensive and still preferred over JB Weld. If you're close to the coolant passage at all (especially if the jacket on the HG is likely to overlap the repaired portion) I would definitely not use JB. A lot of people have had good luck with it, but plenty have had issues too and there are better products available.

EDIT2: I just found my old notes on this. Cat used to sell Belzona, I'm not sure if the still do. I bought a small quantity a long time ago from a local industrial supply shop but it wasn't for engine repairs. A friend of mine (another Supra owner) said he really liked Devcon... adheres better than JB Weld but is a lot less expensive than Belzona. I don't have it written down but I think you would want the Devcon Plastic Steel 10110 putty, it's steel filled unlike their Home Depot JB Weld equivalent.

[Rob1]

ok thanks for the info, im really not trying to cut corners i just dont have the money to have the crank turned and also but main bearings.

from the looks of the rod bearing lobs on the crank the crank seems to be in great shape so thats why im not to worries about the main bearings.

as far as the block goes i already put the JB weld in it unfortunatly but i am going to see if maybe i can heat it up and knock it back out but who knows i may be stuck now.

[cre]

I was referring more to the MHG on an uncut block and the JB Weld.... The MHG is an absolute NO in most people's book; The JB Weld is more suited to fixing handrails... but plenty of people swear it works so just cross your fingers.

[87hilux7mge]

wow, jb weld on the block deck...scary! decking a block at a reputable machine shop should only be about 35 bux. ill have to check my reciept.

and turning cranks, about the same, at least polishing. which would be what theyd do, then you still use standard bearings, and u have a new surface to break in on.

do it right, or dont do it at all. theres not really a way to save money when doing an engine. if you assemble it all yourself and are careful, then you can prolly have all the machining done for under 400 (i did, and i spent 360 for machining, then 110 on pistons, rings , rod and main bearings, and 150 on gasket kit). im also buying a MHG, but thats me. so for about 500 bux, you can rebuild a motor with all new bearings and rings, if you dont bore/hone, figure 650 if you do.

[cre]

A lot of people and even shops use JB on block decks... the good ones are VERY picky about where they'll use it though. I'd still like to see pictures of the block in question.