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914World.com _ 914World Garage _ Bigger valves in 1.8 heads?

Posted by: Korijo Jul 16 2005, 06:23 PM

can you use a 2L exhaust valve in a 1.8L head? [after machining, of corse ]

i was thinking [ ] of only bumping the exhaust up to 36mm, and leaving the intakes at 41mm? common practice? weird?

i have a set of loaded, rebuilt 2L heads; but i want to use the Solex PII 40's Joe Sharp gave me*, so i'm gettin' some 1.8L heads...

* [thanks again joe ]

Posted by: qa1142 Jul 16 2005, 06:28 PM

Valves are not the problem. The porting angles and flow of the 2.0 heads are just that much better. Plug location and angle is different also. This is why I am rebuilding a 2.0 to replace my 1.8

Stick with your 1.8 and save $ for 2.0 heads and or motor

Posted by: anthony Jul 16 2005, 07:55 PM

You can also have the 1.8 spark plug holes welded up and relocated to the 2L position. You can also go for smaller diameter spark plugs so that they don't crack in the future.

Posted by: Korijo Jul 16 2005, 08:39 PM

QUOTE
Stick with your 1.8 and save $ for 2.0 heads and or motor

see my 1st post, already have 2L heads , but thanks for yur post.

QUOTE
You can also have the 1.8 spark plug holes welded up and relocated to the 2L position. You can also go for smaller diameter spark plugs so that they don't crack in the future.

"I did not know this..."

gud reply.

Posted by: tat2dphreak Jul 16 2005, 09:08 PM

QUOTE (anthony @ Jul 16 2005, 08:55 PM)
You can also have the 1.8 spark plug holes welded up and relocated to the 2L position. You can also go for smaller diameter spark plugs so that they don't crack in the future.

I think Jake said that he preferred this... the smaller plug keeps the little cracks from happening too... IIRC, anyway...

Posted by: Jake Raby Jul 16 2005, 09:48 PM

1.8 heads don't have the spark plug cracking issues of the 2.0 because of plug location. We flycut 1.8 heads down almost to the sparkplug on F prod engines and no crack issues..

Going to the 36mm exhaust without upping the intake valve will imbalance the head quite a bit..

42x36 valves(stock 2.0 size) can be used in a 1.8 head and still be supported by stock ports. Porting will help, but is not necessary..

Spark plug relocation has given us 8% more power+ in every instance that we have tested it..

Posted by: Korijo Jul 17 2005, 01:49 PM

i can use 2L valves in a 1.8 head WITHOUT changing guides, seats, or porting the chambers? [i will have it done regardless]

if i use the 1.8 head, it will have the plugs relocated.

any advice on welding the exsiting plug holes?

Posted by: gregrobbins Jul 17 2005, 03:57 PM

Why don't you use the 2.0L heads? Carb manifolds for 2.0L heads are cheap enough. I have a pair I would swap you for 2.0L FI runners if you have extras.

Posted by: Korijo Jul 17 2005, 04:56 PM

QUOTE (gregrobbins @ Jul 17 2005, 01:57 PM)
Why don't you use the 2.0L heads? Carb manifolds for 2.0L heads are cheap enough. I have a pair I would swap you for 2.0L FI runners if you have extras.

b/c i want to try to use the short manifolds w/ the solex 40's...

if'n it doan wurk...