Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

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roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Are cracked blocks safe for reuse?
Posted by: roverman
Date: July 23, 2019 07:19PM

Per Des Hammond(RV8 book). 4.6L blocks with "pink" paint splotch are best as they were sonic tested for wall thickness/ suitability for 4.6L use. Reduce the risk, tank the block and slosh coat coolant passages with sodium silicate,( Smokey Yunic trick).
Good Luck. art.


BeemerNut
Carl Winterbauer

(9 posts)

Registered:
09/07/2019 04:07PM

Main British Car:


Re: Are cracked blocks safe for reuse?
Posted by: BeemerNut
Date: September 07, 2019 06:10PM

Give credit to LR coming up with the cross bolted 4.0 & 4.6 block turning it a 3/4 baked "LR engine success" vs GM's half baked engine project back in the 60's. Always liked and followed the 215 hoping is was to be the future light weight modern era engine. Yes i'm that old.
Now praying the factory 4.6 short block doesn't wet the bed (block) as extended warranty paid for replacing the (yuck) 3.9 in the 95 D1 I own with a suggested by me cheaper for them a 4.6 short block, I won.
New engine back in late 01, installed a MasterLube.cog 3 qt. pre-oiler before engine transplant, best addition for these daily dry start rattling rods engines before oil pressure finally appears.Properly fueled with Tornado chip should keep it alive longer vs super leaned out Kalifornia issued LR's. Head ports matched to intake ports, what's that all about, the British dropped the ball on that issue big time? ....~~=o&o>......


MGBV8
Carl Floyd
Kingsport, TN
(4511 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Are cracked blocks safe for reuse?
Posted by: MGBV8
Date: September 17, 2019 10:20AM

Are cracked blocks safe for reuse?

Sometimes they do get repaired.
Quote:
If you have an engine with one or more cracked areas behind cylinder liner, it can be repaired as follows: The liner(S), of course, must be removed, with liner(S) removed, the cracks are TIG (heliarc) aluminum welded up, a common practice, and machined down by good auto. machine shop, for fitting in new liners. Since you have done this much work, at this point you should have Top Hat sleeves (liners) installed, the ones with "o-rings" at their base. These Top hat liners, essentially, do three things, the "Top Hat" prevents them from moving up or down in bores, so they will never slip. The o-ring prevents coolant from moving down into the oil pan, should the aluminum behind a liner ever crack from serious overheating events, and the top hat seals way better than the original Rover liners (that have a sharp top edge that easily cuts into the head gasket, should the liner slip upward). If installing new top hat liners, of course, you have to put in new head gaskets, as you would have the engine out of vehicle, and in best auto machine shop for installation of the top hat liners (that sort of work is usually not done by most Rover owners, due to machinery needed for the work, and due to skill required to do the work). At same time, you would have same auto machine shop examine the heads for possible warping (all aluminum heads from all engines are very susceptible to warpage from overheating events), wear of valve guides, etc. Machine shop should rebuild heads to good condition; grind in valves.

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