Re bore

[potleyu18]

Just stripped my plus 2 big valve engine apart as compression was very low in all cylinders and now looking for a company to carry out the re bore its +30 as present so can only go one more step up to +40 and don't want to make any mistakes.
Can anyone advise of a reputable company to do this i'm based in Camberley at the borders of Hampshire, Berkshire and Surrey. Don't mind travelling if its worth while.

Secondly and advise on the piston manufacture naturally Omega is the fist choice but are there any others to recommend.

Cheers

Steve

[Craven]

You need to make sure your bores will clean up with just 0.010? that?s just 0.005 step or groove.
There is very little price difference between forged, superior, and cast pistons these days but Mahle is a top quality cast piston.
Talk to http://www.ocservice.co.uk/

[nmauduit]

you may want to have your block carefully inspected by a reputable shop and whom advice you can trust, there usually are a number of options to consider for re bore (+0.20 0.30 0.40 0.60 / 83.5mm 83.65mm 84mm 85mm etc )
see for instance (no affiliation ) https://qedmotorsport.co.uk/qed-shop/lo ... am/pistons

[pauljones]

Your not to far away from my old place of work. Id consider Saunders Engineering in Southamton. Theres a few in Liss but never tried them and names escape my aging brain.

[prezoom]

Before the block is bored, the cylinder wall thickness should be determined that the block can additional boring. If itc has sufficient wall thickness for a cleanup bore, then determine which pistons you want to use. Purchase the pistons and follow the manufacturers recommended piston to wall clearance. Give the pistons to who ever will be doing the boring, and have each piston matched to its respective bore and marked.

[Matt Elan]

Steve - I'm in Fleet, just down the road and I use Roe Engineering - and have done for my engine work for 40 years. They have recently moved from Kings Road down to Redfields Industrial Estate in Church Crookham. Last used them to replace the sleeves in my 'L' block and bore them to fit a set of standard pistons for my Plus 2's Twin Cam. Did a good job at a reasonable cost.
Matt

[Elan45]

Are you sure you couldn't just do w/ a honing and new rings? You need to have a skilled professional look at your block and pistons. There are other reasons to change the pistons such as ring thickness and spec and split skirt vs drilled holes to release the oil scraped from the oil ring groove.

Roger

[JJDraper]

Are you sure you couldn't just do w/ a honing and new rings? You need to have a skilled professional look at your block and pistons. There are other reasons to change the pistons such as ring thickness and spec and split skirt vs drilled holes to release the oil scraped from the oil ring groove.

Roger

+2 on this one. I do wonder if folk are a too eager to scrape away irreplaceable metal in a rebore. I say this from my perspective of my engine with +60 bores. The block was bored before my ownership, but I have done over 100k miles with the bore only now showing a slight wear lip. Compression is still OK, but nothing lasts forever. If my engine is on +60, and I have done 100k miles on them, either it has done stellar mileage, or folk have jumped too early for rebores... Inspect the old components well & replace if needed - rings, consider stepped rings, pistons - check ring lands. My next step? Sleeves....

Jeremy
PS engine & head are matching numbers for the car.

[potleyu18]

Thanks for all of the responses. All are very informative and helpful.

I had the block re honed and fitted new rings when i last re built the engine two years ago, after 400 miles had a rolling road set up only to find the compression's were down significantly and the cause was over fueling due in correct main jets, which is very frustration as thought the person who carrier out the carb re refurbishment knew what they were doing.
I have only done limited mileage since then but its now at a stage where it cannot be left any longer. going to the Gerard Sauer talk on Thursday and hopefully get more information then.

Steve

[pauljones]

Are you saying that the over fueling has caused premature wear? Id be having words to be honest.
But a cheap confirmation exercise would be a halfords compression tester. Mine works fine and is accurate.
Check it first as is, then add a small squirt of oil and do it again.

Hopefully if its the case, it may just need a ring set.

[Matt Elan]

What is the 'Gerard Sauer talk on Thursday'? I'm always keen to learn so if there is a talk on the twin cam I'd be interested?

[mikealdren]

What is the 'Gerard Sauer talk on Thursday'? I'm always keen to learn so if there is a talk on the twin cam I'd be interested?

He did a talk to the Sussex Club Lotus group last night, it was excellent, he is a real expert.

[potleyu18]

The talk by Gerard was fascinating and what he doesn't know about twin cams for a race set up is not with considering. Will certainly use the advice when it comes to running in the engine when all reassembled.

The Block is now at CTM engineering courtesy of Gerard who kindly dropped it off and waiting to hear back from them. will update when i have more info.

[pauljones]

CTM are just few miles from me, in fact theyre next to Southern GT, makers of a GT40 replica.
Ive never used them before. Be interested in feed back if you could.